Soil Testing for Improving Fertilizer Recommendations in China.

The nutrient recommendations through alternative soil testing approaches have facilitated enhanced crop production, economic viability for producers and reduce fertilizers impact on the environment in China. National wide Soil Testing and Fertilizer Recommendations Action sponsored by Chinese government started from 2005 has made great achievements, which helped identify the rational, the most profitable and environmentally stable nutrient application rate. However there are some problems and difficulties in soil testing procedure and developing recommendations from soil available nutrient tests. Slow soil testing service in many counties which still use the traditional facilities for soil testing is probably the worst deterrent preventing farmer use of soil testing services. Returning fertilizer recommendations to farmers too long after samples were taken from the field minimizes the benefit. The another issue is that many laboratories routinely offer an incomplete assessment of soil fertility, providing only an analysis of pH, OM, some form of nitrogen(N), available phosphorus(P) and potassium (K). The most difficulty was in establishing calibration and validation of soil tests by the data from field trials where the conditions such as temperature, moisture, pests, diseases, and nutrients sometimes other than that being examined. A systematic approach to soil fertility evaluation and improvement has been successfully utilized in fertilizer recommendation in China-Canada Cooperative Projects and national researches. A high efficient Soil Testing and Fertilizer Recommendation System for more than 100 crops was developed in Chinese Academy of Agricultural Sciences (CAAS). More than 50,000 Chinese soils have tested in CAAS-PPIC Cooperative Soil and Plant Analysis Laboratory and about 7,000 research and demonstration trials conducted with a wide variety of crops in most provinces over the country. There are still more correlations of soil testing methods and calibrations for crops needed in near future for improving nutrient management and fertilizer recommendations.