ABSTRACT: Irrigated rice in the state of Rio Grande do Sul (Brazil) has shown significant growth in yield in recent years due to improved management practices, especially in regard to fertilizer use. However, the response curves that led to the current fertilizer recommendations do not consider integrated systems prevailing in rice-producing regions that have adopted the practice of integrated crop-livestock systems. The aim of the present study was to evaluate the effectiveness of current fertilizer recommendations for irrigated rice in […]

ABSTRACT: Visual symptoms of Zn deficiency, induced by excessive P applications, have been observed in commercial orchid nurseries. The supply of other metallic micronutrients, such as Fe and Mn, may also be inadequate in the plant due to high application rates of P. The aim of this study was to investigate this interaction in the nutrition of Phalaenopsis plants. Experimental treatments consisted of three P rates (0.0, 0.5, and 1.0 g L-1) and three Zn rates (0.00, 0.35, and 0.70 […]

ABSTRACT: In geostatistical studies, spatial dependence can generally be described by means of the semivariogram or, in complementary form, with a single index followed by its categorization to classify the degree of such dependence. The objective of this study was to construct a categorization for the spatial dependence index (SDI) proposed by Seidel and Oliveira (2014) in order to classify spatial variability in terms of weak, moderate, and strong dependence. Theoretical values were constructed from different degrees of spatial dependence, […]

ABSTRACT: The boundary line is a method frequently used to assess the nutritional status of plants when the relationship between the variables under analysis is influenced by other interacting factors. The objective of this study was to propose and test the boundary line model to estimate the nutrient sufficiency range and nutritional status of irrigated muskmelon. The lower and upper limits of the sufficiency range were calculated as a basis for assessment of the nutritional status of muskmelon. Leaf material […]

ABSTRACT: The mineral nutrient uptake of plants in the field occurs in pulses, due to variations in the substance concentrations at the root surface. The fluctuations in nutrient supply probably induce changes in the plant, which are to date unknown for Eucalyptus. This study evaluated these changes in plant growth, nutritional status, photosynthesis, and gene expression, which can serve as biomarkers of the nitrogen status, of four eucalypt clones exposed to N omission and resupply. A greenhouse experiment with four […]

ABSTRACT Given the increase in crop yields and the expansion of agriculture in low fertility soils, deficiency of micronutrients, such as iron, in plants grown in tropical soils has been observed. The aim of this study was to evaluate Fe availability and Fe uptake by corn (Zea mays L.) plants in 13 different soils, at two depths. Iron was extracted by Mehlich-1, Mehlich-3, and CaCl2 (Fe-CC) and was fractionated in forms related to low (Feo) and high (Fed) crystallinity pedogenic […]

ABSTRACT Composting is a useful way of transforming livestock waste into organic fertilizer, which is proven to increase soil nutrient levels, and thus crop yield. Remains from production and slaughter of small ruminants can become a source of important elements for plant growth, such as N, after microorganism-driven decomposition.The aim of this investigation was to evaluate the effects of this compost on soil fertility and on the nutritional status and yield of the corn crop. The experiment was conducted in […]

ABSTRACT In no-tillage (NT) systems, there is no plowed layer since the soil is not tilled. Thus, the soil layer for fertility evaluation can be defined as the one in which the fertility indices are affected by the surface application of lime and fertilizers and soil properties have the closest relationship with crop yields. The objective of this study was to determine the most appropriate soil layer under long-term NT for sampling for fertility evaluation in the South-Central region of […]

ABSTRACT Soil fertility evaluation through soil analysis traditionally does not consider interaction among elements. To include the interaction effect in interpretation of soil analyses, an experiment was conducted to evaluate the effect of nitrogen fertilization (0, 0.5, 1.0, and 2.0 kg N per plant per cycle) with urea (45 % N) and potassium fertilization (0, 0.55, 1.1, and 2.2 kg K2O per plant per cycle) with potassium chloride (60 % K2O) on soil cationic balance. The experiment was carried out […]

ABSTRACT Guava response to fertilization can be monitored through plant tissue analysis. Correct interpretation of these results, based on standard levels, is of great importance for correct nutrient management of the crop. However, standard levels are constantly criticized for not considering interactions among elements. To improve the nutritional diagnosis of ‘Paluma’ guava (Psidium guajava L., Myrtaceae), an experiment was conducted using nitrogen fertilization (0, 0.5, 1.0, and 2.0 kg per plant per cycle of N, with urea as a source […]