Application of Conservation Agriculture Principles for the Management of Field Crops Pests

Abstract

Worldwide, farmers are called upon to abandon harmful pesticides and adopt conservation agriculture for improving environmental sustainability, soil fertility, pest management and farm profits, among other benefits. Whereas the positive environmental benefits of conservation agriculture are non-questionable, pest management benefits are still a subject of debate. Abandonment of the plough and harmful pesticides towards conservation agriculture presented new challenges to farmers in terms of pest management. Pest problems are frequently reported as the main yield limiting factor for conservation agriculture in many production systems of the world, especially among the resource poor farmers. Here we first review the pest management benefits of conservation agriculture principles, with special focus on weeds and animal pests. In conservation agriculture, emphasis should be placed on use of different multiple and varied tactics incorporated into the cropping system design to avoid damaging levels of pests, thus minimizing the need for curative solutions. Conservation agriculture embraces integrated pest management, as it aims to incorporate reduced pesticide applications with cover crops, conservation tillage and crop rotation to strengthen natural pest control. We show that effective long term weed management in conservation agriculture systems is based on an integration of measures for limiting competitiveness of the weeds that are already in the field and growing with the crop, preventing the introduction of new weeds, and preventing the multiplication of the weeds that are already there. Although the abandonment of tillage towards no-till requires an initial investment on herbicides for weed control, herbicide requirement tends to decline over time with proper application of conservation agriculture. Proper selection of planting date, density and spatial arrangement of a crop can maximize the space it occupies early in the season and put competitive pressure on weeds. Crops can be rotated in sequences that are not only profitable, but highly effective at breaking animal pest cycles. Mixed cropping reduces pest populations by increasing environmental diversity and lowering the overall attractiveness of the environment. We then highlight some possible solutions to the major challenges for pest management through conservation agriculture practice. Promotion of integration of conservation agriculture principles with cultural measures is essential for pest management in conservation agriculture systems. In conservation agriculture, it is important for farmers to employ several strategies simultaneously so that if one strategy fails, then the other ones operate to prevent yield loss. The focus should not be just on how to fit various pest management tactics into the conservation agriculture production system, but also on how the system can be modified to accommodate various pest control tactics. We demonstrate that farmers practicing conservation agriculture have several cultural methods that they can put together to build up a good pest management strategy. Although cover crops and mulches are generally viewed as the first line of defense against weeds, the reduction in weeds is not enough to eliminate the need for chemical control. Cover crops can be used to reduce animal pest dispersal, colonization and reproduction on crops through maintenance of the cover crop as a sink for various pests, confusing the pests visually and by causing microclimate changes that reduce pest success. Fertilizer timing and placement strongly influences crop competition; and deep banding of fertilizer has the potential to enhance not only fertilizer use efficiency, but also crop resistance to animal pests and competitive ability against weeds. Proper selection of planting date, density and spatial arrangement of a crop can put competitive pressure on weeds and break animal pest cycles. Sanitation practices are important tools in conservation agriculture because of their ability to eliminate necessities that are important to the pests’ survival. The development of pest resistance will likely be minimal if host plant resistance is integrated with other control measures through conservation agriculture practice. A more holistic, integration approach of control tactics in conservation agriculture, which goes beyond the three principles, is essential for effective pest management.