Land suitability assessment for Jarak Towo cassava development (case studies in Tawangmangu and Ngargoyoso sub-districts, Karanganyar regency, Indonesia)

Abstract

Jarak towo is one of the local varieties of cassava that has uniqueness and characteristics, including a fluffier and more savory taste, a more expensive price and better market opportunities compared to other types of cassava. However, this cassava requires special land criteria to produce abundant and quality tubers. This is related to the land suitability factor. This study aimed to assess land suitability to obtain potential land for the development of jarak towo. It was carried out in Tawangmangu and Ngargoyoso Sub-districts, Karanganyar Regency. This research was explorative-descriptive with a land survey approach. The survey was carried out in four land map units (LMU) based on land use and altitude. The altitude of each area is 1,400 masl (LMU 1), 1,200 masl (LMU 2), 1,000 masl (LMU 3) and 800 masl (LMU 4). Land suitability was obtained by matching soil and land characteristics with the optimum growth requirements of jarak towo cassava. The results showed that not all land in the Ngargoyoso and Tawangmangu Sub-district was suitable for the development of jarak towo. Some land and soil parameters were at a marginal level, making them a limiting factor for land suitability and affect the growth, quantity and quality of cassava tubers. The limiting factor will reduce production or double the required input. Land in the study area was marginally suitable (S3) and not suitable (N) for jarak towo. The limiting parameters for cassava cultivation were low temperature, low organic C, steep slopes, low P2O5 and K2O and shallow soil. Several locations that had the potential for the development of jarak towo cassava were LMU 2, 3, and 4 in Tawangmangu and LMU 3 and 4 in Ngargoyoso with additional improvement efforts. Improvements that could be made were the application of a well-constructed bench terrace and the addition of organic fertilizers combined with P and K fertilizers. Key words: land evaluation, limiting factors, potential land, jarak towo, land map units, terraces