Effects of soil management systems on soil microbial activity, bulk density and chemical properties

Abstract

The objective of this experiment was to study the effects of soil management systems on the bulk density, chemical soil properties, and on the soil microbial activity on a Latossolo Vermelho distrófico (Oxisol). Soil samples were collected from plots under the following management conditions: a) natural dense "cerrado" vegetation (savanna); b) degraded Brachiaria decumbens pasture, 20 years old; c) no-tillage treatment with annual crop sequence (bean, corn, soybean and dark-oat in continuous rotation), 8 years old; d) conventional tillage treatment with crop residues added to the soil, and annual crop sequence, 10 years old. The continuous use of no-tillage system resulted in an increase in microbial biomass and decrease in soil basal respiration, therefore displaying evident long-term effects on the increase of soil C content. The no-tillage system also provided an improvement in bulk density and chemical properties of the soil. Hence, the no-tillage management system could be an alternative for the conservation and maintenance of physical and chemical conditions and the productive potential of "cerrado" soils.

Effect of Potassium and Crop Residue Levels on Potassium Solubilizers and Crop Yield under Maize-Wheat Rotation

“…Significant effects of K application in sesame, mustard, groundnut, maize wheat were reported by Yadav et al, (2012) and Jat et al, (2014). Potassium solubilising bacterial population was significantly improved with crop residue retention in soil and their population changed from 30 DAS to at crop harvest might be due to crop residues had a stronger impact on soil microbial activity interns of residue decomposition and higher root activity upto 60 DAS there after it decreases and also micro-climate created by zero tillage with residue, availability of substrate provided by crop residues and micro-organism density as earlier reported by Balota et al, (1998), Valpassos et al, (2001) and Chaitanya et al, (2013). K solubilising bacterial population activity was increased markedly by K-mineral fertilization along with seed inoculation of KSB in both crops and variability of microbial population in the present study might have been resulted from growth hormone production and release of organic acid by KSB inoculants with seed in soil.…”

Evaluation of the productivity of soil amended with different animal wastes in an acid ultisol at Abakaliki, Southeast Nigeria

“…This could be due to the low organic carbon recorded in control plots (Table 4) which resulted to increased bulk density and reduced bulk density in animal wastes treated plots. Valpassos et al (2001) had observed that animal wastes treatment led to reduction in bulk density. The total density, hydraulic conductivity, mean weight diameter and state of aggregation except gravimetric moisture content of control were significantly (P < 0.05) lower compared with plots receiving different animal wastes treatment.…”

Persistência de sulfentrazone em Argissolo Vermelho-Amarelo cultivado com cana-de-açúcar

“…Para uso seguro de herbicidas, além do conhecimento dessas características, é necessário conhecer a duração de sua atividade, o processo de controle de sua persistência, a sua seletividade entre as culturas e plantas daninhas e os possíveis efeitos secundários sobre microrganismos do solo (Blanco, 1979). Avaliações mais amplas sobre o efeito de herbicidas no ambiente, as quais incluem a incorporação de indicadores microbiológicos, como a respiração basal (evolução do C-CO 2 ), a biomassa microbiana dos solos e o quociente metabólico, têm permitido antecipar a constatação de alterações na dinâmica dos ecossistemas (Anderson & Domsch, 1993;Valpassos et al, 2001;Santos et al, 2005). O quociente metabólico possibilita que se avalie, também, o estado de equilíbrio no ambiente do solo; quanto menores os valores observados, mais próximo este se encontra da estabilidade (Tótola & Chaer, 2002).…”