Soil Tests for Zinc and their Correlation with Crop Response

摘要

Soil testing and its interpretation have evolved from the need to assess the quality of soils for supporting plant growth, to identify nutritional problems in plants and to predict fertiliser requirements of plants. At present, the soil testing is being viewed as an essential component in the development of sustainable agriculture in many countries. Several methods for extraction of available Zn in soils have been evaluated and the critical values for the most promising ones in different soils for important field crops have been established. Amongst the various extractants used the solution of chelating agents especially DPTA, EDTA, dithizone etc. proved invariably more reliable and efficient in predicting response of crops to applied Zn. This paper reviews the work done on various aspects of soil tests for zinc, their correlation with crop response and the critical deficiency levels of Zn in soils and in different crops.