Water Use Efficiency in Sorghum-Pigeonpea Diversified Cropping Systems in Marginal Areas of Ghana and Mali.

Water use efficiency in sorghum-pigeonpea diversified cropping systems in marginal areas of Ghana and Mali.

Princess Adjei-Frimpong¹, Sieg Snapp², Eva Weltzien³, Saaka Buah⁴

^{1, 2} Plant, Soil and Microbial Sciences Department, Michigan State University, East Lansing, MI 48824, USA

³International Crops Research Institute for Semi-Arid Tropics, BP 320, Bamako, Mali

⁴CSIR-Savanna Agricultural Research Institute, Wa Station, P. O. Box 494, Wa, Ghana.

Abstract

Water use efficiency (WUE) is an important determinant of crop productivity in water-limited environments. This makes monitoring water distribution in the soil profile and the proportion available for plant use in the root zone critical to crop production in environments with highly variable rainfall. The overall crop yield is primarily dependent on the soil nutrient levels and crop water use. Based on this, two agronomic strategies, cropping system and soil fertility management will be used in this experiment as a way of evaluating the WUE of sorghum and pigeonpea. We hypothesized that intercropping sorghum with pigeonpea will enhance water use efficiency relative to sole cropped sorghum by reducing soil moisture competition between the plant species due to spatial differentiation in roots and the hydraulic lift of pigeonpea.

Field studies will be established at three different agroecological zones in Ghana and Mali using a randomized complete block design with 10 and 14 treatments respectively. Two cultivars of pigeonpea (Cajanus cajan), long and medium duration and sorghum (Sorghum bicolor) will be planted as intercrop and sole crops. Changes in soil moisture content over the growing season in all cropping systems will be monitored using Time domain reflectometry (TDR). Access tubes will be installed within the rows of plants to a depth of 100 cm in all treatments. Leaf chlorophyll content, grain yield and biomass will be measured at the vegetative, flowering and physiological maturity stages of the crop growth. Intercropping efficiency will be measured using the Land Equivalent Ratio (LER).

Analysis of variance (ANOVA) will be used to measure treatment effects and interactions. Data will be analyzed using SAS (SAS Inc, 2002). Results from this research will help in designing better cropping systems adaptable to smallholder farmers in West Africa.