生物炭秸秆混施下氮肥后移对苏打盐碱土壤养分和水稻生长的影响

Effects of Biochar Straw Combined with Nitrogen Fertilizer on Nutrients in Soda Saline-alkali Soil and Rice Growth

摘要:

为探究生物炭-秸秆混施与氮肥后移协同调控对苏打盐碱土壤养分含量、水稻生长的影响，于2024-2025年开展2年水稻田间试验。试验采用裂区设计，设置4种还田方式：对照组（CK，无秸秆还田）、9 t/hm2秸秆单独施用（F）、1 t/hm2生物炭+6 t/hm2秸秆（M1）和2 t/hm2生物炭+3 t/hm2秸秆（M2）。并设置2种施氮处理：基肥∶分蘖肥∶穗肥4∶4∶2(N1，氮肥后移)、基肥∶分蘖肥4∶6（N2，常规施肥）。研究结果表明：与F处理相比，生物炭与秸秆混施提高了土壤养分含量与水稻光合特性，且M1处理优于M2处理。其中，M1处理返青期土壤铵态氮含量较F处理增加5.43%。氮肥后移进一步提高了拔节孕穗期土壤氮素含量，并显著增强水稻光合性能，M1N1处理叶绿素含量、气孔导度和净光合速率较M1N2处理分别显著增加8.83％、9.79％和10.42％。此外，M1N1处理同步优化了水稻籽粒氮含量、氮肥利用效率及产量，2年最高产量达到7 614.05 kg/hm2。基于熵权TOPSIS模型的综合评价结果表明，M1N1处理相对贴近度最高，评价等级为"优"。综上，采用生物炭与秸秆1∶6混施耦合氮肥后移，是协同改良苏打盐碱土壤、提升水稻光合能力、实现高产与氮肥利用的有效模式。

Abstract:

Aiming to investigate the effects of biochar-straw co-application and nitrogen fertilizer on the synergistic regulation of nutrient content in sodic saline-alkali soil and rice growth, a two-year field experiment on rice was conducted from 2024 to 2025. The experiment used a split-plot design with four straw returning treatments: control (CK, no straw returning); straw alone at 9 t/hm2 (F); biochar 1 t/hm2 + straw 6 t/hm2 (M1) and biochar 2 t/hm2+ straw 3 t/hm2 (M2). The base fertilizer was set: tillering fertilizer as panicle fertilizer 4∶4∶2 (N1, nitrogen applied later), and base fertilizer as tillering fertilizer 4∶6 (N2, conventional fertilization), totally two types of nitrogen treatments. The research results indicated that: compared with treatment F, the combined application of biochar and straw increased soil nutrient content during the early growth stage and improved the photosynthetic characteristics of rice, with treatment M1 performing better than M2. Specifically, soil ammonium nitrogen in the regreening period under M1 was increased by 5.43% compared with that of treatment F. The deferred application of nitrogen fertilizer further enhanced soil nitrogen content during the jointing and panicle initiation stages and significantly improved rice photosynthetic performance. SPAD, stomatal conductance, and net photosynthetic rate under treatment M1N1 were significantly higher than those under M1N2 by 8.83%, 9.79% and 10.42%, respectively. In addition, M1N1 simultaneously optimized rice grain nitrogen content, nitrogen use efficiency, and yield, with the highest two-year yield reaching 7,614.05 kg/hm2. A comprehensive evaluation based on the entropy-weighted TOPSIS model indicated that the M1N1 treatment had the highest relative closeness, with an evaluation grade of 'excellent'. In summary, the combined application of biochar and straw at 1∶6 ratio along with nitrogen fertilizer was an effective model for synergistically ameliorating sodic saline-alkali soil, enhancing rice photosynthetic capacity, and achieving high yield and nitrogen utilization.