Optimalising potato productivity in Sembalun highlands, Nusa Tenggara Barat - Indonesia.

Potato cultivation in Nusa Tenggara Barat (NTB) Province of Indonesia locates in the Rinjani Valley highlands at 1,050 – 1,250 m above sea level. Farmers grow the Atlantic variety for a crisp processing company. The yield of Atlantic is low which is about 18.2 ton/ha, however, this is a profitable crop for farmers. Elsewhere in Indonesia the frequent cropping of potatoes has led to soil quality decline. To reduce the decline, potato farmers in NTB used compost and superphosphate to increase potato productivity. They also applied a new management technique. This is important because potatoes are a new crop in NTB and specific management suited to local conditions which has not yet been developed. The research was conducted at six farmers‘ fields and involving six Farmer Field School (FFS) groups. The compost treatments applied were local compost at 3,000 and 5,000 kg/ha. The super phosphate treatments applied were 300 and 600 kg/ha. Each treatment had six replicates by having six different farmer groups which had the same experimental design in their fields. The results showed that there was no significant difference in yields of super phosphate at 300 and 600 kg/ha which were 33.0 and 33.1 t/ha, respectively. Similarly there was not a significant difference in yield between the compost treatments with 3,000 kg/ha producing 33.0 t/ha, meanwhile with 5,000 kg/ha of compost produced 32.7 t/ha.