Efficient use of animal manure on cropland - economic analysis

Manure contains all the macro- and microelements needed for plant growth. h owever. it represents one of the most underutilized resources in the US. Th e major problem with the use of manure on cropland is the direct effect of its composition on application cost. This cost is a function of the mineral ization process of organic matter. The mineralization process is influenced by the properties of the manure, properties of the soil, moisture, and tem perature. This study evaluates the simultaneous effect of these variables o n the optimal use of manure on cropland. The results show that the properties of manure and soil significantly affec t the mineralization of organic nitrogen and thus the optimal quantity of m anure required to satisfy the nutrient requirement of crops in a given rota tion system. Manure application costs range from a low of 18% of the cost o f commercial fertilizer for chicken manure applied to one type of soil, to a high of 125% of the cost of commercial fertilizer for cow manure applied to another type of soil. The maximum distance to transfer manure to the fie ld. that will equate its application cost to the cost of commercial fertili zer, ranges from a high of 35 km (22 miles) for chicken manure applied to o ne type of soil, to a low of I km (0.62 miles) for cow manure applied to an other type of soil. For rotation system 2, manure application costs range from a low of 37% of the cost of commercial fertilizer for chicken manure applied to one type of soil, to a high of 136% of the cost of commercial fertilizer for cow manur e applied to another type of soil. The maximum distance to transfer manure to the field, that will equate its cost to the cost of commercial fertilize r, ranges from a high of 20 km (12.5 miles) for chicken manure applied to o ne type of soil, to a low of 0 km (0 miles) for cow manure applied to anoth er type of soil. (C) 2001 Elsevier Science Ltd. All rights reserved.