Effect of Swine Slurry on Alfalfa Production and on Tissue and Soil Nutrient Concentration

Abstract

Alfalfa (Medicago sativa L.) may not be the most suitable crop to utilize all the manure nutrients, but it may be the best crop available, especially when the crop is dormant. The objective of this research was to investigate the effect of swine (Sus scrofa domesticus) slurry manure on alfalfa yield and the concentration of nutrients in soil. A 2‐yr field experiment was initiated in 2001 on two soils: a Typic Xerofluvent and a Calcixerolic Xerochrept. Soil mineral elements were extracted with ammonium bicarbonate diethylenetriaminepentaacetic acid, and initial extractable P and K were 16.7 and 6 mg P kg−1 and 152 and 103 mg K kg−1 for the two soils, respectively. There were four treatments: annual winter applications of 25 and 50 m3 ha−1 of swine slurry manure, annual fertilization of 32.75 kg P ha−1 and 125 kg K ha−1, and a no‐manure or fertilizer control. Application of slurry manure in winter was not detrimental to the crop. Manure and fertilizer treatments increased alfalfa dry matter (DM) yield 37% on the low‐fertility soil. There was no significant effect of manure or fertilizer on alfalfa DM yield on the Xerofluvent soil. Application of the slurry slightly increased the soil concentrations of P, Mg, Zn, and Fe in higher‐fertility soils and copper in low‐fertility soils. The 2‐yr results suggest that the application of slurry in soils with low levels of trace elements, such as those used in the trials, does not produce a significant buildup of these elements that could lead to an environmental problem.