Resposta da Brachiaria brizantha cv. Marandu a fertilizantes nitrogenados associados ao fosfato natural reativo

Abstract

Resposta da Brachiaria brizantha cv. Marandu response to nitrogen fertilizers associated to natural reactive phosphate AbstractThis study aimed to identify a proportion of urea and ammonium sulfate associated to natural reactive phosphate that coud maximize the production of 'marandu' grass in a red clayay oxisol with low phosphorus content. The experiment was conducted in a greenhouse with a completely randomized design , in split plots in the time with seven repetitions. The main plots consisted of six levels of the substitution of urea by ammonium sulfate: 0, 20, 40, 60, 80 and 100%. The split plots consisted of three growth periods, being the first 30 days after plants emergence and the others spaced 20 days after the previous evaluation. The evaluated variables were: number of tillers, SPAD value, shoot, leaf blade and stem dry mass. The ammonium sulfate can provide higher soil acidity when compared to urea, which contributes to the reactive phosphate solubilization. Ammonium sulfate increment changes the SPAD value of 'marandu' grass fertilized with natural reactive phosphate.

Tropical Grasslands-Forrajes Tropicales Vol.8 No.2 [May 2020]

“…The criteria for thinning were based on seedling vigor and uniformity. After seedling emergence, soil moisture was maintained near field capacity, estimated according to the methodology described by Cabral et al (2016).…”

Growth and nutritional efficiency of acacia seedlings in response to phosphate fertilization

“…When analyzing plant biomass, a significant adjustment (p<0.01) was also observed for the quadratic regression model in the SDM, RDM and TDM variables (Figure 3). The addition of P in highly weathered soils (with low available P content) promotes significant increases in plant biomass (Rodrigues et al, 2014;Cabral et al, 2016), as occurred in the soil used in this work, whose initial content P was low (0.8 mg dm -3 ) (Table 1).…”

Fósforo no crescimento inicial de mogno-africano

“…Ao considerar que o fósforo (P) é uma fonte esgotável, com utilização ampla na agricultura brasileira e o predomínio de solos classificados como latossolos, o manejo adequado é vital para a manutenção das reservas químicas e para a viabilidade econômica de projetos; neste contexto a utilização de fontes solúveis além de eficiente é também vantajosa pela disponibilidade instantânea desse nutriente (Cabral et al, 2016). Além da carência generalizada de P nos solos brasileiros, o elemento apresenta forte interação com o solo (fixação), o que reduz a eficiência da adubação fosfatada (Faquin, 2005).…”