Use of Nutrient Balance for Improving Fruit Yield and Quality of Tangerine (<I>Citrus reticulata </I>Blanco) cv. Sainampueng: 1. Production Systems in Chiang Mai Province

Abstract

Chiang Mai is currently considered to be the largest producer of tangerine cv. Sainampueng in Thailand, particularly in Chai Prakan-Fang-Mae Ai valley, where Fang is the production center of these three districts. The objectives of this study were data collection and analysis of tangerine production systems at Fang. In order to gain the understanding, field survey and structured interview were taken from 50 farmers, at 7 out of 8 sub-districts of Fang district by using the open-ended questionnaire. All randomly selected orchards were cultivated on soil group number 59. The studied duration was March 2006 – March 2007. Findings of this study were as follows:- the main agro-ecosystems for tangerine were on the gentle hill slopes as well as the upper terrace; there were seven previous crops found before the cultivation of tangerine but lychee was greatly important (32.9%); most growers (80.3%) held full land ownership certificate; they possessed a single farm and the majority (88.7%) had small ones; Sainampueng was the common (93.4%) cultivar which was generally (94.4%) propagated by air layering method; the majority of trees (82.8%) were at2 – 5 years of age and most of them were already productive; tangerine trees were predominantly (69.0%) planted in a single row on the raised bed system with a close spacing of 4 m x 4 m; most farmers (85.4%) Irrigated their trees by mini sprinkler and source of water came from rainfall harvesting reservoir (84.7%); growers implemented organic, organic-chemical, and chemical fertilizers of 17 different formulas; the preferred fertilizer grade 15-15-15 was applied to trees at vegetative and fruit development, while 0-13-21 at flower development and 13-13-21 at pre-harvesting stages; the decision on fertilizer and pesticide purchasing was made mostly on the basis of self experience while the other source of knowledge was also obtainable; most orchards (71.0%) sold their produce through traders without any fruit grading.