Effects of climate, leaf water potential and foliar fertilizers on nutritional contents and flowering of 'Hong Huay' lychee
1994
Wittaya Sinlaphasomboon
Study on the effects of climate, leaf water potential and foliar fertilizers, monopotassiumphosphate (0-52-34; MPP) and 7-13-34 + 12.5 Zn (NK), has been carried out in 'Hong Huay' lychee during October 11, 1991 and Febuary 6, 1992 at the Nan Horticulture Research Station of Nan Province. First MPP application was started on October 27, four times at one week interval, followed by the NK on November 24, with the same numbers of application and intervals. Both fertilizers were qpplied at the concentrations of 0 2500 3750 and 5000 ppm. The temperature was rather high during starting period and decreasing as time progressed. Recorded minimum temperature was ranged between 8.5-23.8 C. The changing pattern of minimum relative humidity was coincided with the precipitation and foggied days. High precipitation was obtained at the early days and quitted, but reappeared again at the end of December. Pan evaporation and wind speed have had little change during the study period. Only slightly changes in leaf water potential was found in the early study period but decreasing drastically just before flowering. This value was measured beteen -0.37 and -0.74 MPa before it reached the minimum trough. The dipping of leaf water potential continued after panicle emergence and turned upward when irrigation provided. Total nonstructural carbohydrate (TNC) was increased along with the numbers of application in both fertilizers and decreased at the time just before flower bud emergence. Total nitrogen (TN) content was found to be rather high at the early stage but decreased before flowering. NK applicatkon resulted in heightening the TN content and decreased after flower initiation. Changing pattern of leaf P content was similar to TNC's while the level in shoot stem was increased after flower initiation. Within the tree canopy, the north and east sides exhibited highest flowering percentage while the top and bottom position showed no significant differance.
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