Effects of green manure legumes and their termination time on yield of maize and soil chemical properties

ABSTRACT

A two-year field experiment was conducted to examine the effects of interseeded green manure (GM) legumes in maize (Zea mays L.) cropping systems and their termination time on yield of maize and soil chemical properties in southern Ethiopia. Maize variety, BH540 was planted as the main crop while three GM legumes cowpea (Vigna unguiculata L. Walp), lablab (Lablab purpureus (L.) Sweet) and hairy vetch (Vicia villosa Roth) were interseeded between maize rows. The GM legumes were terminated and incorporated into soils at 30, 45 and 60 days after planting. The amounts of dry biomass produced varied significantly (p < 0.05) among GM legumes and their termination time. The results indicated that GM legumes accumulated over 39.3–65.5 kg N ha⁻¹ yr⁻¹ during 2014 cropping season and 53.3–156.6 kg N ha⁻¹ yr⁻¹ during 2016 cropping season. However, maize stover and grain N yields were not significantly influenced by GM. The results suggest GM legumes, lablab and cowpea improved soil chemical properties (N, P and K). Therefore, interseeding and incorporation of GM legumes can be considered as an alternative mechanism of soil fertility management for sustainable crop production in southern Ethiopia, where rotational and successional GM legumes cultivation is practically impossible.

KEYWORDS:

• Green manure legumes
• maize agronomic performance
• sustainable crop production
• N recovery
• termination time

Acknowledgements

Field research was partly supported by Canadian International Food Security Fund and Ethiopian Institute of Agricultural Research. Paper write up was done at University of Hohenheim by the financial support of CLIFOOD project, funded by DAAD under Food Security Center; therefore, we are grateful for their kind support.

Disclosure statement

No potential conflict of interest was reported by the authors.