Tobacco is one of the importan commodities in Temanggung Regency. Temanggung’s tobacco has a nicotine content from 3 – 8%, so it is used as one of the main flavoring ingredients in manufacture of cole cigarettes. The rapid development of tobacco cultivation land in Temanggung Regency was not followed by site selection according to land capability class and land suitability. The aim of this study were to, 1) calculate the aviability of land for the development of tobacco cultivation, 2) determine the land suitability class for tobacco cultivation. The matching method is use in land suitability class. Extensification of tobacco cultivation land in temanggung regency can be carrie out on land with suitability class S3 (according to marginal) covering an area of 17.490,90 ha, covering a dry area of 11.975 ha; rainfed rice fields 3.622,9 ha; and shurbs 1.893 ha . Actual land suitability class of land aviable, among others S3na (8.293,98 ha), S3nr,na (3.621,96 ha), S3rc,na (2.389,78 ha), S3tc,nr,na (1.014,93 ha), S3tc,na (787,04 ha), S3tc (402,73 ha), S3tc,nr (343,43 ha), and S3tc,rc (1,17 ha). Potential land suitability class of land aviable, among others S2na (8.293,98 ha), S2nr,na (3.621,96 ha), S3tc (2.548,13 ha), S3rc (2.389,78 ha), and S3tc,rc (1.17 ha).

Silicon (Si) is one of the important things for rice growth. The importance of Si relates to increased rice yield, increased resistance to disease and resistance to falling. The rice is an accumulator plant of Si which requires Si for its growth. However, the Si in soil is continually decreased therefore the additional Si is needed intothe soil. Trass is one of the natural materials containing Ca and Si, therefore it can be used as a Si fertilizer. This study aims to determine levels of soil Si, straw, husk, and growth in rice. This research consisted of three types of soil, Oxisol, Inceptisol and Vertisol as the main plot and 7 doses of burnt fuel namely 0 (D0); 1.25 (D1); 2.5 (D2); 3.75 (D3); 5 (D4); 7.5 (D5); 10 (D6) g kg-1 of soil as subplots. The treatment which is using in this research is a combination of the two factors and repeated 3 times 63 unit experiments were obtained. The results showed the Trass significant concerning to Si in the husk and Si of the soil. Vertisol gives the highest number of panicles of 27 and Si in the straw of 12.75 mg kg-1.