Effect of organic matter and chemical fertilizers on 2, 4-D degradation: Changes in microbiological status of 2, 4-D-perfused soil

Various groups of microbial populations and 2,4-D-degrading microbes in 2,4-D-enriched soils amended with rice straw, compost and N-P-K fertilizers combined or separately applied were enumerated ·by the most probable number (MPN) and plate (;ount methods. respectively. No recognizable differences. in the numbers of yeast and tolal bacteria were found between the different amendments. The population of 2,4-D-degrading bacteria, however, was greater in N-P-K and compost amendments than in rice straw and control (non-amendment). 2,4-D-degrading bacteria were isolated from the perfused soil and all the strains degraded 2,4-D rapidly with increasing phosphorus concentration. Moreover, in a medium with glucose or sucrose as organic source, the isolates utilized these materials for growth without attacking 2,4-D to any extent and vice versa ill medium containing cellulose or starch

Effect of organic matter and chemical fertilizers on 2, 4-D degradation: Changes in microbiological status of 2, 4-D-perfused soil

(Ghana Journal of Agricultural Science, 1987-90, 20-23: 101-110

Taxa de emissão de CO2 de um latossolo fertirrigado com ácido fosfórico por gotejamento CO2 emission rate from a fertigated bare soil with phosphoric acid by dripping

A aplicação de fertilizantes fosfatados por meio de fertirrigação com sistemas de irrigação localizada pode causar obstrução de emissores. Para evitar esse problema, pode ser utilizado o ácido fosfórico como fonte de fósforo às plantas. Porém, têm sido pouco investigados os efeitos da irrigação relacionados às perdas de CO2 do solo para a atmosfera, em conseqüência da decomposição do carbono orgânico e da infiltração de água no solo. Neste trabalho, investigou-se, no período de um mês, o efeito da fertirrigação com ácido fosfórico nas taxas de emissão de CO2 de um latossolo desprovido de vegetação, na Área Experimental de Irrigação da UNESP, Câmpus de Jaboticabal - SP. Utilizou-se de um sistema de irrigação por gotejamento, com delineamento experimental em blocos casualizados, constando de cinco repetições e cinco tratamentos (0; 30; 60; 90 e 120 kg ha-1de P2O5), aplicados via fertirrigação com ácido fosfórico. Verificou-se que as taxas de emissão de CO2 aumentaram significativamente após as fertirrigações, porém não houve efeito da dose do ácido fosfórico sobre as taxas. A umidade do solo mostrou-se um fator importante na relação entre as variações das taxas de emissão e a temperatura do solo ao longo do período estudado.<br>The application of phosphoric fertilizers through fertigation, with localized irrigation systems, can cause emitters obstruction. In order to avoid this problem, the phosphoric acid can be used as phosphorus source to the plants. However, it has been little investigations on the effects of the irrigation practices, related to the CO2 transference to the atmosphere, due to organic matter decomposition in the soil and its water infiltration. At this work, the rates of emissions of CO2 from a bare soil without vegetation, and fertigated along one month were investigated. The experiment was conducted with randomized blocks design in São Paulo State University - UNESP, Jaboticabal, Brazil. The drip irrigation system was used, with five treatments and five replications. The treatments were constituted by five rates (0; 30; 60; 90 and 120 kg ha-1 of P2O5), applied by fertigation using phosphoric acid. By the results, it is possible to verify that the emissions increased significantly after the fertigation events, however, no effect of phosphoric acid added to water was observed on emissions. Soil moisture was a relevant factor in the relationship among the variations of the emission rates and the temperature of the soil along the studied period