长期不同施肥对南方丘陵红壤旱地生产力和土壤结构的影响

Effect of Long-term Fertilization in Different Patterns on the Productivity and Soil Structure of Red Hilly Upland in Southern China

农田施肥管理能显著影响土壤结构及其团聚体形成。通过长期定位试验,明确了不同施肥措施对南方丘陵红壤旱地(双季玉米-冬闲)周年生产力和土壤结构的影响。结果表明,与无肥对照相比,化肥NPK配施和有机施肥(M和NPK+M)均能显著提高双季玉米的周年产量及产量的稳定性。与对照相比,单施N肥虽然能增加玉米产量,但不能提高作物生产的稳定性。对照和单施N肥处理周年玉米产量均随种植年限延长呈下降趋势,而有机肥处理均呈上升趋势,NPK处理则保持相对稳定。与对照相比,长期施用有机肥显著降低了耕层土壤容重,提高了土壤有机质含量,促进了土壤大团聚体(>2 000μm)的形成,降低了微团聚体(53～250μm)在土壤中的比重,但施用化肥无显著影响。此外,长期施用有机肥能显著提高红壤旱地土壤团聚体的平均重量直径和几何平均直径,而仅施化肥无显著影响。因此,长期施用有机肥可以改善南方丘陵红壤旱地的土壤结构,提高土壤有机质含量,从而增强红壤旱地作物生产的稳定性和可持续性。

Fertilization practice can significantly affect soil aggregation and structure in cropland.In the present study,the effect of long-term fertilization in different patherns on the year-round productivity and soil structure in red upland with double corn cropping was investigated.The results showed that compared with the unfertilized control,inorganic NPK fertilization and manure amendment（M and NPK＋M） significantly increased the year-round corn yield and its stability.Inorganic N fertilization significantly increased corn yield,but did not increase its stability.Corn yields showed significantly declining trends in the control and N treatments with increasing experimental duration,while increasing in the manure-applied plots with no significant trend in the NPK treatment.Compared with the control,long-term manure application significantly reduced soil bulk density in the plow layer,increased the content of soil organic matter,and promoted the formation of soil macroaggregates（2 000 μm） with a corresponding decline in the proportion of microaggregates（53~250 μm）,while no significant effects were found in the inorganic fertilization treatments.Furthermore,the values of mean weight diameter and geometric mean diameter were significantly higher in the manure-applied treatments compared with the control,but not in the inorganic fertilization treatments.Thus,long-term manure amendment improves soil structure and organic matter content in the red upland,thereby enhancing the stability and sustainability of crop production.