不同物候期刈割对羊草再生和根形态及产量的影响北大核心CSCD

刈割是羊草草地一种常见的利用方式,为探究不同物候期刈割对羊草再生和产量的影响程度,分别设置了对照组(CON)和刈割组。刈割组包括拔节期刈割(ES)、抽穗期刈割(HS)和开花期刈割(FS)。对照组不刈割,8月15日收获;刈割组起始刈割后,8月15日收获。结果表明,与对照相比,HS和FS刈割处理增加了(P<0.05)羊草干物质(DM)总产量而ES刈割处理则降低了(P<0.05)DM总产量。此外,所有处理均提高了(P<0.05)羊草的粗蛋白总产量。不同物候期刈割羊草的再生过程是不同的,ES处理羊草细根长、根表面积和体积最低。FS处理羊草再生后期净光合速率高于其余处理(P<0.05),导致其后期再生效率较高,但根中水溶性碳水化合物(WSC)含量最低(P<0.05)。HS和CON处理在羊草根形态和WSC含量上则无显著差异。尽管不同物候期刈割后羊草的再生过程不同,但其再生产量是接近的,特别是ES和HS处理,这是因为较长的再生周期被较低的再生效率所抵消,因此,总DM累积量主要由刈割前的DM来决定。综上所述,应在抽穗期进行刈割,能提高羊草产量并保持其持久性。

Effect of mowing in different phenological growth stages on shoot regrowth,root morphology and forage yield of Leymus chinensis

Mowing is a common practice in the utilization of Leymus chinensis grassland. In this field experiment a single mowing in late season on August 15 （control treatment， CON） was compared with treatments initially mown at various earlier growth stages， and again on August 15， to explore the effect of mowing at different phenological growth stages on the regrowth and yield of L. chinensis. Mowing treatments were： at elongation stage on May 15 （ES）， at heading stage on June 1 （HS） and at flowering stage on June 15 （FS）. It was found that the HS and FS treatments increased （P<0.05） the dry matter （DM） yield compared to CON， while the ES treatment decreased yield （P<0.05）. All mowing treatments had increased crude protein yield compared to CON. The regrowth processes of L. chinensis differed between the treatments mown at different phenological growth stages. The ES treatment had the lowest fine root length， root surface area， and root volume. The FS treatment had highest net photosynthetic rate of L. chinensis in the later stages of regrowth， but the water soluble carbohydrate （WSC） content in roots was lower （P<0.05） than other treatments. The root morphology and root WSC contents of the HS and CON treatments did not differ significantly. Although the regrowth processes of L. chinensis in various phenological growth stages of mowing were different， the regrowth yields were similar， especially those of ES and HS treatments. This was because that longer regrowth cycle was offset by lower regrowth efficiency. Therefore， the total DM accumulation was mainly determined by the pre-mowing DM yield. In conclusion， initial mowing at heading stage should be adopted to increase the production of L. chinensis and ensure its persistence in grassland in northeast China.