Effects of green manure intercropping on soil nutrient content and bacterial community structure in litchi orchards in China

Abstract

Green manure intercropping is an agronomic management practice that effectively increases soil nutrients in understory and reduces weed population. However, the influence of different green manures on soil properties and soil bacterial community in litchi orchards in the tropical regions of China remains largely unknown. Here, we examined the effect of intercropping three leguminous green manure crops in litchi orchards of Hainan Province. No intercropping was used as the control. Different green manures increased the contents of different soil nutrients. For example, Desmodium ovalifolium increased the total nitrogen content by 7.93%; Grona heterocarpos increased the ammonium nitrogen content by 558.85%; and Stylosanthes guianensis increased the available phosphorus content by 1207.34%. However, intercropping with D. ovalifoliu and S. guianensis reduced the content of available potassium by 47.29% and 58.48%, respectively. The intercropping of green manure increased the abundance of several microbial genera, including Bradyrhizobium, Serratia, and Bacillus, which are known to facilitate soil nitrogen accumulation, plant growth, and phosphorus dissolution. Compared with no intercropping, the three intercropping treatments significantly improved the contents of soil ammonium nitrogen and soil available phosphorus in the litchi orchard. Therefore, intercropping with green manure crops in litchi orchards is an effective management measure; however, the choice of the green manure crop should be based on the soil conditions of litchi orchards.

Annual Weeds Suppression and Oat Forage Yield Responses to Crop Density Management in an Oat-Cultivated Grassland: A Case Study in Eastern China

“…Soil AP and NO 3 − -N showed a positive correlation with Bacillaceae, Streptomycetaceae, Paenibacillaceae, and Geodermatophilaceae, as previously observed by Li et al [62], Zhou et al [68], Ribeiro et al [59], and Panhwar et al [69]. This occurs because these plant-beneficial bacteria exhibit a significant potential in N fixation and phosphates solubilization in the soil [65,70]. However, competition with oat signifi-cantly decreased abundance of these beneficial bacteria, resulting in decreasing nutrient acquisition of E. crus-galli and D. sanguinalis.…”

“…Moreover, the beneficial species (i.e., Bacillaceae, Xanthobacteraceae, Streptomycetaceae, Paenibacillaceae, Planococcaceae, Micromonosporaceae) can favor plant growth and improve nutrient availability by stimulating plants to secrete auxin while simultaneously fixing nitrogen, solubilizing phosphate, and decomposing organic matter [59][60][61][62][63][64]. Apart from their ability to stimulate plant growth, Bacillaceae, Streptomycetaceae, and Geodermatophilaceae can prevent plants from soil-borne disease and abiotic stresses (e.g., drought) through the synthesis of substances akin to lipopeptides that make plants more resistant to external stresses [65,66]. These findings imply that neighboring A. sativa can competitively impair plant growth-promoting bacteria of E. crus-galli and D. sanguinalis, resulting in decreased rhizosphere competence on nutrient uptake, growth, and soil-borne pathogen suppression.…”

Apple-marigold intercropping improves soil properties by changing soil metabolomics and bacterial community structures

“…The community structure and diversity of soil bacteria are important biochemical indicators of soil health, which can be affected by agriculture management ( Li et al, 2022 ; Zhao et al, 2022 ). Intercropping can improve the quantity of orchard soil microorganisms which promote plant growth, enhance plant defenses, and inhibit soil-borne diseases ( Wang et al, 2020 ; Yuan et al, 2023 ). In this study, intercropping marigold improved soil moisture, nutrients and enzyme activities, which may affect rhizosphere organisms, and then influence the structure and diversity of the soil bacterial community ( Cui et al, 2018 ).…”

Effects of Understory Vegetation Conversion on Soil Greenhouse Gas Emissions and Soil C and N Pools in Chinese Hickory Plantation Forests

“…Soil NH 4 + -N and NO 3 − -N are the principal forms of nitrogen utilized by microorganisms and plants, according to Yuan et al [34]. It was found that modifying the understory vegetation facilitated the accumulation of soil nitrogen pools.…”