Legume Intercropping With the Bioenergy Crop Sida hermaphrodita on Marginal Soil

Abstract

The cultivation of perennial biomass plants on marginal soils can serve as a sustainable alternative to conventional biomass production via annual cultures on fertile soils. Sida hermaphrodita is a promising species to be cultivated in an extensive cropping system on marginal soils in combination with organic fertilization using biogas digestates. In order to enrich this cropping system with nitrogen (N) and to increase overall soil fertility of the production system, we tested the potential of intercropping with leguminous species. In a 3-year outdoor mesocosm study, we intercropped established S. hermaphrodita plants with the perennial legume species Trifolium pratense, T. repens, Melilotus albus, and Medicago sativa individually to study their effects on plant biomass yields, soil N, and above ground biomass N. As a control for intercropping, we used a commercial grass mixture without N2-fixing species as well as a no-intercropping treatment. Results indicate that intercropping in all intercropping treatments increased the total biomass yield, however, grass species competed with S. hermaphrodita for N more strongly than legumes. Legumes enriched the cropping system with fixed atmospheric nitrogen (N2) and legume facilitation effects varied between the legume species. T. pratense increased the biomass yield of S. hermaphrodita and increased the total biomass yield per mesocosm by 300%. Further, the total above ground biomass of S. hermaphrodita and T. pratense contained seven times more N compared to the mono-cropped S. hermaphrodita. T. repens also contributed highly to N facilitation. We conclude that intercropping of legumes, especially T. pratense and T. repens can stimulate the yield of S. hermaphrodita on marginal soils for sustainable plant biomass production.

Improving the Ecological Performance of Miscanthus (Miscanthus × giganteus Greef et Deuter) through Intercropping with Woad (Isatis tinctoria L.) and Yellow Melilot (Melilotus officinalis L.)

“…In addition, successful intercropping of miscanthus with yellow melilot could improve the biodiversity conservation effects and landscape appearance of miscanthus compared with miscanthus cultivated alone and miscanthus intercropped with WAM. Furthermore, it is expected that yellow melilot contributes to soil fertility and provides additional nitrogen (N) fixation, as has been reported for intercropping Virginia mallow (Sida hermaphrodita L. Rusby) and white melilot (Melilotus albus L.) [71].…”

“…Another question to be addressed is which other legume species would be suitable for intercropping with miscanthus. According to Nabel et al (2018) [56,71], who reported on the suitability of Virginia mallow for legume-intercropping, possibilities include red clover (Trifolium pratense L.), white clover (Trifolium repens L.), and lucerne (Medicago sativa L.). Other legume species worth investigating are common bird's-foot trefoil (Lotus corniculatus L.) and hop clover (Medicago lupulina L.).…”

Prospects of Bioenergy Cropping Systems for A More Social-Ecologically Sound Bioeconomy

“…Conversely, the utilization of marginal agricultural land often promises to improve its overall value, or at least to maintain its current resilience and protect it from further degradation [55]. Many studies have revealed significant evidence to support the positive social-ecological effects of bioenergy crop cultivation on marginal agricultural land depending on the selected bioenergy crops and BCS, respectively [47,52,[86][87][88][89][90]. Some dedicated bioenergy crops for cultivation on marginal agricultural land are shown in Figure 1.…”

Which spatial arrangement of green manure is able to reduce herbivory and invasion of exotic grasses in native species?

“…Recent studies have shown that cultivating the species Sida hermaphrodita (L.) Rusby with maize does not reduce biomass when intercropped with legumes, but that biomass is reduced significantly when intercropped with grasses (Nabel et al. , Weidlich et al. ).…”

“…development of native species (Longo et al 2011). Recent studies have shown that cultivating the species Sida hermaphrodita (L.) Rusby with maize does not reduce biomass when intercropped with legumes, but that biomass is reduced significantly when intercropped with grasses (Nabel et al 2018, Weidlich et al 2018). In addition, attention must be given to green manure seed density at planting since high biomass coverage can result in lower light availability, hindering the growth of native species under legume intercropping .…”