Danielle Pereira Baliza

Calagem e adubação orgânica: influência na adsorção de fósforo em solos

Liming and organic fertilizers can reduce P adsorption/precipitation in the soil, increasing the availability for plant uptake. To evaluate the effect of liming and cattle manure on phosphorus adsorption in the soil, four experiments were conducted in an entirely randomized design, in a 4 x 5 factorial layout with four replications, in a greenhouse. The treatments consisted of four liming levels (0; 0,5; 1 and 2 times the recommended dose to reach V = 60%) and five doses of cattle manure (0; 2,5; 5,0; 7,5 and 10% of the total soil volume), applied in samples of four dm3 of orthic Quartzarenic Neosol sand texture, dystrophic Red-Yellow Latosol sandy clay texture, dystrophic Red-Yellow Latosol sandy clay loam texture and dystrophic Red Latosol clay texture soils; each soil represented an experiment. The values of equilibrium phosphorus (P-rem), maximum P adsorption capacity (MPAC) and the soil P buffering index (PBI) were evaluated and subjected to fitting of multiple regression models as a function of the applied lime and cattle (bovine) manure. Liming and manure fertilizer caused a reduction of MPAC and increase in P-rem and PBI. The alterations of these values was associated to soil mineralogy and texture; P adsorption increased with the oxidic character of the soils. Results evidenced the importance of soil management systems that contemplate acidity correction and increase in organic matter levels to optimize the P use by crops.

Interação entre silício e nitrogênio em arroz cultivado sob solução nutritiva

The present study aimed to evaluate the interaction effect between silicon and nitrogen in the content of chlorophyll, nitrate, ammonium and total nitrogen, dry matter production, number of tillers and number of panicles rice-plant cultivated in nutritional solution. A factorial design 5 x 2 trial installed in a completely randomized design was used being two silicon (0 and 50mg L-1) and five nitrogen (20; 50; l00; 200 and 400 mg L-1) concentrations. In the stadium of the flag leaf collar formation SPDA reading and the a and b chlorophyll contents, ammoniacal and total nitrogen determinations in plants were detemined. During the panicle complete maturity stadium, the number of tillers and panicles were evaluated and the aerial part and root dry matter contents and silicon accumulation were determined. The outcomes show that the silicon supply did not change the tillering, the dry matter production and total nitrogen contents. The silicon increased the SPAD values, the a and b chlorophyll and the root nitrate contents, and the number of panicles, especially at high nitrogen levels.The present study aimed to evaluate the interaction effect between silicon and nitrogen in the content of chlorophyll, nitrate, ammonium and total nitrogen, dry matter production, number of tillers and number of panicles rice-plant cultivated in nutritional solution. A factorial design 5 x 2 trial installed in a completely randomized design was used being two silicon (0 and 50mg L-1) and five nitrogen (20; 50; l00; 200 and 400 mg L-1) concentrations. In the stadium of the flag leaf collar formation SPDA reading and the a and b chlorophyll contents, ammoniacal and total nitrogen determinations in plants were detemined. During the panicle complete maturity stadium, the number of tillers and panicles were evaluated and the aerial part and root dry matter contents and silicon accumulation were determined. The outcomes show that the silicon supply did not change the tillering, the dry matter production and total nitrogen contents. The silicon increased the SPAD values, the a and b chlorophyll and the root nitrate contents, and the number of panicles, especially at high nitrogen levels.

Crescimento, produtividade e bienalidade do cafeeiro em função do espaçamento de cultivo

The objective of this work was to evaluate the consequences of spacing reduction between rows and between plants in the planting row on growth, productivity and bienniality of coffee plants (Coffea arabica). The experimental design was a randomized complete block, with three replicates, in a 4x3 factorial arrangement. Four distances between rows (2.0, 2.5, 3.0 and 3.5 m) and three distances between plants in the planting rows (0.50, 0.75 and 1.00 m) were used, which totalized 12 treatments. The productivity and the production per plant were assessed annually between 1994 and 2001, and the growth was evaluated in 2002. The reduction of spacing between rows and between plants in the planting row increases the productivity of coffee plants. The spacing between the rows and plants influences the growth and architecture of the coffee plant.

Yield per plant and other characteristics of soybean plants treated with kinetin and potassium nitrate

Objetivou-se, neste trabalho, avaliar o efeito de diferentes doses do regulador vegetal do grupo das citocininas, cinetina, e de nitrato de potassio aplicados via foliar na fase fenologica R3 (inicio da frutificacao) na produtividade e caracteristicas agronomicas da soja em condicoes de campo. O experimento foi conduzido em Itutinga, MG, utilizando-se 0, 250, 500, 750 e 1.000 mg de cinetina ha-1 combinadas com as doses de 0, 5, 10 e 15 kg de nitrato de potassio ha-1 em esquema fatorial, num delineamento de blocos casualizados, com tres repeticoes. Avaliou-se o posicionamento dos legumes nas plantas em tres posicoes do dossel, dividido em inferior, medio e superior. A aplicacao de nitrato de potassio nao influenciou nenhuma das caracteristicas avaliadas. A cinetina aumentou o numero total de legumes fixados em ate 27,4%, principalmente, os do terco inferior e mediano do dossel. Observaram-se aumentos dos legumes no terco medio de ate 20,7%, perante a testemunha. A producao por planta foi incrementada em ate 27,1%, utilizando a maior dose. Atribui-se a causa dos efeitos da cinetina ao aumento dos niveis endogenos de citocininas que contribuiram para uma maior producao e melhor redistribuicao de fotoassimilados para os legumes e sementes.

Physiological quality of coffee seeds produced under different levels of solar radiation and maturation stages

In Brazil, although the coffee plantations are predominantly grown under full sunlight, the use of agroforestry systems can lead to socioeconomic advantages, thus providing a favorable environment to the crop by promoting its sustainability as well as environmental preservation. However, there is a lack of information on physiological quality of the coffee seeds produced under different levels of solar radiation. Within this context, the objective of this study was to evaluate the influence of different levels of solar radiation and maturation stages on the physiological quality of coffee (Coffea arabica L.) seeds, cv. Acaia Cerrado MG-1474. Three levels of solar radiation (plants grown under full sunlight; under plastic screens of 35% shading; and under plastic screens of 50% shading) and three maturation stages (cherry, greenish-yellow and green) were assessed. Physiological quality of seeds was assessed by using germination test, first count of germination, abnormal seedlings, dead seeds, and seedlings with open cotyledonary leaves. Electrophoretic analysis of isoenzymes catalase, esterase, superoxide dismutase and peroxidase was also performed. With the evolution of development the coffee seeds presents increases on physiological quality, and at its beginning the seeds show improvements on quality with the reduction of solar radiation.

Crescimento e acúmulo de fósforo pela soja cultivada em sucessão a diferentes gramíneas forrageiras adubadas com super fosfato triplo e fosfato reativo de arad

Conduziu-se este trablho, com o objetivo de avaliar o efeito do cultivo previo de diferentes gramineas forrageiras, adubadas com superfosfato triplo (SFT) e fosfato reativo de arad (FRA), sobre o crescimento, producao e acumulo de P pela soja. Foram realizados dois experimentos, um em Cambissolo Haplico tb distrofico tipico e o outro em Latossolo Vermelho distrofico tipico textura muito argilosa. Para os dois experimentos, o delineamento experimental foi o inteiramente casualizado em esquema fatorial 4 x 2 + 2, sendo o cultivo previo de quatro gramineas forrageiras (Brachiaria decumbens Stapf - braquiaria, Brachiaria brizantha Hochst Stapf - braquiarao, milheto e sorgo forrageiro) adubadas com duas fontes de P (FRA e SFT) e dois tratamentos adicionais que e o cultivo da soja sem o cultivo previo de plantas de cobertura e adubadas com SFT e FRA. As plantas foram colhidas apos completar o ciclo de desenvolvimento. Foram determinadas a produtividade de graos (PG) e de massa seca da parte aerea (MSPA) e o acumulo de fosforo na parte aerea e nos graos da soja, as forrageiras imobilizaram o P do SFT, reduzindo o efeito residual para a soja e o feijoeiro. Quando as gramineas forrageiras foram adubadas com o FRA, houve um aumento do efeito residual, com aumento da produtividade da soja em sucessao as plantas de cobertura, com excecao para o cultivo em sucessao ao braquiarao.

Crescimento e nutrição mineral de cebolinha verde cultivada hidroponicamente sob diferentes concentrações de N, P e K

Em cultivos hidroponicos de hortalicas folhosas destacam-se, dentre os fatores que influenciam a producao e qualidade do produto, as exigencias nutricionais da cultura. Objetivou-se, com este trabalho, avaliar o efeito de concentracoes de N, P e K sobre a producao de materia seca e a nutricao mineral em cebolinha ‘T odo ano’ (Allium fistulosum L.), cultivada em condicoes hidroponicas. Foram conduzidos tres experimentos, um com cada nutriente em tres niveis: deficiente, adequado e excessivo. Empregou-se o delineamento inteiramente casualizado, em esquema de parcelas subdivididas no tempo, com quatro repeticoes e dez plantas por parcela. Aos 15, 30, 45 e 60 dias apos o transplante (DAT), foi avaliada a producao de materia seca da parte aerea e de raizes. Aos 45 e 60 DAT, avaliaram-se os teores e os acumulos totais de N, P e K e os teores de Ca e Mg da parte aerea da planta. Em cultivos hidroponicos, as deficiencias de N e P sao mais limitantes que a de K ao crescimento da cebolinha cultivar ‘T odo Ano’, sendo que niveis baixos de P afetam principalmente o crescimento do sistema radicular da planta. A deficiencia de N afeta a absorcao de P, K, Ca e Mg. O excesso de N em cebolinha manifesta-se pelo crescimento excessivo da parte aerea e pelo aumento da flacidez das folhas. Os excessos de P e de K na solucao nutritiva nao provocam sintomas visuais de toxicidade de P ou de K, mas niveis excessivos de K diminuem os teores de Ca e de Mg da parte aerea da planta. Palavras-chave: Allium fistulosum L., cultivo hidroponico, toxicidade, deficiencia nutricional, diagnose nutricional.

EFEITOS DE TIPOS DE ESTACAS CAULINARES E DO AMBIENTE SOBRE O CRESCIMENTO DE MUDAS DE CAFÉ

Resumen en: Looking to contribute to the formation of an appropriate methodology for Coffea arabica L. stem shoots production through vegetative propagation, this wo...