生物炭对盐渍土理化性质和紫花苜蓿生长的影响

Effects and Evaluation of Biochar on Physical-Chemical Properties of Coastal Saline Soil and Alfalfa Growth

为揭示生物炭对滨海盐渍土理化性质和紫花苜蓿生长的影响规律,采用盆栽试验方法,研究了不同生物炭添加量(炭土质量分数0、0.5%、1%、2%、5%、10%)处理下黄河三角洲盐渍化土壤养分、结构、盐分以及紫花苜蓿产量、品质等变化特征,并采用灰色关联度法评价了生物炭的应用效果。结果表明,添加生物炭后,土壤有机质和全氮含量分别增加了16.27%~246.65%和6.38%~58.51%,全磷、有效磷和全钾含量变化相对较小;土壤容重显著降低,低量生物炭处理显著提高了盐渍化土壤大于0.25 mm团聚体的含量和团聚体稳定性;水溶性盐总量降低了38.90%~46.17%,其中Mg^2+、Cl^-和SO4^2-含量降幅较大;紫花苜蓿产量提高了8.19%~43.00%,品质无显著变化。整体而言,随着施炭量的增加,土壤肥力有所提高,团聚体稳定性降低,盐分含量和紫花苜蓿产量呈先降后增的趋势。施用生物炭改善了盐渍化土壤的理化性质,促进了紫花苜蓿生长,生物炭用量0.5%时施用效果最优。

In order to find out the effects of biochar on salt-affected soil physical-chemical properties and alfalfa growth in the Yellow River Delta,a pot experiment was conducted.Soil nutrients,soil structure,soil salinity,alfalfa yield and quality were analyzed under different biochar application levels(0,0.5%,1%,2%,5%and 10%).Based on grey correlation method,the biochar application effect was evaluated.The results showed that after biochar additions,soil organic matter and total nitrogen content were increased by 16.27%~246.65%and 6.38%~58.51%,respectively,but the changes of total phosphorus,available phosphorus and total potassium contents were relatively small.Meanwhile,soil bulk density was decreased significantly,while aggregates more than 0.25 mm and soil aggregates stability enhanced under lower biochar rate.Compared with CK,biochar addition treatment reduced soil water-soluble salt contents by 38.90%~46.17%,and the contents of Mg^2+,Cl^-,and SO4^2-had significant reductions.The alfalfa yield was increased by 8.19%~43.00%,however,there was no significant difference in quality.With the increase of biochar application,soil fertility appeared a increasing trend,while aggregate stability showed an opposite character.Soil salt content and alfalfa yield were decreased first and then increased.Overall,biochar application improved the salt-affected soil physicalchemical properties and alfalfa growth.And 0.5%biochar addition rate had the best application effect.