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17年定位试验研究的结果表明,在长期不同施肥模式下,红壤性水稻土耕作层、犁底层干筛团聚体均以>5mm粒径为主,且其含量在有机物还田处理中更低;湿筛团聚体(水稳定性团聚体)在耕作层以>5mm粒径含量最高,在犁底层以<0.25mm粒径含量最高。同一土壤层水稳定性团聚体中有机碳、全氮含量因粒径而异,在耕作层,二者均富集于>1mm粒径,且以5～2mm粒径中含量最高;在犁底层,以>5mm粒径有机碳、全氮含量最高,然后随粒径减小而逐渐下降。随粒径从大到小变化,不同施肥处理耕作层水稳定性团聚体中C/N比均表现出由小变大,然后逐渐减小的特征,在2～1mm粒径出现峰值;犁底层水稳定性团聚体中C/N比表现出逐渐下降的趋势。长期有机物还田,尤其与化肥配施,可显著提高耕作层有机碳与全氮含量,对犁底层也有一定的影响;只施用化肥,虽然也能提高耕作层有机碳、全氮含量,但效果不显著。
The result of 17-year experimental study shows that in the long-term different fertilization modes, the aggregates of dry-sieved aggregates in the paddy soil and paddy soil under the long-term paddy soil are mostly> 5mm in grain size and their content is lower in the treatment of organic matter; Wet sieve aggregates (water-stable aggregates) had the highest content of> 5mm in tillage and the highest in <0.25mm in plow bottom. In the same soil layer stability of water-stable aggregates of organic carbon, total nitrogen content varies with particle size, in the tillage layer, both are enriched in> 1mm particle size, and 5 ~ 2mm particle size in the highest content; ,> 5mm diameter organic carbon, the highest total nitrogen content, and then with the particle size decreases and gradually decreased. With the change of particle size from big to small, the C / N ratio of water stable aggregates of different fertilization treatments showed small to large, and then decreased gradually, the peak appeared in 2 ~ 1mm particle size; The C / N ratio of water-stable aggregates showed a gradual downward trend. Long-term return of organic matter, especially with chemical fertilizers, can significantly improve the organic carbon and total nitrogen content of plow layer, and also have some impact on plow bottom; only the application of chemical fertilizers, although organic carbon and total nitrogen content can be increased, but the effect Not obvious.