Effect of spacing and cutting on pigeon pea development under subtropical conditions

ABSTRACT Depending on the purpose of its cultivation, pigeon pea can be grown under different spacings and cuts, since it quickly resprouts. This study aimed to assess the pigeon pea growth, forage production and quality, considering two spacings and one cut. A field experiment using a completely randomized design, with three treatments [1.0 × 0.2 m spacing (between rows and plants, respectively), without cuts; 0.5 × 0.1 m, without cuts; and 0.5 × 0.1 m, with cut at 90 days after emergence (DAE)], was carried out. The spacings did not affect the plant height. The 0.5 × 0.1 m spacing showed an individual plant growth worse, but a forage yield (kg ha-1) higher than the 1.0 × 0.2 m treatment, from 120 to 180 DAE. The 0.5 × 0.1 m spacing was more advantageous than the 1.0 × 0.2 m, with the highest forage yield obtained by harvesting at 150 DAE. It is better to harvest the forage at 90 DAE and harvest it again at 180 DAE than maintaining a continuous plant growth and harvest it at 180 DAE. In each sampling date, there was no difference for stem and leaf crude protein and starch content as a function of the treatments. The forage harvested from 90 to 180 DAE showed similar crude protein and starch contents. So, for this period, the forage quality is not a limiting factor for establishing the harvest time.摘要：根据栽培用途差异，木豆（pigeon pea）可采用不同的种植行距与株距配置，并可进行多次刈割，因其具备快速再生萌发的特性。本研究旨在评估两种种植密度配置下的刈割处理对木豆生长状况、饲草产量与品质的影响，试验设置两种种植密度与一种刈割模式。试验采用完全随机设计（completely randomized design），共设置3组处理：① 行距×株距为1.0×0.2 m，不进行刈割；② 行距×株距为0.5×0.1 m，不进行刈割；③ 行距×株距为0.5×0.1 m，于出苗后90天（DAE，days after emergence）进行一次刈割。结果显示，不同种植密度配置对木豆株高无显著影响；在出苗后120至180天期间，0.5×0.1 m配置下的单株生长状况较差，但饲草产量（kg·ha⁻¹）显著高于1.0×0.2 m处理组。0.5×0.1 m配置整体优于1.0×0.2 m配置，其中于出苗后150天进行刈割可获得最高饲草产量。相较于持续放任植株生长至出苗后180天再进行单次刈割，于出苗后90天刈割后再于180天进行二次刈割的处理效果更优。各采样日期下，不同处理对木豆茎秆与叶片的粗蛋白及淀粉含量均无显著影响；在出苗后90至180天期间采收的饲草，其粗蛋白与淀粉含量无显著差异。因此，在该时段内，饲草品质并非确定刈割时期的限制因素。