The Effect Of Soil And Plant Residues On Net Nitrogen Mineralization
2007
Sheikh-Hosseini, A.R., Ph.D Student, Department of Soil Science Isfehan University of Technology | Nourbakhsh, F., Assistant Professor, Department of Soil Science Isfahan University of Technology
Incorporation of plant residues in soils of semiarid to arid regions is a major principle of sustainable agriculture. Soil N dynamics will be influenced differently following incorporation of various plant residues and it will consequently influence the availability of N for succeeding crop. It is of great importance to understand the effect of soil type on N transformations in plant residue-amended soils. The main objective of this study was to investigate the effects of plant residue and soil types on the N mineralization in plant residue-amended soils. For this purpose, two different soils including Shervedan (clay) and Jouzdan (sandy clay loam) soil were selected and alfalfa, wheat and corn residues were incorporated at the rate of 1 % plant residue C kg-1 soil. A control treatment (without addition of plant residues was also considered for both soils). The rate of net N mineralization was measured at the end of 8-week incubation period. Results indicated that among the plant residues, alfalfa residues induced the highest quantities of N mineralization whereas, N immobilization occurred in corn residue-amended soils (based on the average replications of the two soils). Wheat residue-amended soils showed N mineralization to a lower extent compared to alfalfa residue –incorporated soils. The soil type had a significant effect on N mineralization however, the differences between soils were not observed similarly in the three plant residues-amended treatments. The differences in N mineralization of the two soils were much more pronounced in alfalfa residue-treated than those of wheat or corn-residue treated soils. The differences in N mineralization as affected by the soil type were also significant in wheat residue-treated soil but no significant difference was observed between the two soils when treated with corn residues. Overall, we conclude that the results support the hypothesis that, the effects of soil type on N mineralization is heavily affected by the plant residues quality.
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