Resumo

FLORES-MARGEZ, Juan P. et al. Nitrogen mineralization in lime stabilized biosolids. Terra Latinoam [online]. 2010, vol.28, n.4, pp.307-317. ISSN 2395-8030.

Agricultural soils treated with wastewater and lime stabilized biosolids receive high amounts of nutrients that can cause contamination and unbalanced plant nutrition. For this reason, it is necessary to determine the mineralization of organic matter and factors that affect nutrient availability in soils. The objectives of the study were to estimate potentially mineralizable nitrogen (PMN), and the constant rate of mineralization (k) for three types of soils under soil conditions using the method based on incubation of resin bags, and to calculate the N mineralized through the difference method based on analysis of total soil Kjeldahl nitrogen (NTK). Three experiments were conducted in the Juarez Valley with a random block design and four replications. The rates of biosolids were 0, 200, 400, and 600 kg ha^-1 based on NTK. Soil was incubated, and resins were analyzed at 26, 46, 84, 117, and 190 days. Loamy soil had the highest N mineralization rate 80 mg kg^-1. The biosolids dosage of 600 kg ha^-1 had the highest N mineralization rate in the clay and loam soils; however, in the sandy site there was no significant difference. Constant rates varied between 0.0031 and 0.0219 mg per day, values of potentially mineralizable N (No) varied between 51.08 and 102.48 mg kg^-1. Net N mineralization varied between 0.145 and 0.47 mg N-NH₄ + NO₃ kg per day. Estimated mineralization using the difference method with soil NTK was 28% for the sites. In contrast, no significant difference was detected for sandy site.

Palavras-chave : synthetic resin; total nitrogen; no lineal regression; clay; silt; sand.