氮肥减量配施生物炭对北疆灌区春小麦光合和干物质转运特性及产量的影响

为探讨氮肥减量配施生物炭对北疆灌区春小麦光合和干物质转运特性及产量的影响，通过田间试验，设置对照（不施氮，CK）、常规施氮（300 kg·hm^-2、N1）、单施生物炭（20 t·hm^-2、B）、常规施氮+生物炭（N1B）、减氮15%（255 kg·hm^-2、N2 ）、减氮15%+生物炭（N2B）、减氮30%（210 kg·hm^-2、N3）、减氮30%+生物炭（N3B）8个处理，对比分析了不同处理间春小麦光合作用、干物质积累和转运及产量的差异。结果表明，与常规施氮相比，减氮（N2、N3）对春小麦光合作用、干物质积累和转运均无显著影响，但产量及其构成要素和氮肥农学利用效率随着施氮量的减少而降低，配施生物炭后上述各指标均显著提升。综合表现以减氮15%配施生物炭处理（N2B）效果最优。该处理下旗叶SPAD值和净光合速率处于较高水平，成熟期单茎干重、籽粒占单茎重比例、花前同化物对籽粒产量的贡献率分别为5.01 g、51.31%和18.03%；籽粒产量为8 301.35 kg·hm^-2，较 CK及N1处理分别增产38.09%和18.11%；氮肥农学利用效率最高，为12.40 kg·kg^-1。在本试验条件下，氮肥减量15%配施20 t·hm^-2生物炭最有利于春小麦光合生产、干物质积累和转运及产量提升。

Effect of Reduced Nitrogen Fertilizer Combined with Biochar on Photosynthetic Characteristics,Dry Matter Accumulation and Distribution,and Yield of Spring Wheat in Irrigated Area of Northern Xinjiang

In order to explore the effects of chemical nitrogen fertilizer reduction combined with biochar on photosynthesis,dry matter accumulation and transportation,and yield of spring wheat in Northern Xinjiang irrigated area,so as to provide reference basis for nutrient management in wheat field in irrigation area,eight treatments were conducted:control(no nitrogen application,CK),conventional nitrogen application(300 kg·hm^-2,N1),biochar only(20 t·hm^-2,B),conventional nitrogen application + biochar(N1B),nitrogen reduction by 15%(255 kg·hm^-2,N2),nitrogen reduction by 15% + biochar(N2B),and nitrogen reduction by 30%(210 kg·hm^-2,N3). The effects of reduced nitrogen application combined with biochar on photosynthesis,dry matter accumulation and transport,and yield of spring wheat were studied.The results showed that compared with conventional nitrogen application,nitrogen reduction(N2,N3) had no significant effect on photosynthesis,matter accumulation and transport of spring wheat,while the yield,its components and agronomic utilization efficiency of nitrogen fertilizer decreased with the decrease of nitrogen application. However,the above indices increased significantly after combined application of biochar. The treatment of reducing nitrogen by 15% combined with biochar showed the best,in which,the SPAD value and net photosynthetic rate of flag leaf were higher. The dry weight of single stem at maturity,the proportion of grains to single stem weight,and the contribution rate of pre-flowering assimilates to grains were 5.01 g, 51.31% and 18.03%,respectively. The grain yield was 8 301.35 kg·hm^-2,which was about 38.09% and 18.11% higher than that of CK and conventional nitrogen application,respectively. The agronomic utilization rate of nitrogen fertilizer was the highest(12.40 kg·kg^-1). Thus,under this experimental conditions,the photosynthetic performance,dry matter accumulation and yield of spring wheat were better when nitrogen fertilizer was reduced by 15% and biochar was applied at 20 t·hm^-2.