Phosphorus- and nitrogen-based manure and compost applications: Corn production and soil phosphorus

Manure or compost application based on N needs of corn (Zea mays L.) mag re sult in soil accumulation of P, other ions, and salt because the manure or compost NIP ratio is usually smaller than the corn Nm uptake ratio. This st udy,vas conducted from 1992 to 1996 to evaluate effects of P- and N-based m anure and compost application on corn yield, N and P uptake, soil P level, and weed biomass. Composted and noncomposted beef rattle (Bos taurus) feedl ot 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 add itional fertilizer N as needed. Fertilized and unfertilized checks were als o 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 result ed in similar grain yields to those for N-based treatments but had signific antly less soil available P level after 4 Ivr of application. Biennial manu re or compost application resulted in corn yield similar to that for annual application but increased available P in the soil, Estimated N availabilit y was 40% for manure and 15% for compost in the first gear and was 18% for manure and 8% for compost in the second year after application. Weed biomas s was more influenced by nutrient availability than any weed seed introduce d by manure or compost application. When application rate is based on corre ct N or P availability, manure and compost can produce corn grain yields th at are equal to or greater than that for fertilizer application, Annual P-b ased manure or compost application Is the most effective method of using th ese resources when soil P buildup is a concern.