Phosphorus- and Nitrogen-Based Manure and Compost Applications: Corn Production and Soil Phosphorus

Manure or compost application based on N needs of corn (Lea mays L.) may result in soil accumulation of P, other ions, and salt because the manure or compost N/P ratio is usually smaller than the corn N/P uptake ratio. This study was conducted from 1992 to 1996 to evaluate effects of Pand N-based manure and compost application on corn yield, N and P uptake, soil P level, and weed biomass. Composted and noncomposted beef cattle (Bos taurus) feedlot manures were applied to supply N or P needs of corn for either a 1or 2-yr period. Phosphorus-based manure or compost treatments also received additional fertilizer N as needed. Fertilized and unfertilized checks were also included. Manure or compost application increased corn grain yield in all 4 yr as compared with the unfertilized check. Annual or biennial manure or compost application resulted in corn grain yields similar to those of the fertilizer treatment. Phosphorusbased manure or compost application resulted in similar grain yields to those for N-based treatments but had significantly less soil available P level after 4 yr of application. Biennial manure or compost application resulted in corn yield similar to that for annual application but increased available P in the soil. Estimated N availability was 40% for manure and 15% for compost in the first year and was 18% for manure and 8% for compost in the second year after application. Weed biomass was more influenced by nutrient availability than any weed seed introduced by manure or compost application. When application rate is based on correct N or P availability, manure and compost can produce corn grain yields that are equal to or greater than that for fertilizer application. Annual P-based manure or compost application is the most effective method of using these resources when soil P buildup is a concern. R CATTLE FEEDING is concentrated in the Central and Southern Great Plains. At any one time, there are at least 10 million head of beef cattle on feed in the United States (USDA, 1997) and each excretes =145 g of N in fresh manure daily (Overcash et al., 1983). Thus, =529300 Mg of N are excreted annually in this beef feedlot manure. Comparable values for P and K, based on 42.7 g P and 131.5 g K excreted per head per day (Overcash et al., 1983), would be 156000 Mg P and 480000 Mg K. At a rate of 100 kg N ha', recoverable beef feedlot manure contains enough N (assuming no loss) to fertilize almost 5.3 million ha of grain crops, or 9.6% of the corn and wheat (Triticum aestivum L.) acreage in the United States (Eghball and Power, 1994). Nitrogen, P, and K in cattle feedlot manure have a value of $461 million if purchased as fertilizer (Eghball and Power, 1994). Beef cattle feedlot manure also contains = 15% C that can be used to improve soil physical and chemical properties. Carbon in manure is likely to have far greater value than the nutrients it contains if applied to a low organic matter or eroded soil. Composting manure is a useful method of producing a stabilized product that can be stored or spread with little odor or fly breeding potential (Sweeten, 1988). The other advantages of composting include killing pathogens and weed seeds, and improving handling characteristics of manure by reducing its volume and Dep. of Agronomy and USDA-ARS, Univ. of Nebraska-Lincoln, Lincoln, NE 68583. Joint contribution of USDA-ARS and Univ. of Nebr. Agric. Res. Div., Lincoln, NE, as paper no. 12133. Received 22 Jan. 1998. *Corresponding author ([email protected]). Published in Soil Sci. Soc. Am. J. 63:895-901 (1999). Abbreviations: ANUE, apparent N use efficiency; CN, compost for corn N needs; CN2Y, compost for corn N needs for 2 yr; CP, compost for corn P needs; CP2Y, compost for corn P needs for 2 yr; MN, manure for corn N needs; MN2Y, manure for corn N needs for 2 yr; MP, manure for corn P needs; MP2Y, manure for corn P needs for 2yr. 896 SOIL SCI. SOC. AM. J., VOL. 63, JULY-AUGUST 1999 weight (Rynk et al., 1992). Composting also has some disadvantages, including nutrient and C loss during composting, the cost of land, equipment and labor required for composting, and odor associated with composting. Eghball et al. (1997) found 20 to 40% loss of total N and 46 to 62% loss of total C during composting of beef cattle feedlot manure, as well as significant losses of K and Na (>6.5% of total K and Na) in runoff from composting windrows during rainfall. Beef cattle feedlot manure or composted manure can be effectively used for crop production. In a study conducted in south-central Nebraska, application of beef feedlot manure and composted feedlot manure resulted in corn silage yield similar to yield from commercial fertilizer application (Ferguson and Nienaber, 1995). Schlegel (1992) found that composted manure plus fertilizer addition resulted in greater grain sorghum [Sorghum bicolor (L.) Moench] yield than either source applied alone. The apparent fertilizer N efficiency was 13% for composted manure and 36% for commercial fertilizer in their study. Other studies have shown significant increases in corn yield with application of dairy cattle manure (Mclntosh and Varney, 1972; Jokela, 1992; Zebarth et al., 1996). Poultry manure application to conventional and no-till corn resulted in significantly less soil NO3-N, NH4-N, and the amount of N leached to 0.6-m soil depth than N fertilizer application, but the residual N remaining in the soil was greater with poultry manure than with fertilizer (Sims, 1987). Manure application in excess of crop needs can cause a significant buildup of P, N, other ions, and salt in soils. Cattle feedlot manure application for 20 yr resulted in significant increases (from 9 to 1200 mg kg") in soil P level (Dormaar and Chang, 1995). Bray and Kurtz No. 1 P soil test values increased from 81 to 114 and 132 mg kg" with one-time N-based manure and compost applications, respectively (Eghball and Power, 1995). In another study, Bray and Kurtz No. 1 P soil test values increased linearly from 45 to 391 mg kg" with increasing manure applications rates from 0 to 361 Mg ha" (Vivekanandan and Fixen, 1990). The elevated soil P level is an environmental concern when this P is carried by runoff to streams and lakes and causes eutrophication (Sharpley et al., 1996). Phosphorus leaching into groundwater is another concern with manure or compost application when groundwater is near the surface. Eghball et al. (1996) found P movement to the 1.8-m soil depth following long-term manure application. Manure or compost application to provide for corn N requirements may greatly increase soil levels of P and other ions. This is because the N/P ratios of beef cattle feedlot manure and composted manure are significantly smaller than N/P uptake ratios of most crops. The N/P ratio was 2.6 for feedlot manure and 1.9 for composted manure (Eghball et al., 1997), while N/P grain uptake ratios of winter wheat, corn, and grain sorghum were 4.5, 5.9, and 4.5, respectively (Gilbertson et al., 1979). The objective of this study was to evaluate the effects of application frequency and Nand P-based rates of manure and compost application on corn grain yield, N and P uptake, soil P level, and weed biomass. MATERIALS AND METHODS An experiment was initiated in 1992 on a Sharpsburg silty clay loam soil (fine, smectitic, mesic Typic Argiudoll) under rainfed conditions at the University of Nebraska Agricultural Research Center near Mead, NE. The study area had a Bray and Kurtz No. 1 soil P test of 69 mg kg", which is considered very high in Nebraska (Hergert et al., 1995) and a pH of 6.2 in the top 15 cm. The experimental design was a randomized complete block with four replications. The ten treatments applied included annual or biennial manure or compost application based on N or P removal of corn (151 kg N ha" and 25.8 kg P ha" for an expected yield level of 9.4 Mg ha"; Gilbertson et al., 1979) and fertilized and unfertilized checks. Fertilizer application was made in the spring each year. If necessary, the P-based treatments (annual or biennial application) also received N fertilizer as ammonium nitrate (34-0-0, N-P-K) in the spring so that a total of 151 kg N ha" was available to the crop. To simplify the discussion, the manure and compost treatments are given the following designations: MN, manure application to provide for corn N needs; MP, manure for P needs; MN2Y, manure for N for 2 yr; MP2Y, manure for P for 2 yr; CN, compost for N needs; CP, compost for P needs; CN2Y, compost for N for 2 yr; CP2Y, compost for P for 2 yr. Beef cattle manure was collected from the feedlot pens in late spring each year and composted for ~4 mo using active composting with turning. Beef cattle feedlot manure (collected in the autumn) and composted feedlot manure were applied in the autumn of 1992 on the basis of the assumption that 40, 20, 10 and 5% of the N and P in manure or compost will become available to plants in the first, second, third, and fourth year after application, respectively (Gilbertson et al., 1979). The first year N-availability assumption from compost was found to be too high so availability assumptions were changed to 20, 20, 10, and 5% in the first, second, third and fourth year after compost applications in 1993,1994, and 1995. Similar N-availability assumptions as 1992 (40, 20,10, 5%) were used for manure in the other 3 yr. Phosphorus availability assumptions from manure and compost were changed to 60, 20, 10, and 10% in the first, second, third and fourth year after applications in 1993, 1994, and 1995. Based on the assumptions given above, biennial manure or compost applications were made to provide 151 kg N ha" for N-based and 25.8 kg P ha" for P-based rates in the second year after application. Residual N and P values from previous years were considered when manure and compost were applied. Manure or compost application was made in late autumn after corn harvest. Manure and compost were applied by hand to plots 12.2 m long and 4.6 m wide (six corn rows). Manure and compost characteristics are given in Table 1. The high ash contents of manure and compost reflect inclusion of soil when manure was collected from the feedlot surface. The amounts of manure and compost, and N and P applied for each treatment are given in Table 2. Manure and compost were applied and disked-in within 2 d after application. Corn (Pioneer 3394) was planted at a seeding rate of 47 000 seed ha" and a row spacing of 0.76 m. The planting dates were 21 May 1993, 10 May 1994, 24 May 1995, and 21 May 1996. Weed control was achieved by band application of herbicide in the corn rows at planting and by cultivation. Weed biomass was determined by collecting the weeds from within two 3739cm rings from each plot in 1994 and 1995. Two 900-cm squares were sampled from each plot in 1996. The weed samples were dried in a 70°C oven and weighed. Corn was harvested by hand in October (middle two rows, 6.1 m long) of each year and grain yield determined. The reported yields are adjusted EOHBALL & POWER: PHOSPHORUSAND NITROGEN-BASED MANURE AND COMPOST APPLICATIONS 897 Table 1. Characteristics of beef cattle feedlot manure and composted feedlot manure applied in 4 yr at Mead, NE.f_