Establishment of recommendations and parameters for use of urban waste compost in agriculture in the State of Sao Paulo - Brazil.

AUTOR(ES)
FONTE

INTERNATIONAL ORBIT CONFERENCE

DATA DE PUBLICAÇÃO

2011

RESUMO

The organic matter present in urban waste (45 to 60% of total dry mass), after being stabilized in the form of compost, is recommended for application in agricultural soils, since it improves its physical and chemical properties and benefits the soil biological processes. Also, the urban waste compost has been economically viable for application in agricultural soils. In a network of 36 field trials, urban waste compost was applied at a rate of 16 Mg.ha-1 with 60% of dry matter at 65 ºC. The compost presented NPK concentration of 10 g/kg, 8 g/kg and 5 g/kg expressed as N, P2O5 and K2O, respectively. According to composting time experiments, the compost must be produced from waste originating from selective collection and always properly stabilized ? cured, i.e. organic material that has a pH above 6.5 and C / N ratio below 18, due to immobilization of N in the soil. Such conditions promote elimination of pathogens, especially important when using it for vegetables, cassava and plants where the compound may be in close contact with the edible portion of food. The dose should be less than the maximum of total N to 305 kg / ha, in OESWE to avoid the risk of contamination by NO3 leaching through the soil profile. The agricultural use of urban waste compost produced better results when combined with mineral fertilizers, which enhances the use of nutrients, particularly phosphorus, potassium and nitrogen, but also have a corrective effect of the soil. The production response for each crop group tested was directly correlated to the amount of P and / or K applied as compost and proportional to the concentrations of elements in the soil. A recommendation was proposed by calculating the responses based on the class of original nutrient content in the soil, ensuring that the amount of nutrient to be applied and the need for chemical supplements to achieve adequate productivity for the crop. For vegetables and cassava in particular, we recommend the use of compost from waste selective collection, as it should be free of pathogens. For other crops it is recommended the use the indexes to pathogens equivalent to Class A biosolids, which is: Salmonella spp. - Density of less than 3 MPN/4g TS, coliforms - density of less than 1000 MPN / g TS and helminths - density less than 1/4g TS. The heavy metals limits in the soil were based on the balance of elements in the area and considering the half life of the metal applied to the soil. Composition of heavy metals in CLU should not exceed mg.kg-1 (in the dry matter): Pb (500), Cu (500), Zn (1500), Cr (300), Ni (100), Cd (5) and Hg (2). The maximum dose of metal to be added, in kg ha-1, would be: Cd (1.0), Cu (75), Ni (15), Pb (15), Zn (115), Se (3.0) and Hg (0.5). Care should be taken in relation to the gradual reduction of the levels of heavy metals in compost, as well as glass, coins, needles, etc. Finally urban waste organic material should be applied to the soil and do not use it as a garbage dump.

ASSUNTO(S)

composto de lixo orgânico matéria orgânica agricultura urban waste compost agriculture composting organic matter

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