Recycling waste biosolids to forest propagation of Pinus leiophylla Schltdl. & Cham

Abstract

Purpose: Analyze the use of biosolids, mixed with substrates, as an alternative in the nursery and field production of forest species such as Pinus leiophylla. Method: Biosolids mixed with commercial substrates and chemical fertilizers were tested. The experiment was carried out under nursery conditions, using a randomized experimental design in a 2x2x3 factorial arrangement. Two substrates were tested in this experiment: 60:30:10 (S1) and 50:40:10 (S2) of peat moss, perlite and vermiculite, respectively. Two doses of controlled release fertilizer: 2 g/L and 5 g/L. And three doses of biosolids: 0 L/L, 0.13 L/L and 0.26 L/L. To test the nursery treatments, a field quality test was conducted. The response was evaluated with morphological variables and leaf nutrient concentration. Results: The diameter and the height of plants were favored using biosolids. The high dose of fertilization exceeded the low by 1.24 mm and 2.97 cm in diameter (D) and height (H), respectively. The S1 substrate, recorded higher values of D and H than the S2 substrate. Differences in leaf concentrations were found. The high biosolids dose showed higher means for N, P and Mn. High fertilization produced higher means in P and Mn concentration, and low fertilization only in Mg. In contrast, nutrient concentrations were not affected by the substrate factor. Conclusion: Derived from the results obtained in this research, it is likely that with an adequate dose of biosolids and a balanced mixture, quality plants can be produced for reforestation, enhancing the development of forest species. The data observed, both for nursery propagation and for the field planting stage, indicate that the use of biosolids provides minerals that assign characteristics that improve the adaptability of the species in the natural environment. Research Highlights • The discharge of biosolids generated in wastewater treatment plants is becoming an environmental problem. Depending on the water influent that the plant is treating, the output sludge, free of toxic elements, is suitable for use in the forestry sector. • Reforestation of areas affected by droughts or forest fires is a constant practice. • Pine seedling production can use biosolids in the nursery as a viable alternative in the initial development of the plant, when mixed with other materials up to 30%. • In the critical transplant phase, the contribution of biosolids to the soil is explored as a material with buffer characteristics in the soil, to promote the survival of the pine in adverse conditions of drought and extreme heat. • Biosolids are an alternative to reduce fertilizer cost