EFFECT OF SWINE LAGOON WATER APPLICATION RATE AND ALFALFA HARVEST FREQUENCY ON DRY MATTER PRODUCTION AND N HARVEST

Abstract

Swine (Sus scrofa domesticus) lagoon water can supply valuable fertilizer nutrients for field crops. Reduced landavailability and increased swine operation size can potentially create situations where swine producers may over-applylagoon water and contaminate groundwater. This study was initiated in fall 1992 at the Haskell Agricultural Laboratory nearConcord, Nebraska, on a Blendon sandy loam (coarse-loamy, mixed, Pachic Haplustoll). The objectives were to determinehow harvesting alfalfa three times per year (3-HF), four times per year (4-HF), or five times per year (5-HF) and swinelagoon water application rate affected dry matter production and nitrogen (N) harvest by alfalfa (Medicago sativa L.). Swinelagoon water from an anaerobic lagoon was applied to alfalfa using a line-source sprinkler system at rates of 14, 109, 239,394, 509, and 634 kg N ha-1 in 1993 and 14, 114, 249, 399, 519, and 644 kg N ha-1 in 1994. In 1993, alfalfa dry matterproduction increased linearly with increasing lagoon water application rate. In 1994, lagoon water application of 644 kg Nha-1 significantly increased dry matter production by 1.9 Mg ha-1. Dry matter production averaged 19.2, 22.5, and 21.5 Mgha-1, for the 3-HF, 4-HF, and 5-HF treatments, respectively. Nitrogen harvest increased linearly with lagoon waterapplication rate in 1993 and 1994.