腐熟牛粪对紫花苜蓿根瘤的促生效应

Effect of decomposed cow manure on growth of alfalfa root nodules

摘要:

【目的】 揭示提高紫花苜蓿共生结瘤率和固氮效率的机制。【方法】 通过腐熟牛粪不同量添加处理对紫花苜蓿促生能力进行研究，以甘农9号为试验材料，以添加腐熟牛粪（不同添加量）为处理，进行生产性能和结瘤指标的测定，129 g牛粪/盆表现出最佳促生效果。进一步将腐熟牛粪浸提处理，将获得的粪渣、浸提液与全牛粪添加进行紫花苜蓿室内盆栽控制试验，通过生产性能和结瘤指标比较各处理促生效果。【结果】 粪渣对紫花苜蓿根瘤的促生效应最强（根瘤数（P＜0.05）、有效根瘤数 （P＜0.05）、根瘤重（P＜0.05）、最大根瘤重（P＜0.05）、侵染数（P＜0.05）、侵染区长度（P＜0.05））。 典范对应分析（CCA）表明，全牛粪、粪渣所含养分对结瘤指标具正向的解释作用；特别在粪渣处理中， C/N与最大根瘤重呈极显著正相关（P＜0.01），与总根瘤数、总根瘤重呈显著正相关（P＜0.05）；速效P 含量与包括根系侵染数的结瘤指标均呈显著正相关（P＜0.05）；不同处理的养分对紫花苜蓿结瘤指标的总解释量达到95.6%。【结论】 C/N和速效P含量是调控紫花苜蓿根瘤发育及促生能力的关键因素。

Abstract:

【Objective】 The growth-promoting ability of alfalfa was studied by adding different amount of decomposed cow dung，in order to reveal the mechanism of increasing symbiotic nodulation rate and nitrogen fixation efficiency of alfalfa.【Method】 Gannong No. 9 of alfalfa was used as experimental material and treated by adding decomposed cow dung （different amount）. The biological indexes and the related indexes of root nodules were determined and compared. It was found that 129 g cow dung/basin （2. 75 t/mu） was the best amount of manure for promoting growth.【Result】 According to the experiment，the best amount of rotten cow dung was extracted and separated to obtain dung residue and extract，and pot experiment was carried out with the control and the best amount of rotten cow dung respectively，the differences of root nodule index and growth-promoting ability among the treatments showed that，the feces had the strongest growth-promoting ability to alfalfa nodules （P＜0. 05），effective nodule number （P＜ 0. 05），nodule weight （P＜0. 05），maximum nodule weight （P＜0. 05） ，infection number （P＜0. 05） ，infection zone length （P＜0. 05））. Canonical correspondence analysis （CCA） showed that 95. 6% of the root nodule characteristics could be explained by nutrients from different treatments. The nutrient content in cow dung and feces had a positive effect on the formation of nodule characteristic index. Especially in faecal residue treatment，C/N was significantly positively correlated with the largest nodule weight （P＜0. 01） ，the total nodule number and the total nodule weight （P＜0. 05）.【Conclusion】 There was a significant positive correlation between the content of available P and the nodulation index including the number of root infection （P＜0. 05） .