Abstract:

In recent years, biochar as a soil amendment shows widespread prospects in reducing the salinity of saline-alkaline soil, nutrient loss and improving soil properties. To better understand the potential effect of different types of biochar in saline soil improvement and their possible ameliorative patterns, two types of biochar from animal and plant were used to investigate the optimal dosage in the improvement of physical and chemical property for a coastal heavily saline-alkaline soil in Taizhou, Zhejiang Province. Bone biochar (AB) and bamboo biochar (PB) with different application rates (0, 2%, 5%, 8%, w/w) were set up to study and analyze the effects of AB and PB on the physicochemical properties and nutrient content of coastal saline-alkaline soil through indoor soil culture experiment, so as to screen the best treatment and provide basic scientific basis for the application of biochar in the improvement of coastal saline-alkaline soil. The results showed that both types of biochar demonstrated a certain improvement effect on saline-alkaline soil. (1) The contents of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), alkali-hydrolyzed nitrogen (AN) and available phosphorus (AP) in saline-alkaline soil increased by 43.9%-125%, 61.1%-238%, 632%-1973%, 49.3%-155% and 42.9%-89.2%, compared with the control (CK), with the increased application rates of AB in the range of 2%-8%. (2) The soil physicochemical properties were significantly improved with the increase of PB application. When 8% of PB was added, soil water content, porosity and cation exchange capacity (CEC) increased by 8.37%, 1.59% and 179%, soil bulk weight and salinity decreased by 6.03% and 22.7%, and soil SOM content significantly increased by 535% compared to CK. In conclusion, both kinds of biochar can improve the structure and water holding capacity of saline-alkaline soil, reduce the degree of saline-alkaline soil, and inhibit the loss of soil nutrients. Taken together, animal-derived biochar such as AB can be applied to improve the pore structure and nutrient content of saline soils, while plant-derived biochar such as PB has a stronger ability to enhance the physicochemical properties of saline-alkaline soils. Considering the economic cost and application dosage, 5% of bone biochar is an ideal choice for improving the nutrient content and effectiveness of coastal saline-alkaline soil, and 5% of bamboo biochar is ideal for improving the physical and chemical properties of saline-alkaline soil.

Key words: biochar, bamboo biochar, bone biochar, coastal saline-alkaline soils, soil properties

摘要：

近年来，生物炭作为土壤改良剂在降低盐碱土壤盐分、养分流失和改善土壤性质方面具有良好表现。为更好发挥生物炭在盐碱土壤改良方面的应用潜力，选用骨炭（AB）和竹炭（PB）为改良材料，以浙江省台州市重度滨海盐碱土为研究对象，设置4种不同施用量（0、2%、5%、8%，w/w），通过室内土培实验，研究并分析骨炭和竹炭这两种生物炭在不同施用量下对滨海盐碱土壤的理化性质和养分含量的影响效果及可能规律，以筛选最佳处理，为生物炭应用于滨海盐碱土壤改良提供基础科学依据。结果表明，两种生物炭对盐碱土均具有一定的改良效果，（1）随骨炭施用量增加，盐碱土的土壤有机质（SOM）、总氮（TN）、总磷（TP）、碱解氮（AN）和有效磷（AP）含量呈现上升的趋势，添加2%—8%的骨炭，较对照（CK）相比分别提高了43.9%－125%、61.1%－238%、632%－1973%、49.3%－155%和42.9%－89.2%；（2）随竹炭施用量增加，土壤理化性质得到明显改善，添加8%的竹炭时，土壤含水量、孔隙度和阳离子交换量（CEC）较对照（CK）提高了8.37%、1.59%和179%，土壤容重和含盐量降低了6.03%和22.7%，土壤SOM含量显著提升了535%。综上，两种生物炭均能起到改善盐碱土壤结构和提高土壤持水能力、降低土壤盐碱程度并抑制土壤养分流失的作用，其中，骨炭适用于提高盐碱土壤的孔隙结构和养分含量，而竹炭有更强的提升盐碱土壤的理化性质的能力。考虑到经济成本和施用效果，5%施用量的骨炭是进行滨海盐碱土养分含量及有效性的改良的理想选择，5%施用量的竹炭是改良盐碱土壤理化性质的理想选择。

关键词: 生物炭, 竹炭, 骨炭, 滨海盐碱土, 土壤性质