Abstract Photo-selective shading screens are emerging practices that aim to combine crop physical protection with different solar radiation filtration to achieve desired physiological responses. The ...objective of the present study was to evaluate the effect of photo-selective shading screens on the growth and physiology of purple lettuce for two transplanting seasons in tropical climate in Brazil. A 2 × 4 factorial arrangement was used, being considered the first factor, the transplanting season (spring and fall), and the second factor is the three 35% shading photo-selective shading screens (red, black and silver) and full sun control. The experimental design was a randomized complete block with four replications. The variables studied were: total fresh matter, total dry matter, leaf number, stem diameter, stem length, leaf area, SPAD chlorophyll index, nitrogen balance indexes, chlorophyll, flavonoids and anthocyanins. The photo-selective shading screens influenced the microclimate and the growth variables of purple lettuce, mainly when these plants were sown in the fall. Planting lettuce during spring may result in lower yields due to the higher investment of plants in secondary metabolites to defend against abiotic stress. According to the results, photo-selective shading screens are an appropriate agronomic technique to reduce phenolic compounds and improve lettuce cultivation conditions and can be implemented within protected cultivation practices to improve crop performance.
Tannery sludge has great potential for use in agriculture, however it is a potentially toxic waste, and it is necessary to establish the ideal dose for each crop. The objective of this study was to ...evaluate the influence of fertilization with liquid tannery sludge on growth, chlorophyll a fluorescence and gas exchange of Pennisetum purpureum in two production cycles. A 2 × 6 + 1 split plot scheme was used, where the first factor was composed of two productive cycles, the second factor different fertilizations doses: 0, 30, 70, 110, 150, 190 t ha
−1
of liquid tannery sludge and an additional treatment with nitrogen, phosphorus and potassium control. Plant height, number of leaves and tillers, canopy and stem diameter, leaf area, dry matter, chlorophyll index (SPAD), chlorophyll a fluorescence and gas exchange were evaluated. The highest production of total dry matter was observed in the second production cycle. The range between 72-100 t ha
−1
of liquid tannery sludge showed the greatest gains in growth and production of elephant grass. At doses above 150 t ha
−1
of liquid tannery sludge, the photochemical apparatus begins to show possible damage to the photosystem II (PSII) and reductions in gas exchange.
In vegetable production, seedling propagation is one of the most important steps as it directly influences the final performance of the plants. In order for such condition, the propagation substrate ...must be in good condition. The objective of this work was to evaluate the effect of different combinations of tannery sludge and urban waste compost as substrates in comparison to the commercial substrate Maxfértil
®
on the growth and quality of eggplant seedlings. The experiment was conducted in a greenhouse using a randomized block design with eight treatments and six replications. The commercial substrate was Maxfértil
®
, a crushed pine bark, with limestone, and seven treatments with increasing proportions of tannery sludge/decreasing urban waste compost (0/100; 10/90; 30/70; 50/50; 70/30; 90/10 and 100/0 v/v). Characteristics of emergence, growth, quality and leaf nitrogen (N) content were evaluated. No difference was found in the emergence of eggplant seedlings among the different treatments used; however, the growth characteristics, quality and N content featured significant effects when the seeds were propagated in alternative substrates. Regression adjustments pointed to an optimal range of 41-49% of tannery sludge associated with urban waste compost for the evaluated characteristics. The strong correlation between SPAD and N content shows its potentiality in detecting N deficiencies in seedlings. The use of tannery sludge residues associated with urban waste compost seems to be an appropriate and sustainable practice for recycling with high agronomic potential.
Chrysanthemum is one of the most beautiful flowers and probably the oldest plant grown commercially in different parts of the world. Chrysanthemum, like all other plants, is susceptible to attack by ...various pests and diseases. The use of silicon has been shown to minimize damage caused by insect and also increase shelf life. Thus, the objective of this work was to evaluate the effect of potassium silicate in pest resistance and postharvest longevity of chrysanthemum. The experiment was carried out in the experimental area of the Federal Institute of Education, Science and Technology of Espírito Santo - Itapina Campus, the treatments consisted of four doses of potassium silicate - Sifol® (2, 4, 6 and 8 mL L
−1
) and a control treatment without foliar application of potassium silicate applied to chrysanthemum cv. Zembla. Leaf application of potassium silicate reduced the incidence of cercosporiosis and thrips in chrysanthemum leaves. Chrysanthemum leaf and flower longevity increased when potassium silicate doses were applied. It is recommended for chrysanthemum cv. Zembla applications of 0.6 and 0.8 mL L
−1
potassium silicate.
The estimation of the reference evapotranspiration is fundamental in defining irrigation projects. However, an estimation using the standard equation requires climate variables that are difficult to ...measure and are not very accessible. Thus, the objective of this study was to calibrate and validate alternative methods to estimate evapotranspiration that use simple variables and to compare performance with the standard Penman-Monteith method for the municipality of Nova Venécia, Espírito Santo, Brazil. For this, a 12-year time series (2008-2019) of meteorological data from the Instituto Nacional de Meteorología was used. The standard FAO-56 Penman–Monteith method was used to evaluate alternative methods: Hargreaves and Samani, Benevides and Lopes, Linacre, Hamon and Camargo. Method performance was analyzed by correlation coefficient, Willmott index, root mean square of normalized error, and performance index. Calibration improved the statistical indices, increasing the performance of the Hargreaves and Samani, Benevides and Lopes, and Linacre methods to “very good” in the rainy season and to “intermediate” in the dry season. They were superior to the Hamon and Camargo methods, which continued to show “tolerable” to “very poor” performance in both periods.
Crop models are crucial in assessing the reliability and sustainability of soil water conservation practices. The AquaCrop model was tested and validated for maize productivity under the selected ...climate smart agriculture (CSA) practices in the rainfed production systems. The model was validated using final biomass (B) and grain yield (GY) data from field experiments involving seven CSA practices (halfmoon pits, 2 cm thick mulch, 4 cm thick mulch, 6 cm thick mulch, 20 cm deep permanent planting basins (PPB), and 30 cm deep) and the control (conventional practice) where no CSA was applied. Statistics for coefficient of determination (R2), Percent bias (Pbias), and Nash–Sutcliffe (E) for B and GY indicate that the AquaCrop model was robust to predict crop yield and biomass as illustrated by the value of R2 > 0.80, Pbias −1.52–1.25% and E > 0.68 for all the CSA practices studied. The relative changes between the actual and simulated water use efficiency (WUE) of grain yield was observed in most of the CSA practices. However, measured WUE was seemingly better in the 2 cm thick mulch, indicating a potential for water saving and yield improvement. Therefore, the AquaCrop model is recommended as a reliable tool for assessing the effectiveness of the selected CSA practices for sustainable and improved maize production; although, the limitations in severely low soil moisture conditions and water stressed environments should be further investigated considering variations in agroecological zones.
Currently, industries are increasingly concerned about the destination of their waste, and one of the solutions found may be the reuse of certain waste in the form of organic fertilizers. Thus, the ...aim of this work was to evaluate the growth and physiology of conilon coffee seedlings under foliar application of liquid tannery sludge as an alternative to fertilization. The experiment was conduced in a greenhouse. The experimental design was in randomized blocks, with eight replications and seven treatments, which consisted of different concentrations of tannery sludge (6.20, 8.80, 11.47, 14.10 and 17.60 mL of sludge tannery diluted in 1 L of water), a conventional treatment with urea and a control treatment using only water. Growth and physiological characteristics were evaluated through gas exchange, fluorometric analysis and color analysis using the Colorimeter. The conilon coffee seedlings fertilized with 14.10 and 17.60 mL L−1 showed a satisfactory growth pattern. The doses of tannery sludge used in this study did not promote changes in color analysis and indices obtained by fluorimetry, except for flavonoids, in which the highest dose promoted greater synthesis of this secondary metabolite. Doses below 14.10 mL L−1 promoted changes in gas exchange, however, leaf photosynthesis was only compromised with doses equal to or less than 8.80 mL L−1.
Some components found in the composition of the tannery sludge are nutrients for the plants; it can be considered an alternative source of fertilization as they have favorable agronomic ...characteristics. However, it is reported in some studies that the presence of chromium and sodium in this residue causes physiological and anatomical disturbances that inhibit the development of the plants. The objective of this study was to evaluate the influence of chromium and sodium on the physiology, anatomy, and development of Conilon coffee seedlings grown on substrates produced with tannery sludge and equivalent doses of chromium and sodium. The experiment was carried out in nursery using randomized block design, containing 5 treatments and 7 repetitions. The treatments consisted of the application of a 40% tannery sludge dose and equivalent doses of chromium and sodium mixed with a conventional substrate. Notably, the presence of sodium in the substrate caused greater damage to the plants, negatively influencing the physiology, anatomy, and, consequently, development of the plants, while the presence of chromium suggests that it does not influence much the evaluated characteristics. The treatment with tannery sludge, on the other hand, despite containing the same chromium and sodium contents, revealed a more pronounced negative influence on the physiology, anatomy, and development patterns of the seedlings. This shows that sodium and chromium alone are not the only factors responsible for the lowest growth indicators studied.
Modern agriculture values the most sustainable and dynamic means of production, which can be promoted through the association between coffee and tree components, aiming at the best use of the land. ...However, within our understanding of the physiological and biochemical behaviors of the coffee tree, the irradiance limiting conditions are crucial to maximize the potential gains generated in these systems. In this sense, the objective of this study was to evaluate the effects of different levels of irradiance restriction on the physiological and biochemical characteristics of two genotypes of Conilon coffee. The experiment was conducted in a 2 × 3 factorial scheme, corresponding to two Conilon coffee clones and three levels of light intensity restriction (0, 30 and 50%), in a randomized block design with four replications. The synthesis of total chlorophyll b and the leaf N content of the genotypes CL6 and CL12 increased with the reduction of light. On the other hand, there was a reduction in the levels of carbohydrates, amino acids and phenols with the reduction of light intensity. Restricted levels of irradiance caused different changes in the physiological and biochemical characteristics of the studied genotypes, showing genetic divergences between them.
Abstract Tannery sludge has been highlighted for substrate use in the propagation of seedlings, combining the solution of an environmental problem with its potential for agronomic use. However, when ...a new fertilizer component enters into the composition of a substrate, it remains to be seen whether other characteristics are affected. Thus, the objective of this work was to verify whether supplementary foliar fertilization is necessary when using a substrate with tannery sludge in the propagation of conilon coffee seedlings of the variety “Vitótria Incaper - 8142”. A 2×13 factorial arrangement was used, the first factor being the presence or absence of conventional leaf fertilization, and the second factor being the 13 coffee conilon Vitoria-Incaper 8142 genotypes arranged in a randomized complete block design with four replications. The genotypes V7 and V9 presented leaves of reduced size, leading to a smaller leaf area, which coincided with a lower accumulation of aerial and total dry matter mass. Higher flavonoid indexes were found in the genotypes V1, V2, V6, and V13, indicating a higher sensitivity of these materials to the components present in the tannery sludge. In general, fertilization provided better initial development as well as a better seedling quality index.
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