Plant litter is an important nutrient pool in grassland ecosystems. Management practices affect litter quality and may affect nutrient dynamics in pastures by altering the rates of nutrient mineralization and immobilization. The effect of management intensity on litter decomposition and nutrient disappearance was evaluated in a litter bag study on continuously stocked 'Pensacola' bahiagrass (Paspalum notatum Flü gge) pastures growing on Pomona and Smyrna sands. Treatments were three management intensities: Low (40 kg N ha 21 yr 21 and 1.3 animal units [AU, one AU 5 500 kg live weight] ha 21 stocking rate [SR]), Moderate (120 kg N ha 21 yr 21 and 2.7 AU ha 21 SR), and High (360 kg N ha 21 yr 21 and 4.0 AU ha 21 SR). Litter relative decomposition rate (k) was greater for High (0.0030 g g 21 d 21 ) than Low (0.0016 g g 21 d 21 ). Litter N, acid detergent insoluble N (ADIN), and lignin concentrations were greater for High than the other intensities at the end of the 168-d incubation period because of faster decomposition of soluble compounds. Across management intensities, approximately one-half of litter N remaining at the end of the incubation period was bound to acid detergent fiber (ADF). Net N mineralization through 128 d of incubation was only 200 to 300 g kg 21 of total N. Increasing management intensity resulted in faster litter turnover and greater nutrient release, but nutrient release from litter was small and significant quantities of nutrients were immobilized even under the most intensive management.

Nutrients cycle among pools within an ecosystem, and losses of nutrients to the environment accompany each transfer from pool to pool. Efficient recapture of nutrients by plants is critical in extensively managed grasslands if these swards are to persist. In intensively managed systems, the greatest contribution of efficient recapture of nutrients may be minimizing loss of nutrients to the environment and associated negative impacts. Regardless of management intensity, grassland management decisions should be informed by an understanding of the dynamics of nutrient cycling. A significant body of literature has emerged in recent years describing nutrient dynamics in warm‐climate grasslands. In warm climates globally, grasslands are most often low‐input production systems dominated by C4 grasses. These characteristics affect nutrient cycling, resulting in very different management challenges and opportunities than in higher input, C3–grass or legume‐dominated, grasslands. This paper will focus on warm‐climate grasslands. Within that context its objectives are (i) to describe the most prominent pools of C, N, P, and K, (ii) to discuss fluxes among nutrient pools, with emphasis on plant litter and animal excreta, iii) to describe the importance, management, and dynamics of soil organic matter, and (iv) to review the impact of grazing systems on nutrient cycling.

Warm‐climate grasslands are often N limited. Legume litter decomposition can contribute significantly to N input in grazing systems, but its contribution depends on litter deposition, decomposition, and chemical composition. We evaluated these responses for 2 yr in unfertilized (BG) and fertilized (BGN; 50 kg N ha−1) bahiagrass (Paspalum notatum Flügge) monocultures and in mixed swards of bahiagrass plus the legume rhizoma peanut (Arachis glabrata Benth.). Legume–grass mixture litter had greater initial N concentration (26 g N kg−1 organic matter [OM]) and lower C/N ratio (22) than BG and BGN, which did not differ from each other (18 g N kg−1 OM, C/N ratio of 31). Litter biomass relative decay rate was greater for mixtures than for bahiagrass monocultures. As a result, less biomass and N remained at the end of incubation in mixtures (62 and 76%, respectively) than in monocultures (69 and 80%, respectively). Litter deposition rate was similar across treatments, but faster decomposition and greater N concentration for legume–grass mixtures resulted in larger litter N release than in monocultures (44 and 26 kg ha−1, respectively). At the end of incubation, remaining litter biomass and remaining N decreased with increasing litter legume proportion, whereas litter N concentration and litter decay rate increased. Results indicate that legume–grass mixtures are an alternative to N fertilizer for increasing N cycling through plant litter in grasslands, and although litter deposition rates were similar across treatments, increasing legume proportion in mixtures is likely to be associated with greater litter N release.

Ecosystem services (ES) are the direct and indirect contributions of ecosystems to human well‐being. Grassland ecosystems cover >40% of Earth's ice‐free terrestrial surface, and grassland management affects the ES provided. Our objective was to synthesize the existing literature assessing management effects on regulating and supporting ES provided by grasslands, explore the related mechanisms, and determine which practices favor ES delivery. Current literature supports the following conclusions. Increasing management intensity of grasslands through planting more productive species or increasing fertilizer inputs generally increases soil organic C (SOC) accumulation. Increasing the number of plant species or functional groups, especially when legumes are added, often increases SOC accumulation. Grazed grasslands generally accumulate SOC more rapidly than undefoliated grasslands. Low or moderate stocking rates favor SOC accumulation relative to high stocking rates, especially in lower‐rainfall environments. Short‐term SOC accumulation rates observed after conversion of cropland to perennial grassland do not continue indefinitely. More digestible forages defoliated at optimal maturity may decrease CH4 emitted per unit of feed consumed or per unit of animal product. Substituting legumes for N fertilizer and reducing livestock N excretion through diet manipulation reduce N2O emissions. Managing grazing to increase uniformity of excreta deposition increases efficiency of nutrient cycling. Species‐rich grasslands with flower‐rich legumes and forbs increase foraging opportunities for pollinators. Finally, to optimize delivery of grassland ES, management practices that sustain ecosystem function likely need to replace those that maximize short‐term resource utilization or economic return. To encourage adoption, such practices may need to be incentivized.