Study On Soil Moisture Changes Of The Agroforestry Models And Soybean Yield In Black Soil Zone

The soil moisture,soil moisture dynamics and soybean yield of the models of pure soybean, compound 7 and compound 3 years Larix olgensis-soybean and Populus simonii×P.nigra-soybean were studied in the Hongguang farm of Hailun.Results are as follows:①Bulk density of the models had a trend of deeper level with the soil.In compound 7-years model,the bulk density of Populus simonii×P.nigra-soybean was minimum,which was only 1.09g/cm~3.Bulk density of the compound 3-years model were lower than pure soybean's.With the extended of the compound age,Larix olgensis-soybean model could reduce the 0～10cm soil bulk density,Populus simonii×P.nigra-soybean model could reduce soil bulk density at all levels.②Whe total and capillary porosity of the compound 7-years Populus simonii×P.nigra-soybean model were significantly higher than that of the other models.The total and capillary porosity of the compound 3-years models had no significant difference.With the extended of the compound age,the model of Larix olgensis-soybean and Populus simonii×P.nigra-soybean could improve the level of top and all status of the soil pore.③The water holding capacity of the compound 7-years Populus simonii×P.nigra-soybean model was significantly higher than that of the other models,and it had no significant difference in the 3-years models.With the extended of the compound age,the water holding capacity of the the levels of the Larix olgensis-soybean top soil and the Populus simonii×P.nigra-soybean all soil were improved.④In the horizontal direction,the soil water content of the same age compound models and the pure soybean model had non-significant difference.With the extended of the compound age,the Larix olgensis-soybean model soil water content decreased,which was obvious in the distance of 150cm from tree.The Populus simonii×P.nigra-soybean model storaged much water because of its soil porosity had been improved.⑤In the vertical direction,the 0～10cm soil water content of the compound 7-years models was significantly lower than that of the pure soybean model.The compound 3-years models soil water content was generally lower than that of the pure boybean model.With the extended of the compound age,the 0～10cm soil water of the Larix olgensis-soybean model significantly decreased,and the all levels of the soil water content of the Populus simonii×P.nigra-soybean model were improved.⑥Agroforestry could change soil water content in the scale of time which changes were related with the soybean growing season.⑦The soybean height and diameter of the compound 7-years Populus simonii×P.nigra-soybean model were significantly lower than the other models,and the soybean height and diameter of the compound 3-years Larix olgensis-soybean model were significantly higher than the other models.With the extended of the compound age,the height and diameter showed the downward trend.⑧The compound 7-years Populus simonii×P.nigra-soybean model had the lowest 100-seed weight and the number of the podiforms and the beans per plant and the compound 7-years Larix olgensis-soybean model was second.There was an increasing trend of boybean yeild in the compound 3-years model of Larix olgensis-soybean.