Management strategies such as nitrogen (N) topdressing and clipping can be used to optimize a cover crop for the dual purpose of soil cover and forage. The present study tested oat (Avena sativa) for a holistic provision of soil cover and forage under various levels of clipping frequency and N topdressing. Effects on root and above-ground biomass, acid detergent fiber, neutral detergent fiber, and crude protein (CP) were evaluated. Clipping frequency had four levels, namely clipped only at termination (C1), clipped at 28 days after emergence (DAE) and termination (C2), clipped at 28, 42 DAE, and termination (C3), and clipped at 28, 42, 56 DAE, and termination (C4). Nitrogen topdressing had two levels, namely with (N1) and without (N0) the recommended N topdressing. Increasing clipping frequency reduced the root and aerial biomass and did not affect the forage quality harvested before termination. However, N topdressing increased biomass and CP content across the clipping frequencies. Results suggest clipping thrice combined with N topdressing (C4 + N1) provides the best option to satisfy both soil cover and livestock demands. The treatment (C4 + N1) gave > 2 t ha−1 of biomass during the growing period and 6 t ha−1 at termination which can be used for livestock forage and soil cover, respectively. Clipping thrice without N topdressing (C4 + N0) was the best option for resource-constrained farmers.

No-tillage (NT) organic vegetable production presents several economic opportunities for growers in the southeastern United States while promoting natural resource conservation. This study was conducted to determine if removal of sorghum sudangrass (SS) cover crop biomass as hay, frequency at which the cover crop is mowed, and tillage affect weed suppression and head weight of transplanted organic cabbage. Sorghum sudangrass [Sorghum bicolor (L.) Moench×Sorgum sudanense (Piper) Staph.] was planted in May 2004 at Reidsville and Goldsboro, NC, preceding the planting of organic ‘Bravo’ cabbage (Brassica oleracea L. Capitata group) in August and September 2004, respectively. SS management systems included: low-frequency mowing with hay removed following the first mowing operation (LFM-H), low-frequency mowing with hay not removed (LFM), high-frequency mowing with hay not removed (HFM) and a no cover crop control. Two tillage treatments were applied within each management system: conventional tillage (CT) and NT. Under NT conditions, SS mulch generated by LFM offered broadleaf weed control in cabbage similar to that achieved under CT, regardless of whether cover crop biomass was removed as hay. Mowing with higher frequency reduced SS cover crop biomass by 18–33% and reduced weed suppression in NT cabbage. Mowing frequency did not influence the quantity of SS that re-grew in the cabbage crop. SS re-growth contributed to lower head weight in NT compared to CT cabbage in Goldsboro, and crop failure of NT cabbage in Reidsville. Cabbage head weight was highest when the crop was not preceded by SS in both CT and NT systems (1.6 as opposed to 1.3–1.4 kg head−1). Our findings suggest that the potential for growers to manage a cover crop also as a hay crop does exist; however, SS may not be a compatible cover crop species for organic fall cabbage production due to high amounts of re-growth.

Integration of crops and livestock has the potential to provide a multitude of benefits to soil and water conservation and nutrient cycling efficiency, while reducing economic risk and increasing profitability. We conducted a field study from May 2002 to October 2005 to determine crop and cattle responses to three management factors on a Typic Kanhapludult in Georgia, USA. Summer grain/winter cover [sorghum (Sorghum bicolor L. Moench) or corn (Zea mays L.)/rye (Secale cereale L.)] and winter grain/summer cover [wheat (Triticum aestivum L.)/pearl millet (Pennisetum glaucum L. R. Br.)] were managed with either conventional tillage (CT) or no tillage (NT) and with or without cattle grazing of cover crops. All crops were successfully established, irrespective of tillage and cover crop management. Although pearl millet was often lower in the plant stand with NT than with CT, plants compensated with greater biomass on an area basis. Across years, grain yield of sorghum (1.9 Mg ha−1 during three seasons) and corn (7.3 Mg ha−1 in one season) was 25% greater under NT than under CT when the cover crop was not grazed. Wheat grain yield (2.7 Mg ha−1 during three seasons) was unaffected by tillage and cover crop management. Unharvested stover production of summer grain crops was greater with NT than with CT (6.5 versus 4.1 Mg ha−1; P<0.001). Grazing rye rather than allowing it to accumulate as surface residue reduced summer grain yield 23% and reduced standing grain-crop dry matter 26% under NT, but had no effect under CT. In contrast, grazing pearl millet rather than allowing it to accumulate as surface residue increased wheat standing dry matter yield by 25±14% (mean±standard deviation among 3 years and two tillage systems). Ungrazed cover crop production was greater under NT than under CT for rye (7.0 versus 6.0 Mg ha−1; P=0.03) and pearl millet (10.2 versus 7.6 Mg ha−1; P=0.01). Calf daily gain was either greater or tended to be greater under NT than under CT on rye (2.27 versus 2.09 kg head−1 d−1; P=0.15) and pearl millet (2.05 versus 1.81 kg head−1 d−1; P=0.05). Total cattle gain per grazing season was either greater or tended to be greater with NT than with CT on rye (350 versus 204 kg ha−1; P=0.01) and pearl millet (324 versus 277 kg ha−1; P=0.15). Net return over variable costs was greater with grazing than without grazing of cover crops (US$302 versus −US$63 ha−1; P<0.001). Livestock grazing of cover crops had variable effects on subsequent crop production, but increased economic return and diversity overall. Therefore, an integrated crop–livestock production system with conservation tillage is recommended as a viable option for producers to diversify farming operations to avoid risk, improve ecological production of crops, and potentially avoid environmental damage from soil erosion and nutrient loss.