Phosphorus foliar fertilization in guava trees

Currently there is very little information on the response of fruiting perennial plants to applied P. This is especially true for tropical production areas where soils have a high capacity of P fixation, and are poor in native phosphorus. An alternative to soil P fertilization, which is inefficient in fixing soils, is to apply phosphorus as a foliar spray. P is quickly absorbed by leaves, and is redistributed quite well through the plants because its phloem mobility, and foliar application may be a viable practice. The purpose of this present work, is to determine the effectiveness of foliar P application on the nutritional status and yield of guava. The experiment was done in a Typic Hapludox, for three consecutive agricultural years, in an adult orchard of 'Paluma' guava. Five treatments were tested: four rates leaf applications of P (0-0.5-1.0 and 2.0% of P2O5) and a control where P was applied to soil (200 g of P2O5/plant). Through the results it was verified that the foliar application of P altered the concentration of the nutrient in the soil (13 to 48 mg dm-3 P-resin), and in the guava leaves (1.2 to 1.8 g of P kg-1), but did not affect the production of fruits. In conclusion, in field conditions, it is viable to combine the phosphorus foliar fertilization with disease control, without increasing the operations and, consequently, the production cost.

Nutrients foliar content for high productivity cultivars of guava in Brazil

Commonly grown in tropical and sub-tropical regions, guava (Psidium guajava L.) is an important fruit crop of Brazil. It is cultivated on a large scale in São Paulo state, and covers about 6,500 hectares. As a result of the guava selection program developed at FCAV/UNESP, two new cultivars were created: 'Rica' and 'Paluma' with a high productivity, and also with higher nutritional requirement. Leaves analysis has become a powerful tool in mineral-nutrition research with fruit crops, not only to determine response to different nutrients, but also for diagnostic techniques in making fertilizer recommendations and assessing deficiency symptoms. Nutrient composition of the leaves varies depending on the leaf maturity, tree age, variety and nutrient supply. For the interpretation of analytical values, selection of the index tissue is important. The results of experiments conducted in the field during 1989-2000 were studied. The nutritional status was evaluated by annual leaf sampling, carried out at full bloom. Recent fully developed leaves, corresponding to the third pair (with the petiole) were collected, starting at the end of the branch, all around the tree, at a height of 1.5 m from the soil, with a total of 30 leaf pairs per sample. The yield was evaluated by weighing all the fruits in the useful area of each lot. Foliar chemical analysis showed excellent correlation with the fruit production. Through the results it was verified that the maximum yield was associated to the following levels: N = 22-26; P = 1.5-1.9; K = 17-20; Ca = 11-15; Mg = 2.5-3.5; S = 3.0-3.5 g kg -1; B = 20-25; Cu = 10-40; Fe = 50-150; Mn = 180-250; Zn = 25-35 mg kg-1 DW in the leaves of the 'Rica' guava and to N = 20-23; P = 1.4-1.8; K = 14-17; Ca = 7-11; Mg = 3.4-4.0; S = 2.5-3.5 g kg-1; B = 20-25; Cu = 20-40; Fe = 60-90; Mn = 40-80; Zn = 25-35 mg kg-1 DW in the leaves of the 'Paluma' guava.

Anatomia foliar com ênfase nos tricomas secretores e análise cromatográfica do óleo essencial de Melissa officinalis L. (Lamiaceae)

Adult leaves of Melissa officinalis L. (Lamiaceae) harvested during the time of budding had been used in the study of the leaf anatomy in the identification of the secretory structures. The material was fixed in FAA 50%, dehydrated in alcoholic series (ethyl), infiltrated in paraffin, sectioned at 13 mm, staining and later analyzed through optic microscopy. Also it was carried through a study in gaseous chromatography for attainment of the rude essential oil. Analyses of transversal sections of the leaf of Melissa officinalis, has identified the presence of two types of trichomes secretory: peltate and capitate, beyond the presence of trichome tector. Trichome capitate, identified in literature as (type I), presents variations in its morphology in relation to the cells number stalk and the head secretory cells number. The chromatographic analysis of the essential oil identified the presence of monoterpenes, in two major components, responsible for more than 87.8% of the relative composition in the rude oil, beyond sesquiterpenes in smaller proportions.

Área foliar e evapotranspiração de callas cultivadas em substrato em função do nível freático

The objective of this study was to determine the influence of five different water levels on the crop development of Calla. The crop parameters evaluated were leaf area and evapotranspiration. The study was conducted in glass greenhouse with 50% of sunlight reduction. The plants were grown in PVC pots with 150 mm diameter, which were filled with substrate. The plant tubers weighed from 10 g to 12 g. The pots were placed within containers, under water level constant automatically.. The table water levels used were 10, 17, 24, 31 and 38 cm. Nine evaluations during the growth cycle checked the growth development. The evaporation varied from 26.89 to 46.14 L.plant-1 for 38 and 10 cm water levels, respectively and leaf area per plant showed 1011.6 to 2016.3 for the same levels. The substrate water was more available in the treatment 24 cm, with more restrictions in the upper and lower treatments. There was positive correlation between leaf area and evapotranspiration at the final of the culture.

Tamanho da amostra foliar para avaliação do estado nutricional de goiabeiras com e sem irrigação

The ideal size precision of the foliar sample determines manual work optimization, and also diminishes inherent errors in diagnosis reports of nutritional state. This work aimed to determine the size of the foliar samples and the sample error variation in guava plantations submitted to two hydric cultivations for the nutritional state diagnosis of this fruit. The work included two studies, both under an entirely randomized experimental design. Study 1 was carried out in an orchard under unirrigated cultivation with four treatments and six repetitions that consisted of leaf collection in 5, 10, 20 and 40 plants. Study 2 was carried out in an orchard under irrigated cultivation with five treatments and 10 repetitions that consisted of leaf collection in 10, 20, 30, 40 and 50 guava plants. It was concluded that in unirrigated orchards it is necessary to sample leaves in 40 plants in order to keep the macronutrients sample error between 5 to 10%. For the micronutrients, on the other hand, at least 40 plants were necessary and, if Fe and Zn were considered, the sample must be even larger. In irrigated orchards, leaves deriving from 10 plants were enough to keep the sample error between 5 to 10%. However, considering the micronutrients, it was necessary to sample 20 guava plants.

Nitrogênio em cobertura e molibdênio via foliar em feijoeiro de inverno no sistema plantio direto II - Características agronômicas e produtividade

Nitrogen is the nutrient most uptaken by common bean plant, and molybdenum besides its importance to N fixation process, it is associated to N metabolism. The objective of this work was to evaluate, on common bean crop Pérola cultivar, the effect of N levels application at side dressing (0, 30, 60, 90 and 120 kg ha-1) as well as the leaf application of Mo (0, 80 and 160 g ha-1) at development stadium V3 or V4 under no tillage system. The experimental design was the randomized blocks with 30 treatments and 4 replications. The research was conducted in Selviria-MS on soil previously cropped with corn. The application of nitrogen levels at side dressing provided increasing on dry mass weight, number of pod and seeds per plant and grain yield, in the 2004; the Mo application at V3 or V4 stadia did not effect the production components and grain yield; as well as different doses of Mo depended on the N application at side dressing, in the 2004.

Aplicação de silicato de potássio e crescimento foliar da cana-de-açúcar

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Identification of foliar diseases in cotton crop

The pathogens manifestation in plantations are the largest cause of damage in several cultivars, which may cause increase of prices and loss of crop quality. This paper presents a method for automatic classification of cotton diseases through feature extraction of leaf symptoms from digital images. Wavelet transform energy has been used for feature extraction while Support Vector Machine has been used for classification. Five situations have been diagnosed, namely: Healthy crop, Ramularia disease, Bacterial Blight, Ascochyta Blight, and unspecified disease. © 2012 Taylor & Francis Group.

Propagação assexuada de chacrona (psychotria viridis ruiz & pavon) via estaquia foliar

This study aimed to assess the asexual propagation of Psychotria viridis by leaf cuttings. The treatments were: A - Whole leaf cuttings, B - leaf cuttings with the top third cut off; C - with the lower third of the cuttings removed; D - with cuts on the primary vein of leaf cuttings, and E - poles with cuts on the leaf's secondary veins. The cuttings were immersed in distilled water for a period of 70 days. In all the treatments, the rooting was observed to occur in the region of the cut, or the place where the incision in the vein was. Current assay shows the feasibilities of Psychotria viridis leaf stalks and concludes that cuttings at the nerve ends highlight rooting in so far as the leaf stalks remain in permanent contact with the plant.

Adubação nitrogenada e critérios de amostragem foliar para a cultura da batata

The present study aimed to determine which leave will be displayed and the time of collection of this leave. The treatments consisted on five doses of nitrogen, four times for collection sampling and three types of leaves, arranged in a randomized block design with three repetitions, totalizing one hundred and forty-four experimental units. The leaves collections took place every fifteen days at thirty, forty-five, sixty and seventy five days after budbreak (DAB), collecting the laminated / compound young leaf (first leave), newly mature (second leave) and the mature leave (third leave) from the set of terminal leaflets. For this was installed an experiment with the culture of potato (cv. Atlantic), in Barretos/SP, the period of march the june of 2010. According to this data collected in this study, the best time for collecting the leaves is at 30 days after the budbreak of the potato cultivation containing nitrogen concentrations in the leaves minus heterogeneous of plants from a fraction to another and with values R2 = 0.98 being higher to the all times of harvests. To the diagnostic leaf, the highest determination coefficient was observed in the newly mature (second leaf) with R2 = 0.98. It can be observed that the highest levels of nitrogen were found on the first leaf (39.01 kg-1). Nevertheless, the values were very heterogeneous and did not fit the curve being the second leave (newly mature) the one that best represents the nutritional status of the plant. Therefore the recommendation for nutritional diagnosis will collect the recently matured leaves (2nd leaf) 30 days after budbreak.

Evaluation of different foliar fertilizers on the crop production of sugarcane

Influence of different foliar fertilizers (phosphite, micronutrients, biostimulant, phosphite + micronutrients, phosphite + biostimulant, micronutrients + biostimulant and phosphite + micronutrients + biostimulant) on yield of sugarcane was evaluated after fertilization at 30, 90 and 150 days after harvesting two-year-old sugarcane. The experiment was carried out in a commercial crop employing a randomized block design in four replicates. Higher stalk masses were observed for fertilization at 30 days after harvest, and the higher content of sucrose, total recoverable sugar and Brix degrees were observed for sugarcane fertilized after 150 days. Statistical analysis (Duncan's test) revealed no significant variation (P & 0.05) in Brix degree, sucrose content and total recoverable sugar. For total recoverable sugar x stalk weight (the main payment type for sugarcane producers), the following sequence (time treatment, fertilizer composition) 30-days, micronutrient + biostimulant; 150-days, biostimulant; and 90-days, biostimulant increased 11%, 17%, and 21% the yield of sugarcane. © 2013 Copyright Taylor and Francis Group, LLC.

Inoculação de sementes com bactéria diazotrófica e aplicação de nitrogênio em cobertura e foliar em milho

Considering the importance of nitrogen management and its biological fixation with diazotrophic bacteria, this study was carried out aiming to evaluate the agronomic performance of maize, in response to seed inoculation with Azospirillum brasilense and nitrogen application in side-dressing and leaf. The experiment was conducted in Selvíria, Mato Grosso of Sul State, Brazil, during the growing season 2010/2011, on a clayey Rhodic Haplustox (20° 20' S and 51° 24' W, with altitude of 340 m). Sixteen treatments were established with four replications, in randomized blocks with the combination of the factors A. brasilense (with and without inoculante), nitrogen rate (0 and 90 kg ha-1, in V5 growth stage) and urea leaf application (0, 4, 8 and 12%: application in V5 and V8 growth stage). The maize hybrid used was the DKB 390 YG®, sowed in the row spacing of 0.9 m. Parameters measured were productive and morphological components of culture and crop yield. Increase in maize yield by seed inoculation with A. brasilense was observed. The application of 90 kg ha -1 of nitrogen in side-dressing provided higher chlorophyll leaf index, stalk diameter and prolificacy, however, the yield not was increased. The application of urea leaf did not agronomic efficiency and, therefore, should not be used as the unique form of supply and alternative to nitrogen addition to crop.

Índice de área foliar e produtividade do tomate sob condições de ambiente protegido

The tomato cultivation in the greenhouse has been expanded in the last years, mainly, in the South and Southeast regions of Brazil, whose purpose is to improve the productivity and the quality of the agricultural products, offering regularity in the production. The present study aimed to determine, along the crop cycle, the relationship between the leaf area index and the productivity, and at the end of the cycle, the components of production of the tomato in the greenhouse. The models were generated through polynomial equations of 1st and 2nd order, having as independent variable the number of days after the transplanting. It was verified that it is possible to determine, in the greenhouse, through mathematical models, the leaf area index of the tomato crop considering the days after the transplanting. Basing on values of leaf area index, the productivity of the crop and the period of the maximum productivity can be determined, aiding the farmers to determine the best sowing and transplanting time of the tomato crop.

Foliar and Radicular Absorption of Boron by Beetroot and Tomato Plants

The isotopic technique was employed to study boron (B) mobility in tomato and beetroot plants under protected cultivation conditions. An experiment was conducted in which both species grew in 10-dm3 vases filled with coconut fiber, under hydroponic conditions. The plants were subjected to four different treatments: (1) no B in the substratum and no foliar fertilization; (2) no B in the substratum, with foliar 10B fertilization; (3) B in the substratum, with foliar 10B fertilization; and (4) 10B in the substratum and no foliar fertilization. The biological growth variables and total B and 10B contents in the plant parts grown after the application of the nutrient were evaluated. For increasing B content in young tissues, the foliar application of this element was not as efficient as application via root system, indicating low mobility of B in the tissues of both beetroot and tomato plants. © 2013 Copyright Taylor & Francis Group, LLC.

Effects of soil and foliar application of soluble silicon on mineral nutrition, gas exchange, and growth of potato plants

Silicon can alleviate biotic and abiotic stresses in several crops, and it has beneficial effects on plants under nonstressed conditions. However, there is still doubt about foliar-applied Si efficiency and Si effects on mineral nutrition, physiological processes, and growth of potato (Solanum tuberosum L.) plants under wellwatered conditions. The objective of this study was to evaluate the effect of soil and foliar application of soluble Si on Si accumulation, nutrients, and pigments concentration as well as gas exchange and growth of potato plants. The experiment was conducted under greenhouse conditions in pots containing 35 dm3 of a Typic Acrortox soil. The treatments consisted of a control (no Si application), soil application of soluble Si (50 mg dm-3 Si), and foliar application of soluble Si (three sprays of 1.425 mM Si water solution, prepared with a soluble concentrate stabilized silicic acid), with eight replications. Both soil and foliar application of Si resulted in higher Si accumulation in the whole plant. Foliar application of Si resulted in the greatest Si concentration in leaves, and soil application increased Si concentration in leaves, stems, and roots. Silicon application, regardless of the application method, increased leaf area, specific leaf area, and pigment concentration (chlorophyll a and carotenoids) as well as photosynthesis and transpiration rates of wellwatered potato plants. However, only soil application increased P concentration in leaves and dry weight of leaves and stems. © Crop Science Society of America.