Efeito residual de fontes de fósforo nos atributos químicos do solo, nutrição e produtividade de biomassa da cana-de-açúcar

In tropical regions, the residual effect of phosphate fertilizer source is of crucial importance. This study aimed to evaluate the effects of application of P sources in chemical properties of soil, nutrition and productivity of sugarcane plant and during the first and second ratoon. The sources of P applied in furrows at planting were, triple superphosphate, Arad phosphate, bone meal (100 kg ha-1 P2O5 total) and a control without P, the varieties of sugarcane studied were IAC86-2480 and SP79-1011. A randomized block design in a 4 × 2 factorial was used, with four replications. The study was conducted in the municipality of Alta Floresta-MT, Brazil, in Typic Hapludox. After each cutting, in soil P content, pH and Ca were evaluated. In the plant, the production of green and dry matter of shoots, the concentration of P in the biomass harvested, the export of P and agronomic efficiency of the sources of P were determined. The bone meal had a higher agronomic efficiency resulted in greater accumulation and export of P by crop, higher content of available Ca and P and increase soil pH. The Arad reactive phosphate increased its agronomic efficiency between crop cycles.

Quality of performance of the operation of sugarcane mechanized planting in day and night shifts

The sugarcane mechanized planting is becoming increasingly widespread in Brazil due to a higher operability and better working conditions offered to workers compared to other types of planting. Studies related to this topic are insufficient or scarce in Brazil. In this context, the aim of this study was to evaluate the operation quality of sugarcane mechanized planting in two operation shifts, by means of statistical process control. The mechanized planting was held on March 2012 and statistical design was completely randomized with two treatments, totaling 40 replications for the day shift and 40 replications for the night shift. The variables evaluated were: speed, engine rotation, engine oil pressure, water temperature of the engine, effective field capacity and the time consumption hourly and effective fuel. The use of statistical control charts showed that random intrinsic do not cause this process. The tractor alignment error showed outliers in the day and night shifts operations, indicating a possible delay in receiving the signal. The water temperature of the engine and the effective fuel consumption showed lower variability in nighttime operation with average values of 81°C and 22.66 L ha-1, respectively. The hourly fuel consumption had greater variability and consequently lower quality during the night of the operation, with an average consumption of 25.46 L h-1 while the day shift showed 26.86 L h-1.

Soil and crop residue CO2-C emission under tillage systems in sugarcane-producing areas of southern Brazil

Appropriate management of agricultural crop residues could result in increases on soil organic carbon (SOC) and help to mitigate gas effect. To distinguish the contributions of SOC and sugarcane (Saccharum spp.) residues to the short-term CO2-C loss, we studied the infl uence of several tillage systems: heavy offset disk harrow (HO), chisel plow (CP), rotary tiller (RT), and sugarcane mill tiller (SM) in 2008, and CP, RT, SM, moldboard (MP), and subsoiler (SUB) in 2009, with and without sugarcane residues relative to no-till (NT) in the sugarcane producing region of Brazil. Soil CO2-C emissions were measured daily for two weeks after tillage using portable soil respiration systems. Daily CO2-C emissions declined after tillage regardless of tillage system. In 2008, total CO2-C from SOC and/or residue decomposition was greater for RT and lowest for CP. In 2009, emission was greatest for MP and CP with residues, and smallest for NT. SOC and residue contributed 47% and 41%, respectively, to total CO2-C emissions. Regarding the estimated emissions from sugarcane residue and SOC decomposition within the measurement period, CO2-C factor was similar to sugarcane residue and soil organic carbon decomposition, depending on the tillage system applied. Our approach may define new emission factors that are associated to tillage operations on bare or sugarcane-residue-covered soils to estimate the total carbon loss.

Respostas fisiológicas de cultivares de cana-de-açúcar a herbicidas seletivos

The use of selective herbicides to control weeds has caused different responses in cultivars of sugar cane, and some products affect physiological characteristics and reduce the photosynthetic activity. This study aimed to evaluate the physiological traits in cultivars of sugar cane under the effect of applying post-emergence herbicides. The test was developed in Jau, SP. The experimental design was randomized blocks in factorial scheme 5 x 4 (cultivar x herbicide) with four replications. SP81-3250, RB855156, RB855453, RB867515, IACSP95-5000 were grown in this studied. Herbicides clomazone (1200 g i.a.ha-1); commercial mixture of clomazone + ametryn (1000 + 1500 g i.a.ha-1) and ametryn (3000 g i.a.ha-1) and a control were applied at 30 days after planting. Cultivars IACSP95-5000 and RB867515 were less affected physiologically and can be considered selective to these herbicides. The application of clomazone and ametryn affected negatively the traits maximum photochemical efficiency of photosystem II (Fv/Fm), SPAD index and photosynthetic pigments, but the mixture of these herbicides caused higher reductions, indicating to be the more aggressive to the cultivars.

Tolerância à deficiência hídrica em cultivares de cana-de-açúcar avaliada por meio de variáveis morfofisiológicas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cinética de absorção de silício por cultivares de cana-de-açúcar e de arroz

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

Atributos químicos do solo, densidade de raiz e produtividade da cana-de-açúcar em função da aplicação de gesso agrícola

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Escória de siderurgia na cultura da cana-planta: efeitos no solo, na nutrição e na produtividade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência dos estressores bióticos Diatraea saccharalis (Fabr.) (Lepidoptera: Crambidae) e Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) na produtividade e qualidade tecnológica da cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo das inter-relações patógeno-hospedeiro de Meloidogyne incognita (Kofoid & White) Chitwood, M. Javanica (Treub) Chitwood e Pratylenchus brachyurus (Godfrey) Filipjev & Schuurmans Stekhoven em cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expressão gênica diferencial em cana-de-açúcar em resposta ao ataque de cigarrinha-das-raízes

Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

Isolamento e identificação de bactérias solubilizadoras de fósforo e produtoras de auxinas em solo com cana-de-açúcar

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Identificação em cana-de-açúcar de genes de resistência a Mahanarva fimbriolata (Stål, 1854) (Hemiptera: Cercopidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação de parâmetros fisiológicos em cultivares de cana-de-açúcar submetidas ao déficit hídrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tolerância de cana-de-açúcar a herbicidas avaliada pela diferença testemunha pareada e tratamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)