Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil

Abstract

The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO 2 ). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO 2 . Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g -1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm -3 soil in the conventional system to 110 cm -3 soil in the organic system. Microbial carbon, CO 2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified, the majority in the organic cultivation system. Acaulospora excavata, Entrophospora infrequens, Glomus sp.3 and Scutellospora sp. were found only in the organically managed crop. S. gregaria was found only in the conventional crop. Organically managed vineyards increased mycorrhization and general soil microbial activity.

Biological activity of soils under systems of organic farming, agroforestry and pasture in the Amazon

“…It represents the oxidation of organic matter into CO 2 (ANDERSON; DOMSCH, 1978), having a close relationship with the abiotic conditions of the soil, including humidity, temperature and aeration, which are influenced by the rate of decomposition of the organic matter (SEVERINO et al, 2004). Organic matter, besides contributing to reducing the negative impacts that may arise from the intensive and successive management of cultivated areas (CARDOSO et al, 2009CUNHA et al, 2011, also increases the biodiversity of the soil (FREITAS et al, 2011).…”

“…It may mean, for example, release of nutrients for plants in the short term and the loss of organic carbon from the soil to the atmosphere in the long term (ARAÚJO; LACERDA, 2007). According to Freitas et al (2011) …”

Atividade biológica de solo sob cultivo múltiplo de maracujá, abacaxi, milho, mandioca e plantas de cobertura

“…Os valores elevados de qMIC observados neste trabalho podem ter sido devidos a alta biomassa vegetal produzida, adubação orgânica e ausência de agrotóxicos. Segundo Freitas et al (2011) 3. Em período seco a atividade metabólica é baixa indicando maior eficiência no uso do carbono e menor emissão de CO 2 do solo;…”

“…Por outro lado, a adição de matéria orgânica, a cobertura morta e a adubação verde normalmente interferem positivamente em várias características físicas, químicas e biológicas do solo (GARCÍA-ORENES et al, 2010). Além disso, se o sistema de cultivo for orgânico há maior micorrização e atividade microbiana do solo (FREITAS et al, 2011).…”

Effects of Abiotic Factors on Microbial Characteristics of Petroleum Contaminated Soils in Northern China

“…The basic physical properties of the contaminated soil samples including the pH levels, the nitrogen and the phosphorus content were determined on the basis of a soil-agricultural-chemical process [15,16]. Ultrasonic-Soxhle extraction method of hydrocarbon in oil were analyzed, and column chromatography in combination with gas chromatography-mass spectrometry (GC-MS) was used to analyze the pollutant compositions [19].…”