About the Journal

Agrosystems, Geosciences & Environment is a gold open access journal publishing studies limited in geography or time, confirmatory articles, and reports of negative results, focusing on all aspects of agriculture, plant, environmental, and soil science.

Featured Article

AGE Cover 02-2019
2021 AGE Outstanding Paper: Genotype × Environment Interactions of Industrial Hemp Cultivars Highlight Diverse Responses to Environmental Factors

Starting with the 2014 Farm Bill, hemp is being reintroduced as an industrial crop in the United States. Since the crop has been absent for over 70 years, little is known regarding the genetic mechanisms controlling economically relevant traits. In this study, Campbell et al. conducted cultivar trials under multiple environments in Colorado to assess performance characteristics of a diverse set of germplasm from breeding programs across Europe and Asia. Read more

Browse Articles

Open access

Multispecies cover crops in organic agricultural systems in the upper U.S. Midwest

  •  10 November 2021

Core Ideas

  • We established cover crop mixes in a tilled organic system.
  • Different cover crop mixes did not negatively affect yield of main crop.
  • Weather caused more variation in cover crops than did specific mixes.
  • Except for small grain main crop, cover crops were not successful when planted into or after main crops.

Open access

Gateway‐node wireless data collection system for environmental sensing

  •  30 October 2021

Core Ideas

  • Microcontrollers provide low-cost options for remote environmental sensing.
  • Gateway-node network architecture reduces cost of wireless data logging.
  • Printed circuit boards reduce assembly time and increase production capability.
  • Stable wireless communication and low power consumption are key factors to success.

Open access

Variation in degree of pollen exclusion for ga1‐s unilateral cross incompatibility in temperate maize breeding populations

  •  30 October 2021

Core ideas

  • Unilateral cross incompatibility can be used to maintain hybrid genetic purity.
  • We measured ga1 pollen exclusion of heterozygous Ga1-s/ga1 hybrid plants of different genotypes.
  • We evaluated the effect of heterotic group on ga1 pollen exclusion of Ga1-s/ga1 heterozygotes.

Open access

Characterizing expansiveness and iron reducibility of red‐clay soils for the purpose of on‐site wastewater system placement in Arkansas

  •  25 October 2021

Core Ideas

  • Some soils derived from problematic red parent materials do not show redoximorphic features.
  • Non-iron-reducing, expansive soils with large clay contents limit suitability for on-site systems.
  • Clayey soils that show iron reduction and do not expand may be suitable for an on-site system.

Cover Image, Volume 4, Issue 4

  •  24 October 2021

Abstract

On the cover: Root washing before placement into litter bags for determining root decomposition in soils at a silvopastoral site. See Ashworth et al., “Root decomposition in silvopastures is influenced by grazing, fertility, and grass species,” https://doi.org/10.1002/agg2.20190. Photo by Amanda Ashworth.

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Open access

World Cereal Nitrogen Use Efficiency Trends: Review and Current Knowledge

Abstract

Core Ideas

  • Cereal N use efficiency was estimated at 35, 41, 30, and 21% for the world, the United States, China, and India, respectively.
  • There was a trend for increased N fertilizer consumption for agricultural use.
  • Best N fertilizer management practices could improve N use efficiency.

Two decades ago, world cereal nitrogen use efficiency (NUE) was documented at 33%. Since then, research addressing NUE has advanced. However, there are no current estimates to communicate whether or not research efforts and recent advances have contributed to improved NUE. With the apparent trends for increasing greenhouse gases, NUE values could be used as a management tool for agronomic and environmental sustainability. Our objective was to provide current estimates and trends of NUE for the world and selected countries for cereal crops cultivated in relatively large quantities. Data from the Food and Agriculture Organization (www.fao.org/faostat) website were used to compute NUE. The difference method was employed to derive NUE and trends. Results indicated that cereal NUE in 2015 was 35, 41, 30, and 21% for the world, the United States, China, and India, respectively. Compared with 33% reported in 1999, there was insignificant trend of increase (r2 = 0.01) from 2002 to 2015 for cereal world NUE (p > 0.05). Low NUE for China and India was due to high N consumption. A slight improvement for the United States from 31% in 2002 to 41% in 2015 (r2 = 0.20) could be a result of using improved cultivars and precision crop management. Increasing cereal NUE in the United States echoes the value of new technologies and the heightened importance of the environment. Recognizing year-to-year variability in N fertilizer requirement and implementing a systematic approach that combines agronomic recommendations with improved crop varieties could further improve NUE.

Open access

Topographic Controls on Soil Nutrient Variations in a Silvopasture System

Abstract

Core Ideas

  • Topographic variation influenced soil nutrient distribution in a silvopasture system.
  • High-resolution digital maps of soil nutrients were generated.
  • Terrain attributes identified topographic functional units as management zones.
  • Level of soil nutrients in topographic functional units were different.

Topography plays a crucial role in spatial distribution of nutrients in soils; however, studies to quantify topographic influence on soil nutrient distribution from a silvopasture system are mostly lacking. To address this question, a 4.3-ha silvopasture site in northwest Arkansas was selected and a total of 51 topsoil (0–15 cm thickness) samples were collected and analyzed for primary (total N [TN], P, K), secondary (Ca, Mg, S), and micronutrients (Fe, Zn, Cu, Mn, B, Na). Topographic information was acquired from 12 terrain attributes derived from a 1-m digital elevation model. The prediction model was based on random forest. Results showed TN, S, and P were best predicted, whereas Cu, Ca, and Mn had the lowest prediction performance. Levels of S, Ca, Zn, Fe, and TN increased with SAGA wetness index, valley depth, flow accumulation, and multi-resolution valley bottom flatness index. Normalized height and slope height were positively related to Na but negatively to B and Cu distribution. Aspect had a positive influence on P and Mg concentrations. Based on terrain attributes, the study site could be divided into four topographic functional units (TFU), namely A, B, C, and D; TFU A had the highest nutrients present, whereas TFU B had the lowest P, K, Zn, Cu, Fe, and Ca but highest Na content. However, Mn, Mg, and B did not vary among TFUs. This study affirmed topographic influences on soil nutrient distribution, and the resulting continuous soil nutrient maps are useful for fine-tuning production systems through optimum nutrient and pasture management.

Open access

Consistency of the Threshold Phosphorus Saturation Ratio across a Wide Geographic Range of Acid Soils

Abstract

Core Ideas

  • Establish a common threshold in P saturation across a geographic diversity of soils.
  • Predict water-soluble P from soil P storage capacity to guide fertilizer strategies.
  • Relate runoff P concentration with soil P storage capacity.

Loss of legacy soil phosphorus (P) due to historical over-application of fertilizers and manures can result in eutrophication of water bodies. The soil P storage capacity (SPSC) has been proposed as a tool to estimate the capacity of humid region soils to act as either sinks or sources of P to runoff or leaching. The SPSC is based on a threshold molar ratio of extractable P/(Al+Fe), called the soil P saturation ratio (PSR), above which water-soluble P abruptly increases. Objectives were to (i) document consistency of the threshold PSR for a wide geographic range of acid soils, (ii) determine applicability of a SPSC vs. water-soluble P predictive equation to soils from various regions, and (iii) relate SPSC with water quality parameters. Surface samples were collected from acidic, humid-region soils encompassing multiple physiographic provinces of the United States. Water quality data, including dissolved reactive P and total P, were obtained from various study sites. Phosphorus, Fe, and Al in Mehlich 3 solutions were determined, and PSR and SPSC calculated. The threshold PSR based on 186 samples is 0.1, indicating a common threshold across the geographic range of this study. Phosphorus concentrations in runoff related closely with SPSC, PSR, and M3-P values of soils that were the source of the runoff. However, SPSC has the additional potential of estimating extent of legacy P loss at excessive concentrations for soils of eastern and central United States. Results support general applicability of PSR and SPSC for acid soils.

Open access

Genotype × Environment Interactions of Industrial Hemp Cultivars Highlight Diverse Responses to Environmental Factors

Abstract

Core Ideas

  • Some hemp traits are more strongly affected by environmental factors than others.
  • Multi-environment testing is an integral part of hemp cultivar development.
  • Water availability can have a significant impact on yield and other traits.

Starting with the 2014 Farm Bill, hemp (Cannabis sativa L.) is being re-introduced as an industrial crop in the United States. Since the crop has been absent for over 70 yr, little is known regarding the genetic mechanisms controlling economically relevant traits. Particularly, with federal legality of the crop hinging on a stringent tetrahydrocannabinol (THC) content of 0.3% or less, it is necessary to assess variance in this trait due to environmental effects and genotype × environment interactions (GEI) to avoid running afoul of federal law. Understanding how physical and biochemical traits respond to the environment also plays a strong role in selecting and developing appropriate cultivars for production in diverse growing regions. In 2016 we performed cultivar trials in multiple environments in Colorado to assess performance characteristics of a diverse set of germplasm from breeding programs across Europe and Asia. From these data, we were able to identify traits nearly entirely controlled by genetic factors, like days to maturity and THC and cannabidiol (CBD) production. We also identified traits strongly influenced by the environment and GEI, like grain yield, plant height, and water use. Individual cultivars also exhibited widely varying degrees of sensitivity to the environment. This underscores the importance of continued work to characterize genetic control of hemp traits to expedite breeding of cultivars that are well-adapted to target growing regions.

Open access

Glyphosate‐Resistant Soybean Response to Micro‐Rates of Three Dicamba‐Based Herbicides

Abstract

Core Ideas

  • The impact of simulated dicamba drift on growth and yield of glyphosate-resistant soybean was similar among dicamba formulations.
  • The impact of dicamba drift on soybean could be influenced by moisture condition of the environmental field.
  • Late vegetative or early flowering stage of soybean was the most sensitive growth stage to dicamba drift.

New dicamba-based herbicides such as Engenia (N,N-bis-(3-aminopropyl) methylamine salt) and XtendiMax (diglycolamine salt) with VaporGrip technology were developed to reduce dicamba volatility and drift; however, there are claims that these products can still volatilize or drift. Field studies were conducted to evaluate glyphosate (N-(phosphonomethyl)glycine))–resistant (GR) soybean response to micro-rates (0, 1/1000, 1/500, 1/100, 1/50, and 1/10 of the label rate, 560 g a.e. ha−1) of the two new dicamba products compared with Clarity (diglycolamine salt) applied at three growth stages. The GR soybean [Glycine max (L.) Merr.] was equally impacted by the micro-rates of all three products as measured by visual injury, height reduction, delayed physiological maturity, and yield reduction. The greatest visual injury (80%), plant height reduction (65%), maturity delay (22 d), and soybean yield loss (96%) was caused by 1/10 of the dicamba label rate when applied at V7/R1 soybean growth stage. In addition, estimation of effective dose for 5, 10, or 20% yield reduction suggested that V7/R1 was the most sensitive soybean growth stage to the three dicamba products. For example, 10% yield reduction occurred when 1.83 to 1.85 g a.e. ha−1 (∼1/300 of the label rate) of Engenia was applied at V2 or R2, whereas, a lower dose of 0.32 g a.e. ha−1 (1/1750 of the label rate) of Engenia caused the same level of yield reduction when applied at V7/R1. Similar doses were estimated for Clarity and XtendiMax; therefore dicamba drift should be avoided at all costs, because GR soybean was equally sensitive to low rates of all three tested products with different formulations or technologies.

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