SUMMARYLime application recommendations for amendment of soil acidity in sugarcane were developed with a burnt cane harvesting system in mind. Sugarcane is now harvested in most areas without burning, and lime application for amendment of soil acidity in this system in which the sugarcane crop residue remains on the ground has been carried out without a scientific basis. The aim of this study was to evaluate the changes in soil acidity and stalk and sugar yield with different rates of surface application of calcium, magnesium silicate, and gypsum in ratoon cane. The experiment was performed after the 3 rd harvest of the variety SP 81-3250 in a commercial green sugarcane plantation of the São Luiz Sugar Mill (47º 25' 33" W; 21º 59' 46" S), located in Pirassununga, São Paulo, in southeast Brazil. A factorial arrangement of four Ca-Mg silicate rates (0, 850, 1700, and 3400 kg ha -1 ) and two gypsum rates (0 and 1700 kg ha -1 ) was used in the experiment. After 12 months, the experiment was harvested and technological measurements of stalk and sugar yield were made. After harvest, soil samples were taken at the depths of 0.00-0. de 0,00-0,05, 0,05-0,10, 0,10-0,20, 0,20-0,40 e 0,40-0,60

The correct evaluation of silicon (Si) availability in different soil types is critical in defining the amount of Si to be supplied to crops. This study was carried out to evaluate two methods and five chemical Si extractants in clayey, sandy-loam, and sandy soils cultivated with sugarcane (Saccharum spp. hybrids). Soluble Si was extracted using two extraction methods (conventional and microwave oven) and five Si extractants (CaCl2, deionized water, KCl, Na-acetate buffer (pH 4.0), and acetic acid). No single method and/or extractant adequately estimated the Si availability in the soils. Conventional extraction with KCl was no more effective than other methods in evaluating Si availability; however, it had less variation in estimating soluble Si between soils with different textural classes. In the clayey and sandy soils, the Na-acetate buffer (pH 4.0) and acetic acid were effective in evaluating the Si availability in the soil regardless of the extraction methods. The extraction with acetic acid using the microwave oven, however, overestimated the Si availability. In the sandy-loam soil, extraction with deionized water using the microwave oven method was more effective in estimating the Si availability in the soil than the other extraction methods.

No abstract

In Rio Grande do Sul State (RS), Southern Brazil, aluminum saturation in many areas under no-till system is high and base saturation low in the 0.10-0.20 m layer (subsurface), which may reduce the grain yield of annual crops. The objective of this study was to evaluate if the occurrence of high aluminum saturation and low base saturation in the subsurface, under a no-till system, represents a restrictive environment for crop production, as well as to evaluate forms of lime incorporation for soil acidity correction in the subsurface. For this purpose, an experiment was (2007/2008) were evaluated. Soil acidity in the subsurface did not affect crop yield when the acidity in the layer from 0-0.10 m was at levels for which lime application is not recommended, according to CQFSRS/SC (2004). Lime incorporation through plowing was the most efficient way of correcting acidity at deeper levels.Index terms: lime, soil tillage systems, aluminum saturation, base saturation. No Rio Grande do Sul (RS), muitas áreas sob plantio direto apresentam elevada saturação por Al e baixa saturação por bases na camada de 0,10-0,20 m (subsuperfície), e isso pode diminuir a produção de grãos de culturas anuais. O objetivo do presente trabalho foi avaliar se a ocorrência de alta saturação por Al e baixa saturação por bases em subsuperfície (0,10-0,20 m), no plantio direto, pode representar um ambiente restritivo para a produção de culturas, bem como avaliar os modos de incorporação de calcário na correção da acidez do solo em subsuperfície. Para isso, foi realizado um experimento com os cultivos de soja (

The aim of this study was to verify if the application of silicate or lime, in association with gypsum, on sugarcane residue can lead to amendment of subsurface soil acidity, increasing sugarcane yield and profitability. The treatments were: 1control (without application of amendments), 2gypsum, 3dolomitic limestone, 4silicate, 5dolomitic limestone + gypsum, and 6silicate + gypsum. The surface application of gypsum led to reduction in Al (aluminum) contents and Al saturation, and increase in Mg +2 , Ca +2 , K + , S-SO 4 − , and base saturation in deeper soil layers, as well as increased yield of stalks, sugar, trash, bagasse, and energy, and greater profit. The application of limestone and silicate, alone or in association with gypsum, amend soil acidity throughout the soil profile. It likewise leads to an increase in stalk, sugar, trash, bagasse, and energy yield, however, application of silicate in association with gypsum leads to the greatest profitability. ARTICLE HISTORY

SUMMARYThe response of sugarcane to application of micronutrients is still not very well known. In view of the need for this information, the aim of this study was to evaluate the application of the micronutrients Zn, Cu, Mn, Fe, B, and Mo to plant cane in three soils, with and without application of filter cake. This study consisted RESUMO: ADUBAÇÃO COM TORTA DE FILTRO E MICRONUTRIENTES

The objective of this work was to characterize the commercial quantitative standards of floral stems of gladiolus plants grown under minimum tillage and conventional systems in two harvest seasons in the state of Santa Catarina, Brazil. Experiments were conducted in locations with subtropical climate using soils classified as Typic Dystrudept (Cambissolo) and Typic Hapludox (Nitossolo). Gladiolus plants were grown in beds with intensive soil turning, and under minimum tillage system, in which soil turning was done only in the planting rows. Plants of the cultivars Red Beauty and White Goddess were evaluated in two harvest seasons, Mothers' Day, and Valentine's Day. A completely randomized experimental design with 12 replications was used; the treatments consisted of two harvest seasons and two soil management systems. The flower stem and inflorescence lengths, stem thickness, and number of florets were measured when the plants were at the harvest point to characterize their commercial quantitative standards. These data were used to distribute the stems into four classes (75, 90, 110 and non-marketable). The stem standard of gladiolus plants grown under minimum tillage system and the edaphoclimatic conditions of the state of Santa Catarina in the Mother's Day harvest met the flower market requirements, with most stems classified into the classes 90 and 110. Therefore, gladiolus plants can be grown under minimum tillage system without affecting the flower stem development. This work is the first step to promote the growth of flowers under a conservationist perspective, focused on a more sustainable agriculture.

RESUMOA flutuação no conteúdo de matéria orgânica do solo é severamente afetada pelo uso e manejo do solo. Em solos física e quimicamente frágeis a destruição da vegetação nativa pode levar a diminuição drástica do estoque de carbono. No entanto, solos jovens que apresentam alta resiliência, quando manejados adequadamente, podem recuperar facilmente os valores originais de carbono. O objetivo deste trabalho foi quantificar os teores de carbono orgânico de um Neossolo e um Chernossolo em decorrência de seu uso, em especial após o desmatamento e revegetação natural. Coletaram-se amostras de duas camadas (0-5 e 5-15 cm) em dois solos (Neossolo e Chernossolo) ocorrentes numa pequena bacia hidrográfica com relevo fortemente ondulado, com quatro condições de uso (mata nativa, lavoura nova, lavoura velha e revegetação com capoeira). Avaliaram-se a distribuição granulométrica, a densidade do solo e os teores de carbono orgânico. Os dados foram submetidos à análise estatística considerando um delineamento inteiramente casualizado, num esquema trifatorial (tipos de solos, tipos de usos e camadas amostradas). O estoque de carbono do solo diminuiu após o desmatamento para a inastalação de culturas anuais com baixa adição de resíduos e revolvimento intenso do solo. A revegetação natural das áreas degradadas pelo cultivo convencional recuperou rapidamente o estoque de carbono dos solos, mesmo permanecendo as impressões herdadas da erosão (menor teor de argila) e da aplicação de fertilizantes e corretivos (menor acidez potencial e maior disponibilidade de fósforo e potássio). Palavras-chave: usos do solo; Neossolos; Chernossolos; fracionamento da matéria orgânica. ABSTRACTThe soil organic matter content is severely affected by soil use and management. In physically and chemically fragile soils the destruction of native vegetation can cause a great decrease in the carbon stock. However, soils that present high resilience, when appropriately handled, can easily recover the original values of carbon. The objective of this research was to quantify and analyze organic carbon of young soils in relation to their use, especially those in natural regeneration. Samples of two layers were collected (0-5 and 5-15 cm) in two soils (Neossolo and Chernossolo) that occur in a headslope watershed, with four use conditions