Nitrogen Budgets on a Pasture under Combined Utilization of Grazing and Cutting

Nitrogen Budgets on a Pasture under Combined Utilization of Grazing and Cutting

Nitrogen budgets on a pasture being utilized for both grazing and cutting were investigated. A pasture containing tallfescue, orchard grass and white clover was divided into two areas: initially grazed (IA, 0.41ha) and grazed after cutting for hay (BA, 0.49ha). A herd of 4-5 cattle (heifers or steers of Japanese Black or Holstein) grazed at IA from 22 Apr. to 2 Jul. and grazed at both IA and BA from 3 Jul. to 21 Oct. 1999. The amount of N grazed from IA was 3 times higher than the sum of N of grazed herbage and harvested hay from BA. The amount of N inflow to soil as fertilizer or animal excreta seemed to relate to the difference in herbage production between IA and BA. The value of N surplus for the whole pasture was very similar to the value of the difference between inflow to soil and the sum of grazed herbage and harvested hay. N surplus in the pasture seemed to relate closely to soil N balance.