Biomassa carbonizada como condiciondor de solo: aspectos agronômicos e ambientais do seu uso em solos de cerrado
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2010-07-02
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Universidade Federal de Goiás
Resumo
The effect of biochar on the chemical and biological soil properties, on the physiological response and productivity of soybean and upland Rice and on N2O emission was investigated. The study was carried out in Nova Xavantina, Mato Grosso state between September 2006 and May 2009 on two different soil types: Haplic Ferralsol (soybean) and Dystric Cambisol (rice). The experimental design was a combination of strips and random blocks where 5 doses (0 kg ha-1, 100 kg ha-1, 200 kg ha-1, 300 kg ha-1 e 400 kg ha-1) of NPK (0-20-20) were distributed in strips and 5 doses of biochar (0 Mg ha-1, 2 Mg ha-1, 4 Mg ha-1, 8 Mg ha-1 e 16 Mg ha-1) in random a manner in the case of soybean and 4 doses (0 kg ha-1, 100 kg ha-1, 200 kg ha-1 and 300 kg ha-1) of NPK (05-25-15) were distributed in strips and 4 doses of biochar (0 Mg ha-1, 8 Mg ha-1, 16 Mg ha-1 and 32 Mg ha-1) in random a manner in the case of rice. For rice urea was applied as top dressing corresponding the NPK doses: 0 kg ha-1, 15 kg ha-1, 32 kg ha-1 e 50 kg ha-1 de N, respectively. Every treatment had 4 replications. The biochar was applied only once, before the instalation of the experiments to the 0-15 cm soil layer. Soil fertility parameters were evaluated in samples collected at 0-10 cm, 10-20 cm and 20-30 cm and pH, Ca, Mg, Al, H+Al, P, K, Cu, Zn, Fe, Mn, SOM and total C and N were measured. Among physiological parameters the height and dry mass of plants were evaluated plus the nutrient levels in plant tissue at flowering and yield. The evaluation of soil biological parameters included the basal respiration rate of the soil (C-CO2) and the microbial biomass carbon (MBC). Nitrous oxide (N2O) emissions were also measured. Total C was significantly higher at 0-10 cm in the 1st year after biochar application and at 10-20 cm in the 3rd year in the treatment with 16 Mg ha-1 biochar. There was interaction between biochar and NPK, resulting in increase in K levels at 0-10 cm, 1st and 3rd year after application of biochar and decrease in exchangeable acidity in the 1st year. The 8 Mg ha-1 and 16 Mg ha-1 biochar doses resulted in higher values of plant height and dry mass both in the 1st and 3rd year, however, biochar had no effect on nutrient levels in plant tissue. Soybean yields were, again, significantly affected by biochar doses in a positive and quadratic manner both in the 1st and 3rd year. There was a significant increase in P, Ca, levels and pH, and Al and exchangeable acidity (H+Al) were reduced at 0-10 cm in the treatments with 32 Mg ha-1 biochar. Similar effect was observed for (H+Al) and K at 10-20 cm. Biochar had no effect on other soil chemical parameters. It negatively affected the dry mass of the plants at 25 and 55 DAP, however, did not have influence on plant height. Rice yield was directly and linearly influenced by biochar doses. Increase in nutrient use efficiency (N, P, K) was also observed at the highest biochar dose (32 Mg ha-1). Biochar had no effect on C-CO2 and MBC but seu uso resulted in higher emission rates of N2O at the 32 Mg ha-1 dose. In conclusion, in general, biochar had similar effects on soil chemical properties and yields, however its effect was manifested in a greater manner (larger contrast) in the more sandy soil. It increased nutrient use efficiency. As of plant height and dry mass, soybean gave better response for biochar application than rice. Finally, biochar seems to maintain its effect on yield and increases its effect on SOM accumulation over time.
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Biochar , fertilidade do solo , matéria orgânica , propriedades biológicas do solo , óxido nitroso , uso eficiente de nutrientes , biochar , soil fertility , organic matter , biological properties os soil , nitrous oxide , efficient use of nutrients , 1.Biochar 2.fertilidade do solo 3.matéria orgânica 4.propriedades biológicas do solo 5.óxido nitroso 6.uso eficiente de nutrientes
Citação
PETTER, Fabiano André. Biochar as soil amendment: agronomic and environmental aspects of its application in soils of the Brazilian savana (cerrado). 2010. 130 f. Tese (Doutorado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2010.