湖南双季稻种植区不同生产力水稻土的物理性质

在湖南省东部、中部和西北部8个水稻主产县采集了24个不同生产力水稻土样品，测定了土壤物理性质和黏土矿物组成参数，包括土壤容重、土粒密度、孔隙度、田间持水量、水稳性团聚体、平均质量直径、标准化质量直径、团聚体破坏率、田间持水量、有机碳、有机胶结物质、无机胶结物质和黏土矿物等指标，以研究湖南省双季稻种植区不同生产力水稻土物理性质的差异.结果表明：高产水稻土（>14000 kg·hm^-2）的容重小于1.2 g·cm^-3，总孔隙度大于50%，通气孔隙度多数大于4%，0.5～5mm水稳性团聚体含量多数在20%以上.高产水稻土与中产水稻土(10000～13500 kg·hm^-2)之间的多数物理性质无显著差异，但与低产水稻土(<10000 kg·hm^-2)的差异显著，说明中产水稻土只要在良好的管理条件下可以转变为高产水稻土；而低产水稻土的物理性质较差，应重视这类水稻土的改良.

Physical properties of paddy soils with different productivity in double-rice cropping region of Hunan Province

A total of 24 paddy soil samples with different productivity were collected from eight main rice production counties in east, central, and northwest Hunan Province, with the parameters of soil physical properties and clay mineral composition, including bulk density, particle density, porosity, field water-holding capacity, water-stable aggregates, mean weight diameter, normalized mean weight diameter, aggregate destruction rate, organic carbon, organic cementing materials, inorganic cementing materials, and clay minerals determined. The results showed that highly productive (>14000 kg·hm^-2) paddy soil possessed bulkdensity below 1.2 g·cm³, soil particle density about 2.0 g·cm³, and 5-0.5 mm water-stable macroaggregates about 20%. Most of the test parameters had no significant differences between highly productive and medium productive (10000-13500 kg·hm^-2) paddy soils, but significant differences between highly productive and lowly productive (<10000 kg·hm^-2) paddy soils, suggesting that under good management, medium productive paddy soils could be upgraded to highly productive paddy soils. At present, the physical properties of lowly productive paddy soils were poor, which need to be improved to raise productivity.