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Aggregate re‐formation after a disturbance is important for maintaining soil hydraulic status and carbon stabilization. A study investigating the re‐formation of aggregates after disturbance by spring tillage was conducted at a site located on a south‐facing (6%) slope with a silt‐loam soil at Arlington‐Wisconsin in 2018 and 2019. Treatments were conventional tillage (CT) and no‐tillage (NT) with winter application of solid manure (SM) and no manure in a complete randomized design. Soils under NT had a higher proportion of larger aggregates (>1 mm), whereas the proportion of smaller (<1 mm) aggregates was greater under CT. Soil organic carbon, total nitrogen, bulk density, soil water retention, and micropores of NT treatments were higher compared to CT systems at 0‐ to 5‐cm depth. However, the impacts of manure application on soil properties were not significant, except for those of soil organic carbon (SOC) and total nitrogen. Harvesting in 2018 decreased the relative proportion of aggregates smaller than 1 mm and hydraulic conductivity of saturated soil. These results indicate that the immediate effect of tillage is to decrease larger aggregates, SOC, and total porosity, whereas harvesting decreases the proportion of smaller aggregates. Comparatively, aggregates smaller than 1 mm were mainly influenced by the long‐term effects of the management operations. It appears that larger aggregates can recover on an annual basis, but aggregates smaller than 1 mm do not. In long‐term studies, there is a need to monitor aggregates, including their size distribution and pore structures, to identify aggregate turnover time and rate, which will augment our understanding of aggregate formation. Core Ideas: No‐till developed larger aggregates while conventional tillage lead formation of smaller aggregates.The greater proportion of larger aggregates was linked to higher soil organic carbon (SOC), nitrogen, and bulk density (ρb).Immediate effects of management reduced soil structure due to higher ρb and lower SOC.Note that 1‐ to 4‐mm aggregates were not maintained after tillage disruption.Aggregates <1 mm cannot re‐form annually since they are related to long‐term effect. [ABSTRACT FROM AUTHOR]

Simple Summary: Minimizing the effects of climate change by reducing GHG emissions is crucial and can be accomplished by truly understanding the carbon footprint phenomenon. This study aims to improve the understanding of carbon footprint alteration due to agricultural management and fertility practices. It provides a detailed review of carbon footprint management under the impacts of environmental factors, land use, and agricultural practices. The results show that healthy soils have numerous benefits for the general public and especially farmers. These benefits include being stable and resilient, resistant to erosion, easily workable in cultivated systems, good habitat for soil micro-organisms, fertile and good structure, large carbon sinks, and hence lower carbon footprint. Intensive tillage is harmful to soil structure by oxidizing carbon and causing GHG emissions. If possible, no-till; if not, minimum tillage frequency and depth of tillage, and optimum moisture are recommended. The soil should be at an appropriate level of moisture when tillage takes place. Diverse cropping systems are better for the soil than monocultures. Minimizing machinery operations can help to avoid soil compaction. Building soil organic carbon in the most stable form is the most efficient practice of sustainable crop production. Global attention to climate change issues, especially air temperature changes, has drastically increased over the last half-century. Along with population growth, greater surface temperature, and higher greenhouse gas (GHG) emissions, there are growing concerns for ecosystem sustainability and other human existence on earth. The contribution of agriculture to GHG emissions indicates a level of 18% of total GHGs, mainly from carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Thus, minimizing the effects of climate change by reducing GHG emissions is crucial and can be accomplished by truly understanding the carbon footprint (CF) phenomenon. Therefore, the purposes of this study were to improve understanding of CF alteration due to agricultural management and fertility practices. CF is a popular concept in agro-environmental sciences due to its role in the environmental impact assessments related to alternative solutions and global climate change. Soil moisture content, soil temperature, porosity, and water-filled pore space are some of the soil properties directly related to GHG emissions. These properties raise the role of soil structure and soil health in the CF approach. These properties and GHG emissions are also affected by different land-use changes, soil types, and agricultural management practices. Soil management practices globally have the potential to alter atmospheric GHG emissions. Therefore, the relations between photosynthesis and GHG emissions as impacted by agricultural management practices, especially focusing on soil and related systems, must be considered. We conclude that environmental factors, land use, and agricultural practices should be considered in the management of CF when maximizing crop productivity. [ABSTRACT FROM AUTHOR]

Core IdeasManure improved soil hydrological properties in comparison with those of inorganic fertilizer and control.Manure decreased soil bulk density but increased C stocks and water retention compared with inorganic fertilizer.The higher rate of manure decreased soil bulk density and increased C stocks compared with lower rates of manure and inorganic fertilizer. Manure can enhance soil organic carbon (SOC) and soil hydrological properties, such as soil water retention (SWR) and water infiltration (qs), which are crucial for crop production. The present study was conducted to investigate the impacts of different rates of manure (low, medium, and high) and inorganic fertilizer (INF) on soil bulk density (ρb), penetration resistance (SPRc), SWR, and qs at two long‐term experimental sites located in eastern South Dakota. The study sites were established under reduced‐till corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation. Dairy solid manure was used for the Brookings site, whereas beef solid manure was used for the Beresford site. On an average, manure application (1.02 Mg m−3) reduced the ρb by 19% compared with INF application (1.27 Mg m−3) at 0‐ to 10‐cm depth for the Brookings site and by 11% for the Beresford site (manure, 1.08 Mg m−3; fertilizer, 1.21 Mg m−3). Soil qs was significantly increased by 33 and 29% at the Brookings site and by 43 and 36% at the Beresford site under manure application compared with the INF and control. On average, SWR with manure application was higher compared with that of fertilizer at both depths for the Brookings and Beresford sites. Pearson correlation analysis showed that ρb and SPRc were negatively correlated and that SOC stock and qs were positively correlated with SWR and pore size distributions. This study showed that long‐term manure application can be beneficial in enhancing soil physical and hydraulic properties, which can enhance crop production. [ABSTRACT FROM AUTHOR]

Switchgrass (Panicum virgatum L.) production for biofuel has the potential to produce reasonable yields on lands not suited for conventional agriculture. We assessed nine switchgrass cultivars representing lowland and upland ecotypes grown for 11 years at a site in the upper Midwest USA for belowground differences in soil carbon and nitrogen stocks, soil organic matter fractions, and standing root biomass to 1 m depth. We also compared potential nitrogen mineralization and carbon substrate use through community‐level physiological profiling in surface soils (0–10 cm depth). Average yields and standing root biomass differed among cultivars and between ecotypes, but we found no significant cultivar‐related impacts on soil carbon and nitrogen stocks, on the distribution of particulate and mineral‐associated soil organic matter fractions, nor on potential nitrogen mineralization or microbial community‐level physiological profiles. That these traits did not differ among cultivars suggests that soil carbon and nitrogen gains under switchgrass are likely to be robust with respect to cultivar differences, and to this point not much affected by breeding efforts. [ABSTRACT FROM AUTHOR]

Manure enhances soil fertility and crop yield; however, an optimum rate of manure application is important to avoid any negative impacts to soils and the environment. This study was conducted to assess the long-term impacts of manure and inorganic fertilizer rates on soil organic carbon (SOC), total nitrogen (TN), water stable aggregate (WSA), pH, and electrical conductivity (EC) under corn (Zea mays L.)-soybean (Glycine max L.) rotation at Beresford (established in 2003) and Brookings (established in 2008), South Dakota (SD). Study treatments included low (LM), medium (MM) and high (HM) manure, medium (MF) and high (HF) inorganic fertilizer, and control (CK). Soil samples were extracted from four replicates at 0- to 10-cm, 10- to 20-cm, 20- to 30-cm and 30- to 40-cm depths from either site in 2015. Results showed that manure application maintained the soil pH at 0 to 10 cm depth; whereas, inorganic fertilizer decreased it compared to the control treatment at either site. The highest SOC concentrations at 0- to 10-cm depth were observed under HM (38.3 g kg-1) as compared to that under MM (30.9 g kg-1), LM (27.6 g kg-1), MF application (24.0 g kg-1), HF (25.8 g kg-1) and CK (23.3 g kg-1). Furthermore, HM treatment significantly increased SOC for each depth increment from 0- to 40-cm compared to the inorganic fertilizer at either site. A similar trend was observed for the TN but differences were not always significant. On an average, manure increased the EC (1.56 dS m-1) by 2.2 times compared to that of fertilizer (0.71 dS m-1) for 0- to 10-cm depth. Similarly, manure significantly increased WSA by 7.2 and 5.6% compared to that of fertilizer at 0- to 10-cm depth for Brookings and Beresford, respectively. Data from this study concluded that the long-term annual application of manure improved selected soil properties compared to that of inorganic fertilizer. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the impacts of dairy manure and inorganic fertilizer on soil surface greenhouse gases (GHG) [carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 )] fluxes from soils managed under corn ( Zea mays L.)-soybean ( Glycine max L.) rotation. The experiment was established on a silty loam soil, and the treatments included three manure application rates [phosphorus based recommended rate (low manure, LM), nitrogen based recommended rate (medium manure, MM) and two times recommended nitrogen rate (high manure, HM)], two inorganic fertilizer levels [recommended fertilizer (medium fertilizer, MF) and high rate of fertilizer (HF)], and control (CK) replicated four times. Soil GHG fluxes were monitored once a week during the growing season for 2015 and 2016. Data from this study showed that there were not any significant impacts from manure and inorganic fertilizer applications on the annual CH 4 fluxes in 2015 and 2016. However, annual soil surface CO 2 fluxes were increased by manure treatments compared to inorganic fertilizer treatments in both the years. In contrast, manure treatments decreased N 2 O fluxes, but significantly increased net GWP than the fertilizer treatments in 2016. In general, higher manure and fertilizer rates resulted in higher annual GHG emissions compared to lower manure and fertilizer rates in both years. Data from this study showed that HF application in crops can be detrimental for the environment by emitting higher GHG emissions, therefore, improved application strategies for manure and fertilizer management need to be explored to avoid any negative environmental impacts. [ABSTRACT FROM AUTHOR]

The use of crop residues for biofuel production has the potential to provide environmental and economic benefits to modern societies. Because of the profound impacts that crop residues have on agricultural productivity and soil health, a sustainable utilization of these residues is required. Thus, we determined crop yield and quality response for a range of biomass retention rates in grain cropping systems. Combinations of corn (Zea mays L.) stover (0, 3.33, 6.66 and 10 Mgha−1) and wheat (Triticum aestivum L.) straw (0, 1.0, 2.0, and 3.0 Mgha−1) were soil applied in a corn-wheat/soybean (Glycine max L. Merr.) rotation in Virginia's Coastal Plain. Corn stover (0, 3.33, 6.66, 10 and 20 Mg ha−1) was applied in a continuous corn cropping system in the Ridge/Valley province. For each system, residues were applied following grain harvest over two production cycles. Each experiment was conducted as a randomized complete block design with four replications. Two cycles of crop residue management, with retention rates of up to 20 Mg ha−1 of corn stover retention in Blacksburg, and up to 13 Mg ha−1 of corn stover and wheat straw in New Kent, had no effect on total nitrogen (TN) and carbon (TC) concentrations, CN ratios, bulk density (BD), soil pH, field capacity, permanent wilting point, plant available water and water aggregate stability across soil depths and aggregate sizes in Virginia. In one situation when residue management slightly affected BD (0–2.5 cm depth, NK1), differences across the sixteen total retained residues treatments were less than 5%, thus rendering them not biologically or environmentally meaningful. Overall, results of this study did not show any clear short-term impact, resulting from various rates of crop residue retention in Virginia cropping systems. These incipient negative impacts resulting from very low rates of residue return warrant further studies to corroborate whether these results are to be found following long-term scenarios of crop residue management. [ABSTRACT FROM AUTHOR]

• Aggregate size distribution is an important indicator of physical C stability. • The physical C stabilization and aggregation relies on the range of silt content. • SSA, silt, clay, and albite contents contributed to higher SOC, DR and aggregation. • Agriculture lowered aggregation and SSA where erosion lowered DR, C: N, δ13C and δ15N. • Soil δ13C was higher at deeper depths but aggregation was not related to depth. Soil physical structure under different land-uses is influenced by many factors and conditions in and around the soil environment, especially aggregate size distribution, aggregate stability, SOC, and soil particle size distribution. These soil properties, in turn, are also affected by a variety of mechanisms and factors. The present study focuses on increasing our understanding of the coupled interaction between C stabilization, different aggregate sizes, and the role of relative proportion of soil minerals on this interaction in different ecosystems. Five fields on two soil series were identified to study these mechanisms, where each field represented one long-term (>20 years) land-use. The C f had lower disaggregation reduction (DR) in 1 – 2 mm aggregates, relative mass of aggregates smaller than 0.5 mm, and specific surface area (SSA) in bulk soil (BS) at 0 – 30 cm depth among non-eroded fields. However, W f had a significantly higher C:N ratio, δ13C, and δ15N. Interestingly, the mass of 1–2 mm aggregates and DR were correlated to silt content across the five land-uses at all depths, but not with clay content. Further, the relative percentage of quartz was positively correlated with the mass of smaller aggregates. In contrast, albite and clay minerals were positively correlated with the mass of 1–2 mm aggregates, DR, and C: N of 1 – 2 mm aggregates. Moreover, SSA in BS was positively correlated with 2–4 mm aggregates but negatively correlated with aggregates smaller than 1 mm. Given the nature of how aggregates of different sizes form, soil aggregate size distribution and SSA would be as likely an important factor when considering the physical stability of SOC. In addition, the physical stabilization of SOC and aggregate size distribution appears to be affected by the dominant soil particle, which was silt with a range of 60–76% in this study. [ABSTRACT FROM AUTHOR]

Manure impacts labile pools of soil organic carbon (SOC) and nitrogen (N) which can influence soil microbial composition (MCC) and enzyme activities, and hence soil health. The present study was conducted to investigate the impacts of long-term dairy manure and inorganic fertilizers (INF) on soil carbon (C) as well as nitrogen (N) fractions, enzyme activities, and microbial community structure in different time horizons at planting (P), one month after planting (1MAP), and after harvesting (H) under corn (Zea mays L.)-soybean (Glycine max L.) rotation. Study treatments included three manure application rates (low, phosphorus-based recommended rate; medium, nitrogen-based recommended rate; and high, the double rate of medium nitrogen based recommended rate), two INF rates (medium only nitrogen additions; and high nitrogen, phosphorus, potassium, zinc, and sulfur additions) and a control (no application of manure and/or inorganic fertilizer). In comparison to the INF, the dairy manure not only significantly increased chemical fractions of C and N but also impacted the enzyme activities. Average urease activity after manure was applied was shown to be 26.8% higher than it was with INF applied at planting. The β-Glucosidase activity was 6 and 14% higher with manure than it was with INF at 1MAP and harvesting, respectively. The cold-water extractable nitrogen (CWEN) was enhanced with high manure rate at all timings of sampling compared to the high fertilizer rate (53%), and CK (90%). Principal component analysis indicated that MCC under manure differed from those under the INF treatments. The total bacteria/total fungi ratio at planting was increased with the INF compared to the manure addition. Pearson's correlation analysis showed that CWEC, CWEN, and enzyme activities especially β-Glucosidase activity were the key determinants of MCC. Data from this study showed that, compared to inorganic fertilizers, manure can be beneficial in enhancing soil health indicators. [ABSTRACT FROM AUTHOR]

• Soil profile had a considerable variation of soil properties and SQI with depth and within horizons. • Cubist model can be used to predict SQI. • The grid soil sampling can be used to characterize soil properties and SQI in soil profile wall. • Combined Vis-NIR and pXRF spectra had better prediction performance than individual Vis-NIR and pXRF spectra. A soil quality index (SQI) can be used to manage the soil for potential uses and remediate limitations of soil for sustainable agriculture and ecology. The objectives of this study were to (i) characterize vertical and horizontal variations of some soil properties and SQI in a Fluventic Haploxerepts profile in Eskişehir, Turkey, (ii) compare interpolation methods for mapping the distribution of soil properties and SQI in the profile wall, and (iii) assess cubist model for predicting soil properties and SQI using individual and combined Vis-NIR and pXRF spectra in the profile. The soil profile wall (1 m deep × 1 m wide) was divided into a raster of 10 × 10 cm intervals for collecting a total of 100 soil samples. The soil samples were analyzed for soil physical, chemical properties, and elemental concentrations and scanned using Vis-NIR (350–2500 nm) and pXRF (0–8 and 0–45 kV) spectrometers. Standard scoring function was used for standardization of indicators. Weighted linear combination method was used to calculate SQI and F-AHP for assigning weights of indicators. The 100 samples were split into calibration (70%) and validation (30%) datasets. Individual or combined Vis-NIR and pXRF spectra were used in cubist model to evaluate the feasibility for predicting soil properties and SQI in the Inceptisol. Results suggested that the soil profile had a considerable variation of soil properties and SQI with depth and within horizons. The A horizon had the highest SQI. In addition, Vis-NIR had better prediction performances for pH, SOM, Fe, and Mn (R2 = 0.42–0.88), whereas pXRF had better prediction performances for EC, CaCO 3 , P, and Zn (R2 = 0.18–0.90). In addition, combining Vis-NIR, pXRF8, and pXRF45 had better prediction performance for sand, silt, clay, K, Cu, and SQI (R2 = 0.81–0.97). We concluded that Vis-NIR and pXRF spectra can be successfully used to predict SQI in Fluventic Haploxerepts. Combined Vis-NIR and pXRF spectra had better prediction performance for SQI. [ABSTRACT FROM AUTHOR]

This study aimed to i) explore the land-use effect (former lakebed, pasture, and agricultural areas) on elemental concentrations, enrichment factors (EF s), and geo-accumulation indices (Igeo s), ii) provide X-ray diffractograms of the primary minerals and identify the clay minerals dominant in each land-use scenario, iii) map the spatial distribution of elemental concentration, EF s , and Igeo s using Digital Soil Mapping (DSM) approaches. We collected a total of 240 soil samples. Our findings highlight that vermiculite was a common clay-sized mineral, and aragonite, gypsum, and calcite were dominant primary minerals in each land-use. The remote sensing data (Sentinel-2 MSI and Landsat-8 OLI) were used to calculate some environmental covariates useful for digital mapping of elemental concentrations, EF s , and Igeo s. The highest concordance correlation coefficient (CCC) was found in the prediction of Hg (CCC = 0.79) using remote sensing data based on Sentinel-2 with the Random forest (RF) model. There is neither threat in terms of Cu, Zn, and Pb nor the impact of anthropogenic activities in their distribution under each land-use scenario. The study area was enriched with Hg, Cd, and Ni (very high, EF = 20–40), followed by Cr (significant, EF = 5.88) and As (moderate, EF = 2.08). A similar trend was also found for Igeo s across the study area. We conclude that the distribution of elemental concentration, EF s , and Igeo s were significantly affected by the shrinking of the Burdur Lake and the different land-use scenarios in this semi-arid region. • XRD, pXRF, SEM, RS, and DSM were simultaneously used. • Former lakebeds, pasture, and agricultural areas were the land-use scenarios for investigation. • Land-use changes and agricultural activities impacted EF s and Igeo s. • Sentinel-2 MSI data delivered better prediction than Landsat-8 OLI data. • Random forest outperformed cubists in predictions. [ABSTRACT FROM AUTHOR]

Mycorrhiza has attracted interest as one of the microorganisms that increase a crop's salt stress tolerance. This study was conducted to determine the impacts of mycorrhiza inoculation and applying salt at different ratios on the yield of peppers and amino acid concentrations. The study was conducted in greenhouse conditions on loamy soils with four salt treatments, two mycorrhiza inoculations and a control in a complete randomized block design. The present study indicated that salt treatment alone was significantly correlated with crop stem and root amino acid concentrations, RWC% and leaf sizes, whereas applying mycorrhiza showed a positive relationship to stem height, stem and root wet weight, and root amino acids but led to a decloine in root serine and glutamine, and stem amino acid and glutamine. In conclusion, inoculating with mycorrhiza was observed to make a positive contribution to salt stress tolerance at different levels in almost all the parameters examined. [ABSTRACT FROM AUTHOR]

Wildfire is a key ecological event that alters vegetation and soil quality attributes including biochemical attributes at spatial scale. This knowledge can provide insights into the development of better rehabilitation or restoration strategies that depend on the ecological dynamics of vegetation, fungi, and animals. The present study aimed to understand the causes and consequences of spatial variability of soil organic carbon, microbial biomass C concentrations, and soil quality indices as impacted by wildfire in a red pine forest. This study was conducted using kriging and inverse distance neighborhood similarity (IDW) interpolations methods. The carbon stocks were significantly (P = 0.002) higher in burned areas compared to those of unburned areas by 255% whereas microbial biomass carbon and microbial respiration were significantly (P < 0.0001 and P = 0.02) lower in burned areas by 66% and 90%, The Pearson's correlation analysis showed that carbon stocks were positively correlated with pH (0.61), total nitrogen (0.60) and ash quantity (0.41), but negatively correlated with microbial biomass carbon (−0.46) and nitrogen (−0.61), and microbial respiration (−0.48). The IDW interpolation method better-predicted pH, bulk density, and microbial biomass carbon and nitrogen compared to kriging interpolation, whereas the kriging interpolation method was better than IDW interpolation for the other studied soil properties. We concluded that pH, EC, SOC, C/N, MR, MBC/SOC, and MBC/MBN can be reliable indicators to monitor the effect of wildfire on forest soils. The wildfire event increased soil carbon stocks, TN, pH, and q CO 2 , but decreased MBC and MBN. • Wildfire increased soil organic carbon while biological soil functionality decreased in post-fire. • Soil organic carbon and Cstock was higher in burned areas through the accumulation of ash after the fire. • The effect of the fire on the soil did not change according to elevation and slope. • Fire influenced soil microbial carbon, soil respiration and metabolic quotient. [ABSTRACT FROM AUTHOR]