Impacts of irrigation frequencies and weed control in field grown tuberoses in the western region of Saudi Arabia: 11. vegetative growth, cut flower yield, flowering characteristics, quality indices and n,p, and content of leaves

Controlling emergent and associated weeds, infield grown tuberose, in the Saudi Arabian Western Region Arid Zone, is extremely important, particularly under furrow irrigation system. A Split-Split-Plot field experiment, in Complete Randomized Block Design, with four replicates, was conducted, to investigate the impacts of different irrigation frequency regimes; irrigation every 2, 4, 6 and 8 days, comprising the whole plots; manual hand weeding (unweeded control, weeding every 4, 8, and 12 weeks) representing the sub plots; and herbicidal treatments (control, pendimethalin, glyphosate and pendimethalin plus glyphosate) allocated for the sub-sub-plots, on tuberose vegetative growth, cut flower yield, flowering stalk characteristics, flowering quality indices, and nutrient contents in leaves, during the 2001/2002 and 2002/2003 growing seasons. Frequent irrigation every two and/or four days appreciably increased number of tuberose plant basal leaves, cut flower yield flowering stalk length, diameter, weight and spike length, in comparison with frequent irrigation every six and/or eight days, in the two growing seasons. It also increased number of f orets (in pairs) per spike, considerably improved visual quality rating and noticeably ameliorated tuberose flowering index However, phosphorus as well as potassium contents tended to decrease due to increasing watering frequencies or reducing watering intervals, in tuberose leaves. Hand weeding every four weeks substantially improved vegetative growth, increasing number of basal leaves. It also increased tuberose cut flower yield, flowering stalk length, diameter, weight, and spike length considerably, in both seasons, in comparison with either the unweeded controls or other hand weeding treatments. Moreover, hand weeding every eight or twelve weeks were notably beneficial to tuberose vegetative growth, yield of cut flowers as well as flowering stalk characteristics, in comparison to unweeded controls. Frequent hand weeding every four weeks also remarkably produced the highest number of flowers per spike, superior quality rating associated with noticeably high flowering index, in comparison to either unweeded controls or other weeding treatments. Nevertheless, it conversely recorded the lowest percentages of N, P and K contents, in comparison to the unweeded controls. Pendimethalin plus glyphosate noticeably improved tuberose different characters and parameters, in both seasons, followed by glyphosate and pendimethalin, in a descending order, in comparison to the untreated controls. Tuberose leaves of plants treated with pendimethalin plus glyphosate remarkably registered the lowest nutrient contents of N, P and K, in both seasons. Plants which, received the preemergence pendimethalin plus the postemergence glyphosate, weeded manually every four, eight and/or even twelve weeks, and frequently irrigated every two and/or four days, exhibited conspicuous performances and noticeable floral behavior. Tuberose plant vegetative growth (number of basal leaves) was strongly correlated positively with cut flower yield, owering stalk length, diameter, weight, spike length, number of fowers/spike, visual quality rating and flower index, with highly significant correlation coefficients, in both seasons. Conversely, tuberose leaf nutrient contents (N, P and K) were considerably and negatively correlated with tuberose number of basal leaves.