Nitrogen Fertilization on Triticale plus Italian Ryegrass Pasture under Continuous Stocking: Nitrogen Recovery and Forage Production Efficiency

[摘要] - The objective of this experiment was to evaluate the nitrogen fertilization efficiency using urea, on triticale plus Italian ryegrass pasture, submitted to continuous stocking. Four nitrogen levels were used: 0, 150, 300 and 450 kg of N/ha, divided in five applications. The herbage mass was 1404, 1437, 1619 and 1599 kg of DM/ha. The total herbage production was 6039, 6914, 7877 and 7662 kg of DM/ha and the nitrogen production was 191.6, 247.7, 303.2 and 307.2 kg of N/ha for the 0, 150, 300 and 450 kg of N/ha levels, respectively. The nitrogen fertilization efficiency was 5.83, 6.13 and 3.61 kg of DM produced/kg of nitrogen applied and the nitrogen recovery was 37.39, 37.21 and 25.69% for the levels of 150, 300 and 450 kg of N/ha, respectively. The nitrogen concentration in different depth of the soil profile (0-5, 5-10, 10-20 and 20-40 cm of depth) in two dates (07/20 and 09/20) was evaluated. An increase of the mineral nitrogen content, from the first to the second evaluation, mainly for the deepest layers and for the highest nitrogen levels was observed, indicating that lixiviation losses of nitrogen occured, reducing the nitrogen recovery and his efficiency.

[学科分类] 兽医学

[关键词] efficiency;grazing;lixiviation;nitrogen;recovery;urea     IntroduçãoA produtividade de uma pastagem de gramíneas depende de vários fatores;como condições climáticas e edáficas e manejo a que são submetidas;principalmente em relação ao nível de nitrogênio;por tratar-se do nutriente mais limitante ao crescimento das plantas (Chapin et al