การจัดการปุ๋ยที่เหมาะสมสำหรับการผลิตสตรอว์เบอร์รี พันธุ์พระราชทาน 80 บนพื้นที่สูง จังหวัดเชียงใหม่

Abstract

The study on the appropriate fertilizer management for strawberry cv Pharachatan 80 production in highland, Chiang Mai province was conducted with the following objectives: 1) to determine nutrient requirements (nitrogen, phosphorus, and potassium) and 2) to evaluate the appropriate fertilizer for strawberry. The trials were conducted in the farmer’s field at Khob Dong village, Mae Ngon subdistrict, and Had Sompoi village, Mae Sap sub-district, Samoeng district, Chiang Mai province, from September 2018 to April 2019. The study on strawberry nutrient requirements was performed by randomly collecting the strawberry samples. The fresh and dry weights of strawberry in each growth stage were recorded, and then the concentrations of N, P, and K in plant tissue were analyzed to determine the strawberry nutrient requirements. The result found that the organic strawberry nutrient requirements were 5.80 kg N/rai, 1.49 kg P/rai, and 10.51 kg K/rai. At the vegetative growth stage, organic strawberry need 3.65 kg N/rai, 0.56 kg P/rai, and 4.92 kg K/rai, and in the reproductive growth stage, organic strawberry need 2.14 N kg/rai, 2.15 P kg/rai and 6.27 kg K/rai, respectively. The typical strawberry nutrient requirements were 10.14 kg N/rai, 1.33 kg P/rai, and 10.83 kg K/rai. At the vegetative growth stage, the nutrient requirements of strawberry were 1.68 kg N/rai, 0.24 kg P/rai, and 1.90 kg K/rai. While the reproductive growth stage, the nutrient requirements of strawberry were 8.47 kg N/rai, 1.09 kg P/rai, and 8.93 kg K/rai. The study on appropriate fertilizer management for strawberry production was designed by randomized complete block design with four replications and four fertilizer treatments consisting of 1) fertilization based on common fertilizer rate for strawberry production (CFRS) (68.48 kg N/rai, 185.09 kg P2O5/rai and 120.57 kg K2O/rai), 2) fertilization rate based on nutrient requirements of strawberry (F-NR) (25.02 kg N/rai, 8.25 kg P2O5/rai and 41.89 kg K2O/rai), 3) fertilization rate based on site-specific fertilizer management (SSFM) 25.02 kg N/rai), and 4) control treatment (without fertilizer). The results showed that treatments 1, 2, and 3 had no significant effect on plant height, canopy width, above-ground plant dry weight, the nitrogen concentration in the above-ground plant at 60 days, and yield compared to the control treatment. All treatments did not affect yield quality (titrated total acid (TTA), total soluble solids (TSS), and vitamin C contents (ascorbic acid)) were significant with values in the range of 1.13-1.14%, 11.47-11.67 ᵒBrix and 58.65-64.16 mg/100 g fresh weight. However, treatment 3 gave the highest yield at 3015.90 kg/rai, and fertilizer use efficiency was 14.22%. This study suggests that when strawberry was cultivated in soil that contained a very high available phosphorus and exchangeable potassium level. The fertilizer rate based on SSFM treatment by applying only nitrogen fertilizer at 25.02 kg/rai should be the optimal rate for strawberry production's high yield and quality. A low rate of fertilizer use resulted in reduced production costs and fertilizer contamination to the environment.