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Effects of swine lagoon effluent relative to commercial fertilizer applications on warm-season forage nutritive value

Adeli, A., Vacro, J.J., Sistani, K.R., Rowe, D.E.
Agronomy journal 2005 v.97 no.2 pp. 408
Cynodon dactylon, Sorghum halepense, forage grasses, forage crops, pig manure, effluents, nutritive value, warm season grasses, field experimentation, fertilizer application, crop yield, fertilizer rates, irrigation, NPK fertilizers, crude protein, protein content, neutral detergent fiber, acid detergent fiber, in vitro digestibility, waste management, Mississippi
Two field experiments were conducted on a commercial swine facility near Brooksville, Mississippi, USA, to evaluate the effects of comparable rates of swine lagoon effluent and commercial fertilizer at different harvest dates on dry matter yield and nutritive value of bermudagrass (Cynodon dactylon) grown on an acid Vaiden silty clay (very fine, montmorillonitic, thermic, Vertic Hapludalf) and johnsongrass (Sorghum halepense) grown on an alkaline Okolona silty clay (fine, montmorillonitic, therimic, Typic Chromudert). At each site, a randomized complete block design with a factorial arrangement of treatments replicated four times was used. Treatments were multiple effluent irrigations resulting in four N rates from 0 to 665 kg N ha-1 year-1. In each block, commercial fertilizer (N, P, and K) treatments were applied to additional plots at rates equivalent to swine effluent rates. Total dry matter yield and crude protein (CP) for bermudagrass and johnsongrass reached a plateau with application of approximately 450 kg N ha-1 from either swine effluent or commercial fertilizer. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) peaked at the low fertilizer application rate and then declined with increasing effluent and commercial fertilizer rates. An inverse relationship was obtained for in vitro true digestibility (IVTD) in response to fertilizer application rate for both grasses. Forage dry matter, CP, NDF, and ADF levels peaked in the July harvest and then declined, but forage IVTD level declined in July harvest. Only in July 1996, forage NO3-N concentration was lower for swine effluent than commercial fertilizer. Swine effluent and commercial fertilizer had similar effects on forage dry matter yield and nutritive value.