摘要
为了探究不同草田轮作方式对土壤肥力、微生物及自毒物质的影响,以轮作5年的"甘农3号"紫花苜蓿地为试验材料,研究紫花苜蓿与小麦和玉米在不同轮作处理下对土壤养分含量、微生物数量和自毒物质含量的动态变化及影响。结果表明:1)与CK相比,紫花苜蓿与玉米和小麦轮作后土壤有机质、全氮、碱解氮、速效磷的消耗增加。轮作玉米后有机质、全氮、碱解氮、速效磷的消耗量显著高于轮作小麦(P<0.05)。2)紫花苜蓿轮作玉米、小麦后,土壤细菌和放线菌数量显著增加(P<0.05),且增量大小顺序为5年紫花苜蓿-2年小麦>5年紫花苜蓿-1年小麦>5年紫花苜蓿-2年玉米>5年紫花苜蓿-1年玉米;真菌数量下降,轮作处理较CK显著降低了48.96%、65.19%、66.72%、74.91%(P<0.05)。3)紫花苜蓿轮作玉米和小麦后,土壤主要自毒物质(绿原酸、阿魏酸、咖啡酸、对羟基苯甲酸、香豆素)含量均降低,轮作玉米和小麦后自毒物质总量在第1年较CK显著降低17.90%和27.50%(P<0.05),且轮作小麦第2年比第1年降低24.20%。综上所述,紫花苜蓿与玉米、小麦轮作能显著影响土壤微生物组成,降低自毒物质含量,有效改善土壤环境,而土壤养分缺乏并不是引起紫花苜蓿连作障碍的主要因素。在半干旱地区紫花苜蓿的草田轮作中,以紫花苜蓿-小麦轮作为宜,且轮作2年小麦对土壤的解毒效果更为明显,应避免紫花苜蓿-玉米轮作,以维持农田肥力平衡。通过典型性分析发现,土壤微生物数量和自毒物质含量之间呈显著相关关系,土壤中细菌和真菌数量对自毒物质总含量影响最大,放线菌数量和自毒物质绿原酸、阿魏酸、咖啡酸、对羟基苯甲酸、香豆素显著相关。
This research aimed to explore the effects of different alfalfa crop rotations on soil nutrient, microorganism abundance, and allelochemical(autotoxin) levels. The alfalfa cultivar used was ‘Gannong No. 3’ and rotations compared were alfalfa-wheat(AW), alfalfa-wheat-wheat(AWW), alfalfa-corn(AC), alfalfa-corn-corn(ACC), and continuous alfalfa(CK). The results showed that: 1) Compared with CK, after the AC rotation, soil organic matter, ammonia, alkali decomposed ammonia, quick-test phosphorus were all reduced;after the AC rotation, the same soil parameters were more depleted than in AW(P<0.05). 2) In the various alfalfa-corn and alfalfa-wheat rotations, the numbers of soil bacteria and actinomycetes were increased significantly(P<0.05), with the treatment rankings being AWW>AW>ACC>AC. However, the number of fungi decreased, compared with CK, with percentage decreases being 48.96%, 65.19%, 66.72%, and 74.91%(P<0.05) for AC, ACC, AW, and AWW, respectively. 3) In the various alfalfa-corn and alfalfa-wheat rotations, soil levels of major allelochemicals, including chlorogenic acid, ferulic acid, caffeic acid, p-hydroxybenzoic acid, and coumarin, were all reduced. Average reductions after one year were, respectively, 17.90% and 27.50%(P<0.05) compared with CK, for AC and AW rotations. In AWW the allelochemical reduction compared to CK was 24.20%. It is concluded that well managed rotation of alfalfa, corn, and wheat could significantly improve soil microbial ecology, reduce the soil autotoxin content, and that soil nutrient deficiency was not the primary limiting factor to continuous cropping of alfalfa. In the semi-arid area in which the study was conducted, alfalfa-wheat rotation appeared the most suitable of the tested rotations and 2 years in wheat had a more pronounced soil detoxification effect. Alfalfa-corn rotations should be avoided, as they excessively deplete farmland fertility. Additionally, the population counts of soil microorganisms(particularly actinomycetes) and levels of soil allelochemicals assayed(as listed above) were generally significantly related.
作者
尹国丽
蔡卓山
陶茸
吴芳
陈建纲
师尚礼
YIN Guo-li;CAI Zhuo-shan;TAO Rong;WU Fang;CHEN Jian-gang;SHI Shang-li(Prataculture College,Gansu Agricultural University,Key Laboratory of Grassland Ecosystem,Ministry of Education,Sino-U.S.Centers for Grazingland Ecosystem Sustainability,Lanzhou 730070,China)
出处
《草业学报》
CSCD
北大核心
2019年第3期42-50,共9页
Acta Prataculturae Sinica
基金
现代农业产业技术体系建设专项(CARS-34)
全国牧草种质资源保种项目(NB2130135)资助