不同滴灌方式下生物炭对采煤沉陷区花生根系形态及土壤无机氮的影响

Effects of biochar on root morphological traits of peanut and soil inorganic nitrogen in coal mining subsid-ence area under different drip irrigation methods

采煤沉陷区复垦是采煤区难点问题之一。为探究采煤沉陷区不同滴灌方式和生物炭用量对花生增产的影响,于2021年和2022年开展田间试验,采用裂区试验设计,主区为灌溉方式,分别设置膜下滴灌(M)和浅埋滴灌(Q)两种方式,副区为生物炭施用量,分别设置0(B0)、10(B10)和20(B20)t·hm^(-2)三个水平,研究了不同灌水方式和生物炭施用量对花生根系生长、干物质及氮素积累量、产量及土壤无机氮含量的影响。结果表明:与浅埋滴灌相比,膜下滴灌显著提高了花生根长、根体积、根表面积、饱果期干物质积累量、百仁质量、百果质量及产量,但显著降低了土壤铵态氮和硝态氮含量;膜下滴灌处理下花生产量、百仁质量和百果质量较浅埋滴灌分别提高了14.9%、8.9%和6.3%。随着生物炭用量的增加,花生根长(苗期除外)、根体积(苗期和结荚期除外)、根表面积(苗期除外)、饱果期干物质积累量、百果质量、百仁质量及产量均呈先增后减的趋势,生物炭施用量为10 t·hm^(-2)时达到最大值,B10处理花生产量较B0处理提高了19.8%。土壤铵态氮含量随生物炭用量的增加逐渐降低(花针期除外),而硝态氮(花针期除外)和植株氮素积累量则随生物炭用量的增加逐渐增加;MB10处理下花生根长、根体积(结荚期除外)、根表面积(苗期除外)、饱果期干物质积累量、百果质量、百仁质量及产量均为最优,产量较QB0处理提高了38.8%。花生产量、百仁质量及百果质量与根长、根表面积呈显著正相关,百果质量与土壤铵态氮和硝态氮含量亦呈显著正相关。综上,膜下滴灌条件下,施用10 t·hm^(-2)生物炭处理促进花生根系生长,提高植株对土壤无机氮素的吸收,进而增加干物质积累并最终提高产量。研究结果可为采煤沉陷区土地复垦提供技术支撑和理论参考。

The reclamation of coal mining subsidence area is one of the challenges in coal mining area.We exam-ined the effects of different drip irrigation methods and biochar application rates on peanut yield in coal mining sub-sidence area.A split-plot design experiment was conducted with two irrigation methods(i.e.,film-mulched drip ir-rigation(M)and shallow buried drip irrigation(Q))as the primary plots,and three biochar application rates(0(B0),10(B10),and 20 t·hm^(-2)(B_(20)))as the subplots in 2021 and 2022.Root growth,dry matter,nitrogen ac-cumulation in dry matter,yield and yield components,and soil inorganic nitrogen content were measured.Com-pared with the shallow buried drip irrigation,the film-mulched drip irrigation significantly increased root length,root volume,root surface area,dry matter accumulation at pod filling stage,100-kernel mass,100-fruit mass,and pod yield,but decreased soil NH_(4)^(+)-N and NO_(3)^(-)-N contents.Pod yield,100-kernel mass,and 100-fruit mass under the film-mulched drip irrigation were 14.9%,8.9%,and 6.3%higher than those under the shallow buried drip irri-gation,respectively.Root length(except at the seedling stage),root volume(except at the seedling and pod set-ting stages),root surface area(except at the seedling stage),dry matter accumulation at the pod filling stage,100-fruit mass,100-kernel mass,and grain yield initially increased and then decreased with increasing biochar ap-plication rates.The peak values were observed under the B10 treatment,the pod yield under which was 19.8%high-er than under the B_(0) treatment.Soil NH4+-N content(except at the seedling stage)decreased while soil NO_(3)^(-)-N content(except the seedling stage)and plant N accumulation increased with increasing biochar application rates.Under MB10 treatment,root length,root volume(except at pod setting stage),root surface area(except at seed-ling stage),dry matter accumulation at pod filling stage,100-fruit mass,100-kernel mass and yield were all opti-mal,with the yield being 38.8%higher than that under QB0 treatment.Peanut yield,100-kernel mass,and 100-fruit mass had a significant and positive correlation with total root length and root surface area.The 100-fruit mass was significantly and positively correlated with soil NH_(4)^(+)-N and NO3--N contents.In conclusion,the application of 10 t·hm^(-2)biochar combined with film-mulched drip irrigation promoted root growth of peanut,improved plant in-organic nitrogen absorption,increased dry matter accumulation,and finally increased yield.Our findings would pro-vide technical support and theoretical reference for land reclamation in coal mining subsidence areas.