Extreme High Yield of Tropical Rice Grown Without Fertilizer on Acid Sulfate Soil in South Kalimantan, Indonesia

• Published in: Jurnal tanah Tropika dan Kualitas Lingkungan Vol. 15; no. 1; pp. 33 - 38
• Main Authors: Erry Purnomo, Yasuyuki Hashidoko, Toshihiro Hasegawa, Mitsuru Osaki
• Format: Journal Article
• Language: English
• Published: University of Lampung 01-01-2010
• Subjects: Acid sulphate soil; local rice variety; low input sustainable agriculture; South Kalimantan
• ISSN: 0852-257X; 2086-6682

Local rice varieties are commonly grown by the farmers locatedin acid sulfate soil area of South Kalimantan. In South Kalimantan, more than 100 local rice varieties can be found. In1999, a farmer found one hill (with 5 tillers) rice plant near a canal, later called Padi Panjang. The rice had panicle lengthof 50 cm. The panicle length of common local rice varieties are 25 cm. Since the finding, the farmer multiplied the seedfor 3 years to get a reasonable amount of seeds for nearby farmers to use. In 2004, there were 25 farmers grow the PadiPanjang by themselves. Their paddocks are widely spread out in Aluh-Aluh and Gambut districts. We take thisopportunity to investigate yield variation of the Padi Panjang that may be affected by soil properties variability. Tenpaddocks out of the 25 paddock were selected. At harvest time (in July-August), we measured the rice yield andcollected soil sample from the 10 paddocks. We found that the soil condition in the selected paddocks were marginallysuitable for growing improved rice. Without fertilizer, however, the rice yield varied from 3.21 to 8.09 Mg ha-1. We alsoobserved that the rice yield variations associated with tillers number. We did not find any correlation between riceyields with some selected soil properties, except it was observed that the tillers number was negatively correlated withsoil electrical conductivity (EC). The extreme yield of Padi Panjang might be explained the involvement of N fixingbacteria and P solubilizing bacteria, large rooting system and the ability of Padi Panjang root in modifying the rhizospheresoil