EFFECT OF HARVESTING FREQUENCY ON COWPEA GROWTH AND LEAF YIELD IN TRANS NZOIA COUNTY, KENYA

Abstract

The frequency of leaf harvesting is a yield determinant factor and leaf defoliation has been shown to stimulate leaf production in cowpeas (Vigna unguiculata L. Walp.). However, cowpea farmers continue getting low yields due to harvesting method, among other factors. The purpose of this study was to evaluate the effect of four (4) harvesting frequencies on cowpea growth, and cumulative leaf yield. The four-leaf

harvesting frequency experiment was in RCBD with three replications at KALRO- Kitale (UM4) in Trans Nzoia County. Data were collected on plant height, shoot

number, shoot length, and cowpea yield. The data was subjected to ANOVA on SAS software. Fisher’s Least Significant Difference (LSD) at p=0.05 was used to compare the treatments effects. The cowpea plant height increased significantly with increasing harvesting frequency a time-period. The highest average plant height (22cm) was recorded in F1 (where harvesting was done every seven days) and lower in F3 with an average of 15cm (where harvesting was done after every 21 days) (F3), and lowest for F0 though not significantly different from F3. There were significant differences in the effect of harvesting frequencies on shoot length, which increased significantly as yields increased. The average length of the cowpea plant shoot for uprooted plants at the onset of harvesting frequency (F0) was about 48cm. and longer (about 82cm) where harvesting was done at seven days intervals of leaf harvesting (F1) and lower (67cm) at 21 days interval of leaf harvesting (F3). There was a significant difference in shoot numbers between F0 (no capping) and the rest of the frequencies (F1, F2, and F3). There were significant differences in cumulative yield for the four harvesting frequencies. Harvesting at seven days intervals (F1) was significantly high and outstanding at 5.40 tons/ha while uprooting at the onset of harvesting(F0) was significantly low (1.28 tons/ha). Therefore, the innovation of sequential harvesting promotion will enhance increased yields.