紫云英与化肥配施对水稻生长及磷素利用的影响

Effects of Chinese Milk Vetch Combined with Chemical Fertilizer on Rice Growth and Phosphorus Utilization

紫云英还田替代部分化肥是豫南稻区节肥增效的主要技术措施。为探讨等量紫云英还田条件下,不同化肥减量配施对土壤磷素供应和水稻磷素吸收的影响,依托豫南稻区紫云英与化肥配施的田间定位试验(始于2008年),共设6个处理[不施肥(CK)、单施化肥(F100)、等量紫云英还田(22.50 t/hm^(2))与不同用量化肥配施(100%化肥,MVF100;80%化肥,MVF80;60%化肥,MVF60;40%化肥,MVF40)],通过分析2021年的数据,研究紫云英与化肥配施对土壤有效磷含量、植株磷含量及积累量、叶面积指数和成熟期干物质积累的影响。结果表明,MVF100、MVF80处理成熟期总干物质积累量较F100处理分别显著提高了8.52%、7.14%;MVF100处理成熟期秸秆干物质积累量较F100处理显著提高了12.84%;MVF80处理成熟期穗干物质积累量较F100处理增加了11.05%,但紫云英与化肥配施处理成熟期穗干物质积累量和F100处理之间差异不显著。紫云英与化肥配施处理孕穗期叶面积指数均低于F100处理,而MVF100、MVF60处理成熟期叶面积指数高于F100处理。各施肥处理土壤有效磷含量、植株磷含量和积累量均显著高于CK,整体上与F100处理无显著差异。其中,孕穗期土壤有效磷含量、植株磷含量和积累量均以MVF100处理最高,成熟期均以MVF60处理最高。综合考虑,豫南稻区紫云英还田22.50 t/hm^(2)可替代20%~40%的化肥,替代效果和单施化肥无显著差异。随后,通过显著相关的二次曲线关系发现,适量的土壤有效磷含量和叶面积指数可提高成熟期穗干物质积累量,而要达到最高的成熟期穗干物质积累量所需的最佳成熟期土壤有效磷含量为7.56 mg/kg,叶面积指数为7.02,以MVF60处理接近最佳值。综上,我国南方稻田紫云英还田22.50 t/hm^(2)与60%化肥配施效果较好。

Chinese milk vetch(MV)returned to the field to replace some chemical fertilizers is a main technical measure for saving fertilizer and increasing efficiency in paddy fields in southern Henan rice-growing area. A field experiment was conducted in southern Henan rice-growing area,to explore the effect of different fertilizer reduction ratio on soil phosphorus supply and rice phosphorus uptake under the condition of equal amount of MV returned to the field. The location experiment of MV combined with chemical fertilizer(started in 2008)included six treatments:No fertilization(CK),single application of chemical fertilizer(F100),equal amount of MV returned to the field(22. 50 t/ha)combined with different amount of chemical fertilizer(100% chemical fertilizer,MVF100;80% chemical fertilizer,MVF80;60%chemical fertilizer,MVF60;40% chemical fertilizer,MVF40). The effects of MV returned to the field combined with chemical fertilizer on soil available phosphorus content,shoot phosphorus content and accumulation,leaf area index and dry matter accumulation at maturity were preliminarily studied in the year of 2021. The results showed that MVF100 and MVF80 treatments significantly increased the total dry matter accumulation by 8. 52% and 7. 14% respectively,compared with the F100 treatment at maturity. The dry matter accumulation of straw under MVF100 at maturity was 12. 84% higher than that in the F100treatment. Compared with F100,MVF80 treatment increased the dry matter accumulation of panicle by11. 05% at the mature stage,but no significant difference was observed. The leaf area index at the booting stage under MV returned to the field combined with chemical fertilizer was lower than that in the F100treatment,while the leaf area index at maturity in MVF100 and MVF60 treatments was higher than that in the F100 treatment. The soil available phosphorus,shoot phosphorus content and accumulation of all fertilization treatments were significantly higher than CK,but there was no significant difference among all fertilization treatments on the whole. The highest soil available phosphorus content,shoot phosphorus content and accumulation were showed in the MVF100 treatment at the booting stage and in MVF60treatment at maturity. By comprehensive consideration,it is appropriate that MV is returned to the field(22. 50 t/ha)to replace 20%—40% chemical fertilizer,and the effect is not significantly different between MV returned to the field combined with chemical fertilizer treatments and the F100 treatment in southern Henan rice-growing area. Based on the significantly correlated quadratic curve relationship,appropriate amount of soil available phosphorus content and leaf area index could improve the dry matter accumulation of panicles at maturity. To achieve the maximum dry matter accumulation of panicles,the optimal soil available phosphorus content at maturity was 7. 56 mg/kg,and the leaf area index was 7. 02. The MVF60treatment was close to the optimal value in this study. In conclusion,it is suggested that MV returned to the field(22. 50 t/ha)combined with 60% chemical fertilizer is more suitable in this area.