摘要
本文用大豆与玉米、谷子不同作物的田间对比法和室内培养液栽培法相结合,研究了大豆对耕层土壤物理性状的影响,主要从土壤物理角度探讨了大豆肥田的机制.结果表明,种植大豆当年,大豆与对照作物相比,只减轻了耕层土壤中氮的消耗,并未增加土壤含氮量;大豆生育期间,其根系的分泌物和脱落物以及死亡的根系被分解后所形成的物质可起到胶结剂的作用,改善了土壤颗粒的表面性质,在根系穿插、挤压作用的动力下,有助于水稳性团聚体的形成;耕层土壤孔隙的数量、大小、形态及其分布有较大的改善,协调了土壤三相比例,耕层土壤的导水、蓄水和通气状况增强,调节了土壤肥力,认为大豆对耕层土壤物理性状具有良好的改善作用.
The N_2-fixation by soybean nodule bacteria only reduced the nitrogen consumption of
the soil at the period of soybean growth,but it didn't increase the nitrogen content in the soil.
During the growing periods,both the exudate of the root and matter fallen off the root are
cementing agents improving the quantity of soil aggregates.With the improvement of the
quantity and combination of soil aggregates,the size,number,form and distribution of pore
spaces were changed and the proportion of solid,liquid and gaseous phases were coordinated
greatly,thus enhancing water conducting and holding capacities and aeration of the soil.It
can be seen that soybeans improve the physical properties of the tilth soil.
关键词
大豆
土壤
物理性状
结构性
孔隙性
physical properties of soil
structure
porosity
aggregate
equivalent pore space
