Danos do complexo broca-podridão à produtividade e à qualidade da cana-de-açúcar fertirrigada com doses de nitrogênio

The objective of this work was to evaluate the effect of nitrogen-fertigation on the damage caused by the borer-rot complex to the productivity and quality of fertigated sugarcane. The experiment was carried out in field, using a randomized complete block design, with four replicates and five N doses (0, 50 100, 150, and 200 kg ha-1) applied through drip irrigation. The following variables were determined: number of holes caused by Diatraea saccharalis (Lepidoptera: Crambidae); number of internodes infected with red rot; incidence percentage of red rot; stalk productivity; and sugar content. In laboratory, the attractiveness and the consumption of culm fragments by fourth instar caterpillars, in trials with or without choice, were evaluated. Nitrogen fertigation increased the incidence of D. saccharalis and red rot. The number of holes produced by the larvae was correlated with the occurrence of red rot. Sugar percentage reduced with the increase in the number of red rot affected internodes. Nitrogen doses did not affect the attractiveness of sugarcane culm fragments; however, higher N doses increased the consumption of these fragments by D. saccharalis caterpillars. Despite the damages to quality, nitrogen fertilization expressively enhanced the productivity of stalks and sugar.

Nutrição e produtividade da nogueira-macadâmia em função de doses de nitrogênio

The objective of this work was to evaluate the influence of nitrogen doses on mineral nutrition and yield of macadamia nut (Macadamia integrifolia). The experiment was carried out during three agricultural years, in Jaboticabal, SP, Brazil. The experimental design was a complete block with four replicates. Five doses of N (0, 50, 100, 150, and 200 kg ha-1 per year), applied as urea, were evaluated. The increase in N doses increased the nutrient concentration in the leaves and the yield of nuts and almonds. Ca, Mg, and S contents decreased and the ones of Fe and Mg increased linearly with N fertilization. Nut and almond yields were positively correlated with leaf N concentration, and the range from 14 to 18 g kg-1 allowed the highest yields. The dose of 150 kg ha-1 of N per year provides higher nut yields, without reducing the recovery rate of almonds.

Sistemas de manejo e efeito residual do potássio na produtividade e nutrição do feijão-caupi

Cowpea [Vigna unguiculata (L) Walp] have great social and economic importance for the Para State. It grows well in areas with low precipitation and two crop cycles can be obtained annually. This study aimed to assess the effect of the residual fertilization from a previous culture (Sorghum bicolor L. Moench) and crop systems on cowpea yield and macronutrient concentration on leaves of three cowpea cultivars (BRSMilênio, BRS-Urubuquara e BRS-Guariba). The study was conducted at the UFRA. The treatments were two crop systems (minimum tillage and conventional), four levels of potassium (50, 100, 200 e 300 kg de KCl ha-1 applied to a previous sorghum culture) and the three cowpea cultivars. Treatments were organized as a three (4 x 2 x 3) factor experiment on a randomized complete block design. The soil was a yellow latosol. In each experiment plot five plants were selected to determine shoot dry matter and foliar nutrient concentration. Grain yield was determined after harvesting all plants on the experiment plot. The residual KCl fertilization affected foliar nutrient content, but did not affect shoot dry mass or yield of grain. Yield was higher in the minimum tillage system. Highest yield (1590 kg ha-1) was recorded int the cv. 'Guariba' when 100 kg of KCl ha-1 had been used in the previous crop. The highest content of leaf N and K was found in cowpea under minimum tillage system. The amount of P and Mg were higher in the conventional system whereas the amount of Ca did not change.

Doses e modos de aplicação de fósforo na nutrição e produção do feijoeiro cultivar Pérola

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Níveis de lodo de esgoto no desenvolvimento, nutrição e produtividade da cultura do girassol

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fontes e doses de nitrogênio na nutrição, produção e qualidade do feijoeiro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos do glyphosate sobre o crescimento e absorção de fósforo pela soja

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Resposta do milho à adição de níveis de fitomassa de Brachiaria decumbens Stapf e nitrogênio em latossolo vermelho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Gesso de minério associado a fontes de fósforo na cultura do milho em sistema plantio direto no Estado de Alagoas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ciclagem e disponibilidade de fósforo para a soja em rotação com braquiária como espécie de cobertura

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Resposta de plantas de cobertura a doses de silício e estresse hídrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acidez do solo e produtividade da soja em função de calagem e rotação de culturas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nitrogênio na semeadura e em cobertura para o feijoeiro em sistema plantio direto em fase de implantação e consolidado

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

Variabilidade vertical de formas de fósforo em função de fontes e doses de fosfatos em semeadura direta

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

Manejo do nitrogênio em cobertura na cultura do milho (Zea mays L.) em solo arenoso baseado no índice relativo de clorofila

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