Influence of storage on chemical properties of different peats

The change of chemical properties during storage of 12 fertilized bagged peats of different origins at high temperature was investigated. The average values for N, soluble salts and EC decreased significantly, whereas the pH as well as P and K contents changed only slightly. Differences in N were observed between the peats. The contents of CAT soluble N in the two dredged frozen black peats did not change during storage. However, a decrease in N was found when water extraction was used. In the case of the 10 white peats the loss of N differed considerably, but it was independent of the method of peat harvest. The N decrease resulted mainly from reduced levels of NO3-N. Substances damaging to plant growth do not seem to have developed during storage as shown by trials on the germination and the growth of Chinese cabbage. There were no significant differences between the peats, whether stored or not.

Uso do regulador de crescimento etil-trinexapac em arroz de terras altas

This work was developed with the objective of evaluating the use of trinexapac-ethyl doses (0, 75, 150, 225 and 300 g of the a.i. ha -1) and application times (active tillering, between active tillering and floral differentiation and at floral differentiation) in upland rice crop development and yield. The experiment was carried out in Selvíria-MS, during the agricultural year of 2006/07. Application of 150 g ha -1 of trinexapac-ethyl in Primavera rice cultivar at panicle initiation differentiation reduces plants height, 0.40 m on average comparing to other times, with lodging absence. Trinexapac-ethyl promotes lange number of abnormal grains, reduction of grain yields in doses above 150 g ha -1, when applied in panicle initiation differentiation stadium. Application of 150 g ha -1 of trinexapac-ethyl at any time does not interfere in crop yield.

Fig tree orchard formation using organic fertilization

The present work aimed at evaluating the effects of cattle manure fertilization on the growth and yield of fig trees. The cultivar 'Roxo de Valinhos' was used. One-, two-, three-and four-year-old trees were treated with cattle manure containing 0, 25, 50, 75, 100, 125 and 150% of the recommended nitrogen level per plant. The experiment was carried out using randomized blocks with 7 treatments, 5 replicates and 5 plants per experimental plot. The evaluated characteristics were: plant height, stem diameter, secondary branch length and diameter, yield per plant (kg plant-1), besides some quality characteristics of fruits such as pH, titratable acidity, soluble solids and texture. Manure application enhanced plant growth and fruit production. Significant differences were observed only for soluble solids content, pH and texture, which varied according to the crop cycle. After four crop cycles (2002/03, 2003/04, 2004/05 and 2005/06), the best results (about 5.0 kg of fruits per plant) were obtained with 100% of the recommended nitrogen dose, which corresponded to 14.3 kg of cattle manure per plant, in the last crop cycle (2005/2006).

Ex-post evaluation of the employment effects of a preferential trade agreement: methodological issues, illustrated with a reference to Chile

Includes bibliography

Doses de Nitrogênio na Produção de rabanete fertirrigado e determinação de clorofila por medidor portátil nas folhas

The relative chlorophyll determination is used to predict the need for nitrogen fertilization aiming to increase production in various cultures. The objective of this study was to evaluate the soil nitrogen dose response added to the soil via fertigation in radish production and the relation between chlorophyll and cultivar Redondo Vermelho leaf nitrogen content. Transverse diameter of root, leaf area, green index, leaf N contents, shoots (stem) production, number of commercial and noncommercial roots, and the total commercial mass roots were evaluated. The N doses didn't interfere in the radish production and the readings taken with portable chlorophyll meter are not very accurate in ascertaining the level of N on radish plant growth.

Mango flower induction in the brazilian northeast Semi-arid with gibberellin synthesis inhibitors

Mangoes in the Brazilian semi-arid stands out in the national scenario due to high yields and fruit quality, and also to the possibility of all-year production taking advantage of the climatic conditions as well as management technique (irrigation, pruning and growth regulators application) for plant growth and blossom control. Paclobutrazol soil drench applied is normally used for production management of mangoes. This research deals with the evaluation of the effect of foliar applied growth regulators to mango, cultivar 'Kent', as regard to their efficiency for blossom management, in order to allow off season mango production. Three growth regulators (prohexadione-Ca, trinexapac-ethyl and chlormequat chloride) were foliar applied, at two dosages and compared to paclobutrazol applied as soil-drench. In order to compare the effects of the treatment, data were recorded related to panicle emission (percentage and length), period of time until blossom and production, yield (number and plant weight) and post-harvest quality of the fruit (total soluble solids, titratable acidity, pH, firmness, flesh and skin color and appearance). The results showed that prohexadione-Ca and chlormequat chloride induced a 15-day early harvest, while paclobutrazol, alone or combined with prohexadione-Ca, allow to harvest 25 days in advance, when compared to trinexapac-ethyl and control trees. Growth regulators foliar applied and paclobutrazol applied as soil-drench delayed mangoes fruit ripening in post-harvest.

Uniconazole on mango floral induction cultivar 'Kent' at submedio são francisco region, Brazil

In order to provide efficient crop management which enables the scaling of the production of mango in semi-arid conditions and achieve a greater precision in the recommendation, evaluating the effect and the influence of uniconazole foliar spray, on the emission of vegetative flushes in the cultivar 'Kent', field tests were carried out in a productive orchard. Treatments tested were three uniconazole dosages, 500, 1,000 and 1,500 mg L-1, with one, two or three respective foliar sprayings. Another treatment with paclobutrazol was used at 2.0 g a.i./m of canopy diameter, with a single application via soil and a control (without spraying of plant growth regulators), where spreader-sticker was added and the pH was adjusted. With 30, 60 and 90 days after the first spraying of the flowering inducer the growth of branches were evaluated, as well as the percentage of flowering in all treatments after 120 days of first spraying. The sprayings started in the orchard after the emission of the second vegetative flush after pruning of production, through airassisted sprayer with flow rate of 1,000 L ha-1. The experimental design was done through randomized blocks with four replications, using three plants per plot. It was observed that paclobutrazol was significantly highlighted in relation to other treatments and that the uniconazole with one, two and three foliar sprayings presented inhibition of the vegetative growth in mango 'Kent' and showed, even at low proportions, signs of flowering.

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

The objective of this work was to study the morphological and physiological characteristics of the wheat flag leaf as affected by increasing sowing densities and plant growth regulators application. The experimental design was a split-plot with completely randomized blocks and four replications. Plots were consisted by four sowing densities (30, 50 70 and 90 plants m-1) and the split-plots by plant growth regulators: a product composed by auxin+gebberellin+cytokinin (Ax+GA+CK), Trinexapac-Ethyl e (Ax+GA+CK) + Trinexapac-Ethyl, and a control without application. Dry mass accumulation, plant height, morphological characteristics, SPAD index, nitrogen and photosynthetic pigments contents in the flag leaf were determined. The increase in the sowing density resulted in lower dry mass accumulation and SPAD index of the flag leaves. Trinexapac-Ethyl caused increase in the SPAD index, but the chlorophyll content of the flag leaf was reduced. The SPAD index values were more correlated with the nitrogen than the chlorophyll contents. Ax+GA+CK did not affect flag leaf characteristics in wheat plants.

Fertilizing lychee plants with phosphorus at time of planting in Brazil

The objective of this research was to study the effects of P fertilizers applied at time of planting on lychees' nutritional status and on plant growth. The treatments consisted of five doses of P: zero, 50, 100, 200, and 300 g of P2O5 per plant, furnished by triple superphosphate. Plant diameter was evaluated during two years and the plants' nutritional status on the second year. The second year foliar levels of macro and micronutrients (with the exception of Zn) were increased by the P fertilizer. The orchard's initial development, especially during the second year, was also influenced by the fertilizer. The P doses of 164 and 158 g of P2O5 per plant resulted in the largest plant diameter after the first and the second year, respectively. These doses were found to be associated with a foliar P level of <1.4 g kg-1. © 2012 Renato de Mello Prado et al.

Acúmulo de biomassa em variedades de cana-de-açúcar inoculadas com diferentes estirpes de bactérias diazotróficas

The objective of this study was to evaluate the contribution of inoculation with diazotrophs, applied both individually and in combination, in commercial varieties of sugarcane. The experiment was carried out at the experimental grounds of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, Brazil. The experimental design was of randomised blocks, with sub-divided plots and six replications. Six varieties of sugarcane with six treatments were used: control, control with nitrogen, inoculation of the individual strains: BR 11512, BR 11724 and BR 11411, in addition to inoculation with a cocktail consisting of five strains of diazotrophs. Differences were observed between varieties and between treatments, and an interaction observed between the treatments and varieties. For all the parameters evaluated, no response was observed in the sugarcane varieties RB855536 and RB92606. In the variety RB918639, the only difference was in the accumulation of green biomass. No difference was observed between the treatments for total nitrogen accumulation. The most responsive variety to inoculation was RB867515, differing in the accumulation of fresh and dry biomass. This study showed that inoculation promotes the accumulation of biomass, the contribution being different for the varieties and strains of bacteria, suggesting an interaction between the factors studied. The variety RB867515 is promising for use in studies of inoculation with diazotrophs.

Improvement of grapevine iron nutrition by a bovine blood-derived compound

Iron (Fe) is essential for chlorophyll formation and plant growth. Irondeficiency chlorosis is a major nutritional disorder in several fruit trees cultivated in calcareous and alkaline soils, reducing fruit yield and quality and causing heavy economic losses. Since chelated Fe, the most widespread fertilizers used for preventing or curing Fe deficiency, pose risks of environmental pollution, the development of sustainable agronomic alternatives represents a priority for the fruit industry. In this work, we investigated the effectiveness of a bovine blood-derived product (BB; 0,125% Fe) for preventing Fe-deficiency in grapevine plants. During the vegetative season 2011 potted plants of five graft combinations: Sangiovese/S4O, Cabernet Sauvignon/S4O and Cabernet Sauvignon/140 Ruggeri, 140 Ruggeri/Cabernet Sauvignon, Vitis riparia/Cabernet Sauvignon were grown on calcareous soil. Soil treatments included: 1) Control; 2) Fe-EDDHA (Fe 6%); 3) Bovine-Blood (5 g/L); 4) Bovine-Blood (20 g/L). With the exception of Cabernet Sauvignon/S4O plants, Fe-EDDHA increased SPAD units (leaf chlorophyll content). Bovine-blood at low concentrations had similar or higher SPAD units than Fe-EDDHA. Increasing concentration resulted in further increases in SPAD units only in some graft combinations. Data highlight the efficiency of Fe blood-compound in the prevention of grapevine Fe-deficiency over one growing season.

Resposta da alface à aplicação de biofertilizante sob dois níveis de irrigação

The use of biofertilizers is interesting for agriculture as being an economical alternative as well as it is environmentally friendly by using organic waste and reducing the application of mineral fertilizers. The aim of this study was to evaluate the effect of biofertilizer doses of bovine origin (biodigester effluent) applied on the ground and two levels of irrigation on lettuce. The experiment was conducted under protection of a greenhouse in pots, applying to the soil different doses of biofertilizer of bovine origin obtained from anaerobic reactor (10, 20, 40 and 60 m3 ha-1) and mineral fertilizer as a witness in two irrigation levels calculated at 50 and 100% of reference evapotranspiration. The lettuce plants were analyzed in their: Height, leaves number, crown diameter, fresh weight and dry weight of shoots. The biofertilizer treatments showed better results than the mineral fertilizer and has increased with increasing doses of biofertilizer, the highest dose (60 m3 ha-1) showed the best results in all variables. For dry, mineral fertilization showed higher values. The irrigation levels had no effect on plant growth.

Nitrogen and potassium concentrations in the nutrients solution for melon plants growing in coconut fiber without drainage

With the objective of evaluating the effects of N and K concentrations for melon plants, an experiment was carried out from July 1, 2011 to January 3, 2012 in Muzambinho city, Minas Gerais State, Brazil. The Bonus no. 2 was cultivated at the spacing of 1.1 × 0.4. The experimental design was a randomized complete block with three replications in a 4 × 4 factorial scheme with four N concentrations (8, 12, 16, and 20 mmol L-1) and four K concentrations (4, 6, 8, and 10 mmol L-1). The experimental plot constituted of eight plants. It was observed that the leaf levels of N and K, of N-NO3 and of K, and the electrical conductivity (CE) of the substrate increased with the increment of N and K in the nutrients' solution. Substratum pH, in general, was reduced with increments in N concentration and increased with increasing K concentrations in the nutrients' solution. Leaf area increased with increments in N concentration in the nutrients solution. Fertigation with solutions stronger in N (20 mmol L-1) and K (10 mmol L-1) resulted in higher masses for the first (968 g) and the second (951 g) fruits and crop yield (4,425 gm-2). © 2013 Luiz Augusto Gratieri et al.

Floral induction of mango 'Tommy Atkins' at submedio São Francisco Region, Brazil

Irregular production is a major problem in mango. In an attempt to overcome irregular bearing, effects of two antigibberellins on flowering were evaluated, uniconazole (0.25 g of active ingredient per meter of canopy tree diameter) and paclobutrazol (1.0 g of active ingredient per meter of canopy tree diameter). Treatments were applied as a soil drench using 2 L of solution per tree, in a commercial orchard of 'Tommy Atkins' mango. Treatments were applied after the second vegetative flush commenced, subsequent to pruning. Branch growth was evaluated every 30 days after treatment application up to a maximum period of 90 days. The flowering percentage was recorded at 130 days. Ammonium nitrate (NH4NO3) as a foliar spray (concentration of 0.75%) was applied five times at seven day intervals from 95 to 100 days after treatment application as a dormancy breaking treatment. It was found that both paclobutrazol (PBZ) and uniconazole (UCZ) significantly inhibited the development of vegetative growth compared to the control. Both treatments resulted in identical rates of flowering shoots, 87%; based on results, it can be concluded that the application of antigibberellins (PBZ and UCZ) inhibit vegetative development in mango 'Tommy Atkins', and promote high levels of flowering. Additional tests are being carried out in other farms to confirm these findings, for different cultivars and seasons. © ISHS 2013.

Inibidores de crescimento em gramados

Well-maintained lawns are comfortable and safe places for leisure activities and sports practice, and they also bring environmental benefits; for example, they reduce soil exposure to erosion and releases atmospheric CO2, thus reducing the greenhouse effect. However, regardless of the purpose of use or the choice of the plant species to form the lawn, the highest costs involve cutting that is needed to keep the turfgrass at its appropriate height. Successive lawn cutting operations are necessary basically because of the vegetative and reproductive growth of turfgrass which, in Brazil, occurs mainly from October to March. Expenditures with successive mechanical cuttings have fostered the search of alternative procedures to keep lawn plants at appropriate height, such as the use of plant growth inhibitors, an increasingly interesting procedure. Since the use of this technology in Brazil is still at its early stage, the aim of this literature review is to examine aspects associated with lawn management by using growth inhibitors. Another alternative is to increase the knowledge of the classification and rational application of the different compounds currently available in the market.