秸秆促腐还田对土壤养分和小麦产量的影响

Effects of Returning Rice Straw into Field on Soil Nutrients and Wheat Yields Under Promoting Decay Condition

利用布置在沿淮地区的两处田间试验,通过设计单施化肥(F)、单施化肥基础上加施秸秆(SF)、单施化肥基础上加施秸秆和腐秆剂(SFD)、单施化肥基础上减施20%磷钾肥(按P2O5和K2O计)后加施秸秆和腐秆剂(SF4/5D)和不施肥对照(CK)5个处理,研究秸秆促腐还田对沿淮中低产田土壤养分和小麦产量的影响。结果表明:不同处理小麦产量规律在水稻土上为SFD>SF>F>SF4/5D>CK,其中SFD较F有显著差异(P<0.05),在砂姜黑土上为SF>F>SFD>SF4/5D>CK,其中SF与F相比有显著差异(P<0.05);不同处理土壤全氮和碱解氮含量在水稻土上以SFD处理最高,在砂姜黑土上以SF处理最高,处理间无显著差异;不同处理土壤有机质、速效磷、速效钾和缓效钾含量在水稻土上以SFD最高,与F相比差异达到显著水平(P<0.05),在砂姜黑土上以SF最高,处理间无显著差异;两种土壤上处理SF4/5D与处理F相比,小麦产量和土壤养分元素含量均无显著差异(P<0.05)。从而得出以下结论:在腐秆剂品种选择恰当的条件下,秸秆与化肥配施并添加腐秆剂的秸秆促腐还田方式可以有效提高土壤肥力和作物当季产量,即使在单施化肥基础上减施20%磷钾肥(按P2O5和K2O计),也不会影响该处理的培肥和增产效果。

To study the effects of different nitrogen levels on N absorption and utilization of flue-cured tobacco under high base inorganic N （70% applied as basal）, a field experiment was conducted at Nanxiong in 2009. The results showed that： （1） Combination of cake fertilizer and pig manure （N = 64.5 kg/bm2; nitrogen of cake fertilizer, 42%） exhibited the strong ability of nitrogen supplying in tobacco growth period. From it, nitrate content in tobacco rbizosphere was 550 mg/kg above during 30 to 75 days alter transplanting. （2） Use film mulching in the root extending stage and supplying with the same organic fertilizers, soil nitrate content at the early stage was promoted evidently under the treatment of low inorganic N （48 kg/hm2） when some of NO3-N （15.98 kg/hm2） applied as base, and nitrate content of rhizosphcre amount to 1300 mg/kg above during 30 to 50 days after transplanting, meanwhile nitrogen uptake by tobacco was not affected significantly from it. （3） Based on the same organic fertilizers, nitrate of rhizospher~ was enhanced significantly by the increase of inorgaJlic N bctbr~ 75 days after tobacco transplanting. However, because the increase of nitrate loss from rhizosphere after removing film in the root extending stage, there was no significant influence on nitrate accumulation in rhizosphcre from inorganic N after 75 days of transplanting. （4） In this study, both tobacco nitrogen use efficiency and nitrogen agronomic efficiancy decreased drastically followed with the increase of inorganic N from 48 kg/hm2 to 168 kg/hm2. Under firm mulching in the root extending stage, suitably reducing inorganic N combined with high base inorganic N （70% applied as basal） could enhance the effect of N application significantly.