Soil testing nutrient requirements

For bioremediation, an initial feasibility study is always recommended, and the determination of nutrient requirements should be part of this study. The actual requirements are very much dependent upon the type of contaminants, which are often a mixture of compounds of variable biodegradability, and on the availability of nutrients in the specific contaminated soil, and should be determined with appropriate laboratory tests. However, there are guidelines that provide a useful basis for initial economic evaluations and for calculating ranges to be tested during the laboratory tests. 

The results of the soil tests provide information about any fertilization measures that may be required. The nutrient content of the soil is adequate if the following quantities are contained in 100 g of soil ... 

Methods for determining nutrient requirements Soil testing... 

The analysis of plants gives a reliable indication of what nutrients are actually available and recovered by the crop, However, in many cases, that knowledge comes too late to apply fertilizer to affect the growth of the current crop it is likely useful for succeeding crops or for perennial crops. Tissue analyses also require fairly sophisticated instrumentation and a knowledge base for the interpretation. To maximize the benefits of money spent on fertilizers and to avoid crop nutritional problems and environmental problems, farmers need the techniques of soil testing and tissue analysis to determine which nutrients are needed and in what quantities. 

Increased knowledge about secondary nutrients and micronutrients, including plant requirements, nutrient sources, and methods of application, has resulted in th increased use. Improvements In soil testing and plant analyses have provided more knowledge about plant needs and the unde variations in plant responses to these nutrients. Higher crop yields and the use of h h-analysis NPK fertilizers also have resulted in increased needs for these nutrients. 

Virgin soil can be rich in nutrients but at levels that may not be optimal. The soil should therefore be tested for its nutrient content before planting seeds. Nutrients are depleted with repeated production of crops and hence it is important to monitor the concentration of nutrients in the soil and supplement them as required (Seiler 1986). In most third-world countries fertilizer application and irrigation are costly and, sometimes, impossible. 

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