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Effects of fumigation on mineral nitrogen dynamics in soil profiles from tomato greenhouse

Yan, D. D., Wang, Q. X., Li, Y., Ouyang, C. B., Guo, M. X., Cao, A. C.
Acta horticulturae 2018 no.1192 pp. 47-56
1,3-dichloropropene, Solanum lycopersicum var. lycopersicum, ammonium, chloropicrin, dimethyl disulfide, fumigants, greenhouse experimentation, leaching, nitrates, nitrification, nitrogen, nitrogen fertilizers, risk, soil depth, soil fumigation, soil profiles, tomatoes
Soil fumigation has a significant effect on nitrogen transformation. Better quantification of mineral nitrogen dynamics in soil profiles after fumigation is needed to regulate nitrogen fertilizer volumes and to predict nitrate leaching risks. Four fumigants were studied to determine the vertical transformation of mineral nitrogen within the top 0-100 cm of soil at different sampling times after treatment. Fumigation significantly depressed the conversion of soil ammonium to nitrate, which led to the accumulation of soil ammonium within the top 40 cm soil in the first week after fumigation. Soil ammonium reached a maximum value of 217.80 mg kg-1 at soil sampling depth of 25 cm after treated with 1,3-dichloropropene plus chloropicrin, while the control had the lowest soil ammonium concentration of 123.19 mg kg-1.This inhibition of nitrification lasted for only one week. Nonetheless, no measurable changes of soil ammonium were found at 2, 4, 8, 12, and 16 weeks after fumigation (WAF). For longer WAF soil profile samples, the fumigants increased soil nitrate concentrations in the top 40 cm of soil profiles, especially after being treated with dimethyl disulfide, 1,3-dichloropropene, and 1,3-dichloropropene plus chloropicrin. Fumigation did not affect nitrate concentrations at soil depth of 80 to 100 cm. Soil nitrate content were recovered to control levels at approximately 16 WAF.