Evolution of the mechanical properties of a tropical soil stabilized with lime and ash of rice rind

The ash of rice rind is a pozzolanic material that reacts with the calcium hydroxide (Ca (OH)2) forming bonding composites, when finely worn out and in water presence. Considering this behavior, the objective of the present work was to evaluate the potential use of this residue in the enrichment of the content of pozzolanic materials of a tropical soil stabilized with a commercial hydrated lime. The laboratory testing program incorporated unconfined compression strength tests performed on the soil and on its mixtures with contents of 8% of lime enriched with 5 and 10% of ash of rice rind in relation to the soil dry mass. The results of the testing program supported that the use of the residue was effective in increasing the degree of reactivity of the soil that was also directly related with the increase in the ash content and the period of cure of the mixtures.

Produção de biomassa e composição química de adubos verdes cultivados no Vale do Ribeira

The contribution of green manure to soil improvement and crop production depends primarily on biomass production and its chemical composition, which vary depending on the species, region and growing season. The aim of this research was to evaluate the chemical composition of biomass produced by green manures in Vale do Ribeira, São Paulo, Brazil. In order to develop this research, was carried an experiment in Pariquera-Acu, in 2006/2007, in completely randomized blocks design with four treatments (three green manure and spontaneous vegetation) and five replications. At 30, 60, 90 and 120 after sowing samples were collected in 1m(2) of the shoots and determined fresh and dry, and chemical composition biomass. Sunhemp, pigeon pea and mucuna produced, in decreasing order, the largest quantities of biomass and were more efficient than the spontaneous vegetation. The biomass produced by green manure had higher quality than that produced by spontaneous vegetation. Sunhemp and pigeon pea have a higher proportion of dry matter in stems which have low N, high C/N and L/N ratio, variables indicating slow decomposition of residues. The analysis of dry matter partitioned to better indication of the chemical composition of the residues and the prevision of the availability of nutrients in the soil.

Geoprocessamento aplicado na distribuição espacial da capacidade de uso de uma microbacia

The present study aimed to show the spatial distribution of the Rochas watershed (Avaré-SP, Brazil) soil use capacity using the Idrisi geographical information system in order to contribute to a better territorial organization and the planning of the appropriate soil occupation. The obtained results using this methodology showed that most of the Rocha watershed areas are from the following groups: dystrophic yellow-red latosol (36.64%), eutroferric and distroferric red latosol (30.30%) with sandy texture. There was a predominance of areas with slope classes of 0-12%, plain to wavy relief (61.37% of the watershed area) showing that these areas are appropriate for annual culture plantations with wide use of machinery. Most of these areas were classified as class IV (73.79%) as to use capacity. In the studied area the following subclasses of land use capacity were found: IIe, s; IIIe; IVe; IVs; IVe,s; VIe and VIIe. Capacity subclasses IVe; IVe,s; IVs and Vie were the most significant because they are areas that can be used for agriculture but subject to severe soil impoverishment if there are no special care mainly for annual cultures. The Idrisi geographical information system was efficient to determine soil use capacity of the Rocha's watershed showing that the use of geoprocessing tools makes data analysis easier and faster, allowing digital data storage for future analysis uses mainly for territorial planning and environmental studies.

Analises paramétricas de colunas granulares encamisadas com tecido geossintético através de software Ringtrac

This study attempts a preliminary assessment of the behavior of a soil improvement system with the use of encased columns of granular material with geosynthetic (columns Ringtrac ® ). This evaluation was performed using the software Ringtrac ® (developed by Huesker GmbH, Germany), which required different parameters such as soil Oedometric Module, friction angle of soil, thickness of soft soil and the embankment height .In each analysis, one parameter was varied and the other different parameters considered were fixed, resulting in a total of 726 results. Were considered valid only the results where the radial deformation of the geosynthetic encased column did not exceed the value of 4%, which is the maximum radial deformation of the geosynthetic adopted by the Ringtrac ® program. The analysis results are shown graphically in this study, evaluating the tension values in the column and obtained settlements in each analysis. It’s proven in this preliminary study that the variation of the soft soil friction angle in the Ringtrac ® column, will not significantly affect the values of strain on the tension in the column and settlements on the ground. Furthermore, the variation of Oedometric Module on the soil, will significantly affect the tension values in the column and the settlements in the soil

Spatial variability of soil CO2 emission in a sugarcane area characterized by secondary information

Soil CO2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.

Soil uses in the sugarcane fallow period to improve chemical and physical properties of two latosols (oxisols)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of liming on the mineral nutrition and yield of growing guava trees in a typic hapludox soil

High soil acidity influences the availability of mineral nutrients and increases that of toxic aluminium (Al), which has a jeopardizing effect on plant growth. The objective of this research was to evaluate the effects of soil liming on the development of guava (Psidium guajava L.) plants, on soil chemical characteristics, and on fruit yield. The experiment was carried out at the Bebedouro Citrus Experimental Station, state of São Paulo, Brazil, in a Typic Hapludox soil, from August 1999 to March 2003. The treatments consisted of limestone dose: D0 = zero; D1 = half dose; D2 = total dose; D3 = 1.5 times the dose, and D4 = 2 times the dose to raise the V value to 70%. The doses corresponded to zero, 1.85, 3.71, 5.56, and 7.41tha(-1) applied to the upper soil layer (0-30cm deep) before planting. The results showed that liming caused an improvement in the evaluated soil chemical characteristics up to a depth of 60cm in soil samples both in the line and between lines. The highest fruit yields were obtained when the base saturation reached a value of 55% in the line and 62% between the lines. Foliar levels of calcium (Ca) and magnesium (Mg) were 8.8 and 2.5gkg-1, respectively. The highest limestone dose maintained the soil base saturation (at the layer of 0-20cm) in the line close to 55% during at least 40 months after the incorporation of limestone.

Crop type influences soil aggregation and organic matter under no-tillage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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

Este trabalho teve por objetivo estudar os efeitos de diferentes sistemas de uso e manejo na densidade do solo nas suas propriedades químicas e na atividade microbiana em um Latossolo Vermelho distrófico (Oxisol). As amostras de solo foram retiradas de parcelas dos seguintes tratamentos: cerrado denso preservado, pastagem de Brachiaria decumbens degradada (20 anos), plantio direto com rotação de culturas (8 anos) e sistema convencional com rotação de culturas anuais (10 anos). O delineamento experimental utilizado foi o inteiramente casualizado, com dez repetições. O uso contínuo de plantio direto resultou em mais alta taxa de C-biomassa microbiana e menor perda relativa de carbono pela respiração basal, podendo determinar, desta forma, maior acúmulo de C no solo a longo prazo. Proporcionou, ainda, melhoria na densidade aparente e nas propriedades químicas do solo. Assim, o sistema plantio direto, com manejo de culturas, mostrou ser uma alternativa para a conservação e manutenção das condições físicas e do potencial produtivo de solos de cerrado.

A review on soil carbon accumulation due to the management change of major Brazilian agricultural activities

Áreas agrícolas trocam enormes fluxos de CO2, oferecendo uma oportunidade para mitigar o efeito estufa. Neste trabalho, estudou-se o potencial de sequestro de carbono em razão da conversão no manejo das principais atividades agrícolas do Brasil. Dados de vários estudos têm indicado que no sistema soja/milho e nas respectivas rotações, ocorre um sequestro de carbono no solo significativo ao longo dos anos de conversão do plantio convencional para o plantio direto, com uma média de 0,41 Mg C ha-1 ano-1. O mesmo efeito tem sido observado nos canaviais, porém há maiores acúmulos de carbono no solo quando as áreas de cana-de-açúcar são convertidas da colheita baseada na queima para a mecanizada, em que grandes quantidades de palha são deixadas na superfície do solo (1,8 Mg C ha-1 ano-1). Esse maior potencial de acúmulo de carbono no solo nos canaviais, comparado com outras culturas, está diretamente relacionado com a maior produção primária dessa cultura. Apesar disso, muito desse potencial de sequestro é perdido, uma vez que os canaviais são reformados, sob preparo intensivo do solo. As áreas de pasto mostram uma depleção nos estoques de carbono, quando convertidas de áreas naturais; porém, a integração dessas áreas com agricultura pode promover o aumento nos estoques de carbono do solo. Os trabalhos têm mostrado que as principais atividades agrícolas do Brasil possuem um grande potencial de mitigação, especialmente na forma de acúmulo de carbono no solo, sendo uma oportunidade para estratégias futuras.

Spatial and linear correlations between soil and corn

O conjunto de tecnologias aplicadas ao sistema de produção agrícola tem como características principais a verticalização da produtividade, diminuição de custos, melhoria nas características físicas, químicas e biológicas do solo para proporcionarem o crescimento sustentável do meio de produção. Desta forma, o trabalho teve como objetivo determinar a variabilidade e as correlações lineares e especiais entre os atributos da planta e do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para produção de forragem. No ano agrícola de 2006, na Fazenda Bonança, município de Pereira Barreto (SP), foram analisados a produtividade de forragem do milho outonal (FDM) em sistema plantio direto irrigado e os atributos físicos do solo, num Latossolo Vermelho distrófico. O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e os do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para a produtividade da forragem. Foi instalada a malha geoestatística, para coleta de dados do solo e planta, contendo 125 pontos amostrais, numa área de 2.500 m². Os atributos estudados, além de não terem variado aleatoriamente, apresentaram variabilidade dos dados entre baixa e muito alta e seguiram padrões espaciais bem definidos, com alcances entre 7,8 e 38,0 m. Por outro lado, a correlação linear entre os atributos da planta com o do solo foi baixa e extremamente significativa. Os pares Massa Seca de forragem versus Microporosidade e Diâmetro do colmo versus Densidade do Solo foram melhor correlacionados na camada de 0-0.10m, enquanto os outros pares - Massa Seca de Forragem versus Macroporosidade - e Porosidade Total - apresentaram correlação inversa para a mesma camada. Entretanto, do ponto de vista espacial, houve uma alta correlação inversa entre Massa Seca de Forragem com Microporosidade, de modo que a microporosidade na camada de 0-0.10m pode ser considerada um bom indicador de qualidade física do solo, tendo em vista a produção de forragem de milho.

Recovery of soil microbiological properties in a degraded area planted with Corymbia citriodora and Leucaena leucocephala

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Improvement of grapevine iron nutrition by a bovine blood-derived compound

Iron (Fe) is essential for chlorophyll formation and plant growth. Irondeficiency chlorosis is a major nutritional disorder in several fruit trees cultivated in calcareous and alkaline soils, reducing fruit yield and quality and causing heavy economic losses. Since chelated Fe, the most widespread fertilizers used for preventing or curing Fe deficiency, pose risks of environmental pollution, the development of sustainable agronomic alternatives represents a priority for the fruit industry. In this work, we investigated the effectiveness of a bovine blood-derived product (BB; 0,125% Fe) for preventing Fe-deficiency in grapevine plants. During the vegetative season 2011 potted plants of five graft combinations: Sangiovese/S4O, Cabernet Sauvignon/S4O and Cabernet Sauvignon/140 Ruggeri, 140 Ruggeri/Cabernet Sauvignon, Vitis riparia/Cabernet Sauvignon were grown on calcareous soil. Soil treatments included: 1) Control; 2) Fe-EDDHA (Fe 6%); 3) Bovine-Blood (5 g/L); 4) Bovine-Blood (20 g/L). With the exception of Cabernet Sauvignon/S4O plants, Fe-EDDHA increased SPAD units (leaf chlorophyll content). Bovine-blood at low concentrations had similar or higher SPAD units than Fe-EDDHA. Increasing concentration resulted in further increases in SPAD units only in some graft combinations. Data highlight the efficiency of Fe blood-compound in the prevention of grapevine Fe-deficiency over one growing season.