Potential Production of Four Tropical Pasture Grass Species of Nitrogen Fertilizer after Defoliztions

Abstract

Nitrogen fertilizer as urea (46-0-0) at rate of 78.12 kg/ha was applied to a newly established sward of Panicum maximum, P. maximum cv. Hamil, Pennisetum prupureum and Brachiaria ruziziensis grown in Bangkok clayey soil, prior to commencement and after defoliations 94 week interval0. the experiment was rum form 28 September 1990 to 18 January 1991, with 4 harvests. the maximum cumulative dry matter production was 9,630 kg/ha from P. maximum cv. Hmil, followed by P. purpureum (9,243), P. mazximum (8,695) and B. riziziensis (7,462) ; with of leaf : stem : inflorescence ratios of 1 : 0.62 : 0.2, 1 : 0.46 : 0, 1 : 0.45 : 0.06 and 1 :0.69 : 0, respectively. The maximum crude protien content 9.77% for P. purpureum and 9.79% for B. ruziziensis. The average protein production per harvest was 185.13 kg/ha for P. purpureum, 176.10 for P. maximum cv. Hamil, 148.85 for P. maximum and 108.99 kg/ha for b. reziziensis. Dead tillers were recorded in the first week after harvest, with rapid growth fo newly emerged tillers in the second and third weeks. There was a diverse relationship between plant height and plant tiller within each species and among harvests.