Hygroscopicity and ammonia volatilization losses from nitrogen sources in coated urea
01/Jun/2014
Hygroscopic fertilizers tend to absorb moisture from the air and may have undesirable characteristics such as moistness, clumping and lower fluidity, hampering the application. The increasing use of urea is due to its numerous advantages, although this nitrogen (N) source is highly susceptible to volatilization losses, particularly when applied to the soil surface of management systems with conservation of crop residues. The volatilization losses can be minimized by slow or controlled-release fertilizers, with controlled water solubility of the urea-coating materials; […]
Production and quality of roses as affected by boron fertilization
01/Apr/2014
Many studies have shown the effects of boron (B) application on various crops; however, results on roses are scarce. The aim of this experiment was to evaluate the effects of B on the production and quality of roses (Rosa hybrida Shiny Terrazza®) under controlled conditions. Treatments consisted of five rates of B (0, 1, 4, 8 and 16 mg kg-1) applied in the substrate in a randomized block design with five replicates. We evaluated the cycle; number of flowers per […]
Ammonia volatilization from coated urea forms
01/Aug/2013
Nitrogen fertilization is a major component of the cost of agricultural production, due to the high cost and low efficiency of fertilizers. In the case of urea, the low efficiency is mainly due to losses by volatilization, which are more pronounced in cultivation systems in which plant residues are left on the soil. The objective of this work was to compare the influence of urea coated with sulfur or boric acid and copper sulfate with conventional N fertilizers on N […]
Loss of ammonia from nitrogen fertilizers applied to maize and soybean straw
01/Aug/2013
In Brazilian agriculture, urea is the most commonly used nitrogen (N) source, in spite of having the disadvantage of losing considerable amounts of N by ammonia-N volatilization. The objectives of this study were to evaluate: N lossby ammonia volatilization from: [urea coated with copper sulfate and boric acid], [urea coated with zeolite], [urea+ammonium sulfate], [urea coated with copper sulfate and boric acid+ammonium sulfate], [common urea] and [ammonium nitrate]; and the effect of these N source son the maize yield in […]
Nutrient distribution and visual symptoms of boron deficiency in roots of green dwarf coconut
01/Dec/2008
Roots are usually the first plant organs where boron deficiency symptoms appear. The experimental evaluation of the effects of mineral deficiencies on the root system of trees is rather difficult. This experiment aimed to evaluate the effect of boron deficiency on the formation of roots with different diameters and on nutrient accumulation and to characterize visual symptoms of B deficiency in roots of green dwarf coconut trees. The following treatments were applied: complete nutrient solution (+B) and nutrient solution without […]
