Agricultural Management Systems Affect Soil Health and Crop Production in the Drylands of Eastern New Mexico PDF Download

Author: Vesh Raj Thapa
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Languages : en
Pages : 134

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Book Description
Agricultural management practices influence soil health, short-term nutrient cycling, and agroecosystem functioning in the semiarid drylands of the southern Ogallala aquifer region. The main objectives of this research were to (a) assess the effects of different management systems [ungrazed grassland (UGL), grazed grassland (GGL), and croplands with livestock grazed conventional tillage (LGCT), no-tillage (NY), and strip-tillage (ST) on selected soil health indicators measured at surface (0-0.2 m) and subsurface (0.2-0.4 m) soil depths and (b) evaluate short-term soil carbon (SOC) and nitrogen (N) dynamics, and crop production under different tillage systems [no-tillage (NT) and strip-tillage (ST)] and cover cropping practices (rye cover crop and no-cover crop) in drylands in the eastern New Mexico. The field experiment was established at the New Mexico State University, Agricultural Science Center (ASC) at Clovis, NM (34°35' N, 103°12' W, 1348 elevation) and nearby farmers' fields. The study at ASC, Clovis was established in a corn (Zea mays)-sorghum (Sorghum bicolor) rotation and cereal rye (Secale cereal L.) Cover cropping treatments were nested within each tillage system in 2016/17 and 2017/18. Soil samples were collected from all the plots in the summer 2017 from 0-0.4 m depth and analyzed for soil pH, electrical conductivity (EC), soil bulk density, SOC, soil particulate organic matter (POM), permanganate oxidizable carbon (POXC), POXC:SOC ratio, soil inorganic N, and wet aggregate stability (WAS) in the first study whereas soil pH, EC, soil inorganic N, potentially mineralizable nitrogen (PMN) and carbon (PMC), POXC, gravimetric soil water content (SWC) and wet aggregate stability (WAS) for 0-0.15 m depth were assessed in February, May, and October of 2017, and February 2018 in the second study. The results of the first study revealed that soils under grassland systems had more SOC content, POM content and higher aggregate stability than soils under cropping systems. Soil bulk density was significantly higher in croplands than in grasslands. Livestock grazing in conventional tillage cropping system improved SOC and POM whereas no-tillage and strip-tillage as well as grasslands increased macroaggregate stability. Soil disturbance in LGCT and ST increased N availability over GGL and UGL. Soil properties did not vary significantly between managements in sub-surface (0.2-0.4 m) depth. Results from the second study unveiled that soil pH and POXC were not significantly different between agricultural management practices, but EC was significantly higher under ST than under NT in both crop rotation phases in February, May and October 2017 sampling. Cover cropping increased PMC in no-tillage and strip-tillage. Strip tillage increased nitrogen availability in the soil than no-tillage. There was no significant effect of tillage systems and cover cropping treatments on crop yields. These studies suggested that reducing soil disturbance, restoring grasslands, and diversifying cropping system along with livestock-integration could increase soil carbon sequestration, improve social health, and increase nutrient cycling leading to the development of resilient dryland agroecosystems in the southern Ogallala aquifer region.