Legume Cover Crop Effects on Temperate Sugarcane Yields and Their Decomposition in Soil

Abstract

Sugarcane is commercially produced on 340,000 ha in the US and is valued at over $1 billion US annually. Cultural practices that improve sugarcane sustainability are needed to maintain yields in fields with degraded soils. Historically, leguminous rotation crops provided organic matter and biologically fixed nitrogen (N) for subsequent sugarcane crops. Currently, sugarcane is usually grown as a monoculture with only a short, 6-month fallow period. The objective of these field studies was to determine how growing cowpea (Vigna unguiculata (L.) Walp.) and sunn hemp (Crotalaria juncea L.) as cover crops during fallow affected the yield of subsequent sugarcane crops. A companion laboratory study investigated the decomposition rate of cover crops in soil at different temperatures. Cowpea and sunn hemp production produced 12.8 t/ha dry matter and 250 kg N/ha. Cowpea generally improved plant cane yields, but the effects of sunn hemp varied. However, neither cowpea nor sunn hemp reduced cane or sucrose yields consistently, and mineral N additions may have a role in mitigating yield gains or losses. Based on laboratory data, the average half-life for cowpea and sunn hemp would be 3 months. Overall, using legume cover crops should be viewed as an important component of sustainable sugarcane practices.

Dynamics of Soil Nitrogen Availability Following Sunn Hemp Residue Incorporation in Organic Strawberry Production Systems

“…However, strawberry plant N uptake and utilization need to be further examined to better understand the extent of this benefit. As reported in other studies, the contribution of sunn hemp residues to the subsequent cash crop yield performance in addition to the recovery of N from sunn hemp largely depend on the timing of N release from sunn hemp residues and the growth and nutrient uptake patterns of the subsequent cash crop (Elsaid and Silva, 2017;White et al, 2020). This deserves more research to show how sunn hemp residues as a N source can be effectively and efficiently integrated into organic nutrient management for strawberry production.…”

Utilization of Legume-Nodule Bacterial Symbiosis in Phytoremediation of Heavy Metal-Contaminated Soils

“…Numerous studies confirm that legumes can be cover crops (CCs). Legume CCs exert several positive effects, i.e., they improve soil fertility, prevent soil erosion, provide soil protection, and reduce weed infestation [11][12][13]. Legume crops are commonly used as green manure [14].…”

“…Moreover, nodules with high NFB concentration may also be effective as biosorbents and storage for HMs in comparison with nodule-free plants. For example, the Cd, Cu and Pb uptake by Mimosa punica L. nodulated by Cuprividus taiwanensis from family Burkholderiaceae was 70%, 12% and 86%, respectively, higher than that of non-nodulated plants showing the effectiveness of using nodulated legumes for HM removal [12,165]. Interestingly, Saadani et al [160] showed that legume inoculation significantly increased their biomass production, as well as N and P content.…”