Effects of Organic and Conventional Management of Sugar Cane Crop on Soil Physicochemical Characteristics and Phosphomonoesterase Activity

Abstract

Soil enzymes play an important role in agriculture and particularly in nutrient cycling. They are also involved in the degradation, transformation, and mineralization of organic matter and availability of nutrients in soil. It is believed that organic agriculture causes fewer losses to soil quality and is less aggressive to the environment than conventional management. In this study, the effects of conventional (CM) and organic management (OM) on phosphomonoesterases, an important enzyme for soil fertility, were evaluated and compared to those results from native Cerrado (Brazilian Savanna) soil (NS), because they are the most common phosphatases in soils. The results showed that there were both acid (AcP) and alkaline (AkP) phosphatases in all soils tested and that AcP activity was higher than that of AkP. In contrast to AkP, AcP had its activity affected by land use. In the cultivated areas there was a reduction of almost 50% of AcP activity respect to native unexploited soils and there was no significant difference between organic and CM, demonstrating that independent of the management chosen, there was an impact of land use on AcP activity. Principal component analysis indicated that characteristics related to pH such as alkali saturation (V%), aluminum saturation (M%), Al(3+), soil total acidity (H+Al), and Ca(2+) are the main factors that permit distinguishing NS from OM and CM.

Analyses of technological and biochemical parameters related to the HTC phenomenon in carioca bean genotypes by the use of PCA

“…PCA was performed on the standardized data to explore their underlying complex interrelationships, due to it often reveal previously unexpected associations among variables and thereby allows interpretation that would not be possible otherwise (Purcena, Di Medeiros, Leandro, & Fernandes, 2014).…”

Avaliação da alteração da qualidade do solo em diferentes áreas de Cerrado

“…Na área sob floresta nativa, o elevado valor foi atribuído à espessa camada de restos vegetais depositados na superfície do solo e reduzida perturbação do sistema (PAUL et al, 2010). Diversos estudos realizados em áreas de Cerrado verificaram teores de MOS variando de 28 a 37 g dm -3 para a camada arável (MATSUOKA et al, 2003;PEIXOTO et al, 2010;PURCENA et al, 2014).…”

“…Em condições naturais, solos de Cerrado são pobres em macronutrientes como o K, sendo a vegetação nativa adaptada a essa condição (KOZOVITS et al, 2007;PURCENA et al, 2014). Haridasan (2000) observou baixo conteúdo de K em espécies vegetais de Cerrado, corroborando com esse mecanismo adaptativo.…”

“…Tabela 2.2 -Porcentagem de saturação de potássio, cálcio e magnésio na capacidade de troca catiônica em Latossolo Vermelho-Amarelo sob diferentes coberturas vegetais H+Al mantiveram-se baixos nos sistemas agrícolas e elevados nos sistemas naturais. Em suas condições naturais, solos sob vegetação nativa de Cerrado são ácidos e sustentam vegetação altamente adaptada ao elevado teor de Al e às condições de oligotrofia(SOARES et al, 2011;PURCENA et al, 2014). Em geral, a CTC apresentou variação semelhante à observada para o teor de MOS, com maior valor sob Cerrado nativo e severa diminuição nos sistemas agricultáveis.…”