稻草易地还土对丘陵红壤有机质和主要物理性质的影响

选取新垦坡地和熟化旱地2种典型土地利用类型,研究了稻草易地还土对丘陵红壤有机质含量和主要物理性质的影响,并探讨了土壤有机质、田间持水量、容重、孔隙度间的相关性.结果表明稻草易地还土可提高丘陵红壤有机质含量,改良土壤物理性质,增强土壤蓄水性能.与不施肥或化肥处理相比,稻草易地还土提高了耕层(0～20 cm)土壤有机质含量5.8%～28.9%和＞0.25 mm水稳性大团聚体含量;降低了亚表层(10～15 cm)土壤容重,降低幅度为4.5%～7.5%,提高了亚表层土壤的田间持水量和孔隙度,提高幅度分别为6.8%～16.2%和4.8%～7.7%(P＜0.05).相关分析表明,土壤有机质含量(0～20 cm)与亚表层土壤容重(r=-0.799)、孔隙度(r=0.803)、田间持水量(r=0.844)呈极显著相关(P＜0.01);表层、亚表层土壤田间持水量与土壤容重(r=-0.638)、孔隙度(r=0.664)呈显著相关(P＜0.05).

Effects of ex situ rice straw incorporation on organic matter content and main physical properties of hilly red soil

Two typical land-use types,i.e.,newly cultivated slope land and mellow upland,were selected to investigate the effects of ex situ rice straw incorporation on the organic matter content,field water-holding capacity,bulk density,and porosity of hilly red soil,and to approach the correlations between these parameters.The results showed that ex situ incorporation of rice straw increased soil organic matter content,ameliorated soil physical properties,and improved soil water storage.Comparing with non-fertilization and applying chemical fertilizers,ex situ incorporation of rice straw increased the contents of organic matter(5.8%-28.9%)and >0.25 mm water-stable aggregates in 0-20 cm soil layer,and increased the field water-holding capacity(6.8%-16.2%)and porosity(4.8%-7.7%)significantly(P<0.05)while decreased the bulk density(4.5%-7.5%)in 10-15 cm soil layer.The organic matter content in 0-20 cm soil layer was significantly correlated to the bulk density,porosity,and field water-holding capacity in 10-15 cm soil layer(P<0.01),and the field water-holding capacity in 0-20 cm and 10-15 cm soil layers was significantly correlated to the bulk density and porosity in these two layers(P<0.05).