Volume 36, Number 2, 2012

A large variety of techniques have been used to measure soil CO2 released from the soil surface, and much of the variability observed between locations must be attributed to the different methods used by the investigators. Therefore, a minimum protocol of measurement procedures should be established. The objectives of this study were (a) to compare different absorption areas, concentrations and volumes of the alkali trapping solution used in closed static chambers (CSC), and (b) to compare both, the optimized alkali […]

The SMP buffer contains p-nitrophenol and potassium chromate, both hazardous substances. A solution without toxic substances, the so-called Santa Maria buffer (TSM) was developed to reproduce performance of the SMP buffer used to estimate potential acidity of soils in Rio Grande do Sul and Santa Catarina (SMP-RS/SC). Acid titrations of the SMP- RS/SC buffer and various mixtures of the components of the new buffer were performed, using multiparametric regression analysis to obtain the optimal TSM composition. The efficiency of TSM […]

Leaf analysis is the chemical evaluation of the nutritional status where the nutrient concentrations found in the tissue reflect the nutritional status of the plants. Thus, a correct interpretation of the results of leaf analysis is fundamental for an effective use of this tool. The purpose of this study was to propose and compare the method of Fertilization Response Likelihood (FRL) for interpretation of leaf analysis with that of the Diagnosis and Recommendation Integrated System (DRIS). The database consisted of […]

Informations about fertilization and mineral nutrition of the new fusariosis-resistant pineapple cultivars are still scarce, despite the importance of this crop. The purpose of this study was to evaluate the effect of increasing doses of N on fruit yield and quality of the pineapple cultivar ‘Vitória’ grown on a ‘Humilúvico Espodossolo’ in the region of Tabuleiros Costeiros, in the state of Paraíba. The experiment was arranged in a randomized block design, using five N doses (100, 200, 300, 500 and […]

An increase in plant density of cotton (Gossypium hirsutum L., cv. FM 966 LL) results in increased interplant competition for resources, and consequently the flowering period is shortened and the rate of dry matter accumulation changed. The purpose of this study was to determine the N, P and K uptake rates by cotton plants, identifying the time of greatest absorption and the total uptake and export in narrow spacing (48 cm – 20.58 plants m-2), intermediate (75 cm – 13.30 […]

The spatial variability of soil and plant properties exerts great influence on the yeld of agricultural crops. This study analyzed the spatial variability of the fertility of a Humic Rhodic Hapludox with Arabic coffee, using principal component analysis, cluster analysis and geostatistics in combination. The experiment was carried out in an area under Coffea arabica L., variety Catucai 20/15 – 479. The soil was sampled at a depth 0.20 m, at 50 points of a sampling grid. The following chemical […]

Nitrogen is the most important nutrient for rice (Oryza sativa L) yields. This study aimed to evaluate the response of upland rice cultivars to N rate and application times in a randomized block design, in subdivided plots with four replications. The studied factors were five rice cultivars (BRS MG Curinga, BRS Monarca, BRS Pepita, BRS Primavera, and BRS Sertaneja), three application times (100 % at planting, 50 % at planting – 50 % at tillering and 100 % at tillering) […]

Citrus rootstocks have a strong influence on shoot mineral nutrition and consequently on the adaptation of citrus trees to adverse soil conditions. Since citrus yield is often limited by low P availability, a greenhouse study was carried out to evaluate the effects of P application in the nutrient solution (0.0125; 0.05; 0.2 and 0.8 mmol L-1) on growth and P nutrition of the citrus rootstocks varieties (‘Rangpur’ lime, ‘Swingle’ citrumelo, ‘Cleopatra’ and ‘Sunki’ mandarin). After 100 days of P treatments, […]

The cultivation of Elephant or Napier grass (Pennisetum purpureum) in the gypsum- producing region of Araripe, in the west of the state of Pernambuco in northeastern Brazil, may be viable as alternative energy, especially when the soil fertility is improved. The objective of this study was to evaluate the effect of crude gypsum on the nutritional status, mineral composition, biomass production, and nutrient uptake efficiency of elephant grass varieties in Araripe, Pernambuco. For this purpose, three elephant grass varieties: Cameroon, […]

Soils with high levels of toxic Al can cause damage to plants and consequently decrease yields; a proper management is therefore essential to increase yields. Silicon can be a good alternative to reduce the toxicity of Al in the soil. The objective of this study was to evaluate the influence of the interaction between silicon and Al in rice plants grown in naturally aluminous soil. The experiment was arranged in a completely randomized, 2 x 5 factorial design with four […]