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 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

ABSTRACT:The aim of this study was to evaluate soil fertility amendment, stalk yield, sugar, bagasse, and trash yield as affected by surface application of dolomitic limestone and gypsum in green sugarcane ratoon. A factorial arrangement of four dolomitic limestone rates (0, 900, 1800, and 3600 kg ha -1 ) and two gypsum rates (0 and 1700 kg ha -1 ) was used in the experiment. The experiment was performed from October 2006 to October 2007, starting in the rainy season after the 2 nd ratoon harvest of the variety SP813250 in a commercial green sugarcane plantation of the São Luiz Sugar Mill (47º25'33" W; 21º59'46", 627 m of altitude), located in Pirassununga, state of São Paulo, in southeast Brazil. After 12 months, the experiment was harvested, technological measurements of stalk yield were made, and soil samples were taken and analyzed. Gypsum acts as a subsurface conditioner thus contributing so the benefits of surface limestone application, on soil acidity correction, to reach deeper layers, allowing the development of the root system of plants in greater depth. However, application of gypsum may lead to leaching of Mg and K from the topsoil layers. The higher rates of lime in surface application provided acidity amendment and, consequently, increased soil fertility in the soil profile, and increased sugarcane stalk, sugar, bagasse, and trash yield.

BACKGROUND Thiamethoxam and glyphosate are widely used in sugarcane production as an insecticide and ripener, respectively. In this study, the potential of these chemical products to also elicit phytotonic effects and enhance the physiological development and yield of sugarcane was evaluated. In field experiments, thiamethoxam and glyphosate were applied to sugarcane individually or in combination, and the effects of these chemical management strategies on sugarcane biometric and technological parameters were assessed. RESULTS Thiamethoxam application improved biometric parameters, especially stalk yield. Glyphosate application increased sugar yield, despite reducing the number of stalks and consequently the stalk yield. CONCLUSIONS Application of the insecticide thiamethoxam to sugarcane attenuates the depreciative effect of ripener (glyphosate) and has a potential phytotonic effect by increasing sugar yields in the early and late seasons. © 2022 Society of Chemical Industry.

A ferrugem asiática da soja é motivada pelo fungo Phakopsora pachyrhizi e tem sido objeto de estudos e pesquisas em relação ao uso de fungicidas para seu controle e cuidados. Objetivou-se avaliar os efeitos dos fungicidas pertencentes aos grupos inibidores da desmetilação (DMI - Triazóis); inibidores da quinona oxidase (QoI – azoxistrobina) com fungicidas protetores (Mancozeb, oxicloreto de cobre e clorotalonil), aplicados em diferentes estádios fenológicos da cultura da soja para controle da ferrugem asiática. O experimento foi conduzido na safra 2015/2016 e 2016/2017, na estação experimental da Basf, Pesquisa e Desenvolvimento em Bandeirantes - PR, com a cultivar 5909, Nidera RR. O delineamento experimental foi os blocos ao acaso, com vinte e dois tratamentos e quatro repetições. Avaliou-se a severidade da doença, incidência da doença, peso de mil grãos (PMG, g) e produtividade (kg ha-1 ). A testemunha apresentou maior percentual de severidade da ferrugem asiática.