Abstract

                                It is well realized that nitrogen is one of the essential elements required for plant growth. The necessity of replacing the loss of this element from the soil due to removal by crops or by leaching is, therefore, well understood in all systems of agriculture. No doubt, nitrogen is also the most expensive of plant food elements. The lack of sufficient available nitrogen in the soil to meet the needs of the growing crop is therefore, the most common limiting factor in crop production.

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