Declining biodiversity (BD) is aecting food security, agricultural sustainability,and environmental quality. Agroforestry (AF) is recognized as a possible partial solution forBD conservation and improvement. This manuscript uses published peer-reviewed manuscripts,reviews, meta-analysis, and federal and state agency documents to evaluate relationships betweenAF and BD and how AF can be used to conserve BD. The review revealed that floral, faunal, and soilmicrobial diversity were significantly greater in AF as compared to monocropping, adjacent croplands, and within crop alleys and some forests. Among the soil organisms, arbuscular mycorrhizaefungi (AMF), bacteria, and enzyme activities were significantly greater in AF than crop and livestockpractices. Agroforestry also creates spatially concentrated high-density BD near trees due to favorablesoil-plant-water-microclimate conditions. The greater BD was attributed to heterogeneous vegetation,organic carbon, microclimate, soil conditions, and spatial distribution of trees. Dierences in BDbetween AF and other management types diminished with time. Evenly distributed leaves, litter,roots, dead/live biological material, and microclimate improve soil and microclimate in adjacentcrop and pasture areas as the system matures. Results of the study prove that integration of AFcan improve BD in agricultural lands. Selection of site suitable tree/shrub/grass-crop combinationscan be used to help address soil nutrient deficiencies or environmental conditions. Future studieswith standardized management protocols may be needed for all regions to further strengthen thesefindings and to develop AF establishment criteria for BD conservation and agricultural sustainability.

Restoration of degraded lands by adoption of recommended conservation management practices can rehabilitate watersheds and lead to improving soil and water quality. The objective was to evaluate the effects of grass buffers (GBs), biomass crops (BCs), grass waterways (GWWs), agroforestry buffers (ABs), landscape positions, and distance from tree base for AB treatment on soil quality compared with row crop (RC) (corn [Zea mays L.]-soybean [Glycine max (L.) Merr.] rotation) on claypan soils. Soil samples were taken from 10-cm-depth increments from the soil surface to 30 cm for GB, BC, GWW, and RC with three replicates. Soil samples were collected from summit, backslope, and footslope landscape positions. Samples were taken at 50-and 150-cm distances from the tree base. b-Glucosidase, b-glucosaminidase, dehydrogenase, fluorescein diacetate hydrolase (FDA), soil organic carbon (SOC), total nitrogen (TN), active carbon (AC), and water-stable aggregates (WSA) were measured. Results showed that b-glucosidase, b-glucosaminidase, dehydrogenase, FDA, AC, WSA, and TN values were significantly greater (P < 0.01) for the GB, BC, GWW, and AB treatments than for the RC treatment. The first depth (0-10 cm) revealed the highest values for all soil quality parameters relative to second and third depths. The footslope landscape had the highest parameter values compared with summit and backslope positions. The 50-cm distance of AB treatment had higher values than the 150-cm distance for all measured parameters. Results showed that perennial vegetation practices enhanced soil quality by improving soil microbial activity and SOC.

Although cover crops (CC) are believed to play a major role in soil quality improvement, the effects of CC on microbial populations and community structure is not well understood. The objective of this study was to quantify CC effects on soil microbial biomass and community structure under a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. The study was conducted at the Chariton County Cover Crop Soil Health Research and Demonstration Farm (CCSH) in Missouri, USA, where CC were first established in 2012. Soils were sampled in 2016, 2017, and 2018 from the 0-to 10-cm depth layer using a grid sampling design and phospholipid fatty acid (PLFA) profiles were determined. Microbial biomass and microbial community structure (total fungi, total bacteria, rhizobia, gram (−), and actinomycetes biomass), as estimated from the PLFA biomarkers, were significantly greater (P < 0.05) in the CC treatment compared to no cover crop (NCC) in 2016 and 2018 (2.4-and 1.7-fold larger, respectively). Within the CC treatment, differences by soil type were also observed, finding that the silt loam soil supported greater total microbial biomass than the loam soil in 2018. Spatial distribution patterns of total microbial biomass, bacteria biomass and fungi biomass differed with time. Overall, this study demonstrated that the CC treatment affected the soil microbial community biomass and structure, which has potential environmental, production, and soil quality benefits.

Cover crops (CC) improve soil quality, including soil microbial enzymatic activities and soil chemical parameters. Scientific studies conducted in research centers have shown positive effects of CC on soil enzymatic activities; however, studies conducted in farmer fields are lacking in the literature. The objective of this study was to quantify CC effects on soil microbial enzymatic activities (β-glucosidase, β-glucosaminidase, fluorescein diacetate hydrolase, and dehydrogenase) under a corn (Zea mays L.)–soybean (Glycine max (L.) Merr.) rotation. The study was conducted in 2016 and 2018 in Chariton County, Missouri, where CC were first established in 2012. All tested soil enzyme levels were significantly different between 2016 and 2018, irrespective of CC and no cover crop (NCC) treatments. In CC treatment, β-glucosaminidase activity was significantly greater at 0–10 cm depth in 2016 and at 10–20 and 20–30 cm in 2018. In contrast, dehydrogenase activity was significantly greater in NCC in 2018. Soil pH and organic matter (OM) content were found to be significantly greater in CC. Overall, CC have mixed effects on soil enzyme activities and positive effects on soil OM compared to NCC. This study highlights the short-term influence of CC and illustrates the high spatial and temporal variability of soil enzymes under farmer-managed fields.

Sustainable vegetative management plays a significant role in improving soil quality in degraded agricultural landscapes by enhancing soil microbial biomass. This study investigated the effects of grass buffers (GBs), biomass crops (BCs), grass waterways (GWWs), and agroforestry buffers (ABs) on soil microbial biomass and soil organic C (SOC) compared with continuous corn (Zea mays L.)-soybean [Glycine max (L.)Merr.] rotation (row crop [RC]) on claypan soils. The RC, AB, GB, GWW, and BC treatments were established in 10-cm depth at summit, backslope, and footslope landscape positions. Within AB treatment, soils were collected from the 50-cm and 150-cm tree distance. Total microbial biomass and biomass of gram-positive bacteria, gram-negative bacteria, actinomycetes, rhizobia, fungi, arbuscular mycorrhizae, saprophytes, and protozoa were determined by phospholipid fatty acid (PLFA) analysis. Results showed that soil microbial biomass and SOC across all microbial groups were significantly higher (P < .01) under perennial vegetation treatments compared with RC. The footslope position exhibited the highest total microbial biomass compared with the summit and backslope positions. The sampling distance of 50 cm from the tree base demonstrated 16% greater total microbial biomass and 15% higher SOC compared with 150 cm. These findings highlight the influence of landscape on soil biological properties and show that perennial vegetation systems have the potential to increase soil microbial biomass and enhance agricultural sustainability in degraded RC systems.Abbreviations: AB, agroforestry buffer; AC, active carbon; AB150, agroforestry buffer at 150 cm distance; AB50, agroforestry buffer at 50 cm