Yuan Fang, Li Kai-Yu, Yang Hui, Deng Cheng-Jia, Liang Hong, Song Li-Hong
College of Agriculture, Guizhou University, Guiyang 550025, China.
Huan Jing Ke Xue. 2022 Sep 8;43(9):4655-4661. doi: 10.13227/j.hjkx.202112155.
Due to its special physical and chemical properties, biochar is widely used as a multi-beneficial amendment to improve soil quality. Soil nutrient content and enzyme activities are important chemical and biological factors indicating soil quality. Despite increased interest and studies, a knowledge gap remains regarding the ability of biochar to assess soil nutrient content and enzyme activities due to differences in biochar application amount and soil texture. In the present study, the effects of different amounts of biochar application (CK:0 t·hm, B5:5 t·hm, B10:10 t·hm, B20:20 t·hm, and B50:50 t·hm) on soil nutrient content and enzyme activities were studied based on a field experiment on typical yellow soil in Guizhou province, southwest China. Structural equation models (SEM) were used to quantitatively evaluate the direct or indirect effects of biochar application on soil nutrient content and enzyme activities. The results showed that soil pH, electrical conductivity (EC), soil organic carbon (SOC), alkaline hydrolysis nitrogen (AHN), available phosphorus (AP), and available potassium (AK) increased with the applied amount of biochar. With the increase in biochar application amount, the activities of soil catalase and urease showed first an increasing and then a decreasing trend, and the activities of soil sucrase and phosphatase showed an almost constant increasing trend (<0.05). The highest activities of soil catalase, urease, and phosphatase were recorded under treatment B10. A relatively high activity of soil sucrose was also observed under treatment B10. With the same amount of biochar application, soil pH and the content of soil AHN, AP, and AK in treatments after four months of biochar application were greater than those after 12 months. After 12 months of biochar application treatment, the contents of SOC and EC were greater than those at four months. Compared to those in treatments after four months of biochar application, activities of soil urease and phosphatase increased, activities of soil catalase decreased, and activities of soil sucrose did not obviously change after 12 months of biochar application. The results of SEM showed that biochar application directly decreased activities of soil catalase and indirectly promoted activities of soil sucrase and phosphatase by increasing soil pH, EC, AHN, AK, and AP. In conclusion, the amount and duration of biochar application significantly increased soil nutrient content, directly and indirectly affecting soil enzyme activities. Based on the results of the presents study, biochar application at 10 t·hm was recommended for acidic yellow soil.
由于其特殊的物理化学性质，生物炭作为一种具有多种益处的改良剂被广泛用于改善土壤质量。土壤养分含量和酶活性是指示土壤质量的重要化学和生物学因素。尽管人们对生物炭的兴趣和研究不断增加，但由于生物炭施用量和土壤质地的差异，在生物炭评估土壤养分含量和酶活性的能力方面仍存在知识空白。在本研究中，基于中国西南部贵州省典型黄壤的田间试验，研究了不同生物炭施用量（CK：0 t·hm，B5：5 t·hm，B10：10 t·hm，B20：20 t·hm，B50：50 t·hm）对土壤养分含量和酶活性的影响。采用结构方程模型（SEM）定量评估生物炭施用对土壤养分含量和酶活性的直接或间接影响。结果表明，土壤pH值、电导率（EC）、土壤有机碳（SOC）、碱解氮（AHN）、有效磷（AP）和速效钾（AK）随生物炭施用量的增加而增加。随着生物炭施用量的增加，土壤过氧化氢酶和脲酶活性呈先增加后降低的趋势，土壤蔗糖酶和磷酸酶活性呈几乎持续增加的趋势（<0.05）。在B10处理下，土壤过氧化氢酶、脲酶和磷酸酶的活性最高。在B10处理下也观察到土壤蔗糖酶活性相对较高。在相同生物炭施用量下，生物炭施用四个月后处理中的土壤pH值以及土壤AHN、AP和AK含量均高于12个月后。生物炭施用12个月后处理中的SOC和EC含量高于四个月时。与生物炭施用四个月后的处理相比，生物炭施用12个月后土壤脲酶和磷酸酶活性增加，土壤过氧化氢酶活性降低，土壤蔗糖酶活性无明显变化。SEM结果表明，生物炭施用直接降低了土壤过氧化氢酶活性，并通过提高土壤pH值、EC、AHN、AK和AP间接促进了土壤蔗糖酶和磷酸酶活性。总之，生物炭的施用量和持续时间显著增加了土壤养分含量，直接和间接影响土壤酶活性。基于本研究结果，建议在酸性黄壤上施用10 t·hm的生物炭。
