Fertilizer Value of Swine and Dairy Manure from an Above-Ground Liquid Manure Storage System

Abstract

A three year study was conducted to determine the fertilizer value of liquid swine and dairy manure stored in above-ground steel structures. The magnitude of nitrogen losses from dairy manure stored in above-ground systems was determined. Randomized complete block design agronomic experiments were conducted on experimental corn plots at two swine and two dairy farms in east central Indiana. Manure was injected in the spring at three rates to approximate 84, (75 lb/ac), 168 (150 lb/ac), and 252 kg (225 lb/ac) available N/ha each year. A nitrification inhibitor, nitrapyrin, was added at 1.3 kg/ha (1.2 lb/ac) to another group of manure plots. Corn yields fluctuated due to stressful weather conditions during the study, although in general, yields increased as manure application rates increased for both swine and dairy manure. A greater amount of total N was needed from manure than from commerical fertilizer for crop response due to lower N availability in manure and the normal microbial process of manure decomposition in the soil. Adding the nitrification inhibitor to spring injected dairy manure increased yields but not when applied with swine manure. Soil nutrients showed evidence of P build-up in plots where high manure rates were applied. Total N loss from the two dairy manure management systems during summer collection and storage was 33 and 41%. Nitrogen lost prior to manure collection was 26 to 28% and during storage was 5 and 15% of all total loss.