Legumes in soil fertility management: The case of pigeonpea in smallholder farming systems of Zimbabwe

Abstract

We investigated the current use of legumes in s;il fertility management and the feasibility of promoting use of pigeonpea in smallholder farming systems of a Communal Area in Northeast of Zimbabwe. Participatory rural appraisal methods were used to establish farmer management strategies and perceptions on major constraints to crop productivity. Soil fertility parameters were evaluated through farmer participatory experiments. The study revealed limited cultivation of legumes for both human nutrition and soil fertility management. Legumes were generally regarded as women's crops, and therefore minor, because of men's domination over women in the household decision-making process. Balancing gender interests in terms of allocation of inputs and distribution of benefits at household level was identified as a major challenge to the implementation of legume technologies. Poor extension thrusts with respect to legume production, and poor agronomic practices wereidentified as major production constraints. over-emphasis on maize in the current extension packages led to the relegation of legumes to the status of 'minor crops'. Participatory experiments suggested that pigeonpea can be successfully grown by farmers under poor soil fertility conditions. The crop yielded about 3 to 9 t ha-' of shoot biomass in asingle cropping season, and up to 23 t ha-' after two seasons of growth. High amounts leaf litter released by the crop in one season (up to 3 t ha-') are considered a potentially viable source of nutrients for subsequent crops, as confirmed by a 22% maize yield increase obtained from a field that was previous cultivated with pigwnpea.Key Words: Cajanus cajan, farmer participatory experiments, leaf litter, nutrient replenishment, Zimbabwe Les investigations sur I' utilisation des ltgumineuses dans la gestion de fertilitt du sol ainsi que les possibilitts d' incorporer le pois cajan dans le systbme agricole de petits ferrniers ont Ctt fait dans un milieu rural au NordEst du Zimbabwe. La mtthode "Participatory rural appraisal" a CtC utilisk pour dtterminer les strattgies de gestion du sol et les perceptions qui contribuent ?I la rauction de la productivitt de la r h l t e . Les parambtres de fertilitb du sol ont Ct C analysts en collaboration avec des agriculteurs. Cette Ctude a rtvelt qu' il y a une utilisation lirmttedel6gumineusesdans 1' alimentation des gens ainsi quedar~s lagestion de fertilitt du sol. Les lCgumineuses sont generalement c o n s i d t r b commes la rtcolte pour les femmes, sur ce, de peu d' importance, et ?I cause de la domination des hommes dans la prise de dkision dans le foyer. L'extcution des tkhnologies d' incorporer Ies ltgumineuses dans le systtme de production agricole s' est heurttk ?I un probltme majeur de domination de l'homme, ses prtfkrences dans la rtpartition et la distributions des intrants et les Mntfices. Un autre problbme identifit, c'est une vulgarisation trks limit& de la production de ltgumineuses et une difficile adaptation agronomiquede varitt6s delCgumineuses qui sont ...

Yields and accumulations of N and P in farmer-managed intercrops of maize–pigeonpea in semi-arid Africa

“…Shedded pigeonpea leaves containing approx. 28-40 kg )1 N ha )1 have been reported (Kumar Rao et al 1983;Kumar Rao and Dart 1987;Mapfumo et al 2001) under better growing conditions. The input of pigeonpea root residues must also be expected to exceed those of maize substantially.…”

Farmers’ Preferences for Genetic Resources of Kersting’s Groundnut [Macrotyloma geocarpum (Harms) Maréchal and Baudet] in the Production Systems of Burkina Faso and Ghana

“…Most legumes including Kersting's groundnut have been overlooked by research and development agencies and are generally considered as women's crops in some areas since they are often produced by women producers on small land areas meant primarily for home consumption [44], whereas men tend to dominate in the production and marketing of cereals in the food value chain [45]. This was true for Kersting's groundnut in the farming systems of Burkina Faso and Ghana.…”

Decomposition of Subtropical Fruit Tree Leaf Litter at Nelspruit, South Africa

“…The high content of N, low carbon to nitrogen ratio (C/N), and polyphenol from avocado and mango leaf litter may have contributed to their faster decomposition and rapid release of nutrients compared to that of litchi. Generally, the decomposition rates were slow in the three leaf litter types when compared to litter of other plant species such as Cajanus cajan (Mapfumo, Campbell, and Mpepereki 2001), legumes (Palm and Sanchez 1990), Gliricidia sepium (Zaharah and Bah 1999), Tithonia diversifolia (Partey et al 2011), and Lantana camara (Kayuki and Wortmann 2001). This suggested that the leaf litter from the three subtropical fruit trees was of relatively poor quality, which could impact not only on decomposition rate but on the amount of nutrients released (Musvoto, Campbell, and Kirchmann 2000).…”

“…Because of the high cost of mineral fertilizers, many smallholder farmers in SSA use organic materials, including leaf litter, to supply crop with nutrients (Musvoto, Campbell, and Kirchmann 2000). Incorporation of leaf litter into soil before planting is the common practice among smallholder farmers with the view to enforce the cycling of nutrient within the farm by allowing litter to decompose and release nutrients for plant growth (Mapfumo, Campbell, and Mpepereki 2001). Such a practice, however, requires a proper understanding of the decomposition and nutrient-release processes to avoid compromising the synchrony of nutrient release with plant demand.…”