Shandong Provincial Key Laboratory of Dryland Farming Technology, College of Agronomy, Qingdao Agricultural University, Qingdao, 266109, P.R. China.
BMC Plant Biol. 2022 Mar 16;22(1):121. doi: 10.1186/s12870-022-03506-y.
Intercropping (IC) has been widely adopted by farmers for enhancing crop productivity and economic returns; however, the underpinning mechanisms from the perspective of below-ground interspecific interactions are only partly understood especially when intercropping practices under saline soil conditions. By using permeable (100 μm) and impermeable (solid) root barriers in a multi-site field experiment, we aimed to study the impact of root-root interactions on nutrient accumulation, soil microbial communities, crop yield, and economic returns in a peanut/cotton IC system under non-saline, secondary-saline, and coastal saline soil conditions of China.
The results indicate that IC decreased the peanut pods yield by 14.00, 10.01, and 16.52% while increased the seed cotton yield by 61.99, 66.00, and 58.51%, respectively in three experimental positions, and consequently enhanced the economic returns by compared with monoculture of peanut (MP) and cotton (MC). The higher accumulations of nutrients such as nitrogen (N), phosphorus (P), and potassium (K) were also observed in IC not only in the soil but also in vegetative tissues and reproductive organs of peanut. Bacterial community structure analysis under normal growth conditions reveals that IC dramatically altered the soil bacterial abundance composition in both peanut and cotton strips of the top soil whereas the bacterial diversity was barely affected compared with MP and MC. At blossom-needling stage, the metabolic functional features of the bacterial communities such as fatty acid biosynthesis, lipoic acid metabolism, peptidoglycan biosynthesis, and biosynthesis of ansamycins were significantly enriched in MP compared with other treatments. Conversely, these metabolic functional features were dramatically depleted in MP while significantly enriched in IC at podding stage. Permeable root barrier treatments (NC-P and NC-C) counteracted the benefits of IC and the side effects were more pronounced in impermeable treatments (SC-P and SC-C).
Peanut/cotton intercropping increases crop yield as well as economic returns under non-saline, secondary-saline, and coastal saline soil conditions probably by modulating the soil bacterial abundance composition and accelerating plant nutrients accumulation.
间作（IC）已被农民广泛采用，以提高作物产量和经济回报；然而，从地下种间相互作用的角度来看，其潜在机制还只是部分被理解，尤其是在盐渍土条件下的间作实践中。通过在多地点田间试验中使用可渗透（100μm）和不可渗透（固体）根障，我们旨在研究根-根相互作用对养分积累、土壤微生物群落、作物产量和经济回报的影响，在中国非盐渍、次生盐渍和沿海盐渍土壤条件下的花生/棉花间作系统中。
结果表明，间作分别使花生荚果产量降低了 14.00%、10.01%和 16.52%，而使种子棉产量分别提高了 61.99%、66.00%和 58.51%，与单作花生（MP）和棉花（MC）相比，经济效益也有所提高。在非盐渍、次生盐渍和沿海盐渍三种实验条件下，IC 还使土壤中以及花生营养组织和生殖器官中氮（N）、磷（P）和钾（K）等养分的积累更高。在正常生长条件下，细菌群落结构分析表明，IC 显著改变了上层土壤中花生和棉花条带的土壤细菌丰度组成，而与 MP 和 MC 相比，细菌多样性几乎没有受到影响。在开花期，与其他处理相比，MP 中脂肪酸合成、硫辛酸代谢、肽聚糖生物合成和ansamycins 生物合成等细菌群落的代谢功能特征显著富集。相反，在荚果期，这些代谢功能特征在 MP 中显著减少，而在 IC 中显著富集。可渗透根障处理（NC-P 和 NC-C）抵消了间作的好处，而不可渗透处理（SC-P 和 SC-C）的副作用更为明显。
在非盐渍、次生盐渍和沿海盐渍土壤条件下，花生/棉花间作增加了作物产量和经济效益，可能是通过调节土壤细菌丰度组成和加速植物养分积累。
