Effects of hedgerow pruning and plant spacing on sweet potato (Ipomoea batatas L.) alley crop and soil properties
1997
Nguyen Bao Toan
The highest total tuber yield was obtained from the spacing 25 cm x 30 cm. The lowest total yield was obtained from the spacing 25 cm x 90 cm. The highest marketable root yield was 25 cm x 90 cm treatment and the lowest marketable root yield was at 25 cm x 30 cm treatment. There was no difference between 25 cm x 60 cm and 25 cm x 90 cm treatments. Fresh herbage weight and dry matter yield of Gliricidia sepium hedgerow pruned at 30 day interval decreased with time. Unpruned hedgerows had higher fresh herbage and dry matter yield than pruned hedgerow. Concentration of N, P and K in leaves and green stems of pruned hedgerow were higher than those of unpruned hedgerows. Some soil chemical properties of the alley improved at the end of the experiment. There was an increase in pH, N, K, CEC but slight decrease in organic matter and P. Based on the result of the experiment, it is recommended that it is not necessary to prune hedgerow while growing sweet potato as an alley crop. Instead, pruning can just be done after harvest to save labour cost and to maintain the hedgerows. The appropriate plant spacing of sweet potato for tuber production is 25 cm x 90 cm. It is also necessary to conduct long term experiments to further evaluate changes in soil properties as affected by herbage incorporation and season
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