滨海复垦土地不同间混作模式增产及改良效应

Enhanced crop yield and improvement effects of different intercropping patterns on reclaimed coastal land

[目的]通过研究高粱与野生大豆不同种植模式在滨海废弃盐田复垦土地上的作物增产及改良效应,探讨不同种植模式提高复垦土地生产力的机理及引起高粱根际土壤细菌菌群变化的主要环境因子,可为优化滨海废弃盐田复垦土地种植模式、种地养地相结合提供依据。[方法]在废弃盐田复垦形成的土地进行小区定位试验,设置高粱单作(S)、野生大豆单播(WS)、1行高粱1行野生大豆间作(S1WS1)、1行高粱2行野生大豆间作(S1WS2)、高粱与野大豆同行混播(SWS)共5个处理,以高粱生物量、产量及根际土壤为研究对象,采用高通量测序技术,解析不同种植模式根际土壤细菌的菌群变化,并对细菌群落结构与土壤环境因子进行冗余分析。[结果]与高粱单作(S)相比,高粱-野生大豆间混作S1WS1、S1WS2、SWS模式作物增产率分别为10.16%、13.15%、40.68%,作物增产率与土壤硝态氮、碱性磷酸酶呈显著正相关,土地当量比均大于1,体现了间混作优势;S1WS1、S1WS2、SWS模式提高了土壤有机质、氮磷养分含量、酶活性,降低了土壤pH和含盐量,SWS模式土壤改良效果最好;S1WS2、SWS模式提高了土壤细菌多样性,SWS模式细菌多样性指数最高,Ace、Chao、Shannon指数分别为S模式的1.12倍、1.12倍、1.04倍,细菌多样性指数与土壤硝态氮、脲酶呈显著正相关;放线菌门、变形菌门与绿弯菌门为丰度大于10%的优势菌门,土壤硝态氮、碱性磷酸酶、氮磷比为影响细菌群落结构的主要环境因子。S1WS1、S1WS2、SWS模式均提高了作物产量、土地当量比、土壤有机质和氮磷含量、酶活性。[结论]本试验条件下,相比于其它模式,SWS模式作物增产率与土地当量比均最大,最有利于发挥间混作优势;土壤有机质和氮磷含量均最高,土壤改良效果最好。

[Objective]The study aimed to investigate the impacts of different planting patterns involving sorghum and wild soybean on crop yield and land improvement in reclaimed coastal areas previously abandoned as salt pans.The objective was to understand the mechanisms by which different planting patterns enhance productivity in reclaimed land and to discuss the primary environmental factors influencing changes in the bacterial community within the sorghum rhizosphere soil.This research aimed to provide a foundation for optimizing planting strategies in reclaimed coastal salt pans and integrating cultivation practices with land use.[Methods]A plot positioning experiment was conducted in reclaimed coastal salt pans areas.Five treatments were im‐plemented,including sorghum monocropping(S),wild soybean monocropping(WS),intercropping with one row of sorghum and one row of wild soybean(S1WS1),intercropping with one row of sorghum and two rows of wild soybean(S1WS2),and co-sowing of sorghum and wild soybean(SWS).Sorghum biomass,yield,and rhizosphere soil were selected as the research objects.High throughput sequencing technology was used to analyze bacterial community variations in the rhizosphere soil under different planting patterns,followed by redundancy analysis of bacterial community structure and soil environmental factors.[Results]Compared to sorghum monoculture(S),the yield increase rates for sorghum-wild soybean intercropping patterns of S1WS1,S1WS2 and SWS were 10.16%,13.15%,and 40.68%,respectively.Crop yield increases were significantly positively correlated with soil nitrate nitrogen and alkaline phosphatase,with a land equivalent ratio greater than 1,highlighting the benefits of intercropping.S1WS1,S1WS2,and SWS models improved soil organic matter,nitrogen,phosphorus nutrient content,and enzyme activity.Results indicated that the SWS model demonstrated the most significant soil improvement effect by reducing soil pH and salt content.The S1WS2 and SWS models enhanced soil bacterial diversity,with the SWS model exhibiting the highest bacterial diversity index that ACE,Chao,and Shannon indices being 1.12,1.12 and 1.04 times higher than the S model,respectively.The bacterial diversity index showed a significant positive correlation with soil nitrate nitrogen and urease.Actinomycetes,Proteus,and Curvularia were abundant.Soil nitrate nitrogen,alkaline phosphatase,and N/P ratio were the primary environmental factors influencing the bacterial community structure.S1WS1,S1WS2,and SWS all contributed to improving crop yield,land equivalent ratio,soil organic matter,nitrogen,phosphorus content,and enzyme activity.[Conclusion]In this experiment,compared to other models,the SWS model exhibited the highest crop yield increase rate and land equivalent ratio,demonstrating the most advantageous intercropping benefits.Additionally,it presented the highest soil organic matter and nitrogen-phosphorus content,thus showcasing the most substantial soil improvement effect.