Abstract:

【Objective】 The effect of long-term combined application of chemical fertilizer with pig manure (PM) and rice straw (RS) on physical properties were investigated in a reddish paddy soil of double rice cropping system in southern China.【Method】 The physical properties in seven treatments composed of N, P and K fertilizer and combined application of chemical fertilizer with RS from a long-term experimental field established in 1981 were evaluated to study the effects of fertilization on soil properties of a reddish paddy soil (classified as typical stagnic Anthrosol) derived from parent materials of Quaternary red clay. 【Result】 Results showed that long-term combined application of pig manure (PM), rice straw (RS) with chemical fertilizer decreased significantly the soil bulk density and the soil particle density, and increased the porosity, and the improved effect of PM was similar to that of RS. Combined application of PM and RS with chemical fertilizer were in favor of forming 5-0.5 mm water stable aggregate (WSA) and increased soil aggregate stability compared with application of chemical fertilizer alone. Soil water holding capacity (WHC) in plow layer was higher in combined application of PM and RS treatments than in chemical fertilizer treatments. 【Conclusion】 Long-term combined application of PM and RS with chemical fertilizer decreased significantly the soil bulk density and soil particle density, increased porosity, soil aggregate stability and soil water holding capacity, which was an effective measure to improve soil physical quality and soil fertility in reddish paddy soil.

Key words: long-term fertilization, reddish paddy soil, soil physical property, nutient input