ResumoA falta ou excesso de água no solo são prejudiciais ao desenvolvimento das plantas. Assim, o objetivo deste trabalho foi avaliar o crescimento de plantas de girassol em diferentes capacidades de retenção de água (CRA). O experimento foi realizado em casa de vegetação, com a variedade de girassol Embrapa 122/V-2000, sob o delineamento experimental em blocos casualizados com quatro tratamentos (60% CRA, 80% CRA, 100% CRA e condição de alagamento) e quatro repetições. As plantas foram avaliadas semanalmente entre os estádios V6 (caracterizado pela presença de seis folhas com no mínimo 4,0 cm) ao R4 (inicio da florescência). Avaliou-se a altura das plantas, diâmetro de caule, teor de clorofila, matéria seca das folhas, do caule, da parte aérea e das raízes, número de folhas, área foliar, e a relação entre a matéria seca da raiz e da parte aérea. Os resultados mostraram que as plantas de girassol apresentaram maior altura e diâmetro de colmo quando submetidas à maior disponibilidade de água. Nos tratamentos com estresse hídrico o aumento do teor de clorofila foi limitado, e nos tratamentos com maior disponibilidade hídrica o teor inicialmente aumentou, mas, nas últimas avaliações decresceu. Apesar da relação raiz/parte aérea ter apresentado maiores valores para o tratamento 60% da CRA, a área foliar, número de folhas, matéria seca do caule, da raiz, e da folha apresentou menores valores a 60% da CRA. Portanto, o melhor desenvolvimento dessas plantas foi observado quando submetidas a 80 e 100% da CRA. Palavras-chave: Ácido abscísico, estresse hídrico, etileno, Helianthus annuus, hipoxia AbstractUsually the lack or excess of water in the soil is harmful to plant development. Therefore, our objective was to evaluate the growth of sunflower plants under different water holding capacities (WHC). Trials were conducted in a greenhouse with plants of the sunflower cultivar Embrapa 122/V-2000. The experimental design was a randomized complete block with four treatments: 60%, 80% and 100% of WHC and a flooding level with four replications. Plants were evaluated weekly between stages V6 (with six leaves and 4.0 cm tall) to R4 (flowering). We evaluated the plant height, stem diameter, leaf chlorophyll content, leaves, stems, shoot and root dry matter, number of leaves, leaf area, and the relationship between root and shoot dry matter. The results showed that the sunflower plants had greater

The purpose of this research was to identify the soil organic matter (SOM) fractions changes in a crop rotation system under no-till system (NTS). This research was carried out from October 2010 to February 2014 in a Rhodic Hapludox. The experiment was set up in completely randomized blocks in a factorial design with eight cover crops and three soil depths (0-5, 5-10 and 10-20 cm) with four repetitions. Cover crops: fall-winter corn, intercropping fall-winter corn with Brachiaria ruziziensis, intercropping fall-winter corn with B. brizantha cv. Marandu, intercropping fall-winter corn with Crotalaria spectabilis, B. ruziziensis, B. brizantha cv. Marandu, Pennisetum glaucum L. and set-aside area. The results of SOM granulometric fractionation showed that 6.5% of the total organic carbon (TOC) stocks were in the particulate organic carbon (POC) fraction. The low values of POC observed in this research are associated with the weather condition of experimental site, which shows high temperature and moisture. In relation to the labile carbon (LC), the highest LC stock was observed in 0-5 cm depth, which differed from the 10-20 cm depth. The POC, LC and labile nitrogen (LN) were the SOM fractions that showed to be more sensitive to detect the changes promoted by the cover crops and soil depths in NTS, as well as the carbon management index (CMI). The intercropping fall-winter corn with B. brizantha cv. Marandu and B. ruziziensis were efficient in increasing the CMI in deeper depth (10-20 cm).

ResumoAs usinas de álcool e açúcar geram resíduos, sendo um deles a vinhaça a qual necessita de destino adequado. Uma das alternativas é a aplicação deste resíduo para melhoria de atributos do solo. Objetivouse com esse trabalho avaliar o efeito da vinhaça na agregação do solo, em três épocas de coleta e a produtividade da cana-de-açúcar cultivada. O estudo foi realizado em área cultivada com cana soca de terceiro ano em um Latossolo Vermelho distroférrico, de textura franco argilo arenoso no município de Ponta Porã, MS. O delineamento experimental foi de blocos casualizados, com cinco repetições, em parcelas sub-subdivididas, sendo quatro doses de vinhaça (0; 450; 600 e 750 m 3 ha -1 ), quatro camadas (0,0-0,05; 0,05-0,10; 0,10-0,20 e 0,20-0,40 m), e três épocas de coleta, aos 38, 75 e 111 dias após aplicação das doses de vinhaça, em parcelas de 24 m 2 (6m x 4m). Para a determinação do índice de dispersão dos agregados (ID) foram obtidas amostras de solo com estrutura preservada aos 38, 75 e 111 dias após aplicação das doses de vinhaça. Nas maiores doses de vinhaça o teor de potássio, de matéria orgânica e a estabilidade dos agregados aumentou e o índice de dispersão dos agregados diminuiu. Palavras-chave: Ultrassom, cana-de-açúcar, estabilidade de agregados AbstractThe sugar and alcohol plants generate waste stillage one that needs proper destination. One alternative is the application of this residue to improve soil properties. The objective of this study was to evaluate the effect of stillage in the aggregation and productivity of sugar cane grown in three seasons of the soil sampling. The study was conducted in an Red dystrophic Latosol, sandy clay frank, at the BUNGE Monte Verde plant in the municipality of Ponta Porã, MS, Brasil. Cultivated with sugarcane third year. We used the (4x4) factorial design, evaluated 4 applications of stillage (0, 450, 600 and 750 m 3 ha -1) and their soil characteristics measured at four depths (0,0-0,5; 0,5-0,10; 0,10-0,20; 0,20-0,40 m) with five repetitions. To determine the rate of dispersion of aggregates (ID) sample were obtained undisturbed soil at 38, 75 and 111 days after application of stillage. With increasing doses of stillage were increased concentrations of potassium and organic matter and reduce the rate of dispersion and increased stability of soil aggregates.

The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. the purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo vermelho distroférrico típico (Rhodic Hapludox) under the influence of different tractor-trailers used in mechanical sugarcane harvesting. the experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without trailer (t1); harvester with two trailers with a capacity of 10 mg each (t2); harvester with trailer with a capacity of 20 mg (t3) and harvester and truck with trailer with a capacity of 20 mg (10 mg per compartment) (t4). the least limiting water range and soil bearing capacity were evaluated. the transport equipment to remove the harvested sugarcane from the field (trailer) at harvest decreased the least limiting water range, reducing the structural soil quality. the truck trailer caused the greatest impact on the soil physical properties studied. the soil load bearing capacity was unaffected by the treatments, since the pressure of the harvester (t1) exceeded the pre-consolidation pressure of the soil.

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