蚯蚓及植物促生根际细菌对土壤中氮和钾有效性的影响

采用室内试验的方法研究不同接种方式接种威廉环毛蚓(Pheretima guillelmi)、植物促生根际细菌(钾活化细菌(Bacillus mucilaginous PDSK-1)和固氮细菌(Azotobacter chroococcum PDSN-5))对土壤中固氮细菌和钾活化细菌的生长、土壤脲酶的活性以及土壤钾有效性的影响.7种接种方式均明显增加了土壤中固氮细菌和钾活化细菌的生长.蚯蚓活动对土壤中固氮细菌生长的影响有限,但明显增加了钾活化细菌的生长.接种蚯蚓、接种固氮细菌、接种蚯蚓和固氮细菌均明显增加了土壤中脲酶的活性.土壤中脲酶活性和速效钾的浓度分别与土壤中固氮细菌与钾活化细菌的数量成显著正相关关系(P＜0.05).试验结果表明,混合接种方式是一种有潜力的生物技术,可以用来减少农业生产中化肥的施用量.

Effects of Earthworms and Plant Growth Promoting Rhizobacteria on Availability of N and K in Soil

A pot trial was conducted to investigate the single,dual or triple inoculation of earthworms or plant growth-promoting rhizobacteria(PGPR),including nitrogen-fixing bacteria(NFB)(Azotobacter chroococcum PDSN-5) and potassium-solubilizing bacteria(KSB)(Bacillus mucilaginous PDSK-1),on the growth of NFB and KSB and N and K availability in soils.All of the seven inoculation treatments apparently increased the growth of NFB and KSB.The activity of earthworm had limited influence on the growth of NFB,but significantly increased the growth of KSB.Three inoculation treatments including single inoculation of earthworm,single inoculation of NFB and dual inoculation of earthworm and NFB increased the activity of urease in soils obviously.There was a significant correlation between urease activity and total numbers of NFB and between concentration of NH4OAc-extractable K(r=0.47,P<0.05) and total number of KSB(r=0.44,P<0.05) in soil.The present study suggested that the mixture inoculation may be a promising approach for reducing the need for chemical fertilizers in agriculture.