Crop Production and Soil Salinity in the Tsunami Affected Areas of the Eastern Coast of Aceh Province, Indonesia.
Teuku Iskandar1, Achmad Rachman2, M. Nur1, Malem McLeod3, Kasdi Subagyono2, Natalie Moore4, and Peter Slavich4. (1) Aceh Assessment Institute for Agricultural Technology, Jalan Panglima Nyak Makam No. 27, Banda Aceh, 23125, Indonesia, (2) Indonesian Soil Research Institute, Jalan Ir. H. Juanda 98, Bogor, 16123, Indonesia, (3) NSW Dept of Primary Industries, Tamworth, 4 Marsden Park Road, Calala, Tamworth, NSW 2340, Australia, (4) NSW Dept of Primary Industries, Private Mail Bag 2, Grafton, NSW 2460, Australia
The giant tsunami waves following the earthquake off the west coast of Sumatra on December 26, 2004, have caused soil salinization of agricultural lands and damaged to irrigation and drainage channels along the coastal areas of Aceh province, Indonesia. Approximately 90,000 ha of paddy fields, 25,000 ha of mix gardens, and 90,000 ha of estate crops in Aceh were inundated by seas water after the tsunami. The objectives of this project are to enhance the recovery of cropping in tsunami affected areas along the eastern coast of Aceh where farming communities have resumed agriculture activities. The project is monitoring changes in soil salinity on the tsunami-affected areas using an electromagnetic induction techniques (EM38), and assessing constraints to crop performance. Regular assessment (three monthly) of soil salinity and crop performance are currently being conducted on 20 sites on the eastern coast of Aceh. Crops which have been assessed include rice, corn, peanut, soybean, onion and chillies. At each site, ECa was measured on a fixed transect line (±100 m long), at 4 m intervals, and information on cropping history and crop condition at the time of assessment are recorded. A composite surface soil sample was collected from each site for nutrients analysis. The level of soil salinity in tsunami affected areas appears o be related to the duration of inundation by the sea water and the permeability of the soils. Soils that were inundated for up to 6 days after the tsunami appears to be more saline compared to those inundated for only 1-3 days. Salt appears to have penetrated deeper into the sandier soils commonly used to grow peanut during dry seasons. Peanut crops established after the tsunami were more severely affected (patchy or contained leaf yellowing) possibly due to the accumulation of salt on the surface of beds from shallow groundwater evaporation. In the heavier rice soil, salt accumulates closer to the soil surface, probably because they were flooded at the time of the tsunami and often have a dense impermeable plough layer. Where farmers had access to irrigation water, the vegetative growth of rice crops established after the tsunami appeared unaffected, but grain formation has been severely affected causing up to 50% yield loss. Extension staff in Aceh have been trained in a rapid soil salinity assessment technique based on EM38 measurement. Trials are currently in progress to evaluate the role of salt tolerant varieties and improved soil nutrition during the recovery period.