|Cole, Noel - Andy|
Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 9/12/2003
Publication Date: 10/12/2003
Citation: Rhoades, M.B., Parker, D.B., Sweeten, J.M., Cole, N.A. 2003. Land application of beef feedyard effluent to forage sorghum and winter wheat. ASAE Annual International Meeting. p. 99-106. Interpretive Summary: During rain events water can runoff of beef cattle feedlots. This runoff is captured in lagoons or retention ponds to prevent it from contaminating lakes or streams. This effluent is a potential source of irrigation water for fields close too the feedlot. The effluent also contains nutrients such as nitrogen, potassium and phosphorus. However, it also may contain high levels of nutrients such as sodium and chloride that can adversely affect plant growth. Ideally, the crop produced would be capable of removing most of these nutrients so they do not build up in the soil. To that end, these studies were conduced to determine the effects of irrigating sorghum and(or) wheat with runoff effluent from an experimental beef cattle feedyard. In order to maximize the quantity of nutrients removed, both the sorghum and wheat were cut as hay. Zero, 25, or 50 cm of effluent were applied during each growing season for two years. Three cropping rotations, Sorghum-Fallow, Wheat-Fallow or Sorghum-Wheat, were compared. Plots irrigated with 50 cm of runoff water had greater dry matter yields (28,564 kg/ha), followed by 25 cm (19,153 kg/ha) and no irrigation (14,337 kg/ha). After two years, the ending soil nitrogen and phosphorus concentrations were affected more by the initial nutrient concentrations than by the quantity of effluent applied or the cropping rotation used. The crops were able to remove most of the applied nitrogen and phosphorus, however potassium appeared to accumulate in the soil. To make optimum use of feedyard effluent as irrigation water, the quantity used needs to be balanced with its nutrient content and the crops produced.
Technical Abstract: Feedlot runoff was applied to 27 plots of winter wheat and forage sorghum over 24 months at the Agriculture Research Station located at Bushland, Texas, 12 miles west of Amarillo. Wheat was seeded at the rate of 67 kg/ha, while sorghum was planted in 6 rows, 75 cm apart at 11.25 kg/ha. Runoff was applied by flood irrigation onto level borders. Rates applied were as follows: 0 cm/cropping season (TRT 1, control), 25 cm (TRT 2) and 50 cm (TRT 3). Cropping rotations of sorghum-fallow (SF), wheat-fallow (WF) and sorghum-wheat (SW) (two crops/year) were used for each TRT. Plots were irrigated every two weeks after plant emergence until the appropriate amount of effluent was obtained. Above ground biomass samples were collected and allowed to air dry for three weeks, after which they were ground mixed and sent to the laboratory for analysis. Soil samples were collected before planting and after harvest and also analyzed at the laboratory. Effluent samples were collected three times during each irrigation, composited, and analyzed. TRT 3 SW had the greatest total yield (28, 564 kg/ha) followed by WF (19,153 kg/ha) and SF (14,337 kg/ha). Ending soil nutrient concentrations were more dependent on initial nutrient concentrations than on effluent application or cropping rotations. Ending soil N was 70% dependent on initial N, while ending soil P was 56% dependent on initial P.