Many governments intervene directly in agricultural product, in particular food, markets. A quantitative assessment of the impact of the policy changes on the desired objectives is important as it helps inform and shape the policy debate on the reform alternatives and increases transparency of government policy. This paper reviews the literature on multi-market models which offer more accurate ex ante impact analysis than single-market models by including potentially important indirect effects. While fairly complex and requiring large amounts of data multi-market models are however much simpler than computable general equilibrium models. They are typically applied at the sector level and have proven quite popular in particular in agricultural policy reform impact analysis. While more recent work has emphasized the poverty reduction and income distribution objective the models can generate a range of information relevant to policy makers. Key Words: Multi-market models, agricultural policy impact analysis.
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