Abstract:
Alley cropping -on terraces was compared with traditional open land
cultivation at the Research /arm, Girandurukotte, over three seasons.
Rainfed cowpea, black gram and sesame were planted in yala and maize and
cowpea were planted in rnaha
I ala (1936 and 1987) crop performance was poor; drought reduced
field establishment and growth and increased plant mortality. Crops
grown in alleys, however, had better (P-0.05) field emer ,_nce (73%,
versus 4-5% in the open), lower plant mortality (25% vs. 4.1%), more,, rapid
growth and greater yield (cowpea 515, black gram 397 and sesame 311 kg
ha-1) compared with the crops in bare land (282; 273 and 226 kg ha-”*).
This was attributed to reduced soil (up to 7.5°0) and air (6°C)
temperatures, higher relative humidity (by up to 11%), improved soil
moisture retention (up to 28 mm in the top 4-0 cm), greater organic
matter content (by 4.0%) and soil nitrogen (by 20%) under the avenues.
Due to adequate rains maha field emergence, crop growth and yield
differences between alley cropped and open tracts were non significant
(P-0.05). Mulch from loppings improved the soil and crop yield (maize
by 10% and cowpea by 20%) under the hedgerows. There were also no yield
differences (P-0.05) between untilled and minimum tilled plots, however
the former had an excessive weeding requirement due to presence -erf
pernicious perennials (Imperata cylindrica, Mimosa pudica and Commelina
spp.), though weed weights were lower by almost 60% in the alleys.
Sesame Veb Worm (Antigastra catelannalis), Bean Fly (Ophiomyia
phaseoli). Pod Borer (Haruca testulalis), Cutworm (Spodoptera littura),
rabbits and lizards caused greater damage under the avenues.
The maintenance requirement of the Leucaena cultivar was excessive
due to prolific growth of volunteer plants.
