Chinese Milk Vetch Improves Plant Growth, Development and 15N Recovery in the Rice-Based Rotation System of South China

Abstract

Chinese milk vetch (CMV) is vital for agriculture and environment in China. A pot experiment combined with 15N labeling (including three treatments: control, no fertilizer N and CMV; 15N-labeled urea alone, 15NU; substituting partial 15NU with CMV, 15NU-M) was conducted to evaluate the impact of CMV on plant growth, development and 15NU recovery in rice-based rotation system. The 15NU-M mitigated oxidative damage by increasing antioxidant enzymes activities and chlorophyll content while decreased malondialdehyde content in rice root and shoot, increased the biomass, total N and 15N uptake of plant shoots by 8%, 12% and 39% respectively, thus inducing a noticeable increase of annual 15N recovery by 77% versus 15NU alone. Remarkable increases in soil NH4 + and populations of bacteria, actinomycetes and azotobacter were obtained in legume-rice rotation system while an adverse result was observed in soil NO3 − content versus fallow-rice. CMV as green manure significantly increased the fungal population which was decreased with cultivating CMV as cover crop. Therefore, including legume cover crop in rice-based rotation system improves plant growth and development, annual N conservation and recovery probably by altering soil nitrogen forms plus ameliorating soil microbial communities and antioxidant system which alleviates oxidative damages in plants.

Leguminous Cover Crop Astragalus sinicus Enhances Grain Yields and Nitrogen Use Efficiency through Increased Tillering in an Intensive Double-Cropping Rice System in Southern China

“…Values for RE N in this three-year observation followed the range reported by other studies conducted in paddy soils [12,28,29]. The increase of RE N (Figure 4) in the vetch treatments was the result of a better synchronization between N supply and crop N demand, which was also observed in previous studies [31][32][33]. As reported by Zhu et al [12] and Xie et al [33] from a greenhouse pot trail, vetch combined with urea application resulted in a higher and more persistent soil inorganic N supply than urea applied alone.…”

“…The increase of RE N (Figure 4) in the vetch treatments was the result of a better synchronization between N supply and crop N demand, which was also observed in previous studies [31][32][33]. As reported by Zhu et al [12] and Xie et al [33] from a greenhouse pot trail, vetch combined with urea application resulted in a higher and more persistent soil inorganic N supply than urea applied alone. Furthermore, vetch cropping helped to increase soil microbial activities because vetch covering and incorporation may enhance vetch-microbe interaction by organic C and N input from vetch biomass and root rhizodeposition [23,32].…”

Co‐incorporation of Rice Straw and Green Manure Benefits Rice Yield and Nutrient Uptake

“…The results indicated limited capacity to maintain rice yield by F 80 treatment without straw and Mv co-incorporation relative to F 100 in the long term. Other studies had shown that, compared with inorganic fertilizer alone, the co-incorporation straw and Mv could reshape the soil microbial community and structure and the involved N cycling in paddy soil, thus mitigating N losses and improving the N utilization efficiency (Gao et al, 2015;Xie et al, 2017). This was in agreement with the increased fertilizer use efficiency in the co-incorporation treatments compared with F 100 (Fig.…”

“…When incorporated together with rice straw, the N-enriched Mv could regulate the quality of returned residues. Such a co-incorporation option could shift the microbial genera community involved in N cycling and mitigate N losses, thus improving the N utilization efficiency (Gao et al, 2015;Xie et al, 2017). A recent study showed that long-term rice-rice-green manure rotation enriches the beneficial bacteria in rice rhizosphere and enhances the nutrient uptake and grain yield .…”

Yield performance of machine-transplanted double-season rice grown following oilseed rape

“…A recent study, conducted by Xie et al . 13 , investigated the effects of growing Chinese milk vetch on soil and physiological processes governing plant growth of the subsequent rice crop. Their results showed that growing Chinese milk vetch can improve soil N conservation and recovery, increase leaf chlorophyll content, alleviate oxidative damage to plants, and consequently promote biomass production of the subsequent rice crop.…”