Do cover crops benefit soil microbiome? A meta-analysis of current research

Impact of Cover Crops on the Soil Microbiome of Tree Crops

“…Cover crops can impact the soil microbiome by changing soil characteristics (e.g., pH, temperature, and soil water content) which are known to influence soil microbial communities [11,18,23]. In addition, cover crops offer additional organic substrates through the input of plant residues and rhizodeposition, which may impact soil microbial communities [55][56][57].…”

“…Tillage in the row middles is common for some perennial crops, such as almonds, olives, citrus, and grapevines [11,67], and is generally performed to remove weeds to avoid water and nutrient competition, resulting in bare soil between tree rows [68,69]. Adopting no-tillage in combination with cover crops has been identified as a reliable management practice in tree cropping systems [70,71] that increases soil C sequestration and reduces N fertilization inputs compared with conventional tillage (down to a depth of 15-20 cm), primarily due to the beneficial effects on soil microbial diversity [11,14,18,23]. For example, intercropping olive (O. europea) with grasses increased bacterial diversity in no-tillage systems compared with conventional treatments, and changes in microbial diversity were positively correlated with improved olive yield [49].…”

“…As shown in this review, it is reasonable to suppose that cover crops exert important influences on bacterial and fungal co-occurrence networks. However, while a recent meta-analysis found cover cropping increased soil microbial abundance, activity, and diversity in annuals [18], considerations for potentially important taxa associated with cover crops in annual and perennial systems were not discussed. vetch (Coronilla varia) and resulted in an increase in the number of links for plant degradation, as well as N and P reactions [44,45].…”

“…As shown in this review, it is reasonable to suppose that cover crops exert important influences on bacterial and fungal co-occurrence networks. However, while a recent metaanalysis found cover cropping increased soil microbial abundance, activity, and diversity in annuals [18], considerations for potentially important taxa associated with cover crops in annual and perennial systems were not discussed. From the set of published studies on the effect of cover crops on the soil microbiome in tree cropping systems (Table 1), we selected bacterial, archaeal, and fungal taxa from each study that had a significant and positive correlation to at least one of the following abiotic parameters that are commonly used as indicators of soil quality [112]: content of NH4 + , NO3 − , TN, and SOM; decomposition of complex polymers; and tree production.…”

“…Cover crops are a widely applied soil improvement and conservation technique in agriculture, particularly in annual cropping systems [12,13], and their implementation in tree cropping systems may provide the same benefits found in annual crops, including improved soil and root health; increased production; and reductions in costs due to decreases in fertilizers, irrigation, and herbicides [11,14]. Cover cropping can also improve soil carbon (C), nitrogen (N), and phosphorus (P) cycling [15][16][17], as well as increase soil microbial abundance and diversity [18] and suppress soilborne pests [19].…”