To resolve the problem of soil nutrient and water deficiency in arid and semiarid regions of Northwest China, and considering the symbiotic relationship between microbes and crops, we set up two water regimes: drought stress (35% of the soil water holding capacity) and normal water supply (75% of the soil water holding capacity), two film mulching patterns (non-film mulching and film mulching), and four levels of microbial inoculation [single inoculation with AM fungi (AM), single inoculation with phosphate solubilizing bacteria (PSB), co-inoculation of AM fungi with phosphate solubilizing bacteria (AM+PSB) and the control (CK)]. This study aimed to evaluate the effects of microbial inoculation on maize growth, nutrient absorption, and water use efficiency under different treatments of water regime and film mulching. Results showed that drought stress significantly increased the mycorrhizal colonization of inoculated plants, but significantly decreased soil external hyphal length, T-GRSP and EE-GRSP content. Under drought stress, AM inoculation showed the best promoting and mycorrhizal effect on maize growth by increasing biomass and water use efficiency, soil organic carbon content, the absorption and transportation of soil N, P, K, and thus increasing the N, P, K uptake. Under normal water supply, the inoculation effect of AM+PSB was better than that of AM or PSB treatment, especially combined with film mulching. Results from correlation analysis showed that plant biomass, leaf SPAD value, and nutrient uptake of maize aboveground were significantly positively correlated with soil external hyphal length, whereas water use efficiency was significantly negatively correlated with soil external hyphal length.
针对西北干旱半干旱地区土壤贫瘠与水分缺乏的问题,利用微生物与作物形成互惠互利的共生关系,本研究设置两个水分梯度:干旱胁迫(供试土壤最大持水量的35%)和正常水分(供试土壤最大持水量的75%),两个覆膜方式:无覆膜(NM)和覆膜(FM),4个接种微生物水平:单接AM真菌(AM)、单接解磷细菌(PSB)、联合接种AM真菌与解磷细菌(AM+PSB)以及对照(CK),研究不同水分和覆膜条件下4个接种微生物对玉米生长特性、地上养分吸收与水分利用效率的影响.结果表明: 与正常水分处理相比,干旱胁迫能够显著提高接种AM真菌处理的侵染率,但正常水分处理下土壤根外菌丝密度、总球囊霉素(T-GRSP)与易提取球囊霉素(EE-GRSP)含量明显提高.干旱胁迫下,单接AM真菌处理的促生作用和菌根效应表现最好,能够提高玉米生物量、水分利用效率和土壤有机碳含量,促进土壤N、P、K的吸收与运输,从而增加玉米地上部分N、P、K吸收量;而正常水分下,联合接种AM+PSB处理表现要好于单接AM和PSB处理,且其与覆膜的互作效果最好.相关分析结果表明,玉米生物量、叶片SPAD值和地上部分N、P、K吸收量均与土壤根外菌丝密度呈显著正相关,玉米水分利用效率与其呈显著负相关.
Keywords: AM fungi; film mulching; glomalin; nutrient uptake; phosphate-solubilizing bacteria.