CRESCIMENTO E QUALIDADE DE MUDAS DE Cassia <i>grandis Linnaeus</i> f. EM RESPOSTA À ADUBAÇÃO FOSFATADA E CALAGEM

Abstract

RESUMOO objetivo deste estudo foi avaliar o crescimento e a qualidade de mudas de Cassia grandis Linnaeus f. (cássia-rosa) em função da adubação fosfatada e da calagem. Os tratamentos foram representados por um fatorial de seis níveis de fósforo (0, 120, 240, 360, 480 e 600 mg dm -3 ) por cinco níveis de saturação por bases do substrato (3,5 (original), 25, 40, 55, 70%), sendo dispostos no delineamento em blocos ao acaso, com quatro repetições. Aos 65 dias após a repicagem, foram medidos a altura da parte aérea (H), o diâmetro do coleto (DC), a massa de matéria seca da parte aérea (MSPA), massa de matéria seca de raízes (MSRA) e massa de matéria seca total (MST), e calculada a relação MSPA/MSRA e o índice de qualidade de Dickson (IQD). A adubação fosfatada teve influência significativa em todas variáveis estudadas. A dose de fósforo adequada para a produção de mudas de qualidade de Cassia grandis nas condições estudadas, na saturação por bases de 25%, é de 600 mg dm -3 . Palavras-chave: produção de mudas; nutrição de plantas; fósforo. ABSTRACTThis study aimed at evaluating the growth and seedling quality of Cassia grandis Linnaeus f. in response to liming and phosphate fertilization. The treatments were arranged in a factorial design of 6 phosphorus levels (0, 120, 240, 360, 480 and 600 mg dm -3 ) by 5 base saturation levels (3,5 (original), 25, 40, 55, 70 %), in randomized blocks with four replicates. The height of the aerial part (H), collar diameter (DC), dry matter of shoot (MSPA), dry matter of root (MSRA), and total dry matter (MST) were determined at 65 days after the transplanting. The relation between dry matter of shoot and dry matter of root (MSPA/ MSRA) and Dickson quality index (IQD) were calculated at this stage. There were significant effects from the phosphate fertilization to all studied variables. Based on this study, the recommended P dose for quality seedling production of Cassia grandis is 600 mg dm -3 , for 25% of substratum's base saturation. Keywords: seedling production; plant nutrition; phosphorus. INTRODUÇÃOA expansão agrícola e a alta demanda por produtos madeireiros aumentaram a exploração dos remanescentes florestais nativos, resultando em altas taxas de desmatamento, que culminaram na degradação de extensas áreas no Brasil devido ao seu abandono após a perda da capacidade produtiva ou manejo incorreto. A revegetação dessas áreas é fundamental para melhorar as características físicas e químicas do solo, fornecendo, por meio da cobertura vegetal, a proteção necessária para diminuir a perda de solo por erosão (SILVA et al., 2011).

Effect of phosphorus application on substrate and use of saline water in sugar-apple seedlings

“…A phosphorus efficiency was also observed by other researchers. Freitas et al (2013) reported a positive DQI effect in the dose of 143.16 mg seedling -1 of P in sugar-apple seedlings, and Freitas et al (2017) reported an ascending linear effect for the DQI, in which the greatest phosphorus dose of 600 mg dm -3 Figure 1. Stem diameter (a), proportionally to the use of triple superphosphate (TSP) and irrigation water electrical conductivity (iwEC) levels; plant height (b); shoot dry mass (c); total dry mass (d); absolute growth rate (e); relative growth rate (f); and the Dickson quality index (g), proportionally to the use of TSP in sugar-apple seedlings.…”

MORPHOLOGICAL PARAMETERS IN CLONAL SEEDLINGS OF Eucalyptus spp. IN THE EXPEDITION PHASE

“…According to Freitas et al (2017) and Delarmelina et al (2013), greater estimates of RDW mean better seedlings performance after planting, since the root system will be able to better anchor the seedling, allow better water and minerals absorption, and easly translocate water and minerals to stem. Thus, seedlings with lesser RDW estimates may reduce plants growth speed and increase costs for plantations maintainance over time (BEHLING et al, 2014;LOPES et al, 2016;FREITAS et al, 2017).…”

“…Freitas et al (2017) described the same, considering that various parameters allow nursery manegers to better choose seedlings that will perform better after planting. Tsukamoto-Filho et al (2013) and Lopes et al (2014) also refer to the management practices needed for plantations maintenance and related costs.…”

Production of Cashew Rootstocks Submitted to Organic and Mineral Fertilization

“…Corroborating with the other growth variables, the dose of 3 g of NPK under these conditions decreased 38.86% the quality of the seedlings as the doses of manure increased, probably due to this dosage of the mineral fertilizer causing phytotoxicity. Considering the exposed, it is assumed that the best combination for production of cashew tree seedlings was obtained using the dose of 1 g of NPK conciled with 200 g of bovine manure, because, as affirm Freitas et al (2017) the higher the quality index of the more standardized seedlings these are. The reduction will be observed in the quality of seedlings from 300 g manure and NPK 3 g dose is due to the excess salts from both the manure as fertilizer, these respective concentrations, similar results were found by Oliveira et al (2015) when studying guava rootstocks under different sources and proportions of organic materials, which observed higher quality of seedlings in the proportion of 40% of the organic material declining with increasing proportion.…”