Resumo
Soil aggregation is a very complex issue related to important soil attributes and processes. The aggregate breakdown and dispersion of soil samples amended with sugarcane vinasse were evaluated using ultrasonic energy. Vinasse is an important byproduct of sugarcane industries, intensively applied to soils in Brazil as liquid fertilizer. Samples of two Oxisols and one Ultisol were used in this study. The physical and chemical characterization of soils was performed, and the 1 to 2 mm size aggregates (200 g) were packed in PVC columns (6.0 cm high and 4.0 cm internal diameter) and incubated with sugarcane vinasse under lab conditions for 1, 30 and 60 days. After incubation, aggregates were submitted to levels of ultrasonic energy, and the particle size distribution (53 to 2,000 µm, 2 to 53 µm, and 2 µm fractions) was quantified. Mathematical equations were used to relate the mass of aggregates in each of these fractions to the applied ultrasonic energy, and parameters related to aggregate stability were then obtained. Soils showed an aggregate-hierarchy resulting in a stepwise breakdown under ultrasonic agitation. Considering this soil-aggregation hierarchy, vinasse contributed even in a short time to the bonding between and within 2 to 53 µm aggregates, mainly in the Oxisols. This may be related to organic compounds present in the vinasse, cementing soil particles. Potassium enrichment of soil samples did not contribute to soil dispersion.
Resumo
Soil aggregation is a very complex issue related to important soil attributes and processes. The aggregate breakdown and dispersion of soil samples amended with sugarcane vinasse were evaluated using ultrasonic energy. Vinasse is an important byproduct of sugarcane industries, intensively applied to soils in Brazil as liquid fertilizer. Samples of two Oxisols and one Ultisol were used in this study. The physical and chemical characterization of soils was performed, and the 1 to 2 mm size aggregates (200 g) were packed in PVC columns (6.0 cm high and 4.0 cm internal diameter) and incubated with sugarcane vinasse under lab conditions for 1, 30 and 60 days. After incubation, aggregates were submitted to levels of ultrasonic energy, and the particle size distribution (53 to 2,000 µm, 2 to 53 µm, and 2 µm fractions) was quantified. Mathematical equations were used to relate the mass of aggregates in each of these fractions to the applied ultrasonic energy, and parameters related to aggregate stability were then obtained. Soils showed an aggregate-hierarchy resulting in a stepwise breakdown under ultrasonic agitation. Considering this soil-aggregation hierarchy, vinasse contributed even in a short time to the bonding between and within 2 to 53 µm aggregates, mainly in the Oxisols. This may be related to organic compounds present in the vinasse, cementing soil particles. Potassium enrichment of soil samples did not contribute to soil dispersion.
Resumo
The soil compaction promoted for animal trampling and traffic of machines, is one of great impediments to attainment of raised pasture productivities. However, the soil-pasture relationship studies have not taken in consideration the biological soil descompaction, as well as its effect in productivity. This study objective was to evaluate dry mass production of Tifton 85 grass in function of different soil compaction degrees and potential of structural quality recovery of an Red-Yellow Argisol, promoted by forage plant. The experiment was carried out in green house, in delineation entirely randomized, with the tifton 85 grass crop in the following degrees of compacting: 64%, 84%, 90%, 93% and 100%, gotten for the assay of Normal Proctor. The attributes had been evaluated the soil physical- hydric, least limiting water range and forage dry mass production. Tifton 85 grass recovered the structure of Red-Yellow Argisol. The soil descompaction promoted adequate soil biophysics conditions to forage development. The dry mass production increased with the cutting succession independent of initial degree of soil compaction.KEY WORDS: Biological soil descompaction, Cynodon sp., least limiting water range, recovery of pastures.
A compactação do solo, promovida pelo pisoteio animal e pelo tráfego de máquinas, é um dos grandes entraves à obtenção de elevadas produtividades das pastagens. Entretanto, os estudos de relação solopastagem não têm levado em consideração a descompactação biológica do solo, nem seus efeitos na produtividade. O objetivo deste estudo foi avaliar a produção de massa seca do capim-tifton 85 em função de diferentes graus de compactação do solo e o potencial de recuperação da qualidade estrutural de um argissolo vermelho-amarelo, promovida pela planta forrageira. Desenvolveu-se o experimento em casa de vegetação, mediante delineamento inteiramente casualizado, com o cultivo do capim-tifton 85 nos seguintes graus de compactação: 64%, 84%, 90%, 93% e 100%, obtidos pelo ensaio de Proctor Normal. Avaliaram-se os atributos físico-hídricos do solo, o intervalo hídrico ótimo e a produção de massa seca da forrageira. O capim-tifton 85 recuperou a estrutura do argissolo vermelho-amarelo. A descompactação do solo promoveu condições biofísicas do solo adequadas ao desenvolvimento da forrageira. A produção de massa seca aumentou com a sucessão dos cortes, independentemente do grau de compactação inicial do solo.PALAVRAS-CHAVES: Cynodon sp., descompactação biológica do solo, intervalo hídrico ótimo, recuperação de pastagem.
Resumo
The soil compaction promoted for animal trampling and traffic of machines, is one of great impediments to attainment of raised pasture productivities. However, the soil-pasture relationship studies have not taken in consideration the biological soil descompaction, as well as its effect in productivity. This study objective was to evaluate dry mass production of Tifton 85 grass in function of different soil compaction degrees and potential of structural quality recovery of an Red-Yellow Argisol, promoted by forage plant. The experiment was carried out in green house, in delineation entirely randomized, with the tifton 85 grass crop in the following degrees of compacting: 64%, 84%, 90%, 93% and 100%, gotten for the assay of Normal Proctor. The attributes had been evaluated the soil physical- hydric, least limiting water range and forage dry mass production. Tifton 85 grass recovered the structure of Red-Yellow Argisol. The soil descompaction promoted adequate soil biophysics conditions to forage development. The dry mass production increased with the cutting succession independent of initial degree of soil compaction.KEY WORDS: Biological soil descompaction, Cynodon sp., least limiting water range, recovery of pastures.
A compactação do solo, promovida pelo pisoteio animal e pelo tráfego de máquinas, é um dos grandes entraves à obtenção de elevadas produtividades das pastagens. Entretanto, os estudos de relação solopastagem não têm levado em consideração a descompactação biológica do solo, nem seus efeitos na produtividade. O objetivo deste estudo foi avaliar a produção de massa seca do capim-tifton 85 em função de diferentes graus de compactação do solo e o potencial de recuperação da qualidade estrutural de um argissolo vermelho-amarelo, promovida pela planta forrageira. Desenvolveu-se o experimento em casa de vegetação, mediante delineamento inteiramente casualizado, com o cultivo do capim-tifton 85 nos seguintes graus de compactação: 64%, 84%, 90%, 93% e 100%, obtidos pelo ensaio de Proctor Normal. Avaliaram-se os atributos físico-hídricos do solo, o intervalo hídrico ótimo e a produção de massa seca da forrageira. O capim-tifton 85 recuperou a estrutura do argissolo vermelho-amarelo. A descompactação do solo promoveu condições biofísicas do solo adequadas ao desenvolvimento da forrageira. A produção de massa seca aumentou com a sucessão dos cortes, independentemente do grau de compactação inicial do solo.PALAVRAS-CHAVES: Cynodon sp., descompactação biológica do solo, intervalo hídrico ótimo, recuperação de pastagem.