Emergência e crescimento inicial de mudas de cultivares de alface em diferentes substratos

Resumo: Objetivou-se avaliar os efeitos de combinações de substratos na emergência e crescimento inicial de diferentes cultivares de alface. O estudo foi conduzido em ambiente de telado, no Setor de Horticultura da Universidade Federal do Piauí, no Campus Professora Cinobelina Elvas, em Bom Jesus - PI. Compararam-se as combinações de substratos: biomix® (S1), esterco bovino (S2), paú de buriti (S3), paú de buriti + areia lavada + esterco bovino na proporção de 1:1:1 (S4), paú de buriti + areia lavada na proporção de 1:1 (S5), paú de buriti + esterco bovino na proporção de 1:1 (S6), areia lavada + esterco bovino na proporção de 1:1 (S7) e três cultivares de alface: Solaris, Lucy Brown e Florence. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 7x3, com quatro repetições e 50 sementes por parcela. O substrato S5 (Paú de buriti + esterco bovino na proporção de 1:1) foi o que mais proporcionou condições favoráveis para a emergência das plântulas de alface. As plântulas cultivadas no substrato S1 (Biomix®) apresentaram maior crescimento inicial. Tanto na emergência quanto no crescimento inicial, as cultivares Solaris e Lucy Brown foram as que apresentaram os melhores resultados

Salt stress on physiology, biometry and fruit quality of grafted Passiflora edulis

The production of grafted passion fruit is an alternative for plant adaptation to saline environments. The objective of this study was to evaluate the effect of salt stress on physiology, biometry and fruit quality of P. edulis grafted on Passiflora spp. The experiment was conducted in completely randomized design, in a 3 x 2 factorial scheme, corresponding to three species of Passiflora (P. edulis, P. gibertii and P. cincinnata) with P. edulis scion and two levels of irrigation water salinity (0.5 - control and 4.5 dS m-1), with four repetitions. Water salinity compromises gas exchanges (CO2 assimilation raste and transpiration) and physiological variables (total chlorophyll and total water consumption) in grafted P. edulis. The interaction between the factors (water salinity x species) compromised only the growth in plant height and number of leaves. In relation to the species, auto-grafted P. edulis stood out from the other species, with higher internal CO2 concentration, number of leaves, stem dry mass, peel thickness, total soluble solids (TSS) of the pulp and TSS/TA ratio (titratable acidity). Auto-grafted P. edulis under saline conditions develops vital mechanisms (TSS and TSS/TA), which attenuates the effects of salt stress on the physico-chemical quality of the fruits

CHARACTERIZATION OF YELLOW LATOSOLS (OXISOLS) OF SERRA DO QUILOMBO, IN PIAUÍ STATE SAVANNA WOODLANDS - BRAZIL

The savanna woodlands of Piauí state has great economic importance since it is an area for agricultural expansion, being the fourth most important of Brazil and the first from Brazilian Northeastern. The area accounts for 5.9% of the Brazilian savanna woodlands and 36.9% of the Northeastern savanna, covering 46% of the Piauí state area, in a total of 11.5 million hectares . The goal of this research was to study pedoenvironments of Serra do Quilombo region, which is in Piauí state savanna, as well as identifying existing soil classes, according to the Brazilian System of Soil Classification - SiBCS. Soil identification consisted in characterizing soil profiles along a transect, assessing in - field conditions and collecting soil samples, in areas of native vegetation. The samples were gathered from three distinct points, being two at the edges and one at the center of the plateau. Soil analyses were carried out with samples collected from each horizon through trench digging up to a 2 - m depth. Morphological, physical, chemical and mineralogical characterizations were performed for each soil profile , along with an evaluation of the effect of pedogenic factors on their formation and development. All soils under study were formed with source materials of the same geological formation; however, each rock has a distinct contribution to the process, involving sandstones and shales. The characteristics observed in the soil from Serra do Quilombo have no difference from the pattern found in the Brazilian plateaus, and soil profiles were classified as dystrophic clayey Yellow Latosols (Oxisols), according to the SiBCS

Nutritional status of yellow passion fruit submitted to nitrogen sources by fertigation

Yellow passion fruit is the most cultivated species in Brazil and requires high amounts of nitrogen and an adequate nutritional status to express its entire productive potential. In this sense, this study aimed to evaluate the effect of different sources and doses of nitrogen via fertigation on nutritional status and leaf chlorophyll of yellow passion fruit. The experiment was conducted from June 2013 to August 2014 in Gurgueia Valley, Cristino Castro county, Piaui State, Brazil. The experimental design was randomized blocks with four replications, in a 2 x 5 factorial design related to the application of two nitrogen sources (urea and ammonium sulfate) and five N levels (100, 200, 300, 400 and 500 kg ha-1 year-1). Six plants per replication were considered, totaling 240 plants, spaced 3 m between rows and 3 m between plants, and covering an area of 2,160 m2. At pre-flourishing, it was evaluated leaf chlorophyll index and leaf nitrogen, phosphorus, potassium, calcium, magnesium and sulfur contents. Urea increases Ca and Mg leaf contents and reduces leaf S content in relation to ammonium sulfate. The increase in nitrogen fertilizing levels enhances leaf N and Mg concentrations. For Ca, the optimal ammonium sulfate dose is 296.30 kg ha-1