水膜耦合对青贮玉米土壤微生物群落结构和产量的影响

Effects of water stress under different mulch covers on soil microbial structure and yield in silage maize

为明确不同水分胁迫和地膜覆盖材料对青贮玉米土壤微生物群落结构的影响,于2022年4—10月,以‘陇青贮1号’玉米为试验材料,进行了田间双因素随机区组试验。设置3个水分梯度,即充分灌溉D1(75%~95%θ_f,θ_f为田间持水率)、轻度水分胁迫D2(55%~75%θ_f)、中度水分胁迫D3(35%~55%θ_f);以及4种覆盖材料,即普通白色覆膜(M1)、黑色地布(M2)、生物降解膜(M3)、液态地膜(M4),共12个处理。分析水膜互作对青贮玉米根际土壤中微生物群落结构和产量的影响。研究结果表明:(1)D1处理显著提高青贮玉米根际特有微生物种类,M4处理的根际特有微生物种类相对其他覆膜材料显著提高;(2)各处理土壤细菌共获得43个门、109个纲、285个目、439个科、735个属,土壤细菌的多样性丰富,优势菌群始终为变形菌(Proteobacteria)、放线菌(Actinobacteria)和酸杆菌(Acidobacteria);(3)主坐标分析(PCoA)结果显示,细菌群落结构聚类情况与水分调亏程度高度吻合。综合来看,水分对青贮玉米根际土壤微生物群落多样性影响较大,而覆膜材料对其影响较小;(4)在D1水平时,M3处理青贮玉米的鲜草、干草产量较M4处理分别显著增加21.58%和16.59%。D2和D3处理时,覆膜材料对青贮玉米的鲜草产量影响不显著。所有处理中,D2M3的鲜草和干草产量均最大,较D1M1分别增加38.10%和12.65%。综合土壤健康和产量效益等目标,用M3替代M1或M2可行,M4在产量上不具有优势。本试验中,全生育期轻度水分亏缺组合生物降解膜的处理表现更为优异。

The purpose of this study was to clarify the effects of different water stress and mulch materials on soil microbial community structure of silage maize.From April to October 2022,using ‘Long Silage No.1' maize as the test material,a two-factor randomized block field test was conducted to establish three moisture gradients:fully irrigated(D1,75%~95% θ_f)(where θ_(f) represents the field water holding capacity),mild water stress(D2,55%~75% θ_f),and moderate water stress(D3,35%~55% θ_f).Additionally,four types of mulching materials were tested:ordinary white mulch film(M1),black ground cloth(M2),biodegradable film(M3),and liquid mulch(M4),resulting in a total of 12 treatments.The study analyzed the effects of water-membrane interactions on microbial community structure and yield in the inter-root soil of silage maize.The results indicated that:(1) The D1 treatment significantly increased the inter-root unique microbial species of silage maize,while the inter-root unique microbial species in the M4 treatment were significantly higher than those in the other mulching materials.(2) The soil bacteria across all treatments comprised a total of 43 phyla,109 classes,285 orders,439 families,and 735 genera,demonstrating rich diversity,with dominant bacterial groups consistently identified as Ascomycetes(including Proteobacteria,Actinobacteria,and Acidobacteria).(3) Principal Co-ordinate analysis(PCoA) revealed that the clustering of bacterial community structure was highly consistent with the degree of moisture regulation and deficit.Collectively,these findings suggest that moisture had a more pronounced effect on the diversity of soil microbial communities in the inter-root zone of maize silage,whereas the impact of mulching materials was comparatively lesser.(4) At D1 level,the yield of fresh grass and hay of silage maize under M3 treatment was significantly increased by 21.58% and 16.59% compared with M4 treatment.Under D2 and D3 treatment,the effect of film coating material on the yield of fresh grass was not significant.Among all treatments,the fresh grass and hay yields of the D2M3 treatment were the largest,increasing by 38.10% and 12.65% respectively compared with D1M1.Considering the goals of soil health and yield benefits,it is feasible to replace M1 or M2 with M3,but M4 has no advantage in yield.In this experiment,the treatment performance of mild water deficit during the whole growth period combined with biodegradable membrane was better.