Little or no maize (Zea mays) grain yield loss occurred in intercrop with mid‐maturity lablab (Lablab purpureus) in northeastern Tanzania

Abstract

AbstractIntercropping is among sustainable intensification tactics farmers may use to increase or maintain productivity and environmental quality. Effects of planting lablab [Lablab purpureus (L.) Sweet] 1 or 2 weeks after planting maize (WAPM) are not well characterized, especially when mid‐maturity lablab cultivars are used. Greenhouse (Springfield, MO) and field studies (Arusha, Tanzania) were conducted in 2018 and 2019 to assess early (≤60 days) and full‐season effects on growth and grain production. The greenhouse study characterized early growth characteristics when lablab was sown 0, 1, or 2 WAPM for each of four cultivars of lablab. “Echo Cream” lablab produced greater vine length and more nodes than other cultivars in the greenhouse. Greenhouse lablab biomass and node number were greatest when sown ≤1 WAPM. The field study compared monoculture and intercrop grain yields. Highest maize yields occurred when lablab was sown ≥1 WAPM, but highest lablab yields occurred when planted at the same time as maize. The maize/lablab intercrop always resulted in favorable land equivalent ratios (LERs) ranging from 1.5 to 2.1. The partial LER of maize yield was not reduced by more than 7% relative to monoculture either year. Lablab yield was negatively affected by planting delay, decreasing about 60% in 2018 and 31% in 2019 in the 2 WAPM planting date treatment. Although twining lablab vines complicate grain harvest, our results demonstrate increased grain production per unit area with maize/lablab intercropping, with a potential for increased farmer income and household nutrition.