摘要:农业生产中，肥料和抑菌性农药施用是两种重要的农业生产技术。在施肥过程中，点状和条状施肥是主要的施肥方式，易导致作物生长期内土壤养分以斑块状分布，因此根系趋肥性对农田中作物获取养分具有重要性。而在施用抑菌性农药时，药剂能够通过淋溶等过程进入土体中，对土壤生态环境和根-土过程产生直接或间接的影响。然而目前有关农药施用是否影响作物根系趋肥性，进而改变产量表现还不清楚。本研究选用旱地主要粮食作物玉米和马铃薯为研究对象，通过等量肥料下隔行施用的方式构建土壤养分斑块，在此基础上进行广谱性杀菌剂浇施土壤，研究抑菌性农药对作物利用异质性养分的影响。两年的大田试验数据表明，一定程度上，抑菌剂浇施和隔行施肥能够显著地影响作物的植株生物量、产量，根系生物量及分布，且对玉米生物量影响具显著交互效应，表现为隔行施肥对生物量的显著提高发生在抑菌剂浇施条件下，而抑菌剂对玉米生物量的提高则主要表现在隔行施肥条件下。同时，抑菌剂浇施能够提高作物的根系觅养精确度，其中在马铃薯上达到显著水平，表明抑菌剂浇施对作物适应土壤养分斑块具有一定的促进作用。当然，抑菌农药和养分斑块在影响作物生长过程中的显著性受作物类型和种植年份的影响，具有复杂性。因此，进一步针对不同作物、生态环境和栽培措施，探讨抑菌剂农药在作物适应养分斑块中的作用以及对作物根系趋肥的影响机制，对于了解农药施用对化肥利用的影响具有潜在的价值。
关键词:养分异质性/
抑菌剂/
根系趋肥性/
土壤微生物/
马铃薯/
玉米
Abstract:In agriculture, fertilizer and fungicide applications are critical for high yield. For the fertilization, it is known that block and strip fertilizations are common practices. These methods can result in the formation of pockets of soil nutrients. In this case, the orientation of root growth towards soil nutrients is important for absorbing heterogeneous nutrients. Fungicides can permeate into the soil through leaching, which directly or indirectly affects soil environment and root-soil interaction. However, it is not clear if soil micro-organisms change caused by fungicides adding affects crop root growth orientation and yield. A field experiment was conducted in 2015 and 2016, in which maize and potato were planted to explore the effects of fungicides adding and nutrient patches on crop growth and yield. We first generated soil nutrient patch by interlaced fertilization. Then broad-spectrum fungicides were applied through watering. Next, crop yield, shoot biomass, root biomass and root foraging precision were measured. The two-year field experiment demonstrated that watering fungicides and nutrient patches significantly affected plant biomass, yield, root biomass and root growth orientation. Importantly, we observed significant positive interaction between fungicides and nutrient patches. The significant increase in maize plant biomass was due to the application of fungicides under heterogeneous fertilization. Also the significant increase in maize plant biomass was promoted by nutrient patches after fungicide application. Besides, the results suggested that the application of fungicide benefited the adaptation of crops to heterogeneous fertilization. This was because that root foraging precision of maize and potato was promoted by the application of fungicides. Moreover, there was significant increase in root foraging precision of potato. However, the effect of fungicide and nutrient patches on plant growth was significantly affected by the complex interaction between crop type and planting year. Therefore, further studies were necessary to explore the role of fungicides in adaption of crops to nutrient patches and the mechanisms of growth orientation of roots towards soil nutrients. Such study should be based on various crops, ecological environments and cultivation practices, increasing the potential for in-depth understanding of the effects of pesticides on the use of chemical fertilizers.
Key words:Nutrient heterogeneity/
Fungicide/
Root growth orientation/
Soil microorganism/
Potato/
Maize
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