%0 Journal Article
%T Amendment of Tephrosia Improved Fallows with Inorganic Fertilizers Improves Soil Chemical Properties, N Uptake, and Maize Yield in Malawi
%A Maggie G. Munthali
%A Charles K. K. Gachene
%A Gudeta W. Sileshi
%A Nancy K. Karanja
%J International Journal of Agronomy
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/902820
%X Maize production in Malawi is limited mainly by low soil N and P. Improved fallows of N-fixing legumes such as Tephrosia and Sesbania offer options for improving soil fertility particularly N supply. The interactions of Tephrosia fallows and inorganic fertilizers on soil properties, N uptake, and maize yields were evaluated at Chitedze Research Station in Malawi. The results indicated that the level of organic matter and pH increased in all the treatments except for the control. Total N remained almost unchanged while available P decreased in all plots amended with T. vogelii but increased in T. candida plots where inorganic P was applied. Exchangeable K increased in all the plots irrespective of the type of amendment. The interaction of N and P fertilizers with T. vogelii fallows significantly increased the grain yield. The treatment that received 45£¿kg£¿N£¿ha£¿1 and 20£¿kg£¿P£¿ha£¿1 produced significantly higher grain yields (6.8£¿t£¿ha£¿1) than all the other treatments except where 68£¿kg£¿N£¿ha£¿1 and 30£¿kg£¿P£¿ha£¿1 were applied which gave 6.5£¿t£¿ha£¿1 of maize grain. T. candida fallows alone or in combination with N and P fertilizers did not significantly affect grain yield. However, T. candida fallows alone can raise maize grain yield by 300% over the no-input control. Based on these results we conclude that high quality residues such as T. candida and T. vogelii can be used as sources of nutrients to improve crop yields and soil fertility in N-limited soils. However, inorganic P fertilizer is needed due to the low soil available P levels. 1. Introduction Land degradation and depletion of soil nutrients are widespread in sub-Saharan Africa (SSA) and especially in Malawi. In small-scale farming systems, continuous cropping of cereals without rotation with legumes and inappropriate soil conservation practices have depleted soil fertility [1]. Recent analyses [2] show that N limitation is widespread in Africa. This is specially so due to depletion as a result of soil erosion. According to Stoorvogel et al. [3] and Smaling [4] the annual net nutrient depletion exceeds 30£¿kg£¿N of arable land in Malawi. The inability of most farmers to practice fallowing due to land shortage and reduced inorganic fertilizer use due to high prices of inorganic fertilizer are some of the major causes of decline in crop productivity in Malawi [5] and sub-Saharan Africa at large. Many options have been explored to address land degradation and declining soil fertility in Malawi [6¨C8]. Because organic sources such as animal and plant manure are often in short supply, governments and
%U http://www.hindawi.com/journals/ija/2014/902820/