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

Abstract

Although alley cropping has been shown elsewhere to permit continuous cropping, it has not been widely tested in the highlands of east and central Africa where it has the additional potential of controlling soil erosion. The effect of four rates (0, 30, 60 and 90 kg N ha -~) of inorganic N on the performance of alley cropping using Leucaena diversifolia as the hedgerow species was studied in the central highlands of Burundi. Significant increase in maize yield (average of 26%) due to alley cropping was only first realised in 1992, three years after the commencement of the trial. In 1993, the average yield advantage of the alley cropping plots was 21%. The prunings augmented the response of maize yield to inorganic N in 1992 and 1993. Compared with the control, economic benefits over the five-year period for all the treatments were negative.

Biophysical interactions in tropical agroforestry systems

“…and 1600 mm), significant positive yield responses were observed in seven out of eleven studies where the soils were either inherently fertile (Kang, 1993;Hauser and Kang, 1993;Mureithi et al, 1994;Shannon et al, 1994) or the acid infertile sites received external nutrients and lime (Akyeampong and Hitimana, 1996;Matthews et al, 1992a,b). In the humid tropics (rainfall > 2000 mm), maize and taro did not benefit from HI in four out of eight trials, but interestingly bean and cowpea yields invariably increased.…”

“…One of the sites with yield increases was a highland area in Rwanda with bimodal rainfall, where typical crop yields were very low (Balasubramanian and Sekayange, 1991); at the other site, soil and hedgerow management were very good (Bunderson, 1992). In subhumid environments (rainfall between 1000 Akyeampong and Hitimana, 1996;Balasubramanian and Sekayange, 1991;Bundersen, 1992;Chiyenda and Materechera, 1989;Duguma et al, 1994;Evensen et al, 1995;Fernandes et al, 1993;Hauser and Kang, 1993;ICRAF, 1995;Kang, 1993;Kang et al, unpublished;Kass et al, 1995;Lal, 1989a;Matthews et al, 1992a, b;Mathuva et al, 1997;Mittal and Singh, 1989;Mugendi et al, 1997;Mureithi et al,1994;Rao et al, 1991a;Rosecrance et al, 1992;Schroth et al, 1995b;…”

“…On this site, HI maintained yields of Al-tolerant rice and cowpea crops at 1 and 0.5 Mg ha -1 , respectively, for many seasons (ICRAF, 1995;Palm et al, 1995). Despite declining maize yields in sole-crop systems, HI produced higher yields over a long period in acid soils of Indonesia ICRAF, 1995) and higher yields in the later years after one season fallow in acid soils of Burundi (Akyeampong and Hitimana, 1996). In both sites, rainfall was adequate, phosphorus was not limiting or was added through fertilizer, and 5 to 12 Mg ha -1 of prunings were harvested per year.…”