不同种植模式对土壤质量及马铃薯生长的影响

Influences of Planting Pattern on Soil Quality and Potato Growth

为探究轮作藜麦、玉米及连作对马铃薯根系生理及根系发育的影响及其机制,比较了3种种植模式(轮作藜麦、轮作玉米及连作)对马铃薯根际土壤微环境、根系生理、根系发育及植株生长的影响,以期为减轻马铃薯连作障碍、筛选较好的轮作模式提供理论依据。结果表明:(1)轮作藜麦、玉米明显降低土壤pH,提高土壤中有机质、碱解氮和有效磷含量,增强土壤肥力相关酶的活性,增加土壤细菌、放线菌数量和细菌与真菌数量比值(B/F),降低真菌数量,改善马铃薯根际土壤微环境,对植株生长发育起到促进作用,表现在马铃薯的株高、茎粗、地上部干重、根干重、单株薯重均有一定程度的增加。(2)轮作藜麦、玉米使得马铃薯根系超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性上升,超氧阴离子产生速率下降,丙二醛(MDA)含量减少,渗透调节物质含量增加,表明通过轮作藜麦和玉米使得连作对马铃薯植株造成的胁迫得到了一定程度缓解。(3)轮作藜麦、玉米显著提高了马铃薯根系总根长、根表面积、根体积、根平均直径和根尖数,说明轮作藜麦及玉米促进了马铃薯根系的生长发育,这与轮作藜麦及玉米改善土壤理化性质、生物学性质及促进马铃薯地上部分的发育相对应。比较轮作藜麦及轮作玉米的整体表现,以轮作玉米调控马铃薯连作障碍的效果较好。

【Objective】In poverty-stricken areas of China,potato is a dominant crop that may help promote food production and get rid of poverty.Due to a limited farming area and intensive potato production therein,mono-cropping is prevailing in those areas.However,long-term mono-cropping may reduce soil microbial community diversity and disturb the balance of soil nutrients in ratio,thus affecting crop growth and yield.Although a large number of studies have demonstrated that rotation is an effective practice to alleviate the impact of mono-cropping on the soil,so far little has been reported on how the rotation of potato with quinoa or maize influences microenvironment of the rhizospheric soil of potato and interactions between soil and the root system.So this study was going to investigate influences of the rotation of potato with quinoa or maize on soil quality and potato growth and its mechanism,so as to provide a theoretical support to remove the obstacle of mono-cropping in agriculture and build a better rotation model for those areas.【Method】In the study,an experiment designed to have three treatments,i.e.Treatment M(mono-cropping),Treatment L(rotation with quinoa),and Treatment Y(rotation with maize),was carried out to explore influences of the above three planting patterns on soil properites and root physiology,root development and plant growth of potato.【Result】Results show:(1)Rotation potato with quinoa or maize reduced soil pH in potato rhizosphere significantly,increased the contents of organic matter,alkalyzable nitrogen and available phosphorus,enhanced activities of soil enzymes,decreased fungi population,increased the number of soil bacteria and actinomycetes,and the ratio of bacteria and fungi(B/F),and improved soil properties and promoted potato growth,which was enbodied to some extent in plant height,stem diameter,shoot dry weight,root dry weight and yield of potato tuber;(2)Rotation of potato with quinoa or maize increased the activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)in potato root system,decreased the producing rate ofO×2-and the content of malondialdehyde(MDA),increased the content of osmosis regulating substances.All the findings indicated that the rotation relieved all the stresses of mono-cropping on potato plants;and(3)Rotation of potato with quinoa or maize also increased the total length,surface area,volume,mean diameter and tip number of potato roots significantly.In general,rotation of potato with quinoa or maize promoted the growth and development of potato roots,which corresponded to the improvement of physical,chemical and biological properties of the soil and the development of the shoots of potato as well.【Conclusion】Rotation of potatio with quinoa or maize can improve physical,chemica and biological properties of the soil to some extent,enhance antioxidant capacity and osmosis regulating ability of the roots of potato,reduce membrane lipid peroxidation degree,promote growth and development of the roots of potato.These effects of the rotation are also enbodied in increases in plant height,stem diameter and tuber weight.Comparison between the two rotation patterns shows that the rotation of potato with maize is better than that with quinoa in alleviating the adverse impacts of mono-cropping.