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Intercropping upland rice with forage grasses is a potential strategy for enhancing the sustainability of agriculture in the tropical region by increasing food production, land use per unit area, nitrogen (N) cycling, and profitability. However, little is known about the appropriate N management and N use efficiency of upland rice in these complex systems. Thus, our aim was to verify the feasibility of intercropping upland rice with tropical forage grasses combined with different N management applications at sowing and sidedressing. A field experiment was carried out in three growing seasons with three intercropping systems (monocropped upland rice, upland rice intercropped with palisade grass, and upland rice intercropped with guinea grass) combined with six N applications to upland rice [0−0 (control), 100−0, 80−20, 50−50, 20−80, and 0−100 kg N ha−1 at sowing-sidedressing]. Dry matter (DM) and accumulated N were measured in upland rice and forage grasses. In addition, components of rice yield production, industrial yield, production cost, land equivalent ratio, relative N yield, relative crowding coefficient, aggressivity of upland rice with forage grasses, forage crude protein (CP) concentration, estimated animal stocking rate, and estimated meat production were determined. Despite competition between rice and forage grasses, intercropping systems had superior benefits in terms of production and land use per unit area, N cycling, and profitability compared with monoculture. Forage DM production, CP, estimated animal stocking rate, and estimated meat production increased when N fertilizer was applied at sidedressing to rice (20−80, 50−50 and 0−100 kg N ha−1). Rice intercropped with guinea grass produced a greater amount of biomass, indicating that this forage species may be more advantageous in tropical regions. Net profit, total aboveground biomass, total N content, land equivalent ratio, and relative N yield were greater in intercropping

Intercropping grain with forage crops bridges the gap between agriculture and sustainability. In tropical regions, forage grasses are increasingly being adopted as winter pasture intercropped and in rotation with maize to maximize food production. However, current recommendations for nitrogen (N) fertilizer application are based on monocropped maize (Zea mays), and the best N management approach for intercropping systems remains unclear. A field experiment was carried out in three growing seasons with three intercropping systems [monoculture maize, intercropped with palisadegrass (Urochloa brizantha), and intercropped with guineagrass (Megathyrus maximus)] combined with six different split applications of N to maize (0–0, 100–0, 70–30, 50–50, 30–70, and 0–100 kg N ha−1 at seeding-sidedressing) with four replicates. We measured dry matter (DM) and accumulated N in maize and forage grasses, as well as maize production components and yields. Additionally, land equivalent ratio, relative crowding coefficient, aggressivity of maize with forage grasses, forage crude protein (CP) concentration, estimated animal stocking rate, and estimated meat production and economic outcomes. Greatest maize yield was 8.7 Mg ha−1 for monocropped maize. However, favorable maize yield was also obtained in intercropping systems. Although no difference was observed between intercropping systems, applying all N at sidedressing of maize negatively affected maize and forage yields and, consequently, land use and economic evaluation. For both intercropping systems, estimated meat and land use were 114 and 10% higher when N fertilizer was applied than the control (0–0 kg N ha−1), on average. Maize-forage grass intercropping is a viable alternative production system for improving yields and land use. In addition, estimated meat production and revenue can be enhanced with palisadegrass or guineagrass. At least half of the N fertilizer must be applied early in the

Intercropping forage grasses with upland rice is an alternative cropping system to improve agroecosystem diversification and could potentially enhance sustainability in tropical regions. However, nitrogen (N) immobilization and nutrient competition between rice and forage grasses could reduce rice grain yield and decrease overall productivity. Therefore, fertilizer N requirements of upland rice intercropped with forage grasses needs to be better defined. Field experiments were carried out during three growing seasons on a Typic Haplorthox soil in São Paulo state of Brazil. The experimental design was a randomized block design with a 3 × 4 factorial scheme with four replications. Treatments were cropping system [monocropped rice (Oryza sativa L.), rice intercropped with palisadegrass (Urochloa brizantha), and rice intercropped with guineagrass (Megathyrsus maximus) and sidedress N application rate (0, 40, 80, and 120 kg N ha−1). Intercropped grasses were sown between upland rice rows 30 days after rice emergence. On average, intercropping of rice with palisadegrass or guineagrass decreased rice shoot dry matter and grain yield by 11% and milled rice productivity by 10% compared with monocropped rice. Grain yield, grain protein, and milled productivity of rice increased as N application rate increased. Forage dry matter production (first and second cut) and crude protein (second cut) were greatest in the rice + palisadegrass intercropping system. Production of both forage grasses increased with up to 80 kg N ha−1 in the first cut and increased linearly with N in the second cut. Intercropping of rice with palisadegrass or guineagrass with 80 kg N ha−1 application resulted in the greatest land equivalent ratio (1.96 and 1.55, respectively). Relative N yield was greatest at 120 kg N ha−1 (220 and 173%, respectively). Although rice monocropping had greatest grain yield, intercropping systems with forage grasses were more favo

Soil-test biological activity (STBA) is a key indicator describing the functions of soil to catabolize organic amendments, promote soil organic C sequestration, and cycle nutrients. We explored how climatic zone, land use, and physiographic region affected the relationship of STBA with several soil fertility properties and processes. Soils from Georgia, North Carolina, Pennsylvania, and Virginia (wet climate) were Aquults, Fluvents, Udalfs, Udepts, and Udults and soils from Nebraska and Oklahoma (dry climate) were Udolls and Ustolls. Annual cropland and perennial pasture were the land uses. The Prairie region had silt loam and silty clay loams, the Ridge–Valley region had silt loams, and the Piedmont and Coastal Plain regions had fine sandy loam, loam, sandy clay loam, and sandy loams. Across all locations, STBA with the flush of CO2 during 3 d following rewetting of dried soil was most strongly associated with cumulative C mineralization, basal soil respiration, particulate organic C, potential N mineralization during 24 d of aerobic incubation, residual soil ammonium, soil microbial biomass C, and total soil N. Climatic zone modified the association between STBA and net N mineralization, possibly caused by greater N immobilization in drier soils with 2:1 clays. Physiographic region had a small effect on the relationship between STBA and net N mineralization. Land use did not alter this relationship significantly. Soil-test biological activity was verified as a robust indicator of soil organic N supply, as well as of general soil biological condition to assess the soil’s catabolic potential and potential C storage.

Large-scale, energy-intensive, specialized production systems have dominated agricultural production inthe United States for the past half-century. Although highly productive and economically successful, thereis increasing concern with unintended negative environmental impacts of current agricultural systems.Production systems integrating crops and livestock have potential for providing additional ecosystem ser-vices from agriculture by capturing positive ecological interactions and avoiding negative environmentaloutcomes, while sustaining profitability. A diversity of ecologically sound integrated crop-livestock sys-tems have been and can be employed in different ecoregions: sod-based crop rotations, grazing covercrops in cash-crop rotations, crop residue grazing, sod intercropping, dual-purpose cereal crops, and agro-forestry/silvopasture. Improved technologies in conservation tillage, weed control, fertilization, fencing,and planting, as well as improved plant genetics offer opportunities to facilitate successful adoptionof integrated systems. This paper explores the use and potential of integrated crop-livestock systemsin achieving environmental stewardship and maintaining profitability under a diversity of ecologicalconditions in the United States.

Large-scale, energy-intensive, specialized production systems have dominated agricultural production inthe United States for the past half-century. Although highly productive and economically successful, thereis increasing concern with unintended negative environmental impacts of current agricultural systems.Production systems integrating crops and livestock have potential for providing additional ecosystem ser-vices from agriculture by capturing positive ecological interactions and avoiding negative environmentaloutcomes, while sustaining profitability. A diversity of ecologically sound integrated crop-livestock sys-tems have been and can be employed in different ecoregions: sod-based crop rotations, grazing covercrops in cash-crop rotations, crop residue grazing, sod intercropping, dual-purpose cereal crops, and agro-forestry/silvopasture. Improved technologies in conservation tillage, weed control, fertilization, fencing,and planting, as well as improved plant genetics offer opportunities to facilitate successful adoptionof integrated systems. This paper explores the use and potential of integrated crop-livestock systemsin achieving environmental stewardship and maintaining profitability under a diversity of ecologicalconditions in the United States.

Ecosystem services are the properties and processes of the natural world that contribute to the well-being of plants, animals and humans in a holistic and global context. For too long, members of the agricultural community have been solely focused on the provision of food, feed and fiber. Of course, this essential human innovation has provided hugely important products engineered for mass production that serves all of human society. However, agriculture and the ecosystems in which it is practiced provide numerous other services that are becoming increasingly relevant to its very survival and the survival of humans that it supports. Several recent reviews have expressed the need to balance production and environmental goals to create a sustainable future1–3. Ecosystem services have been categorized into four key components, including supporting, regulating, provisioning and cultural services (Fig. 1). Agricultural landscapes have a large and sometimes dominating influence on several essential ecosystem services, including biomass production (i.e., food, feed, fiber and fuel production), air purification and climate regulation through greenhouse gas exchange, soil formation and retention, water cycling, nutrient cycling, wildlife habitat provision and aesthetic experience.

Global climate change is a natural process that currently appears to be strongly influenced by human activities, which increase atmospheric concentrations of greenhouse gases (GHG), in particular carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Agriculture contributes about 20% of the world’s global radiation forcing from CO2, CH4 and N2O, and produces 50% of the CH4 and 70% of the N2O of the human-induced emission. Interest is increasing among land managers, policy makers, GHG emitting entities, and carbon (C) brokers in using agricultural lands to sequester C and reduce GHG emission. Precise information is lacking, however, on how specific management practices in different regions of the world impact soil C sequestration and the mitigation of GHG emission. In 2002, the USDA Agricultural Research Service (ARS) developed a coordinated national research effort called GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement network) to provide information on the soil C status and GHG emission of current agricultural practices, and to develop new management practices to reduce net GHG emission and increase soil C sequestration primarily from soil management. Managing Agricultural Greenhouse Gases synthesizes the wealth of information generated from the GRACEnet project in over 30 ARS locations throughout the US and in numerous peer-reviewed articles. Although GRACEnet is an ARS project, contributors to this work include a variety of backgrounds and reported findings have important international applications. For example, many parts of the world possess similar ecoregions to the U.S. (e.g., northern Great Plains is similar to the Argentina Pampas and Ukraine Steppe). Such similarities expand the appeal of this exciting new volume to a wide international readership. Frames responses to challenges associated with climate change within the geographical domain of the U.S., while providing a useful model for researchers in the many parts of the

Ecologically sound grazing management is an underused and underappreciated conservation tool in the eastern United States. We contend that significant policy and educational barriers stand in the way of expanding the use of this conservation tool. Well-managed pasture systems combine vigorous perennial vegetation cover, reduced pesticide and fertilizer inputs, and lower costs of production using ecological approaches to generate ecosystem services for society, as well as economic sustainability for the producer. The majority of currently available conservation policy tools were designed to address either rangeland grazing situations in the western United States or conservation cropping in the eastern United States. To promote well-managed pastures in the eastern United States, resource managers and government agencies struggle to adapt programs that are really designed for annual row crop systems. Additional educational and technical assistance resources are needed for promoting well-managed pasture-based farming in the region. This paper summarizes the potential of well-managed pasture systems to provide ecosystem services, provides thoughts for discussion on the barriers to adoption of such systems in the eastern United States, and offers some solutions to move such systems forward through policy and educational efforts. These ideas were first presented at a symposium as part of the 2011 Annual Conference of the Soil and Water Conservation Society in Washington, DC.

Stocker performance and production from mixed cool- and warm-season perennial pastures are important determinants of agricultural sustainability that can be influenced by management. We evaluated the factorial combination of three sources of nutrient application (inorganic only, organic+inorganic combination, and organic only) and two forage utilization regimes [low grazing pressure (LGP) and high grazing pressure (HGP)] on steer stocking density and rate, performance and production during 7 years of pasture management {tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] overseeded into existing Coastal bermudagrass [Cynodon dactylon (L.) Pers.] sod} on a Typic Kanhapludult in Georgia, USA. Nutrient source had few major impacts on responses, except for lower animal performance with organic fertilization (broiler litter) than with organic+inorganic and inorganic only fertilization, especially with LGP. Seasonal changes in stocking weight and rate occurred, not only as expected due to environmental conditions and dominant forage species present, but that also counteracted expected differences imposed by grazing pressure; signaling negative feedback of HGP on forage productivity. Steer performance was greatest in spring and summer under both grazing pressures, but was significantly reduced with increasing grazing pressure in the autumn and winter due to low forage availability.Across years, steer gainha−1 (863kgha−1) was not different between grazing pressures, but gainha−1 declined with time under HGP and was stable with time under LGP. Reducing grazing pressure to a moderate level can lead to equivalent steer production as HGP, and would likely contribute to a more sustainable balance among production, socio-economic and environmental goals. These multi-year results will help cattle producers in warm, moist climates design and implement more sustainable grazing systems.

Semiarid Mediterranean climatic conditions and intensive tillage systems accelerate soil organic matter losses. Therefore, assessing agricultural practices that enhance storage of soil organic matter is needed. Stratification of soil properties with soil depth, expressed as a ratio, could indicate soil quality under different soil management. We measured soil depth stratification ratio (0–5/10–30 cm and 0–5/30– 50 cm) of soil organic C (SOC), total N, active carbon (AC), water soluble carbon (WSC), and soil enzymatic activities [dehydrogenase activity (DHA) and b-glucosidase activity (BGA)] of a Typic Haploxerert in southern Spain. The experimental design consisted of a split–split plot design with three replications and soil properties evaluated at the end of 22 years. Tillage systems included conventional tillage (CT) and no tillage (NT). Dryland, 2-year crop rotations were wheat (Triticum aestivum L.)–fallow (WF), wheat– chickpea (Cicer arietinum L.) (WC), wheat–faba bean (Vicia faba L.) (WFb), wheat–sunflower (Helianthus annuus L.) (WS), and continuous wheat (WW). Nitrogen fertiliser rates were 0, 50 and 150 kg N ha 1. Stratification ratios of total N, WSC, AC, DHA, and BGA were most responsive to tillage systems; NT greater than CT. Stratification ratios of SOC, total N, WSC, AC and BGA were most responsive to crop rotation; WFb and WW greater than WF, WC, and WS. Stratification ratio of BGA was most responsive to N fertiliser rate; higher rates than no fertiliser. Stratification ratios of C and N fractions and enzymatic activities were responsive to choice of denominator used for ratio calculation. Tillage and crop rotation had more influence than N fertiliser rate in affecting stratification ratio of C and N fractions and enzymatic activities. Stratification ratio was relatively low (<2), perhaps due to the large shrinking and swelling characteristics of Vertisols. Stratification ratio of BGA was greater than of all other soil properties, suggesting that it m

A number of scientists have named our age the Anthropocene because humanity is globally affecting Earth systems, including the soil. Global soil change raises important questions about the future of soil, the environment, and human society. Although many soil scientists strive to understand human forcings as integral to soil genesis, there remains an explicit need for a science of anthropedology to detail how humanity is a fully fledged soil-forming factor and to understand how soil change affects human well being. The development and maturation of anthropedology is critical to achieving land-use sustainability and needs to be nurtured by all soil disciplines, with inputs from allied sciences and the humanities,. The Soil Science Society of America (SSSA) has recently approved a cross-divisional Working Group on Soil Change, which aims to advance the basic and applied science of anthropedology, to facilitate networks of scientists, long-term soil field studies, and regional databases and modeling, and to engage in new modes of communications about human–soil relations. We challenge all interested parties, especially young scientists and students, to contribute to these activities and help grow soil science in the Anthropocene.

Surface-soil structural condition in perennial pastures is expected to be modified by how forage is (a) harvested through haying or grazing and (b) stimulated through source of nutrients applied, as well as by compactive forces, e.g., grazing cattle or hay harvest machinery. Changes in surface-soil condition can affect hydrologic processes that have important implications for plant growth, greenhouse gas emissions and off-site water quality. We determined the effects of harvest management and nutrient source on the rate of ponded water infiltration and penetration resistance in a bermudagrass [Cynodon dactylon (L.) Pers.]/tall fescue (Lolium arundinaceum Schreb. S.J. Darbyshire) pasture on a Typic Kanhapludult in Georgia. During a period when soil was wet (61% water-filled pore space), the rate of water infiltration was 2.8±1.5 times greater when forage was left unharvested as when hayed or grazed (mean ± standard deviation among nine nutrient sourcerharvest management comparisons). During a subsequent period, when soil was dry (28% water-filled pore space), the rate of water infiltration followed the same treatment pattern, but was not statistically different among harvestmanagement practices (1.5 ± 0.4 times greater between unharvested and other systems). Penetration resistance of the surface at 10 cm depth followed the order: unharvested (62 J) < hayed (100 J) < low grazing pressure (119 J) < high grazing pressure (137 J). Water infiltration during the wet period was negatively related (P ≤ 0.01) to soil-water content (r = -0.57), penetration resistance at 0–10 cm depth (r = -0.50) and bulk density at 3–6 cm depth (r = -0.53), but was positively related to surface residue C (r = 0.47) and soil organic C concentration at 12–20 cm depth (r = 0.42). These results suggest that complex soil physical (i.e., aggregation, penetration resistance and infiltration) and biological (i.e., plant growth, surface residues and soil organic matter) interactions occur in pastures.