Zhao Ya-Jiao, Liu Xiao-Jing, Wu Yong, Tong Chang-Chun, Lin Fang
College of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, China.
Ying Yong Sheng Tai Xue Bao. 2020 May;31(5):1645-1652. doi: 10.13287/j.1001-9332.202005.038.
Semi-arid region of Northwest China is characterized by barren soil, with high pH and high carbonate content. Saline-alkali land is easily formed in this area, which inhibits soil microbial activity and results in soil nutrient loss. To improve soil health in this area, effects of intercropping alfalfa and triticale on rhizosphere soil nutrients and bacterial community structure were examined though a three-consecutive-year experiment. The results showed that soil organic matter (SOM) content of alfalfa rhizosphere in intercropping was significantly higher than that in monoculture, while pH and available potassium (AK) content were lower than that in monoculture. The concentrations of SOM, available nitrogen (AN), available phosphate (AP) and AK of triticale rhizosphere in intercropping were significantly higher than those in monoculture. The bacterial sequences, OTUs, richness, and diversity of alfalfa and triticale in rhizosphere soil were all higher than those in monoculture. At phylum level, Proteobacteria and Bacteroidetes were dominant, accounting for 31.1%-33.4% and 22.4%-32.2% of the total OTUs, respectively. The relative abundance of Bacteroidete was higher in intercropping than in monoculture. Actinomycetes in the monoculture were significantly higher. Acidobacteria in the intercropping triticale was significantly higher than that in monoculture triticale. Verrucomicrobia in intercropping alfalfa was significantly more abundant than that in monoculture of alfalfa. At genus level, Algoriphagus, Flavobacterium, Gp6, and Chryseolinea in monoculture were greater than those in intercropping, and Cellvibrio showed an opposite trend. Results of correlation analysis showed that the abundance of Proteobacteria and Bacteroidetes were negatively correlated with soil pH, while that of Bacteroidetes were positively correlated with SOM, TN and AN. However, the abundance of Chloroflexi, Planctomycetes, Acidobacteria, Verrucomicrobia, and Gemmatimonadetes was negatively correlated with SOM and AN. Overall, alfalfa-triticale intercropping is an effective strategy to improve soil health in semi-arid region of Northwest China.
中国西北半干旱地区土壤贫瘠，pH值高且碳酸盐含量高。该地区易形成盐碱地，抑制土壤微生物活性，导致土壤养分流失。为改善该地区土壤健康状况，通过连续三年的试验研究了紫花苜蓿与小黑麦间作对根际土壤养分和细菌群落结构的影响。结果表明，间作时紫花苜蓿根际土壤有机质（SOM）含量显著高于单作，而pH值和速效钾（AK）含量低于单作。间作时小黑麦根际土壤SOM、速效氮（AN）、速效磷（AP）和AK含量均显著高于单作。根际土壤中紫花苜蓿和小黑麦的细菌序列、OTU、丰富度和多样性均高于单作。在门水平上，变形菌门和拟杆菌门占主导地位，分别占总OTU的31.1%-33.4%和22.4%-32.2%。间作时拟杆菌门的相对丰度高于单作。单作中的放线菌显著更高。间作小黑麦中的酸杆菌门显著高于单作小黑麦。间作紫花苜蓿中的疣微菌门比紫花苜蓿单作时更为丰富。在属水平上，单作中的噬冷杆菌属、黄杆菌属、Gp6和金黄杆菌属大于间作，而纤维弧菌属则呈相反趋势。相关性分析结果表明，变形菌门和拟杆菌门的丰度与土壤pH值呈负相关，而拟杆菌门的丰度与SOM、TN和AN呈正相关。然而，绿弯菌门、浮霉菌门、酸杆菌门、疣微菌门和芽单胞菌门的丰度与SOM和AN呈负相关。总体而言，紫花苜蓿-小黑麦间作是改善中国西北半干旱地区土壤健康的有效策略。
