Abstract:In this paper, taking a cadmium (Cd) contaminated brown soil as the test soil, the pot experiments were conducted to study the effects of cow manure and straw application on Cd species and Cd uptake by maize. The results showed that: (1) Compared with no cow manure and straw addition, the three treatments with cow manure and straw nitrogen ratios of 1:1, 3:1 and 5:1 reduced the exchangeable Cd content by 34.39%, 28.04% and 20.11%, respectively. The bound and residual Cd contents increased significantly. The organic-bound Cd and residual Cd extensively increased with the combined application of cow manure and straw. There was a significant negative correlation between the exchangeable Cd contents and soil pH values, and a highly significant positive correlation between residual Cd contents and soil pH. (2) Compared with no cow manure and straw addition, soil pH increased by 0.36, 0.17 and 0.16 units, respectively, for nitrogen ratio of cow manure to straw being 1:1, 3:1 and 5:1. (3) Compared with no cow manure and straw addition, the Cd uptake by different parts of maize decreased for the combined application of cow manure and straw. The unptaken Cd accumulated mainly in root, stem and leaf of maize, and Cd contents in grain reduced by 79.64%, 72.70% and 56.38% for the nitrogen ratio of cow manure to straw being 1:1, 3:1 and 5:1, respectively.