Ricardo Antônio Almeida Pazianotto

Residual and cumulative effects of soil application of sewage sludge on corn productivity

The objective of this study was to evaluate the effect of frequent and periodic applications of sewage sludge to the soil, on corn productivity. The experiment was carried out as part of an experiment that has been underway since 1999, using two types of sludge. One came from the Barueri Sewage Treatment Station (BS, which receives both household and industrial sludge) and the other came from the Franca Sewage Treatment Station (FS, which receives only household sludge). The Barueri sludge was applied from 1999 up to the agricultural year of 2003/2004. With the exception of the agricultural years of 2004/2005 and 2005/2006, the Franca sludge was applied up to 2008/2009. All the applications were made in November, with the exception of the first one which was made in April 1999. After harvesting the corn, the soil remained fallow until the next cultivation. The experiment was set up as a completely randomized block design with three replications and the following treatments: control without chemical fertilization or sludge application, mineral fertilization, and dose 1 and dose 2 of sludge (Franca and Barueri). The sludges were applied individually. Dose 1 was calculated by considering the recommended N application for corn. Dose 2 was twice dose 1. It was evident from this work that the successive application of sludge to the soil in doses sufficient to reach the productivity desired with the use of nitrogen fertilizers could cause environmental problems due to N losses to the environment and that the residual and cumulative effects should be considered when calculating the application of sludge to soil.

Estimating 20-year land-use change and derived CO2 emissions associated with crops, pasture and forestry in Brazil and each of its 27 states

Abstract Land‐use change (LUC) in Brazil has important implications on global climate change, ecosystem services and biodiversity, and agricultural expansion plays a critical role in this process. Concerns over these issues have led to the need for estimating the magnitude and impacts associated with that, which are increasingly reported in the environmental assessment of products. Currently, there is an extensive debate on which methods are more appropriate for estimating LUC and related emissions and regionalized estimates are lacking for Brazil, which is a world leader in agricultural production (e.g. food, fibres and bioenergy). We developed a method for estimating scenarios of past 20‐year LUC and derived CO2 emission rates associated with 64 crops, pasture and forestry in Brazil as whole and in each of its 27 states, based on time‐series statistics and in accordance with most used carbon‐footprinting standards. The scenarios adopted provide a range between minimum and maximum rates of CO2 emissions from LUC according to different possibilities of land‐use transitions, which can have large impacts in the results. Specificities of Brazil, like multiple cropping and highly heterogeneous carbon stocks, are also addressed. The highest CO2 emission rates are observed in the Amazon biome states and crops with the highest rates are those that have undergone expansion in this region. Some states and crops showing large agricultural areas have low emissions associated, especially in southern and eastern Brazil. Native carbon stocks and time of agricultural expansion are the most decisive factors to the patterns of emissions. Some implications on LUC estimation methods and standards and on agri‐environmental policies are discussed.

Inference on Arthropod Demographic Parameters: Computational Advances Using R

ABSTRACT We developed a computer program for life table analysis using the open source, free software programming environment R. It is useful to quantify chronic nonlethal effects of treatments on arthropod populations by summarizing information on their survival and fertility in key population parameters referred to as fertility life table parameters. Statistical inference on fertility life table parameters is not trivial because it requires the use of computationally intensive methods for variance estimation. Our codes present some advantages with respect to a previous program developed in Statistical Analysis System. Additional multiple comparison tests were incorporated for the analysis of qualitative factors; a module for regression analysis was implemented, thus, allowing analysis of quantitative factors such as temperature or agrochemical doses; availability is granted for users, once it was developed using an open source, free software programming environment. To illustrate the descriptive and inferential analysis implemented in lifetable.R, we present and discuss two examples: 1) a study quantifying the influence of the proteinase inhibitor berenil on the eucalyptus defoliator Thyrinteina arnobia (Stoll) and 2) a study investigating the influence of temperature on demographic parameters of a predaceous ladybird, Hippodamia variegata (Goeze).

Microbial activities in soil cultivated with corn and amended with sewage sludge

AbstractBackground One of the main concerns related to the increasing use of sewage sludge in the soil is the possible presence of excess nutrients, which could cause environmental problems and detrimental effects on the soil microorganisms, considered essential to soil nutrient cycling. Thus, the objective of this work was to evaluate the microbial biomass and activity and some chemical characteristics of one specific tropical soil, classified as Dark Red Distroferric Latosol, of a loamy/clayey texture, in a long-term field experiment using anaerobically digested household sludge amendment. The sludge doses applied were the recommended dose and 2, 4 and 8 times the recommended dose. The authors hypothesized that the frequent application of this compound to the soil, even when using the recommended dose, could affect the available phosphorus (Pav) and heavy metal contents of the soil, resulting in concentrations above the needs of the culture as well as negatively affecting the activity of the soil microorganisms.ResultsThe results demonstrated that successive applications of sludge, calculated considering the recommended dose of N for corn, did not increase the soil Pav contents in relation to the treatment in which the fertilizer was applied considering the nutrient needs of the culture, contrary to what happened with the highest sludge doses. The Cr, Ni and Cu contents increased with increase in sludge dose, but did not surpass the limits considered inadequate. There were no accentuated differences between the treatments with respect to microbial biomass C. Basal respiration and the FDA hydrolysis were considered to be the parameters that most differentiated the effect of increasing sludge doses on the microbial activity.ConclusionThe application of a sludge dose to a tropical soil, based on the recommended dose, did not affect the Pav or heavy metal contents of the soil even after years of application. Since there were no differences between the treatments with respect to the Cmic values, to the contrary of what happened with the other microbiological parameters evaluated, the possibility of changes in the composition of the microbial community with the higher sludge doses was considered.