Soil thermal properties influenced by perennial biofuel and cover crop management

Heat transport is an important factor that can influence the soil environment. The objective of this study was to determine if perennial biofuel and cover crops could alter soil thermal properties. Experimental treatments included two levels of cover crops (cover crops [CC] vs. no cover crops) [NC], collectively called row crops (RC), and two biofuel crop treatments. Cover crops used included cereal rye (Secale cereale L.), hairy vetch (Vicia villosa subsp. villosa), and Austrian winter pea [Pisum sativum subsp. arvense (L.) Asch. & Graebn]. The two biofuel treatments included perennial biofuel crops (PB): giant miscanthus (Miscanthus × giganteus J.M. Greef & Deuter ex Hodkinson & Renvoize) and switchgrass (Panicum virgatum L.). Soil samples were collected at 10-cm depth increments from the soil surface to a depth of 30 cm. Soil thermal properties (thermal conductivity [λ], volumetric heat capacity [CV], thermal diffusivity [D]), and volumetric water content (θ) were determined at 0, -33, -100 and -300 kPa soil water matric potentials. Additionally, bulk density and soil organic C (SOC) were determined. Results showed that PB had 11% higher CV at saturation, probably because they had significantly higher θ and SOC than RC management. Cover crops had 13% higher CV at saturation probably because they had significantly higher θ and SOC than no cover crop management. Row crops had significantly higher λ and D than PB. The results from the current study imply that CC and PB can change soil thermal properties by reducing λ and D and increasing CV under laboratory conditions

The value of manure - Manure as co-product in life cycle assessment

Research ArticleLivestock production is important for food security, nutrition, and landscape maintenance, but it is associated with several environmental impacts. To assess the risk and benefits arising from livestock production, transparent and robust indicators are required, such as those offered by life cycle assessment. A central question in such approaches is how environmental burden is allocated to livestock products and to manure that is re-used for agricultural production. To incentivize sustainable use of manure, it should be considered as a co-product as long as it is not disposed of, or wasted, or applied in excess of crop nutrient needs, in which case it should be treated as a waste. This paper proposes a theoretical approach to define nutrient requirements based on nutrient response curves to economic and physical optima and a pragmatic approach based on crop nutrient yield adjusted for nutrient losses to atmosphere and water. Allocation of environmental burden to manure and other livestock products is then based on the nutrient value from manure for crop production using the price of fertilizer nutrients. We illustrate and discuss the proposed method with two case studiesinfo:eu-repo/semantics/publishedVersio

No Tillage Improved Soil Pore Space Indices under Cover Crop and Crop Rotation

Assessment of the effects of crop management practices on soil physical properties is largely limited to soil moisture content, air content or bulk density, which can take considerable time to change. However, soil pore space indices evolve rapidly and could quickly detect changes in soil properties resulting from crop management practices, but they are not often measured. The objective of this study was to investigate how soil pore space indices—relative gas diffusion coefficient (Ds/Do) and pore tortuosity factor (τ)—are affected by tillage system (TL), cover crop (CC) and crop rotation (CR). A study was conducted on silt loam soil at Freeman farm, Lincoln University of Missouri during the 2011 to 2013 growing seasons. The experiment design was a randomized complete block with two tillage systems (no tillage or no-till vs conventional tillage), two cover crops (no rye vs cereal rye (Secale cereale L.)) and four crop rotations (continuous corn (Zea mays L.), continuous soybean (Glycine max L.), corn–soybean and soybean–corn successions). All the treatments were replicated three times for a total of 48 experimental units. Soils were collected from two sampling depths (SD), 0–10 and 10–20 cm, in each treatment and soil physical properties, including bulk density (BD), air-filled porosity (AFP, fa) and total pore space (TPS, Φ), were calculated. Gas diffusivity models following AFP and/or TPS were used to predict Ds/Do and τ values. Results showed that, overall, Ds/Do was significantly increased in no-tilled plots planted to cereal rye in 2012 (p = 0.001) and in 2013 (p = 0.05). No-tilled continuous corn, followed by continuous soybean and no-tilled soybean–corn rotations had the highest Ds/Do values, respectively. In magnitude, Ds/Do was also increased in no-till plots at the lower depth (10–20 cm). No-tilled plots planted with cereal rye significantly reduced τ in 2012 (p = 0.001) and in 2013 (p = 0.05). Finally, at the upper depth (0–10 cm), the no-tilled corn–soybean rotation and the tilled soybean–corn rotation had the lowest τ. However, at the lower depth (10–20 cm), the four crop rotations were not significantly different in their τ values. These results can be useful to quickly assess the changes in soil physical properties because of crop management practices and make necessary changes to enhance agricultural resilience

Soil Water Potential Control of the Relationship between Moisture and Greenhouse Gas Fluxes in Corn-Soybean Field

Soil water potential (Ψ) controls the dynamics of water in soils and can therefore affect greenhouse gas fluxes. We examined the relationship between soil moisture content (θ) at five different levels of water potential (Ψ = 0, −0.05, −0.1, −0.33 and −15 bar) and greenhouse gas (carbon dioxide, CO2; nitrous oxide, N2O and methane, CH4) fluxes. The study was conducted in 2011 in a silt loam soil at Freeman farm of Lincoln University. Soil samples were collected at two depths: 0–10 and 10–20 cm and their bulk densities were measured. Samples were later saturated then brought into a pressure plate for measurements of Ψ and θ. Soil air samples for greenhouse gas flux analyses were collected using static and vented chambers, 30 cm in height and 20 cm in diameter. Determination of CO2, CH4 and N2O concentrations from soil air samples were done using a Shimadzu Gas Chromatograph (GC-14). Results showed that there were significant correlations between greenhouse gas fluxes and θ held at various Ψ in the 0–10 cm depth of soil group. For instance, θ at Ψ = 0 positively correlated with measured CO2 (p = 0.0043, r = 0.49), N2O (p = 0.0020, r = 0.64) and negatively correlated with CH4 (p = 0.0125, r = −0.44) fluxes. Regression analysis showed that 24%, 41% and 19% of changes in CO2, N2O and CH4 fluxes, respectively, were due to θ at Ψ = 0 (p < 0.05). This study stresses the need to monitor soil water potential when monitoring greenhouse gas fluxes

Tillage, Cover Crop and Crop Rotation Effects on Selected Soil Chemical Properties

Research results still vary, especially between locations, on the effects of agricultural practices on soil chemical properties and crop yield, and not all reasons for the variation are fully understood. Thus, this study investigated the influence of tillage, cover crop and crop rotation management practices on selected soil chemical properties. The study was conducted on a silt-loam soil in central Missouri during the 2011 to 2013 growing seasons. The soil was managed by moldboard plow tillage at two levels (tillage [till] vs. no-tillage [NT]). Cover crop management included cereal rye (Secale cereale) at two levels (cover crop [CC] vs. no cover crop [NC]). The main crops that were grown were a corn (Zea mays L.) and soybean (Glycine max L.) rotation. The soil samples were collected each year at 0–10 cm, 10–20 cm, 20–40 cm and 40–60 cm depths for the analysis of soil chemical properties. The results showed that after 3 years of study, the relative increase in percent soil organic matter (OM) was 4% under the no-till management as compared with moldboard plow tillage. In addition, the relative change in the percentage of OM was 8% greater in the CC management compared with NC. Furthermore, the results show a significant improvement (p = 0.0304) in total carbon with a combination of no-till management and a corn/soybean rotation as compared with continuous corn and soybean. The interaction effects of the management practices on the soil chemical properties were difficult to predict throughout the study

Global trends in nature’s contributions to people

Declining biodiversity and ecosystem functions put many of nature’s contributions to people at risk. We review and synthesize the scientific literature to assess 50-y global trends across a broad range of nature’s contributions. We distinguish among trends in potential and realized contributions of nature, as well as environmental conditions and the impacts of changes in nature on human quality of life. We find declining trends in the potential for nature to contribute in the majority of material, nonmaterial, and regulating contributions assessed. However, while the realized production of regulating contributions has decreased, realized production of agricultural and many material commodities has increased. Environmental declines negatively affect quality of life, but social adaptation and the availability of substitutes partially offset this decline for some of nature’s contributions. Adaptation and substitutes, however, are often imperfect and come at some cost. For many of the contributions of nature, we find differing trends across different countries and regions, income classes, and ethnic and social groups, reinforcing the argument for more consistent and equitable measurement.info:eu-repo/semantics/publishedVersio

Dataset and Code Accompanying the Study by Medina-Vega et al. in Nature Ecology & Evolution: Tropical Tree Ectomycorrhiza Are Distributed Independently of Soil Nutrients

<p>This Zenodo repository contains the code and the processed dataset used in the research paper titled "Tropical tree ectomycorrhiza are distributed independently of soil nutrients" published in Nature Ecology & Evolution. In this study, we investigate the distribution and abundance of ectomycorrhizal (EcM) trees in lowland tropical forests and their relationship with soil quality.</p><p><strong>Key Finding</strong>: EcM-associated trees' distribution and abundance in lowland tropical forests are independent of soil quality.</p><p><strong>Contents</strong>:</p><ol><li><strong>Code (</strong>CODE_COARSE_SCALE.R and CODE_FINE_SCALE.R<strong>)</strong>: Contains the R scripts used for data analysis.</li><li><strong>Processed Dataset</strong> (PCs_prop_EcM.csv): Includes the processed data for the fine-scale analysis.</li><li><strong>README</strong>: Provides detailed information on how to use the code, interpret the dataset, and access additional required information.</li></ol><p><strong>Data Access Information</strong>:</p><ul><li>To perform the full analyses, please request additional data from the Principal Investigators (PIs) of the plots.</li><li>ForestGEO plot data can be obtained upon request through the ForestGEO portal at http://ctfs.si.edu/datarequest/.</li><li>Refer to Extended Data Table 1 in the manuscript for a comprehensive list of data sources.</li></ul&gt

Tropical tree ectomycorrhiza are distributed independently of soil nutrients

Mycorrhizae, a form of plant–fungal symbioses, mediate vegetation impacts on ecosystem functioning. Climatic effects on decomposition and soil quality are suggested to drive mycorrhizal distributions, with arbuscular mycorrhizal plants prevailing in low-latitude/high-soil-quality areas and ectomycorrhizal (EcM) plants in high-latitude/low-soil-quality areas. However, these generalizations, based on coarse-resolution data, obscure finer-scale variations and result in high uncertainties in the predicted distributions of mycorrhizal types and their drivers. Using data from 31 lowland tropical forests, both at a coarse scale (mean-plot-level data) and fine scale (20 × 20 metres from a subset of 16 sites), we demonstrate that the distribution and abundance of EcM-associated trees are independent of soil quality. Resource exchange differences among mycorrhizal partners, stemming from diverse evolutionary origins of mycorrhizal fungi, may decouple soil fertility from the advantage provided by mycorrhizal associations. Additionally, distinct historical biogeographies and diversification patterns have led to differences in forest composition and nutrient-acquisition strategies across three major tropical regions. Notably, Africa and Asia’s lowland tropical forests have abundant EcM trees, whereas they are relatively scarce in lowland neotropical forests. A greater understanding of the functional biology of mycorrhizal symbiosis is required, especially in the lowland tropics, to overcome biases from assuming similarity to temperate and boreal regions

U.S. cereal rye winter cover crop growth database

Abstract Winter cover crop performance metrics (i.e., vegetative biomass quantity and quality) affect ecosystem services provisions, but they vary widely due to differences in agronomic practices, soil properties, and climate. Cereal rye (Secale cereale) is the most common winter cover crop in the United States due to its winter hardiness, low seed cost, and high biomass production. We compiled data on cereal rye winter cover crop performance metrics, agronomic practices, and soil properties across the eastern half of the United States. The dataset includes a total of 5,695 cereal rye biomass observations across 208 site-years between 2001–2022 and encompasses a wide range of agronomic, soils, and climate conditions. Cereal rye biomass values had a mean of 3,428 kg ha−1, a median of 2,458 kg ha−1, and a standard deviation of 3,163 kg ha−1. The data can be used for empirical analyses, to calibrate, validate, and evaluate process-based models, and to develop decision support tools for management and policy decisions