Agrosystems, Geosciences & Environment
ISSN / EISSN : 2639-6696 / 2639-6696
Published by: Wiley-Blackwell (10.1002)
Total articles ≅ 303
Latest articles in this journal
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20132
Soil organic matter (SOM) in managed grasslands have economic and environmental benefits. This experiment evaluated a stockpiled winter grazing system with two summer management treatments (grazing or hay harvest) and three forage species treatments: tall fescue (TF, Schedonorus arundinaceus Schreb.), switchgrass (SG, Panicum virgatum L.), and mixed big bluestem–Indiangrass [BBIG, Andropogon gerardii Vitman–Sorghastrum nutans (L.) Nash]. Soil was sampled on 18 dates (January 2016–July 2017) at two depths (0–5 and 5–15 cm) in 15 paddocks in central Tennessee. Total organic carbon and total nitrogen concentrations in 0–5‐cm samples were greater in grazed paddocks relative to hay harvest, and greater in TF relative to BBIG and SG. Summer grazing also resulted in greater 0–5‐cm permanganate‐oxidizable carbon (POXC) and 5–15 cm hot‐water extract ultraviolet absorbance at 254 nm (A254). Hot‐water extractable carbon, A254, and POXC concentrations were reduced in SG soils compared with TF and BBIG. Summer hay harvests, compared with grazing, reduced hot‐water extractable C/N in both soil horizons in TF. The interactions between management and plant species suggests contrasting nutrient cycling associated with TF and the morphologically different native grasses BBIG and SG. This study represents the first observations of soil impacts within stockpiled grazing systems and the first observations of grazed native grass species in the southeastern United States.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20135
Soils are the largest terrestrial C pool on Earth. However, most studies only investigated soil organic carbon (SOC) storage on surface soils layers. This has resulted in lack of knowledge on SOC dynamics in deep soil layers despite the fact that they contain a significant portion of the stored organic C. This study assessed how contrasting land uses and agronomic practices affect SOC stocks up to a 5‐m depth, and investigated superficial SOC concentration, and particle and density fractionation in a case study in the U.S. Southeastern Plains. On average, deep (90–500 cm) SOC accounted for 80% of total organic C across the investigated land‐use systems. A close relation between SOC concentration and Mehlich‐3 extractable Al and Fe concentration in deep soil samples suggested that non‐crystalline metals play a key role stabilizing deep SOC in this system. Land use had a significant effect only on superficial SOC concentration, and light, heavy, and mineral associated organic C within micro and macroaggregates. Soils from native vegetation, and non‐irrigated sod‐based rotation plots showed greater concentrations of SOC in almost all assessed micro and macroaggregates fractions, whereas those from the conventional crop rotation and irrigated sod‐based rotation plots showed lower SOC concentration in all assessed fractions.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20116
Soybean [Glycine max (L.) Merr.] yield has increased over time through the introduction of new varieties and improved agronomic practices. However, seed protein concentration has decreased. We conducted field studies in 2018 and 2019 to investigate the effects of fungicide, insecticide, and foliar fertilizer application on grain yield and seed quality in two soybean maturity groups (MG). In‐season treatments targeted nutrient availability and soybean canopy duration during the seed‐filling period by fungicide, insecticide, or foliar fertilizer application at the onset of this period. Biomass samples were collected at R5, R6, and R7 and partitioned into plant parts. Year, location, and MG often influenced yield and seed composition, but foliar fungicide, insecticide, or fertilizer application had no impact on these parameters.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20157
Management of manure and cereal rye (Secale cereale L.) has implications for crop production and nutrient cycling. This 1‐yr, full‐factorial experiment conducted in Pennsylvania quantified the effects of three management factors—(a) rye management (RyeM; early‐terminated cover crop [CC] vs. double crop harvested a week later [DC]), (b) manure application method (ManM; unincorporated broadcast manure [BM] vs. shallow disk injected manure [IM]), and (c) fall field operation prioritization (priority; manure priority [MP] manure application in late September with rye planting in mid‐October vs. rye priority [RP], rye planting in late September with manure application in early November)—on rye biomass, nutrient recovery, and forage yield and the effect of ManM and priority on DC forage nutritive value in a rye–corn (Zea mays L.) cropping sequence. This experiment was intended to be a repeated 2‐yr study, but due to MP treatment rye crop failure in the second year, the resulting 1‐yr dataset was analyzed to assess priority effects. Prioritizing rye planting in the fall with DC increased total forage production and apparent N recovery (ANR) when manure was broadcast. These results highlight the value of prioritizing fall rye planting in DC systems to increase rye spring biomass and nutrient recovery when manure is broadcast. More experiments should be conducted on fall field operation timing to develop reliable recommendations.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20182
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Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20175
Crop production is reduced by insufficient and/or excess soil water, which can significantly decrease plant growth and development. Therefore, conservation management practices such as cover crops (CCs) are used to optimize soil water dynamics, since CCs can conserve soil water. The objective of this study was to determine the effects of CCs on soil water dynamics on a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation at three soil depths over 3 yr. The study was conducted at the Chariton County Cover Crop Soil Health Research and Demonstration Farm (CCSH) in Missouri. Initial CC establishment occurred in 2012. Volumetric soil water content (VWC) was monitored at 15-min intervals with calibrated Waterscout SM100 soil moisture sensors (Spectrum Technologies) at three depths (10, 20, and 30 cm) in 2016, 2017, and 2018. Cover crop soils maintained numerically higher VWC values compared with no CC (NCC) at both 10- and 20-cm depths throughout the study period where the differences were significant in some weeks. The subsurface soil water recharge was greater in CC soils at both 10- and 20-cm depths compared with NCC in March 2017. The results imply that CC soils have maintained higher VWC levels during vegetative period of the CC growth where the differences were significant in some weeks compared with NCC at all three soil depths. These findings can be used to promote CC adoption for better soil water storage and develop CC management plans for corn–soybean rotations on claypan soils.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20181
Management-intensive grazing (MiG) on irrigated, perennial pastures has steadily increased in the western United States due to pressure for reducing public lands grazing, overall declining land available for pasture, and decreasing commodity prices. However, there are still many unknowns regarding MiG and its environmental impact, especially with regards to soil health. Over a 2-yr period, a study evaluating the change in soil health under a full-scale, 82-ha pivot-irrigated perennial pasture system grazed with ∼230 animal units (AUs) using MiG. Soil analysis included 11 soil characteristics aggregated into the Soil Management Assessment Framework (SMAF), which outputs results for soil biological, physical, nutrient, chemical, and overall soil health indices (SHIs). Over time, positive impacts were observed in the chemical and biological SHI due to decreases in salt content and increases in microbial and enzymatic activities. Soil organic C (SOC) remained unchanged, yet positive biological SHI changes are potential precursors to future SOC increases. The chemical and nutrient SHI increased in the soil surface due to reductions in salt content in conjunction with increased plant-available soil P, as a result of salt leaching via irrigation and pre-study inorganic P fertilizer application in conjunction with manure deposition due to MiG, respectively. Finally, a negative impact was also observed in the physical SHI, driven primarily by increasing bulk density due to hoof pressure from cattle grazing. If managed correctly, compaction issues can be avoided, with MiG systems having potential success in supporting grazing while promoting soil health for environmental and economic sustainability.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20205
Edge-of-fieldwater quality monitoring was conducted in cooperation with private landowners through the Mississippi River Basin Healthy Watershed Initiative, a landscape conservation program first offered through the USDA-NRCS in 2010. The study objective was to quantify effectiveness of individual conservation practice or practice combinations on water quality on corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] watersheds. Water samples from northern Missouri farms were collected and analyzed by runoff event for sediment (total suspended solids [TSS]), N, and P to evaluate the effects of crop production, residue types, and conservation land treatment on runoff. The presence of living vegetation in the winter, whether established as a cover crop or cash crop, significantly reduced the sediment loads (p < .0001) and nutrient loads (p ≤ .0077). Additional benefits occurred on sites that produced higher residues, like corn or corn with winter wheat (Triticum aestivum L.). Significantly low TSS losses occurred during soybean years with corn and winter wheat residues. Sites that implemented full land treatment, having conservation practices that serve to avoid, control, and trap a pollutant, were more effective than those with fewer treatments, especially with respect to P loading. The mean rank for orthophosphates was 45% lower from sites with avoid, control, and trap practices instead of control practices only. Data support the conclusion that conservation structural and management practices are effective and can mitigate some negative impacts generated by agriculture. Although an intricate endeavor, edge-of-field water quality monitoring can serve to complement other forms of environmental analysis and inform landowners about efficient farming practices.
Published: 1 January 2021
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20176
A randomized complete block design experiment was performed in a growth chamber study to evaluate the short-term impact of N amendment source on CO2 fluxes, aggregate stability, and aboveground plant biomass. Large intact soil cores (n = 6) were each segmented into three subplot treatment sources: (a) organic N (ORG-N); (b) inorganic N (UAN-32); and (c) no N added (no-N), with both N sources applied at rates of 27.5 kg N ha–1. The experiment was run for 130 d, representing one growing season of winter wheat (Triticum aestivum L.). Soil CO2 fluxes accumulated during the growing season were 47.1, 36.6, and 24.6 mol m–2 for ORG-N, UAN-32, and no-N treatments, respectively. Significantly higher aboveground plant biomass was harvested in the N source treatments compared with no-N. Aggregate stability in ORG-N was significantly higher than inorganic sources, UAN-32 (p < .05). This study highlights that even over a short-term study, organic N sources can increase soil biological activity and aggregation processes, indicating an increased capacity for several soil functions.
Agrosystems, Geosciences & Environment, Volume 4; https://doi.org/10.1002/agg2.20163
Excessive nutrient loss threatens local and regional water resources, and many midwestern U.S. states are adopting nutrient reduction strategies to reduce export of N and P. A common practice to reduce N loss is improved fertilizer management. In this study, we used a strip trial design to assess the effects of split N application form (urea and urea ammonium nitrate [UAN]) and placement method (broadcast, coulter, Y-drop) on corn (Zea mays L.) yields and shallow groundwater quality at an agricultural field at Kirkwood Community College in Cedar Rapids, IA. Twelve shallow monitoring wells were installed within the production field and sampled 14 times across a corn–soybean [Glycine max (L.) Merr.] rotation. Results showed that split application of UAN applied with either coulter injection or Y-drop method produced approximately 8–11% higher corn yields than broadcast urea, but no statistically significant relation was found between groundwater quality and N form and placement method. Instead, we report that groundwater quality and levels were significantly influenced by variations in aquifer lithology. Groundwater within fine-textured glacial till had significantly higher dissolved reactive P, SO4, and specific conductivity, whereas groundwater within the sand aquifer had a deeper water table and had higher NO3–N and dissolved oxygen. Study results suggest aquifer lithology can play a much larger role than varying the N form and application method on shallow groundwater quality in agricultural fields.