不同生物炭用量对滨海盐碱土理化性质和肥力的影响

Effects of Different Biochar Dosages on the Physicochemical Properties and Fertility of Coastal Saline Alkali Soil

为揭示不同生物炭用量对滨海盐碱土改良效果的影响,以土壤肥力和理化性质为主要指标,设计0、5、10、15和20 t/hm^(2) 5个不同生物炭用量处理(分别记为T_(0)、T_(1)、T_(2)、T_(3)、T_(4)),观测不同处理下土壤pH、速效养分、有机质、有机碳、剖面盐分、容重、田间持水量等指标的响应规律。结果表明,土壤pH、速效氮含量、速效钾含量、全氮含量均随着生物炭用量的增加先升高后降低,土壤速效磷、有机质和有机碳含量与生物炭用量呈明显的正相关关系,耕层土壤有机碳最大增幅达到1倍,速效磷和有机质含量增幅分别为16.3%和14.5%;生物炭用量的增加有利于降低0~40 cm土层盐分,试验结束时0~20和>20~40 cm土层全盐含量最高降幅分别达到14.5%和26.3%;随着生物炭用量的增加,土壤容重总体呈降低趋势,孔隙度总体呈升高趋势;与T_(0)相比,生物炭施用处理田间持水量增加1.8%~9.1%,其中T_(3)用量下田间持水量增幅最大;综合土壤肥力指标、理化指标和资源用量,推荐以15 t/hm^(2)作为盐碱土适宜生物炭用量。

In order to reveal the effect of different biochar dosages on the improvement of coastal saline alkali soil,five different biochar treatments(T_(0),T_(1),T_(2),T_(3),T_(4),respectively)were designed with soil fertility and physicochemical properties as the main indicators.The response law of soil pH,available nutrients,organic matter,organic carbon,profile salinity,bulk density and field water capacity under different treatments were observed.The results showed that soil pH,available nitrogen content,available potassium content and total nitrogen content all increased first and then decreased with the increase of biochar dosages.There was a significant positive correlation between soil available phosphorus,organic matter,and organic carbon content and the biochar dosage.The maximum increase in organic carbon in the topsoil was 1 times,and the increase in available phosphorus and organic matter content was 16.3%and 14.5%,respectively.The increase in the amount of biochar was beneficial for reducing the salt content in the 0-40 cm soil layer.At the end of the experiment,the maximum decrease in total salt content in the 0-20 cm and>20-40 cm soil layers was 14.5%and 26.3%,respectively.As the amount of biochar increases,the soil bulk density showed a decreasing trend,while the porosity showed an increasing trend.Compared with T_(0),the application of biochar increased field water capacity by 1.8%-9.1%,with the largest increase in field water capacity was found under T_(3) application.Based on soil fertility indicators,physicochemical indicators and resource usage,it is recommended to use the 15 t/hm^(2) amount as the appropriate amount of biochar for saline alkali soil.