根瘤菌与促生菌双接种对大豆生长和土壤酶活的影响

【目的】慢生大豆根瘤菌和胶质类芽孢杆菌单一菌株固氮或促生效果及机理已有较多研究,但两者双接种对作物的作用和增产机理尚未有所报道。本研究以慢生大豆根瘤菌5136与胶质类芽孢杆菌3016为研究对象,通过田间小区试验研究根瘤菌与促生菌不同施用模式对大豆生长和土壤酶活的影响,以期为开发新型高效复合菌剂提供理论依据。【方法】试验设对照(T1)、接种胶质类芽孢杆菌3016菌剂(T2)、接种慢生大豆根瘤菌5136菌剂(T3),胶质类芽孢杆菌3016和慢生大豆根瘤菌5136双接种(T4)和常规施肥(T5)5个处理,分别于大豆不同生育期调查大豆的农艺性状和结瘤状况,测定土壤酶活性,用BOX-PCR技术监测慢生大豆根瘤菌5136的占瘤率。【结果】1)在大豆成熟期,双接种(T4)处理的大豆单株分枝数、单株粒数、收获指数和产量均为最高,分别比T1高11.3%、9.7%、41.0%和9.3%,且单株空荚数最低,比T1降低了44.0%。2)在花荚期,双接种(T4)处理的占瘤率为25.4%,比T3处理高8.0%,且单株根瘤数和单株根瘤干重均为最高,分别比T1高41.6%和47.1%;说明双接种处理下,胶质类芽孢杆菌3016能够促进慢生大豆根瘤菌5136结瘤固氮。3)接种微生物菌剂均可不同程度地提高土壤酶活性,以双接种(T4)处理的效果最为显著,在大豆成熟期,土壤过氧化氢酶、脲酶和蔗糖酶活性均为最高,分别比对照高12.9%、8.9%和9.4%。4)相关性分析表明,土壤酶活性与大豆收获指数显著正相关或极显著正相关(P0.01或P0.05),其中过氧化氢酶与产量显著正相关;单株根瘤数和单株根瘤干重均与收获指数和蔗糖酶活性呈极显著正相关,与产量呈显著正相关。【结论】慢生大豆根瘤菌和胶质类芽孢杆菌双接种可以促进大豆生长,显著增加大豆的单株分枝数、单株粒数、收获指数和占瘤率,降低单株空荚数,增加大豆产量,同时可显著提高相关土壤酶活性,是一种节本增效的农艺措施。

Effect of Rhizobia and PGPR co-inoculant on soybean characteristics and soil enzyme activities

【Objective】 The effects and mechanism on single inoculant of Paenibacillus mucilaginosus and Bradyrhizobium japonicum have been widely characterized, but few on the that of co-inoculant of them. A field experiment was carried out to reveal the effects of rhizobia and PGPR on soil enzyme activities, soybean growth and nodulation. 【Methods】 Five differents with fertilization measures in this field experiment were designed by T1(CK), T2(inoculant of Paenibacillus mucilaginosus 3016), T3(inoculant of Bradyrhizobium japonicum 5136), T4(co-inoculant of P. mucilaginosus 3016 and B. japonicum 5136) and T5(the regular fertilizer dose). Soil enzyme activities, soybean growth characteristics at different stages of soybean and the nodule occupancy of B. japonicum 5136 were studied. BOX-PCR was used to analyze the nodule occupancy of B. japonicum 5136.【Results】 1) At maturation periods, soybean growth traits, branch number per plant, seeds per plant, harvest index and yield in the T4 treatment were the highest, and respectively increased by 11.3%, 9.7%, 41.0% and 9.3% relative to those in the T1 treatment. The empty pods per plant in T4 treatment was the lowest, and was 44.0% lower than that in the T1 treatment, indicating the prosperous effect of co-inoculant on improving soybean traits. 2) The nodule occupancy of B. japonicum 5136 in the T4 treatment was 25.4%, and 8.0% higher than T3 treatment. Nodules per plant, nodule dry matter per plant in the T4 treatment exhibited the highest values during the flowering and podding periods, and increased 41.6% and 47.1% relative to thosed in the T1 treatment, suggesting that P. mucilaginosus 3016 was helpful to nodulation of B. japonicum 5136. 3) P. mucilaginosus 3016 and B. japonicum 5136 could increase the activities of catalase, urease and invertase in soil. During maturation periods,the activity of these enzymes inT4 treatment was the highest, and were 12.9%, 8.9% and 9.4% higher thanT1 treatment, respectively. 4)The soil enzyme activities were significantly and positive correlated(P0.01) or positive correlated(P0.05) with harvest index, and catalase activity was positive correlated with yield. Nodules per plant and nodule dry matter per plant were significantly positive correlated with harvest index and invertase activity, respectively, and was positive correlated with yield. 【Conclusions】 Co-inoculant of P. mucilaginosus 3016 and B. japonicum 5136 could significantly increase soybean branch number per plant, seeds per plant, harvest index, the yield and nodule occupancy, and reduce the empty pods per plant, and increase enzyme activities, indicating that the co-inoculant of P. mucilaginosus 3016 and B. japonicum 5136 is an optimal application measure in soybean cropping system.