Abstract:In order to find out the effects of biochar on saltaffected 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 0.25mm and soil aggregates stability enhanced under lower biochar rate. Compared with CK, biochar addition treatment reduced soil watersoluble salt contents by 38.90%~46.17%, and the contents of Mg2+, Cl-, and SO2-4 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 saltaffected soil physical-chemical properties and alfalfa growth. And 0.5% biochar addition rate had the best application effect.
