氮磷肥对3种牧草的生长效应和氮磷吸收的影响

Herbage accumulation, and nitrogen and phosphorus absorption responses of three forage species following addition of nitrogen and phosphorus fertilizer

采用田间试验,单因素随机区组排列,以豆科牧草柱花草和禾本科牧草扭黄茅和孔颖草为试验材料,研究适量氮磷肥的施用对3种牧草旺盛期生长及土壤氮磷吸收的影响和效果。试验结果表明,与未施氮磷肥比较,氮磷的施用有利柱花草、扭黄茅和孔颖草旺盛期(7-9月)的生长,3种牧草物候期有所延迟,可以提高3种牧草旺盛期绝对生长量,显著增加了孔颖草总生物量和氮吸收量(P<0.05)。与未施氮肥对比,施氮(施纯氮120 kg·hm^(-2))有利柱花草和孔颖草对氮的吸收,显著提高柱花草含氮量和孔颖草氮的吸收量(P<0.05),促进柱花草和孔颖草的生长,提高柱花草和孔颖草地上部和地下部生物量,提高扭黄茅地上部的生长量和生物量。与未施磷肥对比,施磷(施纯磷75 kg·hm^(-2))显著提高孔颖草氮的吸收量(P<0.05)。本研究为3种牧草和其他牧草氮磷的施用提供理论依据,即:适量的氮磷施用有利3种牧草产量的提高。

Herbage drymatter accumulation, and nitrogen and phosphorus absorption responses of three forage species following addition of nitrogen as urea (N) or phosphorus as superphosphate (P) fertilizer were studied over 2 seasons (2015 and 2016), in a field experiment with a randomized block design. The leguminous forage, Stylosanthes guianensis cv. Seabrana, and the forage grasses black spear grass ( Heteropogon contortus ) and ‘kong ying’ grass ( Bothriochloa pertusa ) were compared with nil-fertilizer and N or P fertilizer treatments. In general, fertilizer application (especially N) delayed crop phenological development by 5-10 days. Averaged over the two growing seasons, addition of either N or P fertilizer increased forage yield by approximately 11%, but data were variable, and the yield, except B. pertusa responses to N and P were not statistically significant. Crop N and P yields (kg·ha^-1 ) of S. guianensis were almost double those of the two grasses tested, but only in the case of N addition to B. pertusa , was there a significant fertilizer-induced increase in forage N or P yield. Root mass of H. contortus was reduced by N or P fertilizer (P<0.05), especially by N addition. This study has provided a theoretical basis for planning the application of nitrogen and phosphorus in sub-tropical forage production. In this article, proper application of nitrogen and phosphorus is beneficial to increase the yield of the three herbages.