Soil testing and plant analysis methodology for dryland research
1997
Rashid, A. (National Agricultural Research Center, Islamabad (Pakistan). Soil Fertility and Fertilizer Use Section)
Almost all soils in the arid and semi-arid fields of West Asia and North Africa are alkaline and calcareous and have low organic matter (OM) contents, and major nutrient deficiencies involving N, P, K, Zn, B, and/or Fe. Fertilization is primarily practiced for N and P only, but generally at lower rates compared with actual requirements, and is imbalanced in favor of N. Soil testing and plant analysis are the practical techniques for diagnosing nutrient disorders and, when combined with field trials, formulating sound recommendations for balanced fertilizer use. Besides determining the soil properties affecting nutrient availability, such as pH, CaCO3, OM, texture and salinity, soils are analyzed for extractable nutrient fractions to obtain indices of nutrient availability. Plant analysis, though of lesser use than soil testing, provides useful information regarding actual nutrient status and uptake by the crop plants which can help improve soil fertility management. The paper discusses soil testing and plant analysis techniques in general use in dryland agriculture as well as interpretation of analytical data for formulating fertilizer recommendations. Simpler, more efficient, and/or economical methods of soil testing and plant analysis are suggested for future emphasis in dryland research. The need for micronutrient soil testing and plant analysis is emphasized for balanced nutrient management in dryland agriculture
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