Produção e composição química da uva de videiras Cabernet Sauvignon submetidas à adubação nitrogenada

Abstract

Produção e composição química da uva de videiras Cabernet Sauvignon submetidas à adubação nitrogenada Grapes yield and chemistry composition in Cabernet Sauvignon grapevine with nitrogen fertilization RESUMOA adubação nitrogenada em videiras é realizada para suprir a demanda da planta pelo nutriente. Porém, o nitrogênio (N)

Nutrient release during the decomposition of mowed perennial ryegrass and white clover and its contribution to nitrogen nutrition of grapevine

“…These results are in apparent contradiction with data from the experiment 1 that showed that after 16 weeks the amount of N release of the litter of ryegrass and clover was about 5 kg total N ha -1 (data not reported in Tables or Figures). Even though it is not possible to draw a definitive conclusion from our data, and we have not assessed the fraction of labeled N present in the root system, the possible explanations for the apparent discrepancy between the results of the two experiments include (i) a relatively low N requirement for root N uptake by mature grapevines (Patrick et al 2004;Brunetto et al 2009); (ii) the failure of labeled N to reach the entire root system of grapes, which is known to explore also deep soil layers (King and Berry 2005); (iii) the availability of other sources of (unlabeled) mineral N in soil; (iv) the ability of microorganisms in competing with plants for N uptake; and (v) the presence of strong physical process of adsorption of mineral N (NH 4 -N) in soil. In addition, it is also possible that the availability of N from decomposing litter material took place (in summer) when the most intensive period of N uptake for grapevines had already occurred (in spring).…”

Phosphorus forms in leaves and their relationships with must composition and yield in grapevines

“…The lack of a positive correlation between yield of the V1 and V2 grapevines of the experiment 1, with the P TOTAL content in leaves collected at FL and V may have occurred because there was no significant difference between P TOTAL content in leaves of grapevines grown with low and high P content available in the soil (Table 3). These results show that regardless of the P content available in the soil and the phenological stage (FL or V), P TOTAL content in full leaves cannot always be used to diagnose P content available in soil and, therefore, cannot be a good indicator of the nutritional status of grapevines (Brunetto et al, 2009). Furthermore, the lack of response can be attributed to the accumulation of P in storage organs, such as roots, which can be redistributed in periods of greater demand (Lima et al, 2011).…”

“…However, total P content in grapevine leaves does not always have a relationship with grape yield (Tecchio et al, 2006;Brunetto et al, 2009), or even with must composition. This may occur because leaves used for total P analysis are collected at the veraison, which is a period of small emission of young roots that are more active in absorbing water and nutrients, including P. At the same time, grapevine leaves show little cell division and increased dry matter production in this period, thus, not acting as P sinks (Tecchio et al, 2007).…”

Organic and Nitrogen Fertilization of Soil under ‘Syrah’ Grapevine: Effects on Soil Chemical Properties and Nitrate Concentration

“…A lack of synchronization between N release from fertilizers and plant uptake may intensify N loss to the environment (Brunetto et al, 2009). Appropriate soil texture and mineralogical characteristics are important for preventing losses, especially when applying high rates of organic fertilizers and, or, high concentrations of readily available N (Fioreze et al, 2012).…”