秸秆直接还田与炭化还田对热带土壤-水稻系统氨挥发的影响

氨挥发是稻田氮损失的主要形式之一。本研究采用温室土柱试验方法,设置不施氮肥(0N)、秸秆还田 (ST)、生物炭(秸秆炭化)还田(BI)、常规施肥(CF)、秸秆还田配施氮肥(NST)、生物炭还田配施氮肥(NBI)6个处理,研究等量氮素投入条件下秸秆还田及其炭化还田对热带土壤-水稻系统氨挥发排放的影响。结果表明,与CF处理相比,NST处理在分蘖期显著(P<0.05)降低了田面水的pH值,提高了田面水的NH₄⁺-N含量;NBI处理显著(P<0.05)提高了水稻成熟期的土壤pH值和土壤NH₄⁺-N含量,降低了土壤NO₃^--N含量。总的来看,NBI处理在试验条件下对土壤氨挥发具有较好的抑制作用,氨累积挥发量较CF处理显著(P<0.05)降低28.9%。

Effects of straw and straw-derived biochar returning on ammonia volatilization in tropical soil-rice system

Ammonia volatilization is one of the main forms of nitrogen loss in paddy fields. In the present study, soil column experiment was adopted with 6 treatments, namely, no nitrogen fertilizer (0N), straw returning (ST), straw-derived biochar returning (BI), conventional fertilization (CF), straw returning with nitrogen fertilizer (NST), straw-derived biochar returning with nitrogen fertilizer (NBI), to evaluate the effects of straw and straw-derived biochar returning on ammonia volatilization in the tropical soil-rice system. The results showed that, compared with the CK treatment, NST treatment significantly (P<0.05) reduced the pH, yet increased the NH₄⁺-N content of surface water at the tillering stage. NBI treatment significantly (P<0.05) elevated the pH and NH₄⁺-N content of soil, yet decreased soil NO₃^--N content as compared with the CF treatment. Overall, NBI treatment could inhibit ammonia volatilization under the experiment conditions, as its cumulative ammonia volatilization was significantly (P<0.05) decreased by 28.9% than that of CF treatment.