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Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (11): 29-39.DOI: 10.11686/cyxb2020407

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Effects of biochar and straw on the C∶N∶P stoichiometry of soil, microbes, and extracellular enzymes in an aeolian sandy soil

Jiao SUN1(), Jin-xiu LIANG1, De-jie KONG2, Xin-nian GUO1, Yong-dong WEI3, Tao ZHOU1()   

  1. 1.Institute of Agricultural Resources and Environment,Academy of Agriculture and Forestry Sciences of Ningxia,Yinchuan 750002,China
    2.Agricultural Biotechnology Research Center of Ningxia Academy of Agricultural and Forestry Sciences,Yinchuan 750002,China
    3.Science and Technology Bureau of Yanchi County,Yanchi 751500,China
  • Received:2020-09-07 Revised:2020-12-17 Online:2021-10-19 Published:2021-10-19
  • Contact: Tao ZHOU

Abstract:

In this research straw or biochar were added to a sandy soil located at Helanshan East Road in Ningxia Province and the stoichiometric characteristics of soil, microorganisms and extracellular enzymes were analyzed to provide a scientific basis for farmland nutrient regulation and sustainable soil utilization. The experiment comprised seven treatments; a control, straw added at 3.5, 7.0, or 10.5 t·ha-1, or biochar added at 3.4, 6.8, or 10.2 t·ha-1. All plots received a standard base fertilizer dressing of 330 kg·ha-1 elemental N, 46 kg·ha-1 elemental P and 75 kg·ha-1 elemental K. Our results demonstrated that the content of soil C, P, available N (AN) and available P (AP) increased significantly with increase in the rate of straw or biochar added, and addition of biochar was superior to addition of straw on an equal carbon basis. However, returning straw and biochar to the field had no significant influence on soil N content. Soil C/N, C/P, N/P and AN/AP ranged from 10.1-10.9, 7.4-8.2, 0.70-0.75 and 2.7-3.4, respectively. Additionally, both soil N/P and AN/AP exhibited a significant positive correlation with the quantity of straw returned, but a significant negative correlation with the quantity of biochar returned. The contents of microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) after biochar addition were higher than those after straw treatment on an equal carbon basis, while the stoichiometric ratios for C∶N, C∶P and N∶P of soil microorganisms and extracellular enzymes were significantly higher after straw addition than those after biochar addition to the field. Finally, correlation analysis revealed that after addition of straw, soil AN was significantly positively correlated with β-glucosidase (BG), L-leucine aminopeptidase (LAP), β-acetylgucosaminidase (NAG), MBC, [BG+α-D-cellobiohydrolase (CBH)]∶β-acetylgucosaminidase (AKP), (NAG+LAP)∶AKP and MBN∶MBP, but negatively correlated with AKP. After addition of biochar to the field, soil AP was significantly positively correlated with BG, CBH, LAP, NAG, MBC, MBN, (BG+CBH)∶AKP, but negatively correlated with MNC∶MBN. Taken together, these findings highlight that addition of biochar to the field increased soil nutrient content and microbial biomass, whereas returning straw to the field was conducive to maintenance of soil nutrient balance.

Key words: biochar addition and straw addition, sandy soil, enzymatic stoichiometry, microbial stoichiometry, nutrient balance