夏播复种光敏型高丹草的养分含量与产量

Nutrient contents and yields of photoperiod-sensitive sorghum-Sudangrass hybrids grown in summer after a winter wheat crop

为了探讨光敏型高丹草夏播复种的高效栽培方式,在陇东旱塬麦茬后用免耕露地(NN)、翻耕露地(TN)和翻耕覆膜(TP)3种穴播方式复种了海牛、BJM和大卡3个品种,测定分析了不同品种和穴播方式下刈割1茬(C_(11))和刈割2茬(第1茬C_(21)和第2茬C_(22))的草产量及其与养分含量和主要养分产量的关系。结果表明,各种养分含量,包括粗蛋白(CP)、可溶性糖(SS)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、总可消化养分(TDN)和相对饲喂价值(RFV)在不同刈割方式下随品种、穴播方式及互作,其差异性表现出复杂的变化。各营养物质的含量与其产量变化趋势多不一致,且不能得到结论一致的模式。生产中需根据主要营养需求,选择最有效的栽培模式。但主要养分粗蛋白(CP)和可消化营养物(TDN)的产量与干物质产量变化趋势基本一致,干物质的产量可以代表营养物质的产量。CP和TDN产量在C_(11)时明显高于C_(21)+C_(22),BJM整体高于其他两品种,TP产量高于其他两穴播方式;TDN产量在所有处理中以BJM在C_(11)、TP处理下最高,达10.97t/hm^2;CP产量在所有处理中以大卡C_(11)、TP处理下最高,达1.25t/hm^2;BJM在C_(11)、TP处理下CP产量为1.11t/hm^2,与大卡无显著性差异(P>0.05)。因此,综合考虑,在本试验条件下,在陇东旱塬地区麦茬后夏播复种高丹草以TP、C_(11)(早霜前1周刈割)和BJM品种相组合的青贮生产模式为最优。但若以2茬青饲利用(C_(21)+C_(22)),建议选择品种海牛和TP播种栽培模式。

The aim of this study was to investigate the nutrient contents and yields of three photoperiod-sensitive sorghum-Sudangrass hybrids cropped after winter wheat in the Longdong dryland area,Gansu Province.The three sorghum-Sudangrass hybrids were Monster,BJM,and Big kahuna（with a brown midrib）.The plants were grown with three dibbling modes：no tillage and no mulching（NN）,tillage and no mulching（TN）,and tillage with plastic mulch（TP）,and were mown once（one-cut,C_（11））or twice（two-cuts,C_（21）,C_（22））.The nutrient contents and yields were determined for the three varieties grown with different sowing patterns and mowing frequencies.The contents of various nutrients,including crude protein（CP）,soluble sugars（SS）,neutral detergent fiber（NDF）,acid detergent fiber（ADF）,total digestible nutrients（TDN）,and relative feeding value（RFV）showed complex variations among the three sowing methods,the two mowing methods,and their combinations.There were no consistent trends in the contents of most nutrients.In practice,the most effective cultivation method should be selected based on the need for particular nutrients.The contents of the main nutrients（CP and TDN）showed the same trends as dry matter yields in the same treatments.Therefore,high dry matter yield was associated with higher contents of the main nutrients.The yields of CP and TDN were significantly higher for the plants mown once than for those mown twice.The yield of BJM was higher than those of the other two varieties.The yields were higher in the TP sowing mode than in the other two sowing modes.The highest yields of TDN（10.97t/hm^2）and CP（1.25t/hm^2）were from Monster in the TP system mown once.The CP yield from BJM mown once with the TP sowing mode was 1.11t/hm^2（not significantly different from that of Big Kahuna,P0.05）.Therefore,under these experimental conditions,the best production pattern was the TP dibbling mode,mown once（1week before the early frost）,and BJM for use in silage.However,the best production pattern for green harvest was Monster and the TP dibbling mode with two mowings.