Biological approaches such as crop residues and biomass as surface mulch; growing Gliricidia sepium on field bunds as source of nitrogen for crops; compost, vermicompost and microbial biofertilizers as soil-building elements; and sources of crop nutrients, and microbial and herbal biopesticides to protect crops have been widely reported as valuable for crop production. Scope of these approaches to meet crop nutrients and crop-protection needs in place of chemical fertilizers and pesticides was examined. Published literature and websites were scanned to look for logically sound comparisons, particularly at on-farm scale. Because farmers using organic farming practices were the major users of some (not all) of the biological approaches, we ended up comparing organic and conventional farms. Experiments with treatments of biological versus conventional inputs (e.g. chemical fertilizers) within a given experiment were the other source of relevant data for comparative performance. Discussion in this paper is restricted to marginal and small farmers in rain fed areas. From the limited evidence, it was apparent that yields comparable to conventional agriculture were harvested by using biological approaches. In addition, a substantial improvement in soil quality due to the biological approach was reported suggesting that these yields would also be sustainable.
Sustainability index was calculated to assess soil quality under the influence of different fertilizer management practices. It is based on the area of the triangle in which nutrient index, microbial index and crop index of soil represented the three vertices of a triangle. Nutrient index reflected the nutrient status of soil and was calculated from the measurements of various soil chemical parameters. Microbial index was calculated by determining various soil microbial and biochemical activities and crop index by measuring of crop yield parameters. Eighteen soil indicators were determined to assess nutrient index, microbial index and crop index in order to compare the effect of different sources of nutrients such as green manure, farmyard manure and chemical fertilizer in a rice/corn– wheat rotation. The indices were applied to assess the sustainability of five field experiments with respect to the different fertilizer treatments. The long-term application of organic manures in rice/corn–wheat cropping system increased the index value because it increased the nutrient index, microbial index and crop index of soils. The use of only chemical fertilizers in the rice–wheat cropping system resulted in poor soil microbial index and crop index. In corn–wheat system, additional application of FYM at 10 t ha−1 before sowing corn made the system more sustainable than application of 100%NPK; the sustainability index values were 2.43 (the highest for this system) and 0.93, respectively.
Crop production systems that require chemical fertilizers, pesticides, machinery for
tillage, and irrigation water are expensive. In countries such as India, they have started
to undermine the water security of future generations, contributing to soil and water
pollution particularly when synthetic pesticides are not used properly. It is true that
agriculture as practiced 100 years ago without modern inputs had lower productivity
than present systems of production. However, many premodern practices, such as the
use of organic manures to enhance soil fertility and of herbal extracts to protect crops,
can be made more efficient by the scientific knowledge that has been gained over
the past century, making crop production more sustainable while still achieving high
An innovative FAO's Project is promoting sustainable insects farming and harvesting for better food security and improved nutrition in LAO PDR. A recent FAO survey found out that over 95% of the population already consumes insects in a way or another. The insects high vitamin and protein content can help improving the country food and nutrition situation.