Short‐term responses of soil carbon, nitrogen, and microbial biomass to cover crop mixtures and monocultures

Abstract

Increasingly, cover crops are being adopted for the purpose of improving soil health, yet the timescale and magnitude by which living annual cover crops might modify soil chemical and biological aspects of soil health is not well understood. At the same time, there is growing interest among farmers in cover crop mixtures due to perceptions that species‐rich cover crop communities will enhance soil health relative to monocultures. In a field experiment in southeast New Hampshire, we investigated how groups of cover crops grown as monocultures and mixtures for specific seasonal niches (winter/spring, summer, and fall) influenced levels of soil nitrogen (N) and carbon (C), microbial biomass carbon (MBC), and nitrogen (MBN). Soils were sampled at cover crop maturity (winter/spring group), and at seeding, mid‐season, and maturity (summer and fall groups). In the winter/spring group, average total soil N ranged from 0.192 to 0.215 mg g−1 dry soil; highest total soil C content was 2.66 mg g−1 dry soil; and average MBC ranged from 304.8 to 387.3 μg C g−1 dry soil. In the summer group soil MBC decreased from 909.5 μg C g−1 dry soil at mid‐season to 644.9 μg C g−1 dry soil at the end of the growth cycle. In the fall group MBC fell and rose over the season in the range of 236.0–808.3 μg C g−1 dry soil. We found little evidence that cover crops influenced soil C and N parameters during the cover crop growth period relative to a weedy control or that mixtures differed from monocultures. MBC and MBN were more influenced by seasonality than the composition or diversity of the cover crop stand.

Effect of nitrogen, phosphorus and potassium fertilization management on soil properties and leaf traits and yield of Sapindus mukorossi

“…Soil organic carbon was determined by potassium dichromate oxidation-external heating method, available nitrogen (AN) was determined by alkaline dissolution diffusion method, soil effective phosphorus was determined by molybdenum antimony colorimetric method, Soil available potassium was determined by flame photometric method, and pH was measured by using a mixture of soil and water (1:2.5) ( Klotz et al., 2023 ; Lin et al., 2023 ). Microbial biomass carbon (MBC) and nitrogen (MBN) were measured by chloroform fumigation-K 2 SO 4 extraction method assay ( Borah et al., 2023 ; de Souza et al., 2023 ).…”

“…Balanced fertilization refers to the application technology of reasonable fertilizer dosage and ratio based on the fertilizer demand characteristics of crops, soil fertilizer supply performance and fertilizer dosage to maintain nutrient balance between the proposed fertilizer dosage and ratio. For example, Zhang et al (2023) showed that N, P and K fertilizers have different effects on fruit yield and quality, of which K fertilizer is the main factor affecting yield and quality, and reasonable fertilization can significantly improve the yield and fruit quality of blueberries (Vaccinium virgatum). Yin et al (2018) found that the crop of mung bean (Vigna radiata) has a significant increase with N, P and K fertilizers.…”