Utilizing swine effluent for sprinkler- irrigated corn production M.M. Al-Kaisi and R.M. Waskom ABSTRACT: The rapid expansion of large swine production facilities in northeast Colorado prompted a need to evaluate the impact of swine effluent applied on irrigated corn grown on sandy soil. The objectives of this study were I) to evaluate the use of swine effluent as a nutrient source for irrigated corn production, 2) to evaluate the response of irrigated corn grown on sandy soils to different application rates, and 3) to evaluate N movement through the soil profile under swine effluent and commercial-N fertilizer for irrigated conditions. The three year study started in 1995 on a 14.5 ha (36 ac) sprinkler-irrigated (center pivot) Valent sand field, (Mixed, mesic Ustic Torripsamments) planted to grain corn (ZEA MAYS L.). Both swine effluent and commercial-N fertilizer treatments were applied at four N rates labeled control, low, agronomic, Copyright © 2002 Soil and Water Conservation Society. All rights reserved. and high. All treatments were replicated three times in a randomized complete block (RCB) Journal of Soil and Water Conservation design. Approximately go% of the total nitrogen from the two-stage lagoon effluent was in ammoniacal form, and the total dry matter content of the effluent was only 0.1 - 0.2% by volume. Corn yields increased with the increase of both swine effluent and commercial-N fertilizer rates. In contrast to the swine effluent treatments, significant soil-N buildup was observed at the 1.5 - 3.0 m (5 - 10 ft) depths for the commercial-N fertilizer treatments. Higher total N and P plant removal for the swine effluent treatments resulted in little N accumulation below the root zone. As the swine effluent application rate increased, the plant N and P removal and recovery rate increased, even at rates of 50 kg N ha-' (45 Ib N ac-l) above the recommended agronomic rate. An increase in extractable P in the top 15 cm (6 in) of the soil was observed in the effluent-treated soils. The results indicate that managing swine effluent-N becomes very similar to managing commercial-N fertilizer under irrigated conditions. 57(2):111-120 Keywords: Corn yield, irrigation, N and P recovery, N and P removal, and swine effluent Animal wastes produced by confined crop fields is the most common way to utilize www.swcs.org swine feeding operations can be a vatu- these materials. Over-application of lagoon able source of nutrients for crop produc- effluent, combined with irrigation or precip- tion. However, when manure is used under itation in excess of crop evapotranspiration, has been implicated in NOJ-N leaching irrigated conditions, especially on sandy soils, an increased potential for nutrient runoff or below the root zone. Burns et al. (1985) leaching occurs. Recent expansion of con- found that soil-N accumulation increased centrated swine production facilities in east- with an increase in the swine effluent appli- ern Colorado has increased concerns about cation rate to bermudagrass, but that soil potential nitrate (NOJ-N) contamination of organic matter did not increase over a six year the Ogallala Aquifer, the sole source of water period. At effluent rates up to 1,340 kg N for drinking and irrigation in the area. ha-' (1,197 lb N ac-'), the crop recovered only Concentrated swine production facilities in the area commonly udze one- or two- stage lagoon systems where effluent must Mahdi M. Al-Kaisi is an assistant professor in the Agronomy Department at Iowa State University, be removed fiom the lagoon periodically to Ames, Iowa, and Reagan M. Waskom is a research prevent overflow. However, effluent fiom scientist in the Department of Soil and Crop second-stage lagoons is used for flush water. Sciences at Colorado State University, Fort Collins, Sprinkler application of swine effluent to Colorado. I MIA 2002 VOLUME 57 NUMBER 2 I 111 1 44% of the applied N. After 11 years, Burns et lines at the recommended rate of 112 kg N suggests a greater potential for environmental al. (1990) reported that low rates of effluent ha-' (100 lb N ac-'), was minimal as compared losses of nutrients in swine emuent. on bermudagrass [335 kg N ha-' (299 lb N to the check treatment. Nitrate-N loss and These studes indicate that swine emuent ac-')I did not pose a groundwater hazard, accumulation in the top 2 m (6.5 f?) of soil can be managed to minimize nutrient losses while medium and high rates [670 and 1,340 increased as the application rate increased if applied at rates that approximate crop kg N ha-' (598 and 1,197 lb N ac-')I resulted (Gast et al. 1978). Maximum N03-N accu- removal. However, if crop requirements are in elevated N levels at the 2 m (6.5 fi) depth mulation in the soil profile occurred at a exceeded, the potential that excess N accu- in the soil profile.They found that high rates depth of 1.0 m (3.3 fi) with little evidence of mulation will occur is significant, perhaps [1,340 kg N ha-' (1,197 lb N ac-')I caused movement below 2.3 m (7.5 fi). Gangbazo et resulting in groundwater contamination. unstable grass stands, and eventually produced al. (1995) compared the effect of chemical A three year study was conducted to eval- forage that had elevated N03-N concentra- fertilizer and hog manure on potential water uate the potential impacts of swine effluent tions. In addition, quantities of certain ele- contamination. Fall spreading of large application on irrigated sandy soils in eastern ments in the soil environment had increased amounts of hog manure on cornfields result- Colorado. The objectives of this study were to levels that had the potential to become soil ed in two to three times the NH4-N losses 1) to evaluate the use of swine effluent as a and water pollutants, especially N, P, K, C1, compared to the check treatment of chemical nutrient source for irrigated corn production, and Na (Burns et al. 1990). ferthzer at 180 kg N ha-' (160 lb N ac-'). It 2) to evaluate the response of irrigated corn Sweeten et al. (1994) found that N removal was concluded that applying hog manure in grown on sandy soils to different application by forage plants increased as the dairy effluent the fall resulted in greater N loss and water rates, and 3) to evaluate N movement though application rate increased. Lysimeter studies contamination, and that hog manure should the soil profile under swine effluent and com- on forage plots receiving effluent applications be applied during the growing season at rates mercial-N fertilizer for irrigated conditions. at two and four times the agronomic N rate that approximate crop requirements. Hegg et resulted in leachate concentrations in excess al. (1984) found that irrigating with swine Methods And Materials Copyright © 2002 Soil and Water Conservation Society. All rights reserved. of 10 mg L-' (10 ppm) N03-N (Evans et al. effluent at daily application rates of 2.5 and The study started in March of 1995 on a Journal of Soil and Water Conservation 1984). Based on this study, the authors pre- 5.0 cm (1 and 2 in) increased the accumula- swine production facility and grain farm in dicted that effluent rates of up to 1.25 times tion of P, K, Cayand Mg in soils. Newton et Yuma County, Colorado, and continued the agronomic N could be applied before al. (1994) observed an increase in NO3-N at through the 1997 growing season. The study leachate concentrations exceeded 10 mg L-' soil depths of 1.6 m (5.2 fi) under swine site was located on a 14.5 ha (36 ac) center- (10 ppm) for N03-N. In another study where effluent application rates of 450 and 900 kg N pivot irrigated circular field with aValent sand groundwater-monitoring wells were installed, ha-' (402 and 804 lb N ac-') on a bermuda- (Mixed, mesic Ustic Torripsamments) (Table no increase in groundwater N was observed grass-fescue field. 1). The field was located near a swine pro- over two years of swine effluent applications Sutton et al. (1982) broadcast-applied and duction facility with a 4,000-head annual at rates up to 874 kg N ha-' (780 lb N ac-') soil-injected swine effluent at rates up to 857 capacity. In 1995 and 1996, the facility was a on bermudagrass (Harvey et al. 1996). kg N ha-' (765 lb N ac-') on corn, and they However, the authors reported a sigmficant found that the application method had a 57(2):111-120 increase in N03-N concentration in tile- greater impact on yield and plant N content I ment site in Yuma Countv. CO. drainage water as the swine effluent rate than did the application rate. Leaching losses increased, implyng that groundwater would were more likely on fields where swine efflu- i Parameters Description be contaminated over time. ent was soil injected because volatilization Texture Sand Westerman et al. (1985) reported that on a losses were much less compared to broadcast Slope (%) 5 - 15 www.swcs.org grass crop system NO3-N movement to applications. King (1981) investigated N PH 6.6 - 7.8 groundwater at the medium and high appli- recovery from municipal sludge, swine Clay content (%) 3-10 cation rates [670 and 1,340 kg N ha-' (598 manure, and chemical ferthzer, and found Bulk density (Mg m-3) 1.6 - 1.7 and I,197 lb N ac-')I would be a greater con- that N recovery by grass was greatest from Organic Matter (g kg-l) 5 - 10 cern than the contaminated runoff caused by fertilizer, followed by municipal sludge.