Enhancing long-term no-till wheat systems with cover crops and flash grazing

Authors: Mubvumba, Partson; DELAUNE, PAUL - Texas A&M Agrilife; HONS, FRANK - Texas A&M University

Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2020
Publication Date: 6/8/2022
Citation: Mubvumba, P., Delaune, P.B., Hons, F.M. 2022. Enhancing long-term no-till wheat systems with cover crops and flash grazing. Soil and Tillage Research. Soil Security p.100067. https://doi.org/10.1016/j.soisec.2022.100067.
DOI: https://doi.org/10.1016/j.soisec.2022.100067

Interpretive Summary: Monoculture dual wheat systems prevalent in the Southern Great Plains are often practiced under conventional tillage (CT) for grazing and grain. Associated soil compaction due to animal trampling, use of heavy equipment, vulnerability to water and wind erosion aggravated by nutrient load downstream and dust bowl is an environmental catastrophe. Scientists at the Texas A&M University and USDA Crop Production Systems Research Unit in Stoneville conducted a study to evaluate the impact of introducing no-till (NT), cover crops (CC), grazing and Intercropping in dual wheat systems on soil quality. Treatments were CT and combinations of NT, CC, grazing and intercropping wheat with radishes and turnips. CT without a CC was compacted the most, top 6 inches, with NT and CC treatments trending the least. No quantified compaction was attributed to grazing. Soil aggregation was more pronounced in the top 2 inches. Large soil aggregates were highest under NT CC and associated with highest soil organic matter and fungal microbiota biomass. This improves soil structure, water infiltration, productivity and environment quality.

Technical Abstract: Monoculture dual wheat systems prevalent in the Southern Great Plains are often practiced under conventional tillage (CT) for grazing and grain. Associated soil compaction due to animal trampling, use of heavy equipment, vulnerability to water and wind erosion aggravated by nutrient load downstream and atmospheric dusts are an environmental catastrophe. Conservation practices that include no-till (NT) and cover crops (CC) have the potential to nurture soil physical, chemical and biological processes creating synergies that can enhance sustainable soil ecosystem services and functions in these regions. The impact of introducing NT, CC, grazing and intercropping in dual wheat systems to soil quality was evaluated on 2000 m2 plot sizes after 3 years of treatment effects. Selected soil properties were measured for soil biogeochemistry synergies and quality evaluation. Treatments were CT and combinations of NT, CC, grazing and intercropping wheat with radishes and turnips.The CT treatment without a CC had the highest bulk density (p<0.05) in the 0-15 cm, with NT and CC treatments trending lowest. No quantified compaction was attributed to grazing. Aggregate-size distribution reflected treatment effects in the top 5 cm of soil (p<0.05). Large macroaggregates (LM) (>2 mm) were highest under NT CC. Similar patterns were observed for mean weight diameter (MWD), Permanganate oxidizable Carbon (POXC for LM) and arbuscular mycorrhizal fungi biomass (AMFB). Positive correlations were shown for: AMFB vs POXC (r2 = 0.55, p=0.0576), LM vs POXC (r2 = 0.60, p=0.0408) and a strong negative correlation for BD vs LM (r2 = 0.96, p=<0.0001). Detrimental effects of CT were significant (p<0.05). This study highlighted importance and interrelationships of soil biogeochemical cycles in defining soil quality for sustainable ecosystem service and function.