ABSTRACT

Seasonality in tropical forage production is common in tropical and subtropical regions and should be identified for decision making on the stocking rate for each period. This study aimed to evaluate the variability of dry matter production of Megathyrsus maximum cv. Mombaça ‘Guinea grass’ over two years. The experiment was carried out from February 2016 to August 2018, under a randomised block design in a 2 × 4 factorial scheme, with four replications. Treatments consisted of (i) two growing years (2016/2017 and 2017/2018) and (ii) four seasons (spring, summer, fall, and winter). The grass was fertilised with 1,000 kg N ha⁻¹ year⁻¹ and sprinkler irrigated, with soil moisture monitored by tensiometry. The evaluated parameters consisted of leaf dry matter, stem dry matter and total dry matter production. The results showed that the irrigated Guinea grass reached an elevated production of dry matter (DM), with the highest yields occurring in the spring/summer period, evidencing the yiel gap in the autumn/winter. The grass showed high daily forage accumulation, expressing high productive potential, demonstrating a good indicator for animal production in intensive systems with irrigated and fertilised pastures for regions of tropical climate. Thus, Guinea grass showed great potential for use in livestock.

摘要

热带草料生产中的季节性在热带和亚热带地区很普遍，应确定其每个时期的放养率决策。这项研究旨在评估Megathyrsus最大cv的干物质生产的变异性。蒙巴萨（Membaça）几内亚（Guinea）草两年。该实验于2016年2月至2018年8月进行，采用2×4析因方案的随机区组设计，重复四次。治疗包括（i）两个生长期（2016/2017和2017/2018）和（ii）四个季节（春季，夏季，秋季和冬季）。草被施以1,000 kg N ha - ¹年^-1和喷头灌溉，通过湿度法监测土壤湿度。评估的参数包括叶片干物质，茎干物质和总干物质产量。结果表明，灌溉的几内亚草的干物质（DM）产量提高，春/夏期间单产最高，表明秋/冬的产量高。这些草显示出高的每日牧草蓄积量，具有很高的生产潜力，这是热带气候地区集约化灌溉和施肥牧场的集约化系统中动物生产的良好指标。因此，几内亚草显示出了用于牲畜的巨大潜力。