施氮量和收获时间对羊草种子产量的影响

Effects of nitrogen application rate and harvest time on Leymus chinensis seed yield

羊草(Leymus chinensis)种植过程中常见发芽率低、分蘖低,甚至颗粒无收的现象,增施氮肥能在一定程度上改善这种情况,收获时间是影响种子产量的关键因素。为此,研究施氮量[不施氮、150、300 kg·(hm^(2)·a)^(-1)]和收获时间(盛花期后25、30、35、40、45 d)对羊草种子产量的影响,以明确新疆地区羊草的施氮量和最佳收获时间。结果表明:1)施氮量和收获时间对羊草种子发芽率、产量及其构成因素产生显著影响。盛花期后35 d收获与40、45 d收获相比,羊草种子发芽率、产量及产量构成因素没有显著差异。盛花期后25 d收获,150 kg·(hm^(2)·a)^(-1)处理的种子发芽率比不施氮和300 kg·(hm^(2)·a)^(-1)处理分别增加了31.25%和12.51%。2)施氮量显著提高了羊草各部位的全氮含量,收获时间对羊草各部位全氮含量并没有显著影响,羊草各部位全磷含量随着施氮量的增加呈现先增加后降低的趋势。研究结果显示,在新疆羊草种子生产时,适宜的施氮量是150 kg·(hm^(2)·a)^(-1),最佳收获时间为盛花期后35 d。

Low germination,low tillering,and even seed failure occurring during sheepgrass(Leymus chinensis)cultivation can be at least partially remedied by applying additional nitrogen fertilizer;further,sheepgrass harvest timing for maximum seed yield warrants further research.Hence,this study was conducted to investigate the effects of nitrogen application rate[0,150,300 kg·(hm^(2)·a)^(-1)]and harvesting time(25,30,35,40 and 45 days after blooming)on sheepgrass seed yield,in order to determine the optimal nitrogen application rate and harvesting time for sheepgrass in Xinjiang.Our results showed that:1)Nitrogen application rate and harvesting time significantly affected seed germination rate,yield,and yield components.There were no significant changes in seed germination rate,yield,or yield components when harvest was performed at 35 days after blooming,compared with harvest at 40 or 45 days after blooming.In the first sampling,seed germination rate in the 150 kg·(hm^(2)·a)^(-1)treatment increased by 31.25%and 12.50%compared with the 0 and 300 kg·(hm^(2)·a)^(-1)treatments,respectively.2)Nitrogen application rate significantly increased the total nitrogen content of each part of sheepgrass,but the harvest time had no significant effect on the total nitrogen content of each part of sheepgrass,and the total phosphorus content of each part of sheepgrass showed a trend of first increasing and then decreasing with the increase of nitrogen application rate.We recommend 150 kg·(hm^(2)·a)^(-1)and 35 days after blooming as the appropriate nitrogen application rate and optimum harvesting time,respectively,for the production of sheepgrass seed in Xinjiang.