计量经济分析 = Econometric analysis

Statistics for Spatial Data.

Statistics and Data Analysis in Geology

Начала политической экономии и податного обложения = The principles of political economy and taxation

Keywords: Mecanique des sols ; Drainage ; Ecoulement souterrain Reference Record created on 2004-09-07, modified on 2016-08-08

Applications of soil physics.

Resumen en: The aim of this study was a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussion...

http://www.redalyc.org/pdf/1802/Resumenes/Abstract_180218547001_2.pdf

Revista Brasileira de Ciência do Solo

The aim of this study was a survey of the estimated costs of soil erosion, an issue of fundamental importance in view of the current worldwide discussions on sustainability. A list was drawn up of research papers on erosion (on-site and offsite effects) and their respective costs. The estimates indicate the amount of resources spent in the process of soil degradation, raising a general awareness of the need for soil conservation. On-site costs affect the production units directly, while off-site costs create a burden borne by the environment, economy and society. In addition, estimating the costs of soil erosion should be effective to alert the agricultural producers, society and government for the need for measures that can be implemented to bring erosion under control. Among the various estimates of soil erosion costs between 1933 a 2010, the highest figure was 45.5 billion dollars a year for the European Union. In the United States, the highest figure was 44 billion dollars a year. In Brazil, estimates for the state of Parana indicate a value of 242 million dollars a year, and for the state of Sao Paulo, 212 million dollars a year. These figures show, above all, that conservation measures must be implemented if crop and livestock farming production are to be sustainable.

/pdf/the-costs-of-soil-erosion-6j8smz37ta.pdf

The costs of soil erosion

Physical characterization of substrates in Brazil is still incipient and, only with the proper definition of reliable methods, substrates can be standard izedand recommendations can be provided for the producer. The objective was to physically characterize six types of substrates for plants and to compare the methods prescribed by Ministry of Agriculture, Livestock and Supply and by European Committee for Standardization. The six substrates evaluated were: granulated coconut fiber, two types of pinus bark, stabilized rice rusk and two mixtures (50:50, v:v), one of rice rusk with granulated coconut fiber and the second pinus bark with rice husk. The project, realized in 2009, has a completely randomized experimental design. The substrates showed differences as to the physical attributes studied: humidity, particle size distribution, bulk density, water retention capacity, particle density and porosity, characteristics with which one can infer on their use. For the physical parameters for each of the recommended methods are suggested: for the determination of the sample humidity, drying at 65 °C ± 5 °C; for particle size distribution, time of 10 minutes of stirring sieves; for the bulk density, the method of self-compaction; for the water retention capacity, the base of sample ring as reference and the adoption of the double saturation and the pre-tension of 50 hPa; for the determination of water retention curve of substrates, the tension points of 10, 30, 50 and 100 hPa; for the characterization of substrates according to its origin, the inclusion of particle density by the determination of the organic matter and ash.

/pdf/caracterizacao-fisica-de-substratos-para-plantas-4errimvsvp.pdf

Caracterização física de substratos para plantas

O objetivo deste estudo e estimar custos da erosao hidrica associados as perdas de nutrientes em quatro taxas de cobertura artificial do solo. O experimento foi conduzido de 1987 a 1996, em talhoes coletores de perdas por erosao, em Campinas (SP), em Latossolo Vermelho distroferrico, sob chuva natural. O delineamento experimental foi inteiramente ao acaso, com quatro tratamentos (taxas de cobertura do solo: 0%, 24%, 40% e 90%) e tres repeticoes. Para estimar os custos, os teores de P, K+, Ca2+ e Mg2+ na agua da enxurrada e na terra carreada pela erosao foram somados, convertidos em superfosfato triplo, cloreto de potassio e calcario dolomitico, e multiplicados pelos seus precos de mercado. Os resultados indicam, para as condicoes experimentais, que quanto maior o percentual de cobertura do solo, menores as perdas de agua, terra, materia orgânica e nutrientes. O solo com 90% de cobertura, em comparacao aquele com 0%, reduziu as perdas medias de agua em 51,97%, de terra em 54,44% e de materia orgânica em 54,91%. Em solo sem cobertura, foram estimadas perdas de 16% de P2O5 e 8% de KCl em relacao a quantidade de fertilizantes recomendada. Os custos variaram de US$ 107,76 ha–1 ano–1 no solo com 0% de cobertura a US$ 18,15 ha–1 ano–1 no solo com 90%. A partir desses valores, estimaram-se para o Brasil perdas de 616,5 milhoes de toneladas de terra ao ano, decorrentes do processo de erosao do solo em lavouras anuais, e custos da ordem de US$ 1,3 bilhao ao ano.

/pdf/perdas-e-custos-associados-a-erosao-hidrica-em-funcao-de-2c4km6n66t.pdf

Perdas e custos associados à erosão hídrica em função de taxas de cobertura do solo

Soil is an essential natural resource for humans and an important part of the environment. However, soil is often used and managed inappropriately, causing its erosion and degradation, with concomitantly negative social, political and economic impacts. This study aimed to discuss sustainable development; and losses and problems caused by soil erosion, and to suggest a model for assessing erosion costs. The relevance of economic models for costing soil erosion is stressed. Based on an economic theory, it presents a procedure for assessing economic costs of soil erosion, centered on the on-site and off-site costs that are generated. The physical processes of soil erosion are described and their economic effects reviewed, drawing on theoretical and empirical sources. Limited data and information is available on the economic losses resulting from erosion, which hampers assessment and valuation.

Sonia Carmela Falci Dechen

Papers

Revista Brasileira de Ciência do Solo

The costs of soil erosion

Caracterização física de substratos para plantas

Perdas e custos associados à erosão hídrica em função de taxas de cobertura do solo

Valuation and assessment of soil erosion costs