The potential of alley cropping im improvement of cultivation systems in the high rainfall areas of Zambia II. Maize production

Abstract

Three trials to evaluate the potential of alley cropping in maize production on the low fertility, acidic soils in Northern Zambia are described. Leucaena leucocephala, Gliricidia sepium, Sesbania sesban, Albizia falcataria, Flemingia congesta, and Cassia spectabilis, were grown in alley crops with hybrid maize and soybean. All trials received recommended rates of P and K fertillser; N fertiliser was applied at three rates as a subplot treatment. One trial received lime before establishment.Only in the limed trial was there a significant improvement in maize yields through alley cropping; when no N fertiliser was applied, incorporation of Leucaena leucocephala pranings resulted in an increase of up to 95% in yields, with a smaller improvement being produced by Flemingia congesta. There was a significant correlation between the quantity of prunings biomass applied and the proportional increase in maize yields over the control treatment. It is suggested that the lack of effect of most of the tree species on crop yields was due to low biomass production.An economic analysis showed that alley cropping with limed Leucaena was only profitable when fertiliser costs were high in relation to maize prices. However, lime is both expensive and difficult to obtain and transport for most small scale farmers in the region, and is therefore not a practical recommendation. It is suggested that future alley cropping research should focus on screening a wider range of tree species, including other species of Leucaena, for acid tolerance and higher biomass production.

Evaluation of the effect of hedgerow intercropping using Leucaena leucocephala and fertilizer application on growth and yield of garden eggs (<i>Solanum melongena</i>)

“…The low initial fertility level of the soil may account for the lack of significant soil improvement even in plots mulched and/or treated with fertilizer. This confirms reports on a Leucaena alley cropping trials in Zam-bia by Matthews et al, (1992), in which the authors remarked that it appears that soil improvement may occur where the soil fertility is already relatively high, but where it is low, then even further depletion occurs. The removal of the nutrient by the crop for vegetative growth and fruit formation might also contribute to the lower or constant level of nutrient elements at the end of the trials.…”

Effectiveness of calcined rock phosphate and leucaena prunings as a source of nutrients for maize in a tropical soil

“…The finding that L increases the agronomic efficiency of P, with and without the effects of drought, illustrate that an improvement in nutrient-use efficiency at the farm level is needed. Furthermore, although the application of organic material alone cannot meet the P requirements of crops owing to the low P concentrations involved, evidence suggests that the practice of leguminous pruning can increase total P availability and uptake (Mathews et al 1992;Mweta et al 2007). In acid soil, phenolic and aliphatic acids produced during decomposition of organic matter are responsible for the solubilization of appreciable amount of phosphates, resulting in increased P availability in soil (Ramesh et al 2003).…”

Agronomic and economic appraisal of alley cropping with Leucaena diversifolia on an acid soil in the highlands of Burundi

“…Working on an Entisol of pH 6.0, Atta- Krah [1990] applied 45 to 60 kg ha -1 of each of N, P, and K. In addition to 2 t ha -1 of lime, Matthews et al [1992] applied 250 kg ha -~ of single superphosphate and 200 kg ha -~ of KC1. The successful agronomic use of L. diversifolia in alley cropping is important because L. diversifolia, unlike L. leucocephala, is tolerant to soil acidity [Hutton, 1990] because its roots are able to absorb calcium [Brewbaker, 1987].…”

“…Although prunings improved maize yield over the control, in 1992 and 1993, without N they could only sustain maize yields of 1.6 to 1.7 t ha -l. Similarly, in many trials from diverse environments, although alley cropping resulted in significant maize yields above the control, the ability to produce maize yields above 2 t ha -I on prunings alone without external N was limited [Kang et al, 1981a;ICRAF, 1992;Yamoah and Burleigh, 1990;Rosecrance et al, 1992;Matthews et al, 1992].…”

“…In terms of benefits, the prunings are a source of nutrients and fuelwood or stakes are obtained from the hedges. In their economic analyses of maize production under alley cropping in northern Zambia, it is not clear whether Matthews et al [1992] considered the added costs of labour or valued the fuelwood harvested. Therefore to obtain indications of the potential of alley cropping in the highlands of Burundi, net returns determined through a partial budget analysis were assessed.…”