生物炭对不同水氮条件下小麦产量的影响

研究生物炭与氮肥互作在不同水分条件下对小麦关键生育期旗叶光合参数、产量与主要农艺性状的影响,探讨生物炭改良不同水肥条件土壤并提高其作物产量的效果与内在机理,可为农田有机物资源合理利用提供理论支撑。本研究采用盆栽试验,生物炭用量设置五个水平(0,1%,2%,4%和6%),氮肥设置N0,N1和N2(0,0.2 g·kg~(-1)和0.4 g·kg~(-1))三个水平,小麦拔节期控制土壤田间持水量的80%和50%模拟正常水分和干旱胁迫两种水分环境。于小麦拔节期和抽穗期测定旗叶光合参数和SPAD值,成熟后对小麦籽粒产量及主要农艺性状进行统计。结果显示:(1)与不施生物炭处理相比,1%和2%生物炭用量平均增产6.62%和11.01%,4%和6%生物炭用量平均减产6.88%和10.1%,同时会导致千粒重、穗粒数和株高的降低;(2)正常水分条件下,1%和2%生物炭用量与N1和N2之间存在协同增产作用,而4%和6%生物炭用量表现出负面效应;(3)干旱胁迫条件下,仅1%和2%生物炭用量与N1存在协同增产作用,生物炭处理削弱N2增产潜力;(4)N0水平下,生物炭处理均表现出促进小麦旗叶光合速率,增加产量的作用;(5)N1条件下,生物炭促进小麦旗叶光合速率且在干旱胁迫条件下效果更明显。总体上生物炭对小麦旗叶光合参数和产量的影响受生物炭用量、氮素水平和水分条件共同制约且存在复杂的交互作用,干旱会限制生物炭与氮肥的协同增产作用;在低肥力土壤上应用生物炭的增产效果较好,而在质地较细且肥力中等的土壤应用时推荐48 t·hm~(-2)(2%)生物炭用量。

Effects of biochar on wheat yield under different water and nitrogen conditions

Studying how biochar affects wheat yield under different fertilizers, soil water conditions and explore the inner mechanism to providing a scientific support for the efficient use of agriculture organic wastes. A three factors interaction (biochar, nitrogen and soil water) pot experiment was conducted. Biochar addition rates were 0, 1%, 2%, 4% and 6% (mass ratio), nitrogen fertilizer application rates were 0, 0.2 g·kg^-1 and 0.4 g·kg^-1(N0, N1 and N2), soil water content were 80% and 50% field water capacity (began with wheat jointing stage). Wheat flag leaf photosynthetic parameters and SPAD value were measured at jointing stage and heading stage, wheat grain yield and main agronomic traits were recorded at maturity. The results showed that: (1) With compared to no biochar treatments, 1% and 2% biochar application rates increased wheat yield by 6.62% and 11.01% (on average) respectively. 4% and 6% biochar application rate decreased wheat yield by 6.88% and 10.1% (on average) respectively, at the same time, it also decreased thousand kernel weight, kernels per spike and plant height; (2) Under the normal water conditions, there were synergistic effects in 1% or 2% biochar addition rates with N1 and N2 treatments, but 4% and 6% biochar addition rate treatments showed negative effects; (3) Under the condition of drought stress, there were synergistic effects in 1% or 2% biochar addition rates with N1 treatment only, N2 production improved potential were inhibited by all biochar process; (4) Under the N0 conditions, compared with no biochar treatment, biochar increased wheat flag leaf photosynthetic rate and final yield; (5) Under the N1 and drought stress condition, biochar improved wheat flag leaf photosynthetic rate more obvious than under N1 and normal water condition. Consequently, the effects of biochar on wheat flag leaf photosynthetic parameters and final yield affected by biochar addition rates, nitrogen level and soil water content, and there were complex interactions. The potential of crop productivity increased by biochar, fertilizers and their coordination was limited by drought stress. In terms of increasing wheat yield, adding biochar to barren soil was good, moreover, 48 t·hm^-2(2%) biochar addition rate was recommended to improve the quality of fine texture and medium fertility soils.