ABSTRACT Delay of sowing date in subtropical environments with long growing seasons can modify the yield response of corn hybrids to nitrogen (N) fertilization. This study evaluated the effects of the sowing time, and N top-dress rate on corn hybrids’ yield and N-use efficiency with different cycles. Two field experiments were carried out in subtropical environment of southern Brazil. The following factors were investigated: corn hybrids (AG9025, super early cycle and P30F53, early cycle), sowing times (early and late spring), […]

ABSTRACT The management of nitrogen fertilization in wheat has proven to be a limiting factor for grain yield in the southern region of Brazil, and new techniques like the normalized difference vegetation index (NDVI) can be useful for estimating crop yield potential and, consequently, for determining N fertilization requirements. The objective of this study was to evaluate the use of NDVI, obtained through active and passive sensors, as a tool for estimating the grain yield of wheat cultivars under different […]

To achieve high wheat yield, correct management of N fertilization and the use of high yield potential cultivars are necessary. The aim of this study was to evaluate the effects of different application rates and sources of N, applied totally at sowing or in topdressing, on grain yield and yield components of two irrigated wheat cultivars under a no-till system, grown in a Cerrado (Brazilian tropical savanna) region of low altitude. A randomized block design was used in a 5 […]

Crop residues on the soil surface of no-till systems can intensify ammonia volatilization from N fertilizers applied to cereal crops. This study assessed the magnitude of N losses through ammonia volatilization from urea applied to no-till winter (wheat) and summer crops (maize) on a Typic Hapludox in the south-central region of Paraná, southern Brazil. In addition, the potential of alternative N sources (urea with urease inhibitor, liquid fertilizer, ammonium nitrate and ammonium sulfate) and different urea managements (fertilizer applied in […]

The presence of trash from the mechanical harvest of green cane on sugarcane plantations promotes changes in the agricultural management, for example, in the mechanical cultural practices of ratoon cane in-between the rows and nitrogen (N) fertilization. The goal of this study was to evaluate the performance of sugarcane in different harvest systems, associated to the mechanical cultural practices in interrows and N rates. The study was carried out on a sugarcane plantation in Sales Oliveira, São Paulo, Brazil, with […]

Research has investigated the best nitrogen rate for maize under the most diverse types of soil management. The aim of this study was to evaluate the influence of cover crops, soil management and topdressed N rates on the dry matter production, nutritional status, plant lodging, plant height and first-ear insertion of maize. Field experiments were carried out in Selvíria, Mato Grosso do Sul State, Brazil, in the growing seasons of 2009/2010 and 2010/2011, on a clayey Rhodic Haplustox (20o 20′ […]

Research has been conducted to identify the best nitrogen (N) rate for maize in most diverse types of soil management. However, there is no agreement on the results, once the dynamic of N is influenced by soil management and cover crops. This study evaluated dry mass production and nutrient uptake by cover crops, agronomic parameters and grain yield of maize in response to soil management and N rates. Field trials were carried out in Selvíria, Mato Grosso do Sul State, […]

Common bean grown in no-tillage (NT) systems has increased markedly in Brazil. Thus, to optimize the fertilizer recommendations, it is important to know the nutritional requirements of this crop when grown under new and established NT systems, which can change the nutrient availability and crop response to nitrogen (N) fertilization. The objective was to evaluate the extraction and exportation of nutrients by common bean as function of N fertilization on soil under new and established NT systems. The experiment was […]

The adoption of crop rotation and crop sequence systems is one of the fundamental prerequisites for the sustainability of agricultural production. Therefore, the objective of this study was to evaluate the effects of ryegrass desiccation time and nitrogen fertilizer applied at sowing of irrigated rice, in succession, as a management strategy in irrigated rice cultivation. The field experiment was carried out in two growing seasons (2008/09 and 2009/10), in Cachoeirinha, State of Rio Grande do Sul, Brazil, on a typical […]

Yield and conservation of onion bulbs are influenced by nitrogen (N) availability in the soil, which is required in large amounts. This study aimed to evaluate the effect of N application rates and splitting on the plant nutritional status, yield and conservation of onion bulbs after harvest. Three field experiments were carried out in Southern Brazilian Haplumbrepts. Treatments consisted of a factorial combination (4 x 3) involving four N rates (0, 50, 100, and 200 kg ha-1) and three times of sidedressing (only 45, […]