Here is a compilation of essays on ‘Dryland Agriculture’ for class 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Dryland Agriculture’ especially written for school and college students.
Essay on Dryland Agriculture
Essay Contents:
- Essay on the Introduction to Dryland Agriculture
- Essay on the Concept of Dryland Agriculture
- Essay on the History of Dryland Agriculture
- Essay on the Present Status of Dryland Agriculture in India
- Essay on the Problems of Dryland Agriculture
- Essay on Monsoon and Length of Crop Growing Season under Dryland Agriculture
- Essay on the Strategy for Dryland Agriculture
- Essay on Moisture Conservation in Drylands
- Essay on Water Harvesting and Protective Irrigation for Dryland Agriculture
- Essay on the Fertiliser Use in Dryland Agriculture
- Essay on the Alternate Land Use Systems for Dryland Agriculture
- Essay on the Recommendations of Areas for Dryland Agriculture
- Essay on the Improved Implements for Dryland Agriculture
Essay # 1. Introduction to Dryland Agriculture:
Even after the utilisation of all our water resources for irrigation, about half of the cultivated area will remain rainfed. As there is hardly any scope for increasing the area under cultivation, it is really a colossal task for meeting the future food needs. It is against this background that the role of dryland agriculture gained importance.
Very often, the words dry farming, dryland farming and rainfed fanning are used synonymously to indicate similar farming situation. Clearly, all the three exclude irrigation.
Dry agriculture is cultivation of crops in regions with annual rainfall less than 750 mm. Crop failure is most common due to prolonged dry spells during the crop period. These are arid regions with a growing season (period of adequate soil moisture) less than 75 days. Moisture conservation practices are necessary for crop production.
Dryland farming is cultivation of crops in regions with annual rainfall more than 750 mm. Inspite of prolonged dry spells, crop failure is relatively less frequent. These are semi-and tracts with a growing period between 75 and 120 days. Moisture conservation practices are necessary for crop production. However, adequate drainage is required, especially, for Vertisols.
Rainfed farming is crop production in regions with annual rainfall more than 1,150 mm. Crops are not subjected to soil moisture stress during the crop period. Emphasis is often on disposal of excess water. These are humid regions with growing period more than 120 days.
In dry farming and dryland farming, emphasis is on soil and water conservation, sustainable crop yields and limited fertiliser use according to soil moisture availability. In rainfed agriculture, emphasis is on disposal of excess water, maximum crop yield, high levels of inputs and control of water erosion.
Essay # 2. Concept of Dryland Agriculture:
The concept of rainfed agriculture (farming) under which both dry farming and dryland farming (dryland agriculture) is included has been changed. Dryland farming was the earlier concept for which amount of rainfall (Jess then 500 mm annually) remained the deciding factor for more than 60 years.
In modern concept, dryland areas are those where the balance of moisture is always on the deficit side. In other words, annual evapotranspiration exceeds precipitation. In dryland agriculture, there is no consideration of amount of rainfall.
It may appear quiet strange to a layman that even those areas which receive 1100 mm or more rainfall annually fall in the category of dryland agriculture under this concept. To be more specific, the average annual rainfall of Varanasi is around 1100 mm and the annual potential evapotranspiration is 1500 mm.
Thus the average moisture deficit so created comes to 400 mm. This deficit in moisture is bound to affect the crop production under dryland situation, ultimately resulting into total or partial failure of crops. Accordingly, production is either low or extremely uncertain and unstable which are the real problems of dryland in India.
Success of crop production in these areas depends on the amount and distribution of rainfall, as these influences the stored soil moisture and moisture used by crops. Amount of water used by crop and stored in soil is governed by water balance equation: ET = P – (R + S).
When balance of the equation shifts towards right, precipitation (P) is higher then ET, so that there may be water-logging or it may even lead to runoff (R) and flooding. On the other hand, if the balance shifts to left, ET becomes higher then precipitation, resulting in drought.
Taking the county as a whole, as per meteorological report, severe drought in large area is experienced once in 50 years and partial drought once in five years while floods are expected every year in one part of the country or the other, especially during rainy season. In fact, the balance of the equation is controlled by weather, season, crops and cropping pattern.
Essay # 3. History of Dryland Agriculture:
First systematic scientific approach to tackle the problems of dry farming areas was initiated by Tamhane in 1923 on a small plot at Manjri farm near Pune and the work passed on to Kanitkar in 1926. A comprehensive scheme of research was drawn up by Kanitkar with financial support from the ICAR.
Realising the importance, the 1CAR launched a comprehensive project on dryland farming at five centres: Sholapur and Bijapur in 1933, Hagari and Raichur in 1934 and Rohtak in 1935. A decade of work upto 1943-44 mainly on rainfall analysis, physico-chemical properties of soils, physiological studies on millets and on agronomic aspects resulted in a series of dry farming practices commonly known as the Bombay dry farming practices, Hyderabad dry farming practices and Madras dry farming practices.
These practices stressed the need for contour bunding, deep ploughing, application of FYM, low seed rate with wide spacing, mixed cropping and crop rotation. These recommendations could not motivate the farmers to adopt them as the yield advantage was about 15-20 per cent over a base yield of 200-400 kg ha-1.
By the mid-1950s, importance of soil management (soil and moisture conservation) was realised for improving the productivity of drylands and the ICAR established eight Soil Conservation Research Centres in 1954.
However, yield improvement was not more than 15-20 per cent over the basic yield of 200-400 kg ha-1. Importance of short duration cultivars maturing within adequate soil moisture available period (crop growing period) was recognised during 1960s.
The place of high yielding varieties and hybrids for yield advantage in dryland agriculture was realised in mid-1960s. With the establishment of All India Coordinated Research Project for Dryland Agriculture (AICRPDA) in 1970, emphasis was shifted to multi-disciplinary approach to tackle the problem from several angles.
Similar efforts were initiated at ICRISAT, Hyderabad in 1972. The ICAR selected 23 dryland agricultural centres oil over the country on the basis of the moisture deficit, soil type and rainfall characteristics (Fig. 5.1).
Major events in dryland agricultural research are:
1920: Scarcity tract development given importance by Royal Commission on Agriculture.
1923: Establishment of Dry Farming Research Station at Manjri.
1933: Research Stations established at Bijapur and Sholapur.
1934: Research Stations established at Hagari and Raichur.
1935: Research Station established at Rohtak.
1942: Bombay Land Development act passed.
1944: Monograph on dry farming in India by Kanitkar.
1953: Establishment of Central Soil Conservation Board.
1955: Dry Farming Demonstration Centres started.
1970: Twenty three Research Centres established under AICRPDA.
1972: Establishment of ICRISAT.
1976: Establishment of dryland Operational Research Projects (ORPs).
1977: Krishi Vigyan Kendra (KVK), Hyatnagar.
1983: Starting 47 model watersheds under ICAR.
1984: Establishment of Dryland Development Board in Karnataka and World Bank assisted Watershed Development Programmes in four states.
1985: Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad.
1986: The NWDPRA programmes in 15 states by Government of India.
The ICAR collaborated with Canadian dryland research (Indo-Canadian Dryland Research) from 1970 to 1987. The ICAR-ICRISAT collaborative research programmes are working in areas of biological nitrogen fixation, agroforestry, soil and moisture conservation, economics of watershed technology and vegetative barriers in soil and water conservation.
The Indo-US collaboration started in 1980. Currently, CR1DA-US collaborative research projects are working on fertiliser use efficiency, germplasm enhancement, evaluation of legumes for high nitrogen fixation, crop simulation modelling and implements for dryland agriculture.
Essay # 4. Present Status of Dryland Agriculture in India:
Out of 142 M ha of net sown area in the country, rainfed agriculture is practiced in 95 M ha (67%). Nearly 67 M ha of rainfed area falls in the mean annual precipitation range of 500- 1500 mm.
Average annual rainfall of the country is 1200 mm amounting to 400 M ha-m of rainwater over the country’s geographical area (329 M ha). However, distribution across the country varies from less than 100 mm in extreme arid areas of western Rajasthan to more than 3600 mm in NE states and 1100 mm from East Coast to 2500-3000 mm in the West Coast.
Broad area of summer monsoon activity extends from 30°N to 30°S and from 30°W to 16.5°E. Detailed information or rainfall and monsoonal pattern in India has been summarised in Table 5.1.
Dryland farming comprises about 91 per cent area of coarse cereals (sorghum, pearl-millet. maize and finger-millet), 91 per cent pulses (chickpea and pigeon-pea), 80 per cent of oilseeds (groundnut, rapeseed, mustard and soybean) and 65 per cent of cotton. Also, about 50 per cent area under rice and 19 per cent area under wheat is rainfed.
During the past 25 years, there occurred significant changes in the area and yield of important crops of rainfed areas. Area under coarse cereals decreased by about 10.7 M ha and most of this was under sorghum. Area under oilseeds increased by 9.2 M ha and most of this increase was due to irrigated rapeseed and mustard and soybean.
Total area under pulses and cotton remained constant but more of cotton became irrigated and shifts in the area occurred from one agro-ecological region to others. Area under chickpea in northern belt decreased but increase in central belt. This change occurred due to increase in area under rice-wheat cropping system which displaced chickpea and also pearl-millet to a great extent and maize to a small extent.
According to the present concept, there are 128 districts in the country which face the problems of dryland. Of these 25 districts, covering 18 M ha of net area sown with 10 per cent irrigation, receive 375-750 mm rainfall annually spread over central Rajasthan, Saurashtra region of Gujarat and rain shadow region of Western Ghats in Maharashtra and Karnataka.
Twelve districts have irrigation covering 30-50 per cent of the cropped area and do not pose serious problems. The remaining 91 districts covering mainly Madhya Pradesh, Gujarat, Maharashtra, Andhra Pradesh, Karnataka, Uttar Pradesh, parts of Haryana, Tamil Nadu etc., represent typical dryland area.
Total net sown area in these districts is estimated to be 42 M ha of which 5 M ha are irrigated. Rainfall in these districts varies from 375 to 1125 mm. Therefore, more and more efforts are to be made for enhanced and stable production in these areas so that the recurring droughts do not stand in the way of meeting the growing food demands.
Essay # 5. Problems of Dryland Agriculture:
In dryland agriculture, scarcity of water is the main problem. Apart from low and erratic behaviour of rainfall, high evaporative demand and limited water holding capacity of the soil constitute the principle constraint in crop production in dryland area. Yield fluctuations are high mainly due to vagaries of weather, often much behind risk bearing capacity of farmers.
Monsoon starts in the month of June and ends in last week of September or sometimes in first week of October. Most of the rainfall is received during this period. With undulating topography and low moisture retention capacity of the soil, major portion of the rainwater is lost through runoff, causing erosion and adding to water-logging of low lying areas. After the rain stops, very little moisture is left in the profile to support plant growth and grain production.
In dryland area, deficiency and uncertainty in rainfall of high intensity causes excessive loss of soil through erosion which leaves the soil unproductive. Owing to erratic behavior and improper distribution of rainfall, agriculture is risky, farmers lack resources, tools become inefficient and ultimately productivity is low.
(i) Vagaries of Monsoon:
Based on average annual rainfall, the country can be divided into three zones: low (less than 750 mm), medium (750-1,150 mm) and high (more than 1,150 mm) rainfall zones. Dryland area is nearly equally distributed among the three. Areas with less than 1,150 mm (arid and semiarid) are the problem areas for crop production.
Main characteristics (features) of rainfall influencing crop production are its variability, intensity and distribution, late onset and early withdrawal of monsoon and prolonged dry spells during the crop period.
a. Variable Rainfall:
Annual rainfall varies greatly from year to year. Table 5.2 indicate annual rainfall and its coefficient of variation. Generally, higher the rainfall, less is the coefficient of variation. In other-words, crop failures due to uncertain rains are more frequent in regions with lesser rainfall.
b. Intensity and Distribution:
In general, more than 50 per cent of total rainfall is usually received in 3 to 5 rainy days. Such intensive rainfall results in substantial loss of water due to surface runoff. This process also accelerates soil erosion. Distribution of rainfall during the crop growing season is more important than total rainfall in dryland agriculture.
c. Late Onset and Early Cessation of Rains:
Due to late onset of monsoon, sowing of crop is delayed resulting in poor yields. Sometimes the rain may cease very early in the season exposing the crop to drought during flowering and maturity stages which reduces the crop yields considerably
d. Prolonged Dry Spells during Crop Period:
Long breaks in the rainy season are an important feature of Indian monsoon. These intervening dry spells when prolonged during crop period reduces crop growth and yield and when unduly prolonged crops fail.
(ii) Soil Constraints:
Alluvial soils occupy the largest area in dryland agriculture. Problems of crop production are not so acute in these soils as they are in black and red soils. Major problems are encountered in Vertisols, Alfisols and related soils. Black (Vertisols), red (Alfisols) and associated soils are mostly distributed in central and south India. The coastal areas have Alfisols, laterite and lateritic soils.
a. Alfisols:
These are commonly referred as red soils. Problems relating to crop production are:
1. Poor crop stand due to crusting and rapid drying of surface soil.
2. Poor crop growth due to unreliable soil moisture supply, low moisture storage capacity due to shallow depth and drought spells during crop season.
3. Low soil fertility due to low organic matter, poor nutrient status particularly with respect to N, P, S and Ca and compact subsoil layer (argillic horizon).
4. Land degradation from soil erosion and crusting.
b. Vertisols:
These soils commonly called as black soils are characterised by high clay content (30-70%).
Important constraints for crop production are:
1. Physical constraints such as narrow range of soil water content for tillage, tendency to become waterlogged and poor trafficability.
2. Low soil fertility due to low N and available P.
3. Land degradation from soil erosion and salt accumulation, especially in low-lying areas.
c. Inceptisols and Entisols:
These are commonly termed as alluvial soils. They have low water holding capacity and low nutrient holding capacity. Management of these soils for crop production is relatively easy compared to red and black soils. Soil erosion is, however, a problem leading to land degradation.
Sub-mountain soils are medium in texture and depth is medium to deep as well as moderate in clay content. Moisture retention capacity is high (300 mm m-1 profile depth). These soils are poor in nitrogen. Phosphorous may be limiting in high production system. Due to high rainfall, double cropping is possible in these soils.
Sierozems are extremely light soils, effective depth being influenced by the Ca CO3 concentration in soil profile. Its moisture holding capacity is low (150 mm m-1 soil depth). Sierozemic soils are low in nitrogen and sometimes inadequate in phosphorous. Subsoil salinity is common. These soils are mostly monsoon cropped, except in deep sandy loams where post- monsoon cropping is also possible. Crusting is very frequent.
(iii) Socio-Economic Constraints:
The socio-economic status of dryland farmers, generally, will not permit them in adopting the recommended dryland technology.
Major socio-economic constraints are:
1. Lack of capital, support price for the produce, marketing and credit facilities make the farmers hesitate to invest on recommended technology.
2. Most of the resource poor farmers opt for avoiding risk in dryland agriculture.
3. Poor organisational structure for input supply in dryland areas.
Essay # 6. Monsoon and Length of Crop Growing Season under Dryland Agriculture:
In the Central Arid Zone Research Institute, Jodhpur, maps of India showing the normal duration and commencement and cessation dates of the crop growing season with nil or slight water stress under dryland farming with normal rainfall were prepared by Krishnan and Thanvi in 1972.
These were computed by the climatological water budgeting approach of Thornthwaite and Mather (1955), taking into account soil storage values for various major soil types of the country and using mean monthly potential evapotranspiration values computed by Penman method.
Dates of Commencement:
Commencement of the crop growing season is, generally, much ahead of the normal onset of the southwest monsoon in Bengal, Bihar, Orissa, Madhya Pradesh, Assam, Kerala and Karnataka, due to considerable pre-monsoon thunder showers. This feature is specially marked in Karnataka, Kerala, West Bengal and Assam.
The beginning of the growing season in the west peninsula varies from April in Kerala to the first week of June in north Maharashtra. The gradient is from east to west in north India. It varies from 1 April in Assam to later than 15 July in western Rajasthan. In Tamil Nadu, the growing season begins only in September/October in the Ramanathapuram and Tirunelveli districts, etc. which receive rainfall mainly during the northeast monsoon.
Dates of Cessation:
The growing season ends by the end of September in the arid zone of northwestern India, while it ends in October-November in the southern arid regions. The extension of the growing season beyond February occurs mainly in east Madhya Pradesh, and southern Bihar, West Bengal and Assam. In southeast Tamil Nadu, the growing season also extends beyond January-February, but here it also starts very late.
Crop Growing Season:
The crop growing season with nil or slight water stress under rainfed was defined as the period for which actual evapotranspiration (AE), estimated by taking into account both the rainfall and the stored soil moisture, exceeds half the value of potential evapotranspiration (the period for which AE >PE/2).
The period of moderate drought under rainfed farming was defined as the period for which actual evapotranspiration lies between 1/4th and half of the value of the potential evapotranspiration (PE/2 > AE > PE/4). The period of severe drought under rainfed farming was defined as AE < PW/4.
Crop growing season with little water stress under rainfed farming for the year with normal rainfall conditions varies from less than a month in the Jaisalmer district and western portions of Barmer, Jodhpur, Bikaner and Ganganagar districts and western Rajasthan to more than 300 days in Assam and parts of Kerala. The period covers the entire 365 days in many parts of Assam.
The portions of the northwest and arid zone, other than the districts, have a normal growing season of 30 to 90 days, while the arid zone in the southern peninsula has an average growing period of 120 days due to receipt of rainfall during the northeast monsoon. Another region having less than 120 days of growing season is the southern-most districts of Tamil Nadu, which receive most of their rainfall during the northeast monsoon.
The black soil regions of Vidarbha, Madhya Pradesh and adjoining Rajasthan, as well as coastal Andhra Pradesh, Orissa, Bengal and eastern Bihar have a growing season exceeding 210 days. In the Gangetic alluvial plains of Uttar Pradesh and western Bihar, the growing season is less than 180 days, with an increase towards the south as well as north.
In the western coastal areas, the growing season gradually increases from 180 days in Maharashtra state to more than 300 days with the progressive increase in rainfall due to northeast monsoon and pre-monsoon thunder showers.
Interior peninsular India has, generally, less than 180 days of growing season, except for the portions covering south Karnataka and adjoining Tamil Nadu, where values exceed 210 days because of contributions from both monsoons and pre-monsoon thunder showers.
Table 5.3 shows the duration of the crop growing season under rainfed farming of 30 selected stations representing typical soil climatic zones of India. While climatic zone 1 has a duration of 10 days, the duration is a whole year in portions of Assam and Kerala coming under zone 8.
Duration of the crop growing season also varies considerably within a particular climatic zone with the variation in the water holding capacity of the soils.
For instance, duration of the crop growing season in alluvial soil and medium to deep black soil stations of climatic zones 2 to 6 is shown below:
Thus, considerable variation exists in the crop growing season in the name climatic zone under different soil types. In the climatological water budgeting mentioned, the available soil moisture storage in each station, depending upon its soil type, has been taken into account.
Accordingly, in a region with black soil and high available moisture storage, soil moisture is available to plants from storage for a long time after the rains cease. This results in longer crop growing seasons in these soil climatic zones. Such factors must be taken into account in selecting the proper cropping pattern for each of these zones.
Drought Period:
Droughts do not occur in Assam, south Kerala and eastern part of West Bengal. Severe drought begins on 1 October in the northwest arid zone and even much earlier in the western part. In the southern arid zone and adjoining interior portion of Maharashtra state, the severe drought begins by the end of November.
However, in most of the central portion of the country to the east of the line joining Delhi, Udaipur and Baroda, the commencement is only in the month of February or later.
This is due to high water holding capacity of the black soil region. In the western coastal region of Maharashtra and Karnataka states, the rainfall is very high. In spite of this, severe drought begins by December-January, probably because of the lower water holding capacity of the soil. Severe drought commences only after April in Gwalior, Guna, Jabalpur, Pendra, and Satna region of Madhya Pradesh.
On the average, severe drought ends outside the regions of east Bihar, Tamil Nadu, Karnataka, and southern Andhra Pradesh only by 1 May. In most of these regions it ends mainly after 15 May. In the arid zone of northwest India, severe drought ends normally during the second fortnight of June, except in the Jaisalmer and Bikaner regions where normal cessation of severe drought is only by the first week of July.
Essay # 7. Strategy for Dryland Agriculture:
Any technology for drylands should be able to maximise the benefits of a good season and minimise the adverse effects of an unfavorable season. Attempts were made to develop a good weather code and a drought code. When the monsoon is normal, it should be used most effectively, using a best variety and the recommended package of practices.
Drought code come into operation with aberrant weather and the drought programmes indicate:
1. Maximising production through alternate cropping pattern, if necessary.
2. Midseason correction to standing crops.
3. Crop lifesaving irrigation.
4. Buildup of seed and other inputs to implement the drought complex strategies.
Measures necessary for counteracting aberrant weather are:
1. Thinning the plants or rows in a sole crop.
2. Removal of the more sensitive crop in intercropping system (sorghum in sorghum-pigeon-pea system).
3. Ratooning on receipt of rain if the damage is not beyond recovery.
4. Sowing a new crop suitable to the remaining part of the season.
5. Urea spray.
6. Lifesaving irrigation.
Essay # 8. Moisture Conservation in Drylands:
Annual rainfall in several parts of drylands is sufficient for one or more crops per year. Erratic and high intensity storms leads to runoff and erosion. The effective rainfall may be 65 per cent or sometimes less than 50 per cent.
Hence, soil management practices have to be tailored to store and conserve as much rainfall as possible by reducing the runoff and increasing storage capacity of soil profile. A number of simple technologies have been developed to prevent or reduce water losses and to increase water intake.
(i) Tillage:
The surface soil should be kept open for the entry of water through the soil surface. Offseason shallow tillage aids in increasing rain water infiltration besides decreasing weed problems. Deep tillage once in 2 to 3 years has been extremely beneficial in shallow red soils of Anantapur (AP).
Contour cultivation is effective in reducing soil and water loss. On red soils, crusting is a serious constraint to seedling emergence and soil and water conservation. Shallow tillage during initial stage of crop with inter-cultivation implements will be effective in breaking up the crust and improving infiltration.
Unfortunately, all the tillage practices that increase entry of water also tend to increase evaporation losses from surface soil. This is the major component of storage inefficiency in soils with high water holding capacity.
(ii) Fallowing:
Traditional dryland cropping systems of deep vertisols involve leaving the land fallow during rainy season and raise crops only during post-rainy season on profile stored soil moisture. The main intention of fallowing is to provide sufficient moisture for the main post-rainy season crop. The monsoon rains, even in drought years, usually exceeds the storage capacity of root zone soil depth.
This system probably provides some level of stability in the traditional system, though in years of well distributed rainfall, the chance of harvesting a good crop is lost. Probably poor drainage, tillage problems (workability of soil) and weed control have forced the farmers to adopt post-rainy season cropping. Since the soil has to be kept weed free during rainy season, the problem of erosion and runoff increases considerably.
(iii) Mulching:
Mulching is a practice of covering the soil surface with organic materials such as straw, grass, stones, plastics etc. to reduce evaporation, to keep down weeds and also to moderate diurnal soil temperatures. Soil and runoff losses can also be reduced considerably.
The effectiveness of mulches in conserving moisture is relatively higher under conditions of more frequent rains, drought and during early plant growth when canopy cover remains scanty. Though, mulches are useful in mitigating moisture stress effects, availability and cost is limiting their use.
As the surface water infiltrate into the soil, colloidal soil particles are filtered out in surface layer. This process impedes water flow into and through soil pores leading to surface scaling and soil compaction. Hence, reduced infiltration increase surface runoff. A modification of traditional mulching called vertical mulching has been developed for heavy soils where infiltration is a problem.
Trenches are dug at 5-10 m intervals depending on slope at sizes of 30 x 60 cm across the slope on grade. They are filled with stalk materials which keep the cracks open and allow better water intake.
(iv) In Situ Moisture Conservation:
In the past, emphasis was given to contour bunding as a potential tool for soil and water conservation which was never widely adopted by dryland farmers due to:
1. Substantial yield reduction in the pit near the bund due to removal of surface soil during construction of bund. Even when the advantage was there, it was only marginal
2. Quantity of water held by the soil did not increase due to water trapped near the bund
3. Delay in cultural operations and crop damage due to stagnant water above the bund considerably reduced the yield
4. Increase in yield due to the effect of bunding could not compensate for the yield reduction due to area removed (5-10%) by bunds and soil excavation.
Bunding may be the last line of defence and the land between bunds should be treated culturally for effective moisture conservation. Appropriate land configurations like broad beds and furrows, inter-row and inter-plot water harvesting system etc. hold great promise for in situ water harvesting systems.
a. Broad Beds and Furrows (BBF):
These are effective on black soils. Beds of 120-180 cm separated by furrows on grade are effective for in situ water conservation. Beds function as mini-bunds at a grade normally less than the maximum slope of the land. When runoff occurs, its velocity is reduced and infiltration opportunity time increased. Excess water is removed in a large number of small furrows. Crops are sown on broad beds. (Fig. 5.2)
b. Compartmental Bunds:
They convert the area into small square/rectangular blocks. They are useful for temporary impounding water and improving the moisture status of soil. These can be made with bund formers or country plough. Size of bunds depend on inter bunded land area. Areas having a slope of 1 per cent or less suitable for compartmental bunding.
c. Dead Furrows:
Dead furrows on contour at 2.4 to 3.6 m are effective in shallow red soils of Anantapur (AP) for increasing the groundnut yield. Dead furrows are formed between two rows of the crop before start of heavy rains (September-October). They increase infiltration opportunity time besides reducing soil erosion.
d. Opening Ridges and Furrows:
In this practice, entire land is laid out into ridges and furrows across the slope. Ridges and furrows are opened before onset of monsoon so that the flow of water may be reduced and erosion may be controlled to minimum.
During rainy season, crops like maize, sorghum, pearl-millet etc., may be grown in the furrows and legumes like soybean, pigeon-pea, green-gram, black-gram, cowpea etc. may be grown on the ridges. After the monsoon, the land is again leveled. This way, the furrows are used to accumulate maximum water which will supply moisture for rabi crops.
e. Tie-Ridging:
The practice of tie-ridging (Fig. 5.3), where adjacent ridges are joined at regular intervals by barriers or ties of the same height, allows the water to infiltrate and prevent runoff except during intense storms. This method is adequate in moderate rainfall areas, except on very steep slopes.
f. Bedding System:
In this system, small furrows are opened and soil from furrows is uniformly spread in space left between the furrows. Thus, inter-furrow spaces form raised beds of about 4-5 m width. This method helps in conservation of soil, moisture and checking excess runoff. Raised beds are used for growing such crops which need less water like legumes and oilseed crops, while furrows are used for crops which need more water.
g. Inter-Row Water Harvesting:
Under this system, furrows of about 30-40 cm width (15 cm deep) are alternated by ridges of 60-70 cm. (Fig. 5.4).The furrows and ridges are formed with ridger at right angles to the slope. It reduces runoff and water is conserved in furrows. It is, particularly, suitable for heavy textured soils. In light soils, crops are grown in furrows whereas in heavy soils, planting is usually on ridges to eliminate the problem of water-logging.
h. Inter-Plot Water Harvesting:
In this method, runoff water is made available to cropped plots from adjacent bare plots either on one side or both sides. Adjacent plots are given certain slope to augment runoff towards cropped plot for improving profile moisture storage.
Slopes on both sides of cropped area appear to be more appropriate for arid horticultural crops. (Fig. 5.5) Catchments with strips of 0.75 m width on either side of 3.0 m wide levelled area are desirable. Catchment to cultivated area ratio of 0.5 could be optimum for most crops.
i. Scoops on Land Surface:
They are small pits on soil surface. Main aim of forming small scoops is to increase opportunity time for water to infiltrate into the soil and to reduce soil erosion by trapping the eroded sediment that would otherwise lost from the field. Scooping should be before start of monsoon rains.
j. Subsurface Moisture Barrier:
An artificial layer of a material with less permeability placed at 60-79 cm depth, can retain water over the barrier for longer period of crop use. This concept is based on the observation that sandy soils with clay subsoil are more productive soils. Subsurface barrier of bentonite clay and pond or tank sediments can be effectively used for orchard crops and establishment of trees in arid region, though not for field crops on large scale.
(v) Control of Water Losses:
Water is lost from the soil surface by evaporation and through vegetative surfaces (plants) by transpiration. Control of these losses can increase the crop water use for improving the productivity of drylands.
a. Evaporation Control:
Evaporation from soil surface can be restricted by:
a. Reducing external evaporativity.
b. Reducing energy supply to evaporating surface.
c. Decreasing the conductivity/diffusivity of soil.
d. Reducing the potential or force driving water upwards through the profile.
b. Shelterbelts/Windbreaks:
In arid and semiarid tracts, wind is responsible for loss of soil moisture by evaporation. Shelterbelts/windbreaks are effective in reducing external evaporativity.
These are effective for increasing the air resistance to water vapour transfer. Wind strip-cropping consisting of growing annual crops between strips of perennial grasses has also been found effective in conserving moisture at CAZRI, Jodhpur.
Weeds frequently transpire greater amount of water per unit dry matter produced than do the crop with which they are associated. Therefore, weed control can minimise the loss of water through transpiration by weeds leading to high crop water use efficiency.
c. Mulching:
Evaporation can be reduced by covering the soil surface with organic residues, straw, grass, stones, plastics etc. Surface mulch controls external evaporativity and also reduces energy supply to the evaporating site by obstructing the solar radiation falling on the ground. Mulching also reduces crop weed competition for soil moisture.
d. Tillage:
Soil-water regime, aeration, soil thermal characters and mechanical impedance to root penetration are influenced by tillage. Thin layer of soil formed (soil mulch) due to tillage restrict the upward movement of water to the evaporating surface by reducing the diffusivity gradient.
e. Transpiration Control:
Water is lost through transpiration mainly from stomatal pores on leaves.
Transpiration can be reduced by:
a. Increasing the leaf resistance to water vapour loss by using anti-transpirants.
b. Reducing the net energy uptake by leaves by increasing leaf reflectance.
c. Reducing shoot growth by growth retardants.
d. Increasing the air resistance to water vapour transfer with windbreaks/shelterbelts.
Anti-Transpirants:
About 99 per cent of water absorbed by plants is lost in transpiration. If transpiration is controlled, it may help in maintenance of favourable water balance.
Anti-transpirant is any material applied to transpiring plant surfaces for reducing water loss from the plant.
These are of four types:
(i) Stomatal closing.
(ii) Film forming.
(iii) Reflective.
(iv) Growth retardant.
i. Stomatal Closing Type:
Most of the transpiration occurs through stomata on the leaf surface. Fungicides like phenyl mercuric acetate (PMA) and herbicides like atrazine in low concentrations serve as anti-transpirants by inducing stomatal closing. These might reduce photosynthesis also simultaneously. PMA was found to decrease transpiration to a greater degree than photosynthesis in a number of plants.
ii. Film Forming Type:
Plastic and waxy materials which form a thin film on leaf surface retard the escape of water due to formation of physical barrier. Mobileaf, hexadeconol, silicone are some of the film forming type of anti-transpirants. Success of these chemicals is limited since they also reduce photosynthesis.
Desirable characteristics of film forming type of anti-transpirants are:
1. They should form a thin layer.
2. They should be more resistant to passage of water vapour than carbon dioxide and the film should maintain continuity and should not break.
iii. Reflectant Type:
These are white materials which form a coating on leaves and increase leaf reflectance (albedo). By reflecting the radiation, they reduce leaf temperatures and vapour pressure gradient from leaf to atmosphere and thus reduce transpiration. Application of 5 per cent kaolin spray reduces transpiration losses. A diatomaceous earth product (celite) also increases reflection of solar radiation from crop canopy.
iv. Growth Retardant:
These chemicals reduce shoot growth and increase root growth and thus enable plants to resist drought. They may also, induce stomatal closure. Cycocel (CCC) is one such chemical useful for improving water status of the plant.
Anti-transpirants, generally, reduce photosynthesis. Therefore, their use is limited to save the crop from death under severe moisture stress. If crop survives, it can utilise rainfall received subsequently. Anti-transpirants are also useful for reducing transplantation shock of nursery plants. They have some practical use in nurseries and horticultural crops.
Essay # 9. Water Harvesting and Protective Irrigation for Dryland Agriculture:
A prerequisite for substantial improvement of farming system in drylands is decrease or elimination of risk associated with crop production. Large number of tanks in south India indicate ancient knowledge of collecting and storing excess rain water at times of excessive rainfall and using it during subsequent dry season.
The process of runoff collection during periods of peak rainfall in storage tanks, ponds etc. is usually referred to as water harvesting. Results of experiments is dry-land areas indicated feasibility of harvesting and storing excess runoff in small farm ponds and reusing the same for supplemental (protective) irrigation to crops during periods of prolonged drought.
(i) Farm Ponds:
Farm ponds are small storage structures for collecting and storing runoff water.
Depending on their construction and suitability to different topographic conditions farm ponds could be classified into:
1. Excavated ponds suitable to flat topography.
2. Embankment ponds for hilly and rugged terrains with frequent wide and deep water courses.
3. Excavated-cum-embankment ponds.
Excavated farm ponds are ideal for soils with mild to moderate slope. There are three types of excavated farm ponds: square, rectangular and circular. Circular ponds have the geometrical advantage that they have higher storage capacity with least circumferential length for a given surface area and side slopes. However, their curved shape is disadvantageous as substantial area is lost for agricultural operations.
Selection of Catchment Area:
Catchment area is selected on the basis of its potentiality for yielding sizeable quantity of runoff. Too big catchment area results in silling, while too small area may not yield enough water into the pond. Amount of runoff from catchment depends on several factors.
a. Rainfall:
Intensity, duration and distribution of rainfall.
b. Topography:
Degree and length of slope, size and shape of the catchment, extent of depressions on the catchment.
c. Soil:
Soil moisture content, infiltration rate, texture, structure and erodability.
d. Land Use:
Intensity of cultivation, crop, soil and moisture conservation measures adopted and cultural practices.
Expected water yield in different regions are given in Table 5.8:
e. Runoff Inducement:
Runoff collection can be substantially increased by several ways. Smoothing (shaping) the land surface, surface covers and decreasing the infiltration rates increase the runoff for water harvesting.
f. Land Shaping:
Proper shaping the land surface and compaction yield higher runoff. Land smoothing reduce surface depression storage and infiltration losses.
g. Decreasing Infiltration Rate:
Application of sodium salts to the surface disperse the clay particles which seal the soil pores to reduce infiltration rate. Various hydrophobic compounds like sodium methyl silanolate, sodium silanolate, sodium rosinate, fatty amino-acetate etc. have been suggested for use as surface coat for increasing runoff. Surface treatment of soil with bitumen and asphalt is effective for inducement of runoff.
h. Surface Covers:
All the surface runoff can be effectively harvested by covering the land surface by galvanized sheets, butyl rubber covers and low density polyethylene sheets. Most of the treatments for inducing runoff are location specific and depends on importance of runoff collection and cost associated with the treatment.
i. Storage Losses:
Seepage and percolation losses and high evaporative demand of the dry climate considerably reduce the amount of stored water in farm ponds for protective irrigation. These losses can be mitigated by using suitable lining material and evaporation retardants.
Lining of Farm Ponds:
Excessive seepage and percolation from farm ponds can be reduced by lining. An ideal lining material should be impermeable to water, durable, resistant to mechanical damage and locally available at low cost. Natural clays, bentonite, stone or brick in cement mortar, cement concrete, asphalt compounds, rubber and polyethylene sheets, chemical additives are used for lining.
Natural clay soil linings are most economical for fairly large ponds. The minimum thickness of clay lining should be 30 cm upto 3 m depth and 5 cm extra for each additional 30 cm pond depth.
Reducing Evaporation:
High temperature, low relative humidity and high wind velocities in dryland areas increase the loss of water from ponds through evaporation. Several materials like oil emulsions, fatty alcohols, gum mixtures, polyethylene oxides and cationic, anionic and non- ionic chemicals can be used for minimising evaporation losses.
Wax is the recently tested for reducing evaporation. Floating blocks of wax are added to the water. In sun light, they soften and flow to form a flexible continuous film. Even if the film breaks during cold weather, subsequent high temperatures reforms the blocks. Rubber and plastic floats can reduce the evaporation losses by about 80 per cent.
In the absence of durable, efficient and economical evaporation retardant, it is advisable to use the water as-early as possible such that it can be stored in soil profile for subsequent use, atleast from deeper soil layers.
(ii) Percolation Ponds/Wells:
Percolation ponds/wells are constructed across a natural water course having permeable formations to impound from streams for a longer time with the object of effecting charge of groundwater. Percolation wells encourage digging of wells downstream of recharged area for irrigation purpose. These are provided with emergency spillways for safe disposal of flow during floods.
(iii) Checkdams:
These are permanent engineering structures constructed in gullies which are not stabilised or lack vegetation on their sides or coarse particles on the surface. All gullies encountered within a sub-catchment have to be protected with a suitable check dam. These are also effective in recharging the downstream wells.
(iv) Minor Irrigation Tanks:
These are constructed across the major streams with low earthen dams. A narrow gorge should be preferred for making the dam in order to keep the ratio of earthwork to storage as minimum. These tanks are provided with well-designed regular and emergency spillways for safety against side cutting.
(v) Protective Irrigation:
Runoff water collected in form ponds or similar structures is of immense use for protecting the dryland crops from soil moisture stress at times of prolonged dry spells during the crop season. Harvested water can also be used for rabi crops grown in Vertisols on stored soil moisture.
Results of experiments at ICRISAT and other dryland research centres have clearly proved the yield advantage due to one or two supplemental irrigations. Time of application, depth of irrigation, method of application and fertiliser use determine the efficiency of supplemental irrigation.
Time and Depth of Irrigation:
In kharif regions, supplemental irrigation may be given to save crops from cyclic stress during July and August. In potentially double cropped areas, it may be used for crop establishment, as the surface soil is dry enough to affect stand establishment.
Depth of water application influence the response of dryland crops to supplemental irrigation. Application of 1 to 2 cm depth may increase the yield of shallow rooted crops. Atleast 3 to 5 cm depth of application is essential for deep rooted crops.
Method of Application:
Application methods to minimise unproductive losses can improve water use efficiency. Alternate furrow irrigation to shallow rooted crops increases water use efficiency. At Bijapur, drip irrigation saved 50 per cent of pond water compared to surface methods. Sprinkler irrigation is more effective than contour furrow irrigation to rabi sorghum at Sholapur.
Use of Fertiliser:
One of the limiting factors in fertiliser use for dryland crop is poor response of crops to applied fertilisers due to soil moisture stress during the crop period. Supplemental irrigation increases the yields by two to three times even with moderate rates of fertiliser application.
Since water harvesting in farm ponds involve considerable expenditure, it must be used judiciously for realising maximum returns. This could be achieved by using the water for high value crops than seasonal/annual crops.
Essay # 10. Fertiliser Use in Dryland Agriculture:
Soils of dryland agriculture are not only thirsty but hungry also because these soils are severely eroded horizontally as well as vertically. Whenever efforts are made towards bunding and levelling of the fields, it is the surface soil which is removed. The resultant effect is that the fields are rendered shallow in depth and completely deprived of plant nutrients, particularly nitrogen, phosphorus and potassium.
It is, therefore, necessary to apply all the three major nutrients in adequate amounts. Since soil moisture is limiting in drylands, availability of nutrients becomes the limiting factor. For efficient use of applied fertiliser, it should be applied in furrows below the seed using seed-cum-fertiliser drills. Results of the experiments have shown that fertiliser use aids in efficient use of profile soil moisture leading to higher yields (Table 5.14).
Studies on management of legumes in crop sequences for their residual effect indicated an advantage around 25 kg N ha-1 in rabi crops after black-gram or green-gram during rainy season. Another possibility for nitrogen management in cropping system is to use legumes as green manures either at flowering stage or after one picking.
Studies at several situations clearly showed yield advantages in rabi crops when legumes raised in the previous season were incorporated into the soil after first picking as compared to that harvested at normal maturity.
In dryland agriculture, application of bulky organic manures along with inorganic fertilisers leads to complementary effect of applied manures and fertilisers. Bulky organic manures help to improve the moisture holding capacity of soils for crop use by increasing soil organic matter content. Yield advantage due to conjunctive use of organics and in-organics has been demonstrated under different situations of dryland agriculture.
Essay # 11. Alternate Land Use Systems for Dryland Agriculture:
All drylands are not suitable for profitable field crop production. Some lands may be more suitable for range/pasture management, while others for tree farming, ley farming, dryland horticulture, agroforestry systems including alley cropping. All these systems which are alternatives to crop production are called as alternate land use systems.
This system not only helps in generating much needed off-season employment in mono-crop dryland but also minimises risk, utilises off-season rains which may otherwise go waste as runoff, prevents degradation of soils and restores balance in the ecosystem.
Crop production may be disastrous during drought years, whereas drought resistant grasses and trees could be remunerative. Scientists of dryland have developed many alternate land use systems to suit different agro-ecological situations. These are alley cropping, agri-horticultural system and silvi-pastoral systems which utilise the resources in better way for increased and stabilised production from drylands.
Various land use options for dryland areas under different land capability classes and mean annual rainfall pattern are presented in Fig 5.6:
Alley Cropping for Arable Lands:
Food crops are grown in alleys formed by hedge rows of trees or shrubs in arable lands. It is also known as hedgerow intercropping. Hedgerows are cut back at about one meter height at planting and kept pruned during cropping to prevent shading and to reduce competition with food crops.
It is recommended for humid tropics, primarily as an alternative to shifting cultivation. In semiarid regions of India, alley cropping provide fodder during dry period since mulching the crop with hedgerow prunings usually does not contribute to increased crop production.
Advantages of this system are:
1. Provision of green fodder during lean period of the year.
2. Higher total biomass production per unit area than arable crops alone.
3. Efficient use of offseason precipitation in the absence of a crop.
4. Additional employment during offseason.
5. It serves as a barrier to surface runoff leading to soil and water conservation.
Based on the objectives, three types of alley systems are recognised:
1. Forage-alley cropping.
2. Forage-cum-mulch system.
3. Forage-cum-pole system.
In all the three systems, crops are grown in alleys and forage obtained from loopings of hedgerows.
Forage-Alley Cropping System:
In this system, both yield of crop and forage assume importance.
Only a few tree species are suitable for hedge rows:
(i) Leucaena leucocephala,
(ii) Colliendrci and
(iii) Sesbania.
Pigeonpea or castor crops are suitable for growing in the allies of Leucaena. Crop yield decreases with decrease in row width. Increase in cutting height of hedgerows decrease the crop yield due to shading effect. Longer harvest intervals narrows the yield differences between the cutting heights.
Forage-Cum-Mulch System:
In this system, hedgerows are used for both forage and mulch. Loopings are used for mulching during the crop season and used as fodder during offseason. Substantial reduction in crop yields of sorghum, groundnut, green-gram and black-gram have been observed at several places.
Forage-Cum-Pole System:
Leucaena alleys are established at 5 m intervals along the contours. Hedge rows rows are established by direct seeding and topped every two months at 1.0 m height during crop season and every four months during the offseason. A Leucaena plant for every 2 m along hedgerows is allowed to grow into a pole.
Crop yield is usually reduced due to competition from hedgerows. However, gross returns are higher in all alley cropping system than with sole crop.
Agri-Horticulture for Arable Lands:
It is one form of agroforestry in which the tree component is fruit tree. It is also called as food- cum-fruit system in which short duration arable crops are raised in the interspaces of fruit trees. Some of the fruit trees that can be considered are guava, pomegranate, custard apple, sapota and mango. Pulses are the important arable crops for this system. However, depending on the requirements, others like sorghum and pearl-millet can be grown in the interspaces of fruit trees.
Reasons for this system not being widely adopted are:
1. Economic position of farmers may not permit awaiting income after 5 or 6 years.
2. Watering of fruit trees, till their establishment is a problem in summer period.
3. Marketing problems for perishable horticultural produce.
Horti/Silvi-Pastural System for Non-Arable Lands:
Class IV and above soils, uneconomical for arable crop production, are termed as nonarable lands. Hortipastural system is an agroforestry system involving integration of fruit trees with pasture. When fruit tree is replaced by a top feed tree, it is called as silvipastural system.
Guava, custard apple and ber suits well in an hortipastural system with grasses like Cenclirus ciliaris (anjan), C. setigerus (bird wood), Panicwn antidotale (blue panic), Dicanthicum anmdcitum (marvel) and Chloris gayana (rhodes) and legumes like Stylosantiies liemata (hemata) S. scarba (stylo) and Macroptilum atropurpuream (siratro).
Top feed trees ideal for silvipastural system are:
1. Acacia nilotica (babul)
2. Acacia senagal (gum arabica)
3. Bauhinea purpurea (khairwal)
4. Dalbergia sissoo (shisham)
5. Gmelina arborea (gumhar)
6. Harwickia binata (anjan)
7. Leucaena leucocephala (subabul)
8. Sesbania grandiflora (agathi).
Grasses and legumes indicated under hortipastural system are also suitable for silvipastural system.
Ley Farming for Non-Arable Lands:
A rotation system which includes a pasture (ley) for grazing and conservation is called alternate husbandry or mixed farming. A farm or part of it. entirely cropped with leys which are reseeded at regular intervals is termed ley farming.
It helps to conserve soil and improve its structure and fertility. For drylands, it is a low risk system. A four year rotation system involving Stylosantiies hamata and sorghum has yield advantage of sorghum besides improvement in soil physical properties.
Tree Farming for Non-Arable Lands:
Trees can flourish and yield abundantly where arable crops are not profitable. Farmers of drylands are inclined to tree farming because of labour cost, scarcity at peak periods of farm operations and frequent crop failure due to drought. A number of multipurpose tree systems (MPTS) have been tested for their suitability and profitability under different situations.
Timber-Cum-Fibre System (TIMFIB):
Subabul intercropping with agave appears to be more remunerative at Bijapur area of Karnataka. High density plantations (10,000 plants ha-1) and short rotation intensive culture (4 – 5 years) have gained popularity in Nellore and Prakasam districts of Andhra Pradesh.
About 50 per cent of rainfed area in these districts is under Casuarina and Leucaena. Such system will not be viable in marginal and degraded lands due to problems associated with survival of seedlings.
Medicinal and Aromatic Plants:
There are opportunities for growing a variety of shrubs and herbs yielding essential oils, medicines, aromatic compounds and eyes in dryland areas.
Some of the economic species promising under rainfed conditions include:
Economic Plants:
Lawsonia inermis (henna)
Jatropha carcus (jatropha)
Murraya kounigii (curry leaf)
Agave sisilana (agave)
Medicinal Plants:
Withania sommifera (aswaganadha)
Cassia angustifolia (cassia)
Mucuna purients (mucana)
Ocimum basilicum (ocimum)
Cammiphora wiglitii (camphor)
Plantago ovata (isobagol)
Essential Oil Plants:
Pogostemon pachouli (patchouli)
Pelargonium graveolens (geranium)
Agroforestry:
Agroforestry may be defined as an integrated self-sustained land management system, which involves deliberate introduction/retention of woody components with agricultural crops including pasture/livestock, simultaneously or sequentially on the same unit of land, meeting the ecological and socio-economic needs of people.
It is also defined as a collective name of land use systems and technologies where woody perennials are deliberately used from the same land management units as agricultural crops and/or animals in some form of spatial arrangement of temporal sequence. In agroforestry systems, there is both ecological and economic interaction between different components.
Based on the kind of associated agricultural products, major function of the tree component, spatial arrangement of trees and duration of combination, several systems have been identified.
In India, agroforestry systems are classified as:
1. Agrisilviculture: Crops + trees.
2. Silvipasture: Trees + pasture.
3. Agrisilvipasture: Crops + trees + pasture/animals.
4. Hortipasture: Fruit trees + MPTS + pasture/animal.
5. Agrihortisilviculture: Crops + fruit trees + MPTS.
Essay # 12. Recommendations of Areas for Dryland Agriculture:
Research programmes of All India Coordinated Research Projects for Dryland agriculture have resulted in formulation of the following recommendations for improving the productivity of dryland areas:
1. Bunding across the slope and levelling the land should be done before onset of monsoon.
2. Deep summer ploughing should be followed by surface tillage during monsoon months and also rest of the year.
3. Application of organic manures like FYM, compost etc., at 15-20 t ha-1 or green manuring should be done. These manures should be applied about 20-25 days before sowing and should be well mixed in the soil.
4. Fertilisers should be basal placed at a depth of 7.5-10.0 cm in the soil and the seeds should be sown in the same furrows about 3 cm above the fertilisers. Nitrogen (20-50% of total) should be top dressed by side or band placement at about 15 cm apart. In the absence of sufficient moisture in the soil, nitrogen should be sprayed over the foliage with urea solution containing 3-5 per cent nitrogen. Zinc and sulphur should be applied at sowing.
5. Soil application of BHC (10%) dust at 25-30 kg ha-1 for termites and Thimet 20 G at 15 kg ha-1 for white grub should be done.
6. Selection of suitable crops and varieties according to their suitability to a particular region/microclimate.
7. Seeds must be treated with a suitable fungicide and that of legume with rhizobium culture before sowing. Soaking seeds in plain water for rabi sowing helps in getting higher germination, better seedling vigour and early maturity.
8. Proper crop rotation, preferably with a legume every year.
9. For better seed-soil contact, soil compaction should be done by running a plank or roller especially for rabi crop.
10. At the event of total crop failure during kharif, a suitable catch crop like green-gram or toria should be sown.
11. Intercropping of oilseeds and pulses with sorghum, pearlmillet and maize for best use of soil and inter-row moisture harvesting.
12. Line sowing at a depth of 7.5 to 10 cm or even more depending upon the situation for better seed germination and stand establishment.
13. Timely weed management practices followed by integrated weed management.
14. Frequent intercultural operations for creating soil mulch. If intercultural operations are not possible then use of artificial mulches like covering the surface with tree leaves, uprooted weeds, sugarcane leaves, saw dust or polythene sheets to check evaporation of water from the soil.
15. Water harvesting between the rows should be done by growing some pulse crops and runoff water should be collected in some nearby located ponds and used as life-saving irrigation.
16. Efficient plant protection measure should be adopted to protect the crop from insect pests and disease damage.
17. Kharif crop should be harvested at physiological maturity so that the succeeding rabi crop can be sown slightly earlier than the scheduled time to avoid possible terminal soil moisture stress to the rabi crop.
18. Crops like cotton, chilies etc. should be sprayed with CCC and groundnut should be sprayed with planofix for modified growth, higher drought resistance and better yield.
Essay # 13. Improved Implements for Dryland Agriculture:
Tillage implements in drylands are used for seedbed preparation, seeding and fertiliser application, inter-cultivation and harvesting. Tillage implements used for seedbed preparation are country plough, mould board plough, blade harrow, tyne harrow and disc-harrow. Tractor mounted implements have gained importance.
Seeding and Fertiliser Application:
Fespo Plough:
A single row, bullock drawn implement for seeding and band placement of fertiliser has been developed by CRIDA. Its name is derived from the words fertiliser-seed-pora plough. It is a modified version of country plough with two funnels connected behind the share of the plough by two plastic pipes. One funnel is about 5 cm below the other to facilitate dropping of seed deeper than the fertiliser.
A U shaped blade frame covers the soil on seed and fertiliser. One pair of animals with three persons can complete fertiliser placement, seeding and covering the two simultaneously. The coverage is 0.15 to 0.20 ha in a day, depending on row spacing of the crop.
CRIDA-Drill-PIough:
Seed-cum-fertiliser placement device, as an attachment to the country plough has been developed at CRIDA. The hopper box consists two compartments for seed and fertiliser with tubes to place them in furrow. Steel shaft with rubber agitator is fixed to the bottom.
Drive wheel is attached to the left side. Metering plates with orifice are centered exactly below the rubber agitator. A U-shaped floating iron frame bolted to hopper bottom side covers the seed and fertiliser. Only ploughman to operate, it covers 0.4 to 0.6 ha day-1.
Ridger Seeder:
It is a two row bullock drawn seeder developed at AICRPDA, Hisar. It is ideal under dry and receding soil moisture conditions. Sowing is done on the sloped side of ridges to avoid crust formation during rainy season. In post-rainy season, it can seed in furrows after scrapping dry soil to the sides. Like in Fespo Plough, it has two funnels with plastic tubes for seed and fertiliser placement.
CRIDA Seed-Cum-Fertiliser Drill:
It is a three row seed-cum-fertiliser drill developed at CRIDA, Hyderabad. It has a 100 cm long tool bar to which a wooden beam is fitted through an adjustable iron plate. Three pipes, each of 50 cm long are clamped vertically on the tool bar.
Shovels are bottled at the bottom of the pipe to open the furrows. Hoppers are fitted on top of the tool bar, one each for seed and fertiliser. Metering is done manually. Plastic pipes guide seed and fertiliser to the openers. This does not have provision for seed covering. One pair of animals with three persons can cover 0.3 ha hr-1.
Rayala Gorru:
It is developed at AICRPDA centre, Anantapur (AP). Body of the seed drill is constructed with an angle iron and three steel furrow openers, similar to local drills. A small pipe with shovel at bottom is bolted to main opener for fertiliser.
Two funnel bowls are mounted on the frame and transparent tubes connects the bowls to furrow openers. A covering blade is bolted to the body of the drill. In addition to placement of seed and fertiliser, it also covers them simultaneously.
Malaviya Seed-Cum-Fertiliser Drill:
This animal drawn seed-cum-fertiliser drill was developed at AICRPDA centre, Varanasi. It is a two row machine with adjustable row spacing and sowing depth. Seed drill mechanism is flutted roller. It has common furrow opener for seed and fertiliser.
A vertical rotor over adjustable orifice is used for fertiliser metering. Power transmission to metering device is through sprocket and chain arrangement from ground wheel. It can cover an area of 0.25 ha hr-1.
Shivaji Multi-Purpose Farming Machine:
This was developed at AIRPDA centre, Sholapur. It can be used for land preparation, seed a. d fertiliser placement and inter-cultivation. Row spacing is adjustable from 25 to 90 cm. It consists of two seed boxes, one for small seed metering and the other for larger seed. Seeding rate adjustment on both the boxes is by sliding the flutted roller to provide contact with a greater width of seed.
The fertiliser box works on an agitator and sliding gate principle. In double cropping system, after the harvest of first crop the field is prepared for sowing the next crop. Provision is made in the machine to sow the seed at harrowing to minimise the soil moisture loss.
CRIDA Groundnut Planter:
Four row mechanical planter, based on inclined plate mechanism for seeding and agitator and orifice mechanism for granular fertiliser has been developed at CRIDA, Hyderabad. Hopper is mounted on 1.7 m long tool bar with clamps. Pipe beam is attached to tool bar with arrangement for angle adjustment. Drive to mechanism is from ground drive wheel with chains and sprockets.
Four furrow openers are clamped to tool bar at 30 cm row spacing. Blade is attached for covering the seed. Tool bar is mounted on two rubberised wheels at 1.5 m apart. Depth can be adjusted by raising or lowering the wheel shank on tool bar. It can be drawn by a pair of animals and one person operate it.
Hand-hoe (Khurpi) is common tool for manual weeding. Dryland weeder with long handle developed at TNAU, Coimbatore gives three times higher output compared to traditional hand-hoe. Of the four shapes of blades, performance index is highest for sweep followed by triangular blade, curved blade and straight blade.
Harvesting Equipment:
Traditional harvesting tool (sickle) is not efficient and induce human drudgery during operation. Improved serrated sickle is effective for harvest. However, the operation remains labour dependent. Power operated combine harvesters and vertical conveyer reapers, widely used for rice and wheat harvest are not popular under dryland conditions.
Single row rotary reaper windrower developed at IARI, New Delhi looks promising under dryland conditions. It is portable machine mounted on a small trolley with ground wheel. It uses serrated disc cutter at 18 m s-1 speed with field efficiency of 83 per cent at 12 per cent moisture content.
Groundnut digger developed at CIAE, Bhopal gives 98 per cent digging efficiency in black soils. The peg type V shaped groundnut digger developed at ICRISAT, Hyderabad has shown promising results in lighter soils.