อิทธิพลของฤดูปลูกและการให้น้ำต่อการเติบโตและผลผลิตของหญ้าหวาน

Abstract

The study of the Influences of Growing Seasons and Irrigation Regime and Yield of Stevia was conducted at the Mae Hia Agricultural Research, Demonstration and Training Center, Faculty of Agricultural Chiang Mai University. The objectives were (1) to compare the water use efficiency of stevia at different levels of irrigation and (2) to evaluate the growth and yield capacity of stevia. with different levels of water supply in the rainy season and summer. Conducted an experimental study on stevia planting in 2 growing seasons: rainy season (July-September 2019) and summer season (February-April 2020). The experiment was Factorial in Randomized Complete Block design com prised with irrigation as 1 st factor: Seasons (Rain and Summer) as 2 nd factor 1) Control the water supply according to farmer practices 2) Provide water in accordance with daily evapotranspiration value (ETc) 3) and 4) provides water by controlling soil moisture at 30% and 50% of available water capacity. A total of 1 6 0 samples were collected per week, including plant information, i.e. plant growth (height, canopy shape) and at 30 days of planting, fresh and dry weights (leaves, stems) were collected for soil data. One non-destructive soil sample per plot was taken at a depth of 0-30 cm for moisture determination. Throughout the growth phase of the stevia. The collected data were analyzed for variance. (analysis of variance:ANOVA) of the water treatment on growth and yield and compare the differences of experimental subject by the least ช significant difference (LSD) method at the confidence level of 9 5 % with the following study results: growth (Mean height and average canopy) in the rainy season were higher than in the summer. The average height of the rainy season and the summer was 13.69 cm and 13.44 cm, which were significantly different from the average canopy in both seasons. The canopy shape was higher in the rainy season (20.08 cm. and 11.57 cm.).From the analysis results of each watering treatment. It was found that the two seasons were not significantly different statistically. The method of watering according to the crop evapotranspiration (ETc) had the highest value, followed by irrigation according to farmers' practice, controlling the soil moisture level between the field moisture capacity and that of 3 0 % of the soil's useful moisture capacity and 5 0 % AWC, respectively. In terms of yield (fresh leaves, dry leaves, fresh stems and dry stems), it was found that the yield in the rainy season was higher than that of summer. Fresh leaf weight (53.40 g and 51.07 g) and dry leaf weight (12.09 g and 11.85 g) were used for stem weight (fresh and dry), fresh stem weight (21.04 g and 16.88 g) and dry stem weight (3.97 g and 3.34 g) and in every process of both seasons there were statistically significant differences. It was found that the watering demand of plants in treatment 2 had the highest value, followed by treatments 1, 4 and 3 respectively. The results of the study indicated that Stevia planted in the rainy season grows well and yields more than summer. But the yield was more damaged than in the summer as the waterlogging of the growing area prevented the sweet grass from growing. Farmers should have management to avoid waterlogging in the growing area. For the study, it was found that the treatments 2 method of watering had the best growth and highest yield. Followed by the irrigation method treatments 1 , while the treatments 3 and 4 irrigation methods had similar growth values. and yield the least respectively.