Alexandre Campelo de Oliveira

Produtividade, eficiência de uso da água e qualidade tecnológica de cana‑de‑açúcar submetida a diferentes regimes hídricos

O objetivo deste trabalho foi avaliar a produtividade de colmos e de acucar, a eficiencia de uso da agua e os atributos tecnologicos de cinco variedades de cana-de-acucar de maturacao precoce e seis de maturacao media a tardia, submetidas ao regime de sequeiro (1.141,4 mm) e a irrigacao plena (1.396,6 mm). Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repeticoes. A produtividade de colmos das variedades RB92579, RB72454 e SP81-3250 apresentou ganhos superiores a 180%, com uso da irrigacao. A irrigacao promoveu aumentos na produtividade de acucar superiores a 200%, nas variedades RB92579 e RB943365. A irrigacao plena proporcionou maior eficiencia de uso da agua, com producao media de 70,2 kg ha-1 mm-1 de colmos a mais em comparacao ao regime de sequeiro. Com excecao das variedades RB72454, RB763710 e RB943365, nao houve diferenca nos atributos tecnologicos entre a irrigacao plena e o regime de sequeiro. As variedades RB92579 e SP81-3250 de maturacao media a tardia se destacam quanto a produtividade de colmos e de acucar e a eficiencia de uso da agua, e sao recomendadas para estudos de resposta a irrigacao pela cana-de-acucar.

Acúmulo e alocação de nutrientes em cana-de-açúcar

The objective of this study was to evaluate, along the first cycle of sugar cane, the capacity of eleven varieties of sugar cane (SP79-1011; RB813804; RB863129; RB872552; RB943365; RB72454; RB763710; SP78-4764; SP81-3250; RB867515 and RB92579), cultivated under full irrigation,the accumulation of the nutrients N, P, K, Ca and Mg in the plants aerial parts (stem, leaf and pointer). The research was carried through under field conditions, during the agricultural season 2006/2007, in the Sugar Cane Agricultural Station of the Federal Rural University of Pernambuco, in Carpina County, PE/Brazil. The experimental set was a complete randomized block design, with four replications. The accumulation of nutrients in the components of the aerial part was evaluated at 120; 180; 240; 300 and 360 days after plant (DAP). It was observed along the cycle of the sugar cane, mobilization of nutrients N, P and K from the leaves to the points and stems. At 360 DAP the accumulation of N, P and K in the aerial part was higher than the amount added by fertilizers. The varieties RB92579 and SP81-3250 were detached by the highest nutrients accumulation in stems, while RB867515 and RB943365 were the varieties that allocated more nutrients in leaf, which identifies them as the varieties of larger capacity of cycling of those nutrients.

Adsorption and chemical extraction of phosphorus as a function of soil incubation time

The objectives of this work were to evaluate the relationship between phosphate adsorption in different mineral soil constituents of the clay fraction to determine the P recovery rate by the Mehlich-1, Mehlich-3, Bray-1 and CaCl2 0.01 mol L-1 extractants as a function of incubation time of soil as well as to compare this rate with physical and chemical soil characteristics. In five soil samples five doses of P based on the maximum phosphate adsorption capacities (MPAC) of the soil, were applied, corresponding to 0, 0.2, 0.4, 0.8 and 1.0 level. The samples were incubated for 90, 60, 30, 15 and 0.5 days. The experiment consisted of a 5 x 4 x 5 factorial (five doses, four extractants and five different periods of incubation time) in five different soils, all distributed in blocks, with three replicates. The P content in soil was determined by the Mehlich-1, Mehlich-3, Bray-1 and CaCl2 0.01 mol L-1 extractants. The soil characteristics that best correlated with the recovery rate of applied P were the remaining P (rem-P) and the MPAC. Soils high in gibbsite presented the highest P adsorption. Soils possessing high MPAC and the low rem-P presented higher reversibility for the non-labile P (residual P) for smaller time periods.

Fator capacidade de fósforo em solos de pernambuco mineralogicamente diferentes e influência do pH na capacidade máxima de adsorção

O Fator Capacidade de Fosforo (FCP) e definido pela razao de equilibrio entre o fator quantidade de P (Q) e o fator intensidade (I) e representa uma medida da capacidade do solo em manter um determinado nivel de P em solucao. As caracteristicas e o teor dos constituintes minerais da fracao argila sao responsaveis por uma maior ou menor FCP, interferindo nas relacoes solo-planta. Por outro lado, o pH do solo tem, em alguns casos, mostrado-se com efeito na adsorcao e, em outros, com pequena e nao consistente alteracao na Capacidade Maxima de Adsorcao de P (CMAP). Objetivou-se, neste trabalho, determinar o FCP de solos mineralogicamente diferentes em Pernambuco; correlacionar caracteristicas fisicas e quimicas dos solos com o FCP; e avaliar o efeito do pH na CMAP. Amostras subsuperficiais de quatro solos, mineralogicamente diferentes, foram caracterizadas quimica e fisicamente e determinado o FCP. Essas amostras foram corrigidas com CaCO3 e MgCO3 na proporcao 4:1 e incubadas por 30 dias, com excecao do Vertissolo. Determinou-se a CMAP antes e apos a correcao dos solos. O experimento consistiu de um fatorial 4 x 2 (quatro solos com e sem correcao), distribuidos em blocos ao acaso, com tres repeticoes. As caracteristicas dos solos que melhor refletiram o FCP foram o P remanescente (P-rem) e a CMAP. Independentemente dos constituintes mineralogicos da fracao argila, solos com elevados teores de aluminio apresentaram aumento da CMAP com a correcao. A energia de adsorcao (EA) nos solos corrigidos foi, em media, significativamente menor, independentemente do solo.

Características agroindustriais da cana-de-açúcar em função da adubação fosfatada, em solos de Pernambuco

The P recommendations in Northeastern Brazil are based on research carried out in the decades of 70 and 80, being necessary a modernization in this recommendation, to focus the maximum capacity of P adsorption. Therefore, this work aimed to evaluate agroindustrial sugarcane characteristics in soils in function of phosphate fertilization. Five experiments were carried out at Pernambuco State Forest Zone Region. The soils were: Argisoil Yellow distrocoeso (PAdx); Latosoil Yellow distrofic (LAd); Argisoil Yellow distrofic (PAd); Gleisoil haplic eutrofic (GXve); and Espodosoil carbic duripanic (ESKo). The treatments consisted of seven P doses, determined in function of the maximum adsorption capacity of P. The experimental design was a completely randomized block, with four replications. The sugarcane variety RB863129 was used in PAd, LAd, GXve and EKo soils and RB855536 on PAd soil. The P fertilization increased agricultural and industrial productivities. Total recoverable sugar (ATR) values were not affected by phosphate fertilizer, being more elevated in soils with higher maximum adsorption capacity of P.

Níveis críticos de fósforo em solos cultivados com cana-de-açúcar em Pernambuco

Critical levels of phosphorus in sugarcane soils of Pernambuco State, Brazil Physical, chemical and mineralogical properties of soils are not observed to estimate phosphorus (P) availability in Pernambuco, Brazil. The aim of this work was to determine phosphorus critical levels in distinct soils, using different chemical extractors, considering clay fraction content and quality , and to relate soil physical, chemical and mineralogical characteristics with P critical levels. The soils were classified like: Typic Haplustults; Typic Hapludox; Typic Hapludults; Typic Hydraquents and Typic Haplohumods. Treatments consisted of seven P doses, determined in function of P maximum adsorption capacity (PMAC). The experimental design was in randomized blocks, with four replicates. Samples of soil were collected at lots useful area. This sampling was made 30 days after the plantation and treatments application at 0,0-0,2 m depth. In these samples it was determined P content by the extractors Mehlich-1, Mehlich-3, Bray-1 and

Effects of different soil sampling instruments on assessing soil fertility in the caatinga area, Brazil

Vinicius Mendes de Azevedo, Duarte Barbosa, Fernando José Freire, Luis Carlos Marangon , Emídio Cantídio Almeida de Oliveira*, Alexandre Tavares da Rocha, Alexandre Campelo de Oliveira and Marcos Ribeiro da Silva Vieira Departamento de Agronomia, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil. Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, CEP: 59909-460, Serra Talhada, PE, Brasil. Departamento de Ciência Florestal, Universidade Federal Rural de Pernambuco, CEP: 52171-900, Recife, PE, Brasil.

Avaliação da disponibilidade, adsorção e níveis críticos de fósforo em diferentes solos

The evaluation of P availability in soils with different mineralogy using a same methodology can produce inappropriate estimates. The aim of this work was to evaluate P availability using different chemical extractors in soil with high Ca concentration, in comparison with hemathitic soil, and to study the relations between the critical levels and the P adsorption as a function of the soil incubation time. An experiment using subsurface samples of a Orthic Ebanic Vertisol (VEo) (Mollisol), clay textured with predominance of 2:1 clay mineral rich in Ca and a Distroferric Red Nitosol (NVdf) (Nitosol), high clay content, predominantly hematitic, colleted at the semi-arid and humid regions of Pernambuco State, Brazil, respectively. The P doses were defined as a function of the levels 0, 0.2, 0.4, 0.8 and 1.0 of the Maximum Capacity of P Adsorption (MCPA) of each soil and incubated for 90, 60, 30, 15 and 0.5 days. The experiment was carried out in a greenhouse in a factorial scheme (2 soils, 5 P doses and 5 different periods of incubation), in a randomized blocks design, with three replicates each. The available P was determined by the extractors Mehlich-1, Mehlich-3 and Bray-1 and corn was used as indicative plant. The capacity of prediction of available P by Mehlich-1 was not suitable for the soil with predominance of 2:1 clay mineral rich in Ca. For this special case, the highest operationallity of Bray-1 accredits this extractor as the most recommended. The critical levels in the soil decreased with the increase in incubation time, independently of the soil.

Adubação fosfatada para cana-de-açúcar em solos representativos para o cultivo da espécie no Nordeste brasileiro

The objective of this work was to evaluate P availability in representative soils for plant cane cultivation in the Brazilian Northeast region, and to establish a new P‑fertilizing recommendation for this crop in these soils. The study was done in five soil types, in Zona da Mata of Pernambuco: Argissolo Amarelo distrocoeso (Ultisol), Argissolo Amarelo distrofico (Ultisol), Latossolo Amarelo distrofico (Oxisol), Gleissolo Haplico eutrofico (Gleisol), and Espodossolo Humiluvico ortico (Spodosol). Seven P doses were evaluated for maximum P adsorption capacity of each soil (solution equilibrium phosphorus, P‑rem). Thirty days after soil fertilization, P contents in soils were determined with the extractors Mehlich‑1, Mehlich‑3, Bray‑1, and anion exchange resin. P critical levels were calculated for each soil and extractor. From P availability ranges, five fertility classes were defined for different clay contents in the soils: very low, low, medium, high, and very high. Mehlich‑1 and anion exchange resin are able extractors to adequately represent soil‑P availability for plant cane cultivation in the evaluated soils.

Presence of orange rust on sugarcane in the state of Pernambuco, Brazil.

Sugarcane leaf rust symptoms were observed on seven month-old plants in March 2012 at Santa Teresa Farm, north coast of Pernambuco, Brazil. Plants were identified as a genotype coded as RBUFRPE0032 developed by the Sugarcane Breeding Program of Universidade Federal Rural de Pernambuco (UFRPE/EECAC). Evaluations under field conditions showed characteristic leaf rust symptoms and high severity. Analysis of symptomatic leaves under the optical microscope at the Plant Pathology Laboratory of UFRPE/EECAC confirmed the presence of fungal urediniospores showing specific characteristics of the fungus. Molecular evaluation by real-time PCR yielded positive results for Puccinia kuenhii. This is the first report of sugarcane leaf rust in Pernambuco. Although the disease has been reported in other Brazilian states, producers and researchers are worried since the behavior of promising commercial varieties and clones from breeding programs directed at the soil and climatic conditions of the state is unknown. The Ministry of Agriculture in Pernambuco was officially informed for notification purposes.