UJI EFEKTIFITAS BERBAGAI MACAM PUPUK NPK TERHADAP PERTUMBUHAN DAN PRODUKSI KENTANG (Solanum Tuberosum L.) VARIETAS GRANOLA KEMBANG

Potatoes (Solanum tuberosum L.) are horticultural crops that have high economic value so that they are widely planted by farmers. Generally, potato plants are planted in the highlands at the beginning or end of the rainy season so the risk of losing fertilizer due to erosion or washing is very high. According to data from the Indonesian Central Statistics Agency (BPS, 2018) states that potato production in Indonesia as a whole has decreased from 2015 to 2017, from 1.34 million tons / year in 2014 to 1.22 million tons / year in 2015 until 2017 the production is 1.17 million tons/year. This amount of production has not been able to meet the consumption needs of the Indonesian people for potatoes. To increase the productivity of potato plants can be done by growing superior varieties such as Granola Flower, Granola is one of the varieties that have high production potential and is resistant to several types of diseases that commonly attack potato plants, and has high production potential of 30-50 tons/hectare. This study aims to study the types of NPK fertilizer on the growth and yield of potatoes and the right type of fertilizer to increase the productivity of potato plants. The study was conducted in open land in the Tosari District, Pasuruan Regency. The study began in November 2018 until April 2019. This study used a randomized block design with 7 treatments and was repeated 4 (four) times, with treatments, (P1u1) control farmer (Za+Npk Mutiara), (P2u1) Za+Phonska Plus, (P3u1) Za+Petro Nitrat, (P4u1) Za+Pelangi, (P5u1) Za+Mutiara, (P6u1) Za+Yara Mila, (P7u1) Za+Tawon. Observation variables consisted of plant height (cm), number of leaves (strands), number of branches, chlorophyll content (mg / l), number of tubers per plant, tuber weight per plant (g), production potential (tons / ha), grade grading tubers based on weight. The results showed that the treatment of various types of NPK fertilizers on high growth on observations of 21 to 70 days after planting showed no effect between the treatments given, the highest number of crop tubers was found in the ZA + Phonska Plus (P2) treatment compared to the treatment the other. the highest tuber weight per plant was found in (P2) ZA + Phonska Plus with a value of 476.29g, the potential for expansion tuber weight resulted in the highest yield in P2 treatment with a weight of 22.83 tons / Ha and the lowest potential yield at P5 treatment with a weight of 11.10 tons /Ha