The following points highlight the six major hazards of improved crop production technology. The hazards are: 1. Reduction in Biodiversity 2. Buildup of Pests, Diseases and Weeds 3. Hazards of Indiscriminate Use of Agrochemicals 4. Accelerated Soil Erosion 5. Irrigation Related Problems 6. Depletion of Soil Fertility.
Hazard # 1. Reduction in Biodiversity:
Development of high yielding cultivars has been possible due to wide range of genetic source material provided by land races. Apparently, the vast genetic diversity within the same crop species is being forced out by narrow genetic range of economically advantageous cultivars.
The very success now threatens the source of genetic diversity on which further progress depends. Widespread use of modern cultivars raises question about the stability of production and threatens the pest and disease attack.
As the biodiversity is reduced, natural process that control and influence habitat quality and genetic expression decline. As such, internal and natural controls must be replaced by more externally applied artificial controls in the form of management and inputs. Similar to crops, the biodiversity among animals should be conserved to sustain the overall improvement in their production capacity witnessed in the recent years.
Hazard # 2. Buildup of Pests, Diseases and Weeds:
Pests, diseases and weed problems are now more serious than ever before. This situation is the result of monoculture of selected crops leading to buildup of pests, diseases and weeds. Carryover of stem borer (pink borer) and buildup of soil borne pathogens in continuous cereal system and Phalaris minor weed problem in rice-wheat system are examples of such serious problems. Farmers have to incur huge amounts on plant protection relative to traditional crop rotations.
Hazard # 3. Hazards of Indiscriminate Use of Agrochemicals:
Modern cultivars are responsive not only to inorganic fertilisers but also to other agrochemicals (in-organics) use in plant protection. In general, pest, disease and weed problems are more in modern improved cultivars compared with traditional varieties. Keeping in view the productivity of high yielding cultivars, farmers used agrochemicals including the fertilisers indiscriminately.
The natural enemies thus eliminated with agrochemicals resulted in pest and disease incidence. Some of the pests and weeds developed resistance to the pesticides and herbicides, thus complicating the plant protection. Pesticide, fungicide and herbicide residues entering the food chain have serious health hazards in both humans and animals.
Hazard # 4. Accelerated Soil Erosion:
The most deleterious impact of agriculture on environment is man induced accelerated soil erosion. Continuous cultivation has replaced longer fallow and extended further into areas where either the climate and/or soil are marginal for cultivation. Continuous cultivation and decline in soil organic matter content has resulted in blowing of lighter drier soil and the sheet washing, rilling and gullying of heavier soils.
When once the fertile topsoil is lost, the parent material will not respond to any inputs or management practices for improving the crop productivity. Of the soil lost by water erosion, high proportion finds its way finally into oceans besides silting up of lakes, reservoirs and tanks leading to depletion of surface water resources.
Hazard # 5. Irrigation Related Problems:
Inadequacies in irrigation water management resulted in serious resource degradation problems. In areas of canal irrigation without adequate drainage, salinity, alkalinity and high water table are the serious constraints in enhancing the productivity. There are other areas where unrestricted installation of tube-wells has resulted in continuous lowering of groundwater tables leading to increasing costs in lifting water for irrigation.
Many productive soils have become unproductive under canal water irrigation due to misuse of irrigation water. Most water management problems are system related and defy solutions arrived in piece meal fashion.
Hazard # 6. Depletion of Soil Fertility:
With increasing harvests, especially in intensive cropped areas, more quantities of nutrients are removed from soil than restored through manures and fertilisers. Availability of FYM is decreasing as tractors replace draught animals in many cases and large quantities used as fuel. Hence, use of organics is not to the desired level. There is imbalance in the use of nutrients resulting in low use efficiency.
Decline in quality and quantity of organic matter in most soils is adversely affecting soil biodiversity and biological regulation of soil process. Strategies to reverse the process of soil fertility decline or enhancement of soil productivity require a long term perspective.
These and other related issues are by no means amenable to economically, socially and environmentally viable simple solutions. This calls for systems approaches in finding solutions through multidisciplinary and multi-institutional efforts to understand interdependence of different components of ecosystem.
This prompted the necessity for recasting the production technology in use for over three decades. Sustainable production systems appear to be the way out of emerging problems from present production technology.