Estimation of Total and Collectable Amounts of Rice Straw in Jiangsu Province

23 rice cultivars (including 19 Japonica rice and 4 Indica rice) cultivated widely in Jiangsu Province were sampled and investigated for estimation of total straw yields and collectable amountsof the straw,separately,of the crops different in cultivation system and in yield target in combination with relevant statistical data.Results show that the differences in grain/straw ratio were relatively small between cultivars(0.98-1.03),but quite large between crops different in cultivation pattern(0.80-1.19)and in yield level (0.83-1.12).When the stubbles left in the field were 5,10,20,and 25 cm tall separately,the rice straw collectability coefficient was 0.815-0.868,0.668-0.732,0.600-0.669 and 0.533-0.618,respectively and the maximum amount of collectable straw was 1352.16×10⁴-1458.09×10⁴,1145.70×10⁴-1228.13×10⁴,1043.20×10⁴-1121.52×10⁴and 951.37×10⁴-1021.30×10⁴t,respectively.The rice straw (dry weight) resource of Jiangsu in 2009 was estimated at 158.93×10⁴-1704.92×10⁴t,which was 2.45%-10.14% higher than the estimation using the conventional method.It is,therefore,concluded that the rice straw resource of Jiangsu Province is rich,but the amount of collectable rice straw is mainly affected by how tall the stubbles are left in the field and how the crop is cultivated.