Winter green manure cultivation benefits soil quality and ecosystem multifunctionality under upland paddy rotations in tropics

Aims

Soil fertility depletion caused by intensive farming is a major constraint on crop production in tropical regions. However, the ability of winter fallow or green manure cultivation to improve soil quality and ecosystem multifunctionality remains largely unknown, particularly in tropics.

Methods

Here, a 4-year field study was conducted to evaluate soil quality, and ecosystem multifunctionality under four cropping systems, including pepper-double rice, cowpea-double rice, fallow-double rice, and green manure-double rice.

Results

Fallow-double rice has a limited impact on soil quality compared to vegetable cultivation, while incorporation of green manure increases soil quality by 23.0–41.2% in 0–40 cm depth (p < 0.05). Similarly, green manure-double rice increased C- and N-cycling enzyme activities by 54.2–62.3% and 80.1–106.9% in 0–40 cm depth compared to vegetable cultivation (p < 0.05), respectively. However, the cropping system has no significant effect on soil P-cycling enzyme activity. Fallow-double rice can slightly increase soil nutrients, but it does not affect soil quality and ecosystem multifunctionality. Pearson’s index showed that total soil C and NO₃⁻-N were positively correlated with soil ecosystem multifunctionality in the topsoil (0–20 cm) (p < 0.05).

Conclusion

winter green manure improves soil quality and ecosystem multifunctionality by increasing soil available nutrients and extracellular enzyme activities under the paddy system, which could be recognized as a promising strategy for soil restoration.

Graphical abstract