Low Input Approaches for Soil Fertility Management in Semiarid Eastern Uganda

Abstract

Grain sorghum [Sorghum bicolor (L.) Moench] is an important food crop of semiarid sub‐Saharan Africa. Crop yields are generally low, partly due to low soil fertility. Research was conducted with farmers to evaluate, soil fertility management practices in sorghum‐based cropping systems including: mucuna [Mucuna pruriens (L.) DC.] fallow; cowpea [Vigna unguiculata (L.) Walp.] rotation with sorghum; animal manure application; N and P fertilizer application; and reduced tillage. Four studies, comprised of 142 on‐farm trials, were conducted at three locations over 3 yr in drought‐prone parts of eastern Uganda. Mucuna on average produced 7 Mg ha−1 of aboveground dry matter containing 160 kg N ha−1 across the three locations. Application of 2.5 Mg ha−1 of manure and of 30 kg N plus 10 kg P ha−1 increased grain yield by 1.05 and 1.30 Mg ha−1, respectively. A combination of 2.5 Mg ha−1 manure with 30 kg N ha−1 increased grain yield by 1.50 Mg ha−1 above the control (1.1 Mg ha−1). The increase in sorghum grain yield in response to 30 kg N ha−1 alone, to a mucuna fallow, and to a rotation with cowpea was 1.15, 1.55, and 0.82 Mg ha−1, respectively. These soil fertility management practices, as well as reduced tillage, were found to be cost effective in increasing sorghum yield in the predominantly smallholder agriculture where inorganic fertilizer was not used much. On‐farm profitability and food security for sorghum production systems can be improved by use of inorganic fertilizers, manure, mucuna fallow, sorghum–cowpea rotation, and reduced tillage.

Footprints of water and energy inputs in food production – Global perspectives

“…In irrigation systems with already high fertilizer inputs such as in South Asia, an efficient use of fertilizer must be warranted. Reduced tillage as well as soil fertility management practices, where inorganic fertilizer is not used much, can improve on-farm profitability and food security in smallholder production systems such as in sub-Saharan Africa (Kaizzi et al, 2007). However, fertilizer use for carbon sequestration has its limits, and is sensitive to soil condition, land management practices, and climate (Lal, 2007).…”

Graphical Determination of Leaf Area Index and its Relationship with Growth and Yield Parameters of Sorghum (Sorghum bicolor L. Moench) as Affected by Fertilizer Application

“…There has been an increase in grain yields of the crop following the application of N, P or K based fertilizers to the crop (Kaizzi et al, 2007). In crop production, leaf area index, defined as the total leaf area per unit ground area, is commonly used to quantify vegetative canopy structures (Welles and Norman, 1991).…”

Validation of Farmer Perceived Soil Fertility Improving Tree Species in Agropastoral Communities of Bushenyi District

“…Previous studies in Uganda have concentrated on different socioeconomic and ecological values of trees such as Tamarindus indica [7] and others [8,9]; some attempts on soil fertility and carbon sequestration abilities of some tree species retained on livestock farms have been elucidated [8,10], but no empirical studies specifically evaluating the soil fertility improving effects of such trees and farmer perception of their influence to this effect. In addition, there is limited information documenting and characterizing the soil fertility-enhancing effects of these species.…”