有机肥绿肥配施对水稻土有机碳组分和水稻产量的影响

Effect of applying organic fertilizer and green manure on organic carbon fractions and rice yield in a paddy soil

该研究以两年稻田定位试验为基础,设置有机肥(OF)、有机肥+绿肥2000 kg·hm^-2(OF+GM1)、有机肥+绿肥3000 kg·hm^-2(OF+GM2)和有机肥+绿肥4000 kg·hm^-2(OF+GM3)4个处理,探讨不同处理对土壤有机碳组分和水稻产量的影响。结果表明,与OF处理相比,有机肥绿肥配施未提高土壤及团聚体有机碳含量,却显著提高水稻产量(OF<OF+GM1<OF+GM2和OF+GM3);把0.25~2 mm团聚体直接分成3个组分后发现,有机碳含量随各组分粒径增大而提高,与OF处理相比,绿肥还田能显著提高0.05~0.25和<0.05 mm两个组分有机碳含量,通过密度分组实验对比,发现这两个组分有机碳变化主要由游离轻组有机碳引起;相关分析表明,水稻产量与0.25~2 mm团聚体和0.05~0.25 mm组分有机碳含量显著正相关,由于0.25~2 mm团聚体有机碳在处理间无显著差异,绿肥还田可能主要通过0.05~0.25 mm组分有机碳含量变化间接影响水稻产量。综上所述,水稻生产中,提倡有机肥配施绿肥以提高水稻产量和进行土壤培肥,配施绿肥量可根据田间绿肥实际产草量选择3000~4000 kg·hm^-2较为适宜。

Based on the 2-year experiment,four fertilization treatments(organic fertilizer;organic fertilizer plus 2000 kg·hm^-2 green manure;organic fertilizer plus 3000 kg·hm^-2 green manure;organic fertilizer plus 4000 kg·hm^-2 green manure)were established to investigate their effects on soil organic carbon fractions and the rice yield.The results showed that compared with organic fertilizer alone(OF),no significant differences on soil and aggregate organic carbon concentrations were seen under the three treatments with green manure return,while the rice yield was significantly increased.With aggregates of 0.25~2 mm divided into three fractions,it was found that the organic carbon concentration increased with the increase of their particle size.Compared with OF,green manure return significantly increased organic carbon concentrations within the 0.05~0.25 and<0.05 mm fractions,which was probably caused by changes of the free light fraction,demonstrated through the density floating experiment.Correlation analysis showed that the rice yield was positively correlated with organic carbon concentrations within the 0.25~2 mm aggregates and within the 0.05~0.25 mm fraction.Green manure return could indirectly affect the rice yield by increasing organic carbon concentration within the 0.05~0.25 mm fraction.Therefore,during the clean production(organic production)of rice,it is recommended to combine organic fertilizer with green manure to improve the rice yield and soil fertility and the application rates of green manure could be from 3000~4000 kg·hm^-2 accordingly.