Movimentação de nitrato e amônio em colunas de solo

Abstract

RESUMONo sistema de plantio convencional, a prática anual de revolvimento do solo provoca alterações nas propriedades físi-cas, como diminuição da porosidade, modificação da estabilidade de agregados e destruição dos canais deixados pelo sistema radicular. No sistema de plantio direto, não há revolvimento do solo. Portanto, a aplicação de calcário, assim como de N, deve ser feita em superfície, em razão da impossibilidade de sua aplicação em profundidade. Objetivou-se com este trabalho estudar a movimentação de Termos para indexação: Lixiviação, nitrogênio, colunas de solo. ABSTRACTIn the conventional tillage, the annual practice of revolving the soil leads to modifications in the soil physical properties as decrease of the porosity, modification of aggregate stability and destroction of the channels left by the root system. In the no-till system, there is no revolving of the soil. Therefore, liming as well as nitrogen fertilization applied must be made on the surface due to impossibility of this application in depth. The objective of this work was to study the movement of

Perdas de Nutrientes por Lixiviação na Produção de Mudas de Cedro Australiano

“…A oxidação de praticamente todo o N amoniacal nas condições subtropicais do sul do Brasil ocorre em 20 dias (Aita et al, 2007) e, sendo o nitrato fracamente adsorvido aos coloides do solo, provavelmente isso favoreceu sua perda por lixiviação (Araújo et al, 2004).…”

Nitrate leaching through climatologic water balance in a fertigated coffee plantation

“…However, Primavesi et al (2006), state that peaks of losses of N-NO 3 -by leaching appear in the upper soil layer (0 to 40 cm) preferentially after rainfall, mainly for those preceded by dry periods, independently of the application of N fertilizers. Araújo et al (2004), cite that in a treatment which had received urea and lime leaching of N-NO 3 -was greater as compared to a treatment that received only urea, with these treatments showing values much higher than the control. Table 5 show that the accumulated value of drainage soil water fluxes is of 951.1 mm, which represents 42.6% of the sum rainfall + fertigation.…”

“…In a study carried out by Oliveira et al (2001), they observed losses over 100 kg de N-NO 3 -ha -1 year -1 for soils that received sewage sludge or even conventional N fertilization for sugarcane crop. For Araújo et al (2004), such magnitude of leaching represents a risk for the environment. Furthermore, Dynia (2000) mentions that even in electro-positive soils with high clay content, the N-NO 3 -is capable to move out of the root zone of most crops, reaching depths between 2 to 6 m and finally accumulating there.…”

“…Primavesi et al (2006), states that the greatest variation of N-NO 3 -content happened in the top soil layers (down to 20 cm) with a tendency of moving downwards to depths below 1 m, in the case of applications of doses of N greater than 500 kg ha -1 year -1 . This implies in more attention to N fertilizer management practices because it represents major concern due to economic and environmental issues (Araújo et al, 2004).…”

Nitrate and potassium concentration in fertigated soil cultivated with wine vines

“…In agricultural systems, N sources are: atmospheric deposition, nitrogen fertilization (Rocha;, biological fixation of atmospheric N 2 , and mineralization of the organic N of the soil (Siqueira Neto et al, 2010). Although N can be absorbed by plants as anion (NO 3-) and cation (NH 4+ ), its absorption in the form of NO 3-is faster because it travels through the soil solution until reaching the roots of the plants via mass flow, and its leaching can also occur with greater ease due to excess of water (Araújo et al, 2004). According to Zanini, Villas Bôas and Feitosa Filho (2002), potassium movement depends on the type of soil and, in most cases, is limited.…”