Nutrient cycling via livestock excreta is an important grassland ecosystem service. This study was conducted in 2016 and 2017 and determined nutrient excretion from cattle grazing three systems: (a) N‐fertilized bahiagrass (Paspalum notatum Flüggé) overseeded with rye (Secale cereale L.) and oat (Avena sativa L.) during winter (Grass+N), (b) unfertilized bahiagrass overseeded with rye–oat–clover (Trifolium sp.) mixture (Grass+clover), and (c) rhizoma peanut (Arachis glabrata Benth.)–bahiagrass mixture overseeded with a rye–oat–clover mixture (Grass+CL+RP). Urinary volume excreted in the warm season ranged from 122 to 182 L ha⁻¹d⁻¹, more than double that in the cool season (56–70 L ha⁻¹ d⁻¹). Urinary N concentration during the warm season was greater in Grass+CL+RP compared with Grass+N (4.4 vs. 3.1 g kg⁻¹, respectively). In addition, fecal dry matter and organic matter output was greater for Grass+N than for steers grazing Grass+CL+RP during the warm season (3.8 and 3.2 vs. 2.8 and 2.2 kg hd⁻¹ d⁻¹, respectively). Total annual feces excretion concentrations of P, K, Mg, and N were greater in the Grass+N than in Grass+CL+RP system. The introduction of legumes increased the proportion of N returning via urine. However, when summed across seasons, total N excretion (feces and urine) was greater in Grass+N than in Grass+CL+RP (89 vs. 71 kg ha⁻¹ yr⁻¹), mainly due to the greater stocking rate in the former. Grass–legume systems receiving 34 kg N ha⁻¹ yr⁻¹ recycled 80% of the N recycled in the grass system receiving 224 kg N ha⁻¹ yr⁻¹, indicating the potential of forage legumes to add N to grasslands.

Replacing N fertilizer with forage legumes may increase sustainability of grazing systems. The objectives were to evaluate herbage and animal responses and to quantify the water footprint associated with beef production in N‐fertilized grass or grass–legume systems during 4 yr under continuous stocking. The three year‐round forage systems were: Grass+N which included N‐fertilized bahiagrass (Paspalum notatum Flüggé) during summer which was overseeded with N‐fertilized cereal rye (Secale cereale L.) and oat (Avena sativa L.) during winter; Grass+Clover included bahiagrass without N fertilizer during summer which was overseeded with rye, oat, and a mixture of clovers (Trifolium spp.) during winter; and Grass+Clover+RP included rhizoma peanut (Arachis glabrata Benth.)–bahiagrass mixture during summer which was overseeded with a similar rye–oat–clover mixture as for Grass+Clover. Clover inclusion improved uniformity of herbage distribution throughout the winter. Including rhizoma peanut increased cattle average daily gain (ADG) by 74% during summer. The ADG in Grass+Clover+RP was 0.61 kg d⁻¹ compared with 0.35 kg d⁻¹ on Grass+N and Grass+Clover. The water footprint during summer was less in Grass+Clover+RP than Grass+Clover (18 and 25 m³ kg⁻¹ bodyweight, respectively). Gain per area (GPA) was similar across all treatments through the year, indicating similar productivity in grass–legume and N‐fertilized grass systems. The N‐fertilizer inputs were reduced from 224 to 34 kg N ha⁻¹ yr⁻¹ in Grass+Clover+RP, compared to Grass+N. Inclusion of rhizoma peanut and clovers contributes to developing sustainable grazing systems with reduced levels of off‐farm inputs.

Integrated crop‐livestock systems provide an array of benefits to agricultural systems, including a reduction in nitrogen (N) leaching. A farm approach to integrate crops and livestock is the adoption of grazed cover crops. Moreover, the addition of perennial grasses into crop rotations may improve soil organic matter and decrease N leaching. However, the effect of grazing intensity in such systems is not fully understood. This 3‐year study investigated short‐term effects of cover crop planting (cover and no cover), cropping system (no grazing, integrated crop‐livestock [ICL], and sod‐based rotation [SBR]), grazing intensity (heavy, moderate, and light grazing), and cool‐season N fertilization (0, 34, and 90 kg N ha⁻¹) on NO₃‐N and NH₄‐N concentration in leachate, and cumulative N leaching by using 1.5‐m deep drain gauges. The ICL was a cool‐season cover crop‐cotton (Gossypium hirsutum L.) rotation, whereas SBR was a cool‐season cover crop‐bahiagrass (Paspalum notatum Flüggé) rotation. There was a treatment × year × season for cumulative N leaching (p = 0.035). Further contrast analysis indicated that cover crops decreased cumulative N leaching compared to no cover (18 vs. 32 kg N ha⁻¹ season⁻¹). Nitrogen leaching was lesser for grazed compared to nongrazed systems (14 vs. 30 kg N ha⁻¹ season⁻¹). Treatments containing bahiagrass had lesser NO₃‐N concentration in leachate (7 vs. 11 mg L⁻¹) and cumulative N leaching (8 vs. 20 kg N ha⁻¹ season⁻¹) compared to ICL systems. Adding cover crops can reduce cumulative N leaching in crop‐livestock systems; moreover, warm‐season perennial forages can further enhance this benefit.