腐植酸水溶肥部分替代化学氮肥对土壤-水稻体系镉迁移富集的影响

为探明腐植酸水溶肥部分替代化学氮肥对调控镉(Cd)在土壤-水稻体系吸收转运效果，采用盆栽试验方法，设置不施氮肥(CK)、化学氮肥(CF)、替代20%化肥氮(HF1)、替代45%化肥氮(HF2)及替代70%化肥氮(HF3)5个处理，探究腐植酸水溶肥部分替代化学氮肥对Cd高污染酸性稻田土壤有效态Cd含量及水稻各部位Cd吸收、转运和积累的影响。结果表明:施氮和腐植酸水溶肥替代氮肥处理均不同程度降低土壤pH、增加土壤有效态Cd含量，土壤有效态Cd含量随腐植酸水溶肥替代比例增加而升高，但差异不显著；施氮和腐植酸水溶肥替代氮肥处理促进水稻植株各部位对Cd的吸收富集，显著影响器官间Cd的转运。与CF处理相比，HF2和HF3处理分别显著提高Cd转运系数TF叶片/茎秆90.00%和190.00%，分别提高叶片Cd富集系数100.00%和233.33%，分别降低转运系数TF糙米/穗轴35.06%和41.56%，抑制了Cd向稻米迁移分配；施氮能有效促进干物质形成，与CF处理相比，HF2处理显著提高糙米和地上部干物质重，分别达26.82%和23.03%，有利于稻米干物质重形成。本试验条件下，腐植酸水溶肥适宜替代氮肥45%～70%能提高水稻干物质重，有效降低Cd向稻米迁移富集。

Effects of humic acid liquid fertilizer partial substitution chemical nitrogen fertilizer on cadmium migration and accumulation in soil-rice system

The aimed to clarify the effect of equal nitrogen amount of humic acid liquid fertilizer replacing part of chemical nitrogen fertilizer on regulating the migration and accumulation of cadmium(Cd) in soil-rice system. A pot experiment was conducted and five treatments set up as:no nitrogen fertilizer(CK)，chemical nitrogen(CF)and different replacement ratios of chemical nitrogen(20%，45%，70% marked as HF1，HF2，HF3，respectively). The Cd-polluted paddy soil was used as potted soil and the effects of treatments on the soil available cadmium，cadmium absorption，transport and accumulation in different parts of rice plants were explored. The main results showed that both the nitrogen application and humic acid liquid fertilizer substitution treatments decreased soil pH and increased soil available Cd content in different degrees，and the soil available Cd content increased with the increase of humic acid liquid fertilizer substitution ratio，but the difference was not significant. The nitrogen application and humic acid liquid fertilizer substitution treatments promoted Cd absorption and enrichment in each part of rice plant，and significantly affected Cd transport between organs. Compared with CF treatment，HF2 and HF3 treatments significantly increased the TFleaf/stem of Cd by 90.00% and 190.00%，increased the Cd bioconcentration factor in leaf by 100.00% and 233.33%，reduced the TFbrown rice/rachis of Cd by 35.06% and 41.56%，respectively，and inhibited the Cd migration and distribution to rice. The nitrogen application effectively promoted the dry matter formation，compared with CF treatment，the appropriate substitution ratio(45%-70%)increased the dry matter weight，and HF2 treatment significantly increased the brown rice and aboveground dry matter weight by 26.82% and 23.03%，respectively，it was conducive to the rice yield formation. Under the experimental conditions，the suitable replacement range of humic acid liquid fertilizer(45%-70%)could increase the rice dry matter weight and effectively reduce Cd migration and enrichment to rice.