Manure or compost application based on N needs of corn (Zea 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 P‐ and 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 1‐ or 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. Phosphorus‐based 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.

posting has some disadvantages that include nutrient and C loss during composting, the cost of land, equip-Manure or compost application based on N needs of corn (Zea ment, and labor required for composting, and odor assomays L.) may result in soil accumulation of P, N, and other ions, ciated with composting. since the manure or compost N/P ratio is usually smaller than the corn N/P uptake ratio. This study was conducted from 1992 to 1996Manure application in excess of crop requirements to evaluate the effects of annual or biennial application of N-and can cause a significant buildup of P, N, and salt in soil. P-based composted and noncomposted beef cattle (Bos taurus ) feed-After 18 yr of manure application, surface soil cation lot manure on soil properties. Fertilized and unfertilized checks were exchange capacity, total organic C, and total N increased also included. Soil surface (0-15 cm) pH significantly increased with with increasing rate of manure application (Gao and N-based manure (MN) or compost application (CN), but decreased . Schlegel (1992) found that soil P, K, and with NH 4 -N fertilizer application as compared with the check. Soil organic matter increased with increasing rate of combulk density was unaffected by manure or compost application. After posted beef cattle feedlot manure applied from 1987 4 yr of manure and compost applications, soil surface (0-15 cm) Cto 1990, while increasing rates of synthetic N fertilizer and N concentrations and quantities were greater for N-than P-based application decreased soil P and K, but had no effect management systems. About 25% of applied manure C and 36% of applied compost C remained in the soil after 4 yr of application, on soil organic matter content. In this study, soil nitrate indicating greater C sequestration with composted than noncomposted levels were unaffected by compost application but inmanure. No significant difference was observed between fertilizer and creased with chemical fertilizer application. In another check plots for soil total C or N. Soil properties in the 15-to 30study, eleven annual applications of cattle feedlot macm increment were unaffected by the applied treatments except soil nure increased soil organic matter, total N, NO 3 , total electrical conductivity (EC). Residual soil NO 3 to a depth of 1.2 m was P, available P, soluble Na, CaϩMg, Cl, SO 4 , HCO 3 , greater for inorganic fertilizer than manure and compost treatments in and Zn (Chang et al., 1991). About 1 Mg ha Ϫ1 NO 3 -N drier years. Soil property changes were greater for the annual or accumulated at the recommended application rate of biennial N-based than P-based manure or compost applications, re-30 Mg ha Ϫ1 yr Ϫ1 after 11 yr of application. Davis et al. flecting the differences in application amounts.(1997) showed that residual soil NO 3 -N after heavy manure application was greater in heavy-textured soils than sandy soils. Chang and Janzen (1996) found that

Quantification of nutrient and mass loss during composting is needed to understand the composting process, to implement methods for nutrient conservation, and to reduce potential adverse environmental impact. Beef cattle feedlot manure was composted in a windrow on an open concrete area in 1992, 1993, and 1994 to determine the amounts of nutrient, C, and mass loss during composting. The area was enclosed on all sides with a 0.2 m high metal sheet to direct runoff to a fiberglass tank (4000 L) during rainfall. Nutrients in runoff represented combined runoff and leaching losses. Nutrients, C, and mass loss during composting was determined by the difference between the amounts at the beginning and at the end of the composting. Nitrogen loss during composting ranged from 19 to 42% and was related to the initial manure N content. Ammonia volatilization (calculated by difference) accounted for >92% of the N loss whereas combined runoff nitrate and ammonium loss was <0.5%. Mass loss was relatively low (15–20%) while loss ranged from 46 to 62% and was basically all through bio‐oxidation. Phosphorus runoff loss, the main mechanism for P loss, was low (<2%). Manure N/P ratio decreased during composting, indicating a greater soil P buildup potential with compost application. Potassium and Na losses in runoff were high (>6.5% each) 1992 and 1993; they were low (<2% each) in 1994 due to fewer rainfall. Calcium and Mg losses were <6% each year. Nutrient and salt loss during composting resulted in reduced electrical conductivity of the composted manure. Ammonium and P concentrations in runoff would create surface water pollution if runoff was not diluted with fresh water.

To apply manure or compost to fulfill N requirements of a crop, the amount of N mineralized in actual field conditions needs to be determined. Nitrogen mineralization from composted and noncomposted beef cattle feedlot manure applied to no‐till and conventional tillage systems was determined under field conditions for 3 yr. Manure, composted manure, and inorganic fertilizer were applied to provide for N needs of corn. A no‐treatment check was also included. An in situ resin method was used to determine N mineralization from a soil receiving manure, compost, and no treatment during the growing season (June–October). Of the organic N applied the previous autumn, ≈11% was mineralized from composted manure and 21% from noncomposted manure during the succeeding growing season. Lower N availability from compost reflects the loss of easily convertible N compounds during composting and the presence of stable N compounds. Nitrogen mineralization was similar in the no‐till and conventional tillage systems even though manure and compost were surface‐applied in the no‐till. Nitrogen mineralization was significantly, but not closely , related to thermal unit (cumulative mean daily temperature >0°C). Mineralization rate constants indicated that availability of residual manure and compost N was less than expected. The in situ mineralization approach seems to be a good method of measuring N mineralization during the growing season or during periods when the soil is not frozen or excessively dry. Nitrogen mineralization needs to be considered when manure and compost are used for an environmentally acceptable crop production system.

Manure or compost from beef cattie feediots can be an excellent sources of nutrients and organic matter when added to soils, but they can also pollute runoff. We determined the effects of simulated rainfall on runoff losses of P and N, and EC and pH following application of manure and compost to a Sharpsburg silty clay loam (fine smectitic, mesic Typic Argiudoll) soil having grain sorghum [Sorghum bicolor (L.) Moench] and winter wheat (Triticum aestivum L.) residues. Manure, compost, and fertilizer were applied to no‐till fields at rates required to meet N or P requirements for corn (Zea mays L.) production and were either left on the soil surface or disked to 8 cm. There were also untreated checks. Runoff concentrations of dissolved P (DP), bioavailable P (BAP), and NH4‐N were significantly greater when the soil was not disked. Total and particulate P concentrations in runoff were generally less under wheat than sorghum residue and were less for the no‐till than the disked condition. In the disked system, N or P‐based manure or compost application resulted in DP concentration <1 mg L−1. Manure and compost application resulted in greater runoff EC values than fertilizer application. Phosphorus concentration of runoff receiving P fertilizer or N‐based manure and compost application can be an environmental concern when these sources are applied under no‐till conditions without incorporation.