Life-cycle assessments (LCAs) of switchgrass (Panicum virgatum L.) grown for bioenergy production require data on soil organic carbon (SOC) change and harvested C yields to accurately estimate net greenhouse gas (GHG) emissions. To date, nearly all information on SOC change under switchgrass has been based on modeled assumptions or small plot research, both of which do not take into account spatial variability within or across sites for an agro-ecoregion. To address this need, we measured change in SOC and harvested C yield for switchgrass fields on ten farms in the central and northern Great Plains, USA (930 km latitudinal range). Change in SOC was determined by collecting multiple soil samples in transects across the fields prior to planting switchgrass and again 5 years later after switchgrass had been grown and managed as a bioenergy crop. Harvested aboveground C averaged 2.5± 0.7 Mg C ha −1 over the 5 year study. Across sites, SOC increased significantly at 0-30 cm (P=0.03) and 0-120 cm (P=0.07), with accrual rates of 1.1 and 2.9 Mg C ha −1 year −1 (4.0 and 10.6 Mg CO 2 ha −1 year −1 ), respectively. Change in SOC across sites varied considerably, however, ranging from −0.6 to 4.3 Mg C ha −1 year −1 for the 0-30 cm depth. Such variation in SOC change must be taken into consideration in LCAs. Net GHG emissions from bioenergy crops vary in space and time. Such variation, coupled with an increased reliance on agriculture for energy production, underscores the need for long-term environmental monitoring sites in major agro-ecoregions.

corn-soybean cropping systems predominate. The effect of these cropping systems on indicators of soil quality Understanding long-term management effects on soil properties is only partially understood. Soil organic C has been is necessary to determine the relative sustainability of cropping systems. Soil physical, chemical, and biological properties were measured shown to increase in monoculture corn where N fertilin a long-term cropping system study in the Western Corn Belt. Prop-ization is adequate and no-till is used (Studdert and erties were evaluated after 16 yr in four crop sequences [continuous

market conditions, input prices, government programs, and new technology and information represent broad Research to integrate the vast array of information needed by categories of externalities that producers must deal with producers to make decisions allowing them to remain sustainable in on a continual basis ( Fig. 1). This is a daunting challenge, our ever-changing agricultural environment is in its infancy. Present research has not provided crop production and soils information that is especially when one considers that producers' decisions adequately comprehensive and holistic for producers to make critical are carried out in a financial environment of diminishing decisions. We propose a dynamic cropping systems approach to help economic returns, where one wrong decision could mean producers make those critical decisions they need to remain sustainfinancial hardship and potentially the end to a way of able. Our definition of a dynamic cropping system is a long-term life. strategy of annual crop sequencing that optimizes crop and soil useTo meet this challenge, producers must manage exteroptions and the attainment of production, economic, and resource nalities by arriving at decisions that optimize the outconservation goals by using sound ecological management principles. come of multiple goals. This is not a simple task. Produc-Implicit to this strategy is the need for producers to possess informaers need to possess the ability to integrate vast amounts tion necessary to respond to continual change. Key factors associated of information on externalities that are constantly with dynamic cropping systems are diversity, adaptability, reduced input cost, multiple enterprise systems, and awareness of environment changing. The information needs to be understood well and information. Development of a dynamic cropping systems re-enough to take advantage of situations in which extersearch program involves creating a crop portfolio, crop sequence nalities interact (e.g., choosing an appropriate crop to evaluation, and multidirectional flow of information among research,

Wheat (Triticum spp.) dominates dryland grain crop production in the North American Great Plains and other regions with semi‐arid steppe climates. A common practice is to alternate winter or spring wheat with a 14‐ to 21‐mo fallow period to allow for soil‐water recharge, despite economic inefficiencies and environmental degradation. Replacing fallow with non‐cereal grain and seed crops often reduces future wheat yields due to increased water stress during grain fill. The use of annual forages may not have the disadvantages associated with grain and seed crops. The objective of this review was to determine benefits and challenges of incorporating annual forages into dryland wheat systems in semi‐arid steppe climates, using the Great Plains within the United States as a model system. Results indicate that: (a) cool‐ and warm‐season, annual grass and broadleaf species can be grown for forage across the region; (b) forage production will be less risky than grain and seed crop production under predicted climate‐change scenarios; (c) grazing annual forages may offer advantages (e.g., nutrient cycling, improved soil structure, added revenue from livestock) over mechanically harvesting annual forages; (d) the lack of infrastructure and local markets impede the use of annual forages to diversify wheat‐based cropping systems in the region; and (e) limited networking among researchers hinders the advancement in knowledge on how annual forages can be used to improve dryland wheat system resilience.

Abstract. In this paper, we present and analyze a global database of soil infiltration measurements, the Soil Water Infiltration Global (SWIG) database, for the first time. In total, 5023 infiltration curves were collected across all continents in the SWIG database. These data were either provided and quality checked by the scientists who performed the experiments or they were digitized from published articles. Data from 54 different countries were included in the database with major contributions from Iran, China, and USA. In addition to its global spatial coverage, the collected infiltration curves cover a time span of research from 1976 to late 2017. Basic information on measurement location and method, soil properties, and land use were gathered along with the infiltration data, which makes the database valuable for the development of pedo-transfer functions for estimating soil hydraulic properties, for the evaluation of infiltration measurement methods, and for developing and validating infiltration models. Soil textural information (clay, silt, and sand content) is available for 3842 out of 5023 infiltration measurements (~76 %) covering nearly all soil USDA textural classes except for the sandy clay and silt classes. Information on the land use is available for 76 % of experimental sites with agricultural land use as the dominant type (~40 %). We are convinced that the SWIG database will allow for a better parameterization of the infiltration process in land surface models and for testing infiltration models. All collected data and related soil characteristics are provided online in *.xlsx and *.csv formats for reference, and we add a disclaimer that the database is for use by public domain only and can be copied freely by referencing it. Supplementary data are available at doi:10.1594/PANGAEA.885492. Data quality assessment is strongly advised prior to any use of this database. Finally, we would like to encourage scientists to extend/update the SWIG by uploading new data to it.

Revegetation of mined lands in North

Integrated crop-livestock systems have been purported to have significant agronomic and environmental benefits compared to specialized, single-enterprise production systems. However, concerns exist regarding the effect of livestock in integrated systems to cause soil compaction, thereby decreasing infiltration of water into soil. Such concerns are compounded by projections of more frequent high-intensity rainfall events from anticipated climate change, which would act to increase surface runoff and soil erosion. A study was conducted to evaluate the effects of residue management, frequency of hoof traffic, season, and production system (e.g., integrated annual cropping versus perennial grass) on infiltration rates from 2001 through 2008 in central North Dakota, USA. Imposed treatments had no effect on infiltration rate at three, six, and nine years after study establishment, implying that agricultural producers should not be concerned with inhibited infiltration in integrated annual cropping systems, where winter grazing is used. The use of no-till management, coupled with annual freeze/thaw and wet/dry cycles, likely conferred an inherent resistance to change in near-surface soil properties affecting soil hydrological attributes. Accordingly, caution should be exercised in applying these results to other regions or management systems.

Agricultural land management may influence crop nutritional quality. However, few studies have explored potential connections between crop quality with different land management strategies. We analyzed mineral and crude protein concentrations in spring wheat grain (Triticum aestivum L.) samples from a study in Mandan, ND conducted from 2006 to 2014. The study introduced a perennial forage phase into an annual spring wheat cropping system, in three to four replicates, and previously found yield benefits and enhanced soil parameters in the perennial forage treatments. We determined whether integrating a perennial forage phase into continuous wheat would also affect crop nutritional quality by measuring wheat grain mineral and protein concentrations. Crude protein concentration was greater (p < .05) when wheat followed alfalfa (Medicago sativa L.) and increased linearly after 2–5 yr of established alfalfa. We observed comparable wheat grain crude protein and mineral concentrations between continuous annually fertilized wheat and unfertilized wheat following perennial forages. Negative correlations (p < .001) were observed between wheat grain yield and crude protein, potassium (K), magnesium (Mg), nickel (Ni), phosphorus (P), sulfur (S), and zinc (Zn) concentrations. Discriminate multivariate analyses showed, with 96% predictive accuracy, that differences in crude protein and mineral concentration were largely driven by year of wheat harvest. Differences between harvest years were likely due to timely precipitation at critical Growth Stage 3, during spikelet development. Study outcomes highlighted the important role of perennial forages and environmental factors to influence protein and mineral concentration in spring wheat grain.