化肥减量配施生物炭和秸秆对砂姜黑土区水稻产量、养分吸收和土壤碳的影响

Effects of reducing chemical fertilizers combined with applying biochar and straw on yield of rice and nutrient absorption and carbon in soil in lime concretion black soil areas

为探讨砂姜黑土区养分资源高效管理和秸秆资源化利用方式,采用田间定位试验,连续2 a研究化肥减量配施生物炭和秸秆对该区域水稻产量、养分吸收和土壤碳的影响。试验设5个处理:①不施肥(CK);②常规施肥(100%NPK);③化肥减量20%(80%NPK);④化肥减量20%+秸秆(80%NPK+S);⑤化肥减量20%+生物炭(80%NPK+B),测定并分析水稻籽粒产量、地上部生物量、植株氮、磷、钾养分含量、土壤总有机碳(TOC)和微生物量碳(MBC)。结果显示,化肥减量20%配施生物炭或秸秆均有利于提高水稻产量和地上部生物量,且生物炭较秸秆的效果更为显著。化肥减量20%配施生物炭(80%NPK+B)处理的水稻产量和地上部生物量较100%NPK处理分别增加5.2%和4.7%,较80%NPK处理分别增加7.9%和7.2%;化肥减量20%配施秸秆(80%NPK+S)较100%NPK处理的水稻产量和地上部生物量分别增加3.4%和3.0%;80%NPK与100%NPK处理的籽粒和地上部生物量无显著差异;化肥减量20%配施生物炭显著提高了水稻地上部N、P_(2)O_(5)和K_(2)O养分累积量,较100%NPK处理分别提高了10.4%、7.2%和20.0%;化肥减量20%配施秸秆可显著提高氮、钾养分累积量,但却同时显著降低了磷素累积量;化肥减量20%配施生物炭或者秸秆,均有利于改善土壤总有机碳的累积,并且显著提高了土壤微生物量碳的含量,其中生物炭提高土壤总有机碳含量效果优于秸秆,而秸秆提高土壤微生物量碳含量效果优于生物炭。综合来看,在沿淮砂姜黑土区,化肥减量20%配施生物炭或者氮钾减量20%配施秸秆可增加或维持水稻产量,提高水稻对养分的吸收能力,利于固碳培肥。

The reduction of chemical fertilizer combined with applying biochar and straw is an effec⁃tive way of realizing the green and sustainable development of agriculture in China.A field plot experiment was conducted to study the efficient management of nutrient resources and the utilization of straw resources in the lime concretion black soil areas.The effects of reducing chemical fertilizers combined with returning straw to the field and biochar on the yield of rice,nutrient absorption and carbon in soil in the region were investigated for 2 consecutive years.5 treatments including no fertilizer(CK),conventional application of chemical fertilizer(100%NPK),20%reduction of chemical fertilizer(80%NPK),20%reduction of chemical fertilizer plus straw returning(80%NPK+S),20%reduction of chemical fertilizer plus biochar(80%NPK+B)were set up.The yield and biomass aboveground of rice,the content of N,P and K in plant,the content of total organic carbon(TOC)and microbial biomass carbon(MBC)in soil were mea⁃sured and analyzed.The results showed that 80%NPK+S or 80%NPK+B was beneficial for increasing the yield and biomass aboveground of rice,with the effect of 80%NPK+B more significant than that of 80%NPK+S.The average yield and biomass aboveground of rice treated with 80%NPK+B was 5.2%and 4.7%higher than that with 100%NPK,and by 7.9%and 7.2%higher than that with 80%NPK,re⁃spectively.The average yield and biomass aboveground of rice treated with 80%NPK+S was 3.4%and 3.0%higher than that with 100%NPK,respectively.There was no significant difference in the average yield and biomass aboveground of rice between the 80%NPK treatment and the 100%NPK treatment.The accumulation of N,P_(2)O_(5),and K_(2)O nutrients in the aboveground parts of rice treated with 80%NPK+B significantly increased,10.4%,7.2%,and 20.0%higher than that with 100%NPK.80%NPK+S treatment significantly increased the accumulation of nitrogen and potassium in rice,but significantly re⁃duced the accumulation of phosphorus in rice at the same time.80%NPK+B treatment or 80%NPK+S treatment was beneficial for improving the accumulation of total organic carbon in soil and significantly in⁃creasing the content of microbial biomass carbon in soil.Among them,the effect of biochar on increasing the content of total organic carbon in soil was better than that of straw,while the effect of straw on increas⁃ing the content of microbial biomass carbon in soil was better than that of biochar.Overall,80%NPK+B treatment or 80%NPK+S treatment can increase or maintain the yield of rice,improve nutrient absorp⁃tion capacity of rice,and facilitate the fixation of organic carbon in soil in the lime concretion black soil ar⁃eas along the Huai River.