Harvesting Winter Forages to Extract Manure Soil Nutrients

Abstract

Harvested hay captures soil manure nutrients, which, if not utilized, could cause pollution of surface water or aquifer. This study determined yields of hay and N, P, K, Mg, Mn, Ca, Fe, Zn, and Cu of three winter forages for five harvest systems. Dormant bermudagrass [Cynodon dactylon (L.) Pers.] sod fertilized with swine (Sus scrofa domesticus) effluent was fall seeded with ‘Kenland’ red clover (Trifolium pratense L.), ‘Bigbee’ berseem clover (T. alexandrinum L.), or ‘Marshall’ annual ryegrass (Lolium multiflorum Lam.). Forage was removed for three springs with single 1 June harvest or with one of four two‐harvest‐day systems: 1 April and 1 June, 15 April and 1 June, 1 May and 1 June, and 15 May and 1 June. Mean herbage yields were similar for the forages, but nutrient yields and best harvest date varied. Ryegrass yields across harvests were similar except for a reduced 1 May and 1 June harvest. 1 April and 1 June was usually the best harvest for the clovers while the single 1 June was the poorest. The use of two spring harvests for the legumes increased yields up to 130% of the single harvest. The legumes yielded up to 64% more N, 24% more P, and 40 and 72% more of the metals Zn and Cu than the ryegrass. The 1 April harvest of berseem clover removed >30 kg ha−1 yr−1 of soil P. Management of soil nutrients is critically affected by choice of winter forage and harvest system.