Poultry floor litter containing 4.2% total N, 0.2% mineral N, and 2.5% total P is used to supply N to a crop of bermudagrass hay. The N requirement for the desired level of production is 200 kg N/hectare. a) Assuming there will be negligible N mineralized form the soil organic matter, how much poultry litter should be applied the first year?

b) How much poultry litter should be applied the second year?

c) Will the quantity of P supplied by these litter application rates be less than, equal to, or greater than the P requirement of the crop?

8 4 Table 16.11 RELEASE OF MINERAL NITROGEN FROM VARIOUS ORGANIC MATERIALS APPLIED TO SOILS, AS PERCENT OF THE ORGANIC NITROGEN ORIGINALLY PRESENT For example, if 10 Mg of poultry floor litter initially contains 300 kg N in organic forms, 50% or 150 kg of N would be mineralized in year 1. Another 15% (0.15 x 300) or 45 kg of N would be released in the year 2. Organic nitrogen source Year 1 Year 2 Year 3 Year 4 Poultry floor litter 55 20 3 Dairy manure (fresh solid) 25 18 9 Swine manure lagoon liquid 45 12 6 2 Feedlot cattle manure 30 15 6 2 Composted feedlot manure 18 18 4 1 Lime-stabilized, aerobically digested sewage sludge 40 12 5 2 Anaerobically digested sewage sludge 20 8 4 1 Composted sewage sludge 10 5 3 2 Activated, unstabilized sewage sludge 45 15 4 2 Flowering stage legume cover crop foliage 80 15 5 2 *These values are approximate and may need to be increased for warm climates or sandy soils and decreased for cold or dry climates or heavy clay soils. Release rates estimated from many sources