秸秆生物炭配施沼液对土壤有机质和全氮含量的影响

为增加沼液中养分在土壤中的滞留量,提高沼液利用效率,本文采用室内土柱试验,研究了不同生物炭混掺量(CK、0.5%、1.0%、2.0%)、生物炭混掺厚度(0、5、10、15、20 cm)和土壤容重(1.30、1.35 g·m^-3)对土壤有机质和全氮含量的影响。结果表明:土壤容重相同时,土柱入渗液渗出速率随生物炭混掺量和混掺厚度的增加而增大;土壤容重不同时,1.35 g·cm^-3土壤土柱入渗液渗出速率小于1.30 g·cm^-3土壤,土壤有机质和全氮含量均呈1.30 g·cm^-3土壤容重小于1.35 g·cm^-3土壤容重;土柱内有机质和全氮含量随生物炭混掺量增大而逐渐增加,生物炭混掺量为2.0%时对土壤有机质和全氮含量影响最大;土柱内有机质含量随生物炭混掺厚度增大而逐渐增加,生物炭混掺厚度为20 cm时对土壤有机质含量影响最大,而全氮含量在土壤容重为1.30 g·cm^-3、混掺厚度10 cm时影响最显著,土壤容重为1.35 g·cm^-3、混掺厚度15 cm时效果较为显著。研究表明生物炭配施沼液时土壤有机质和全氮含量受生物炭混掺厚度、混掺量和土壤容重综合作用的影响。

Effect of biogas slurry combined with straw biochar on soil organic matter and total nitrogen content

To increase the retention of nutrients in soil and improve the utilization efficiency of biogas slurry, the effect of different biochar mixing amounts(BMAs), biochar mixing thicknesses(BMTs), and soil bulk densities(ρ)on soil organic matter(SOM)and total nitrogen(TN)content was studied in laboratory soil column experiments. The results showed that the infiltration rate of the soil column increased with increases in BMA and BMT when ρ remained constant. When ρ increased, the infiltration rate was lower in the soil column also increased;however, the SOM and TN content exhibited the opposite behavior. In contrast, the SOM and TN content in the soil column increased when BMA increased;the most remarkable impact was found for a BMA of 2.0%. Moreover, the SOM content rose with the increase in BMT;the biggest influence in these experiments for a BMT = 20 cm. The TN content with different BMTs was related to ρ;when ρ=1.30 and 1.35 g.cm^-3, the effect was most significant for BMT =10 and 15 cm, respectively. The results indicate that the effect of biochar on SOM and TN content is also dependent on the BMA, BMT, and ρ.