Dickson Quality Index Research Articles

Bentonite as substrate conditioner under different water regimes – A Eucalyptus dunnii seedling assay

The substrate has a lot of functions in the process to develop a high-quality seedling, including the responsibility to hold water and to make the water available for the plants. A compound that can be used to hold water is bentonite. So, the research aimed to evaluate the effects of different proportions of bentonite as a substrate component under two water conditions in the production of Eucalyptus dunniii seedlings. The research was carried out in the forest seedlings nursery in Curitiba/PR - Brazil. For the treatments, bentonite substrate conditioner was used in different proportions, 0 %, 5 %, 10 %, 15 % and 20 %, in a commercial substrate (with sphagnum peat) here named as S0, S5, S10, S15 and S20 respectively, in two water regimes for the blocks. The seedlings produced with these bentonite proportions was analyzed by the height, stem diameter, dry matter (shoot, root and total), and two parameters: height/stem diameter ratio (H/SD) and Dickson Quality Index (DQI). The substrate analysis shown a contrary behavior of expected. The bentonite in the substrate for seedlings of E. dunnii did not increase water holding capacity in a linear form and the high proportion of bentonite did not improve seedling in the lower water regime, although the 5 % of bentonite gave a good results of seedlings growth, so the purpose of bentonite in the substrate to improve water holder capacity and minimize the irrigation would not be fully attended.

Drill cuttings from oil exploration improve properties of substrate and growth of Ipê-branco ( Tabebuia roseoalba ) seedlings

ABSTRACT More information is needed on the potential of using drill cuttings (crushed rocks) from the oil industry in agriculture and forestry. An experiment in forest nursery was carried out to evaluate the influence of substrates formulated from onshore gravel on characteristics of Ipê-branco (Tabebuia roseoalba) seedlings (i.e., growth, quality, and nutrition). We used five gravimetric proportions of gravel from drill cuttings mixed with Pinus-bark - commercial substrate (Mecplant® Florestal 3): control with only commercial substrate and zero gravel (G0), 2.5 % gravel (G2.5), 5 % gravel (G5), 7.5 % gravel (G7.5), and 10 % gravel (G10). In general, high proportion of drill cuttings increases density and decrease current moisture and total porosity of the formulated substrates. The drill cuttings proportions G2.5, G5 and G7.5 significantly contributed to the available water and readily available water in these substrates, with percentage values ranging 23 – 30 % higher than the G10 substrate. Increasing the gravel proportion generally resulted in increased pH levels, P, Na, K and metals (Cu, Fe, Ni, Mn, Cd, Zn, Cr and Pb), except for Ca and Mg nutrients that decreased. Heavy metal contents in all substrates did not exceed the permissible values in legal standards. The G2.5 and G5 substrates increased by 20 % approximately the stem diameter and height of seedlings, and G2.5 proportion also affected the root dry mass and Dickson quality index, with values two times higher than G0 substrate. Multivariate analysis proved suitable as a complementary approach to evaluate the seedling quality. Drilling cuttings addition, in general, increased the accumulation of nutrients and heavy metals of the Ipê-branco seedlings, and G2.5 and G5 substrates provided the greatest accumulation of the nutrients P, Ca, Pb and Zn in the shoot, while G2.5 proportion contributed with higher accumulation of N, Ca, Fe, Cr, Mn and Pb in the root. Adding drill cuttings as a conditioning component of the substrate at 2.5 and 5 % proportions is a viable alternative for using this residue to produce high-quality Tabebuia roseoalba seedling.

Seedling Growth and Nutritional Status of Elaeagnus angustifolia and Robinia pseudoacacia as Response to Arbuscular Mycorrhizal Fungi and K-Humate

ABSTRACT This study aimed to reveal the effects of arbuscular mycorrhizae and K-humate on some of the morphological characteristics and growth of Russian olive (RO; Elaeagnus angustifolia L.) and black locust (BL; Robinia pseudoacacia L.). The indigenous mycorrhizal spores (Claroideoglomus claroideum, Claroideoglomus etunicatum, Claroideoglomus luteum, and Funneliformis mosseae) collected from rhizospheres of RO and BL trees in afforestation sites located in Central Anatolia. In addition, commercial mycorrhizal mixture and K-humate were used as treatments. Five treatments (1—indigenous mycorrhizal fungi, 2—K-humate, 3—indigenous mycorrhizal fungi + K-humate, 4—commercial mycorrhizal fungi, and 5—control) were assigned in a completely randomized design for both tree species. Four months after the treatments, inoculation rate, above-ground seedling height, fresh and dry weight, root collar diameter, length, fresh, and dry weight, leaf area index, shot-to-root dry weight ratio, seedling height to root collar diameter ratio, and Dickson quality index were determined. Plant and soil analyses were carried out to determine the effects of treatments on plant and soil nutrition. Indigenous arbuscular mycorrhizal fungi and K-humate combinations had positive effects on the morphological characteristics and nutritional status of the seedlings. The indigenous mycorrhizal and K-humate interaction showed the most pronounced effects on RO growth and nutrition.

Potentiating Chlorella vulgaris bioinput as a growth biostimulant in the production of basil seedlings with the addition of vitamin B3

Microalgae have been studied due to their biotechnological potential in agriculture and could be an important source of biostimulants. Similarly, other compounds, such as B3 vitamins (niacin and nicotinamide), have been found to enhance the biostimulant effect on plant growth. This study aimed to evaluate the potentiating effect of Chlorella vulgaris bioinput as a growth biostimulant in the production of basil seedlings (Ocimum basilicum L.) with the addition of vitamin B3. The experiment was conducted in a protected environment on the Mato Grosso do Sul State University - Cassilândia University Unit and the Sustainable Development Center of the Bolsão Sul Mato Grossense. The experiment was conducted in a completely randomized design, with four treatments: control, microalgae bioinput (Bio), vitamin B3 (niacin + nicotinamide), and joint application of Bio + vitamin B3, with four replications. The agronomic traits of growth and photosynthetic pigments of the seedlings were evaluated. For the growth of basil seedlings, applying bio input combined with vitamin B3 had a significant impact (p < 0.05) on several variables. This combination increased seedling height, stem diameter, root dry matter, shoot dry matter, total dry matter, and Dickson quality index (DQI) by 19 %, 11 %, 11 %, 41 %, 37 %, and 17 %, respectively, as well as regulating the production of photosynthetic pigments in basil. The results indicate that bioinput combined with niacin and nicotinamide stimulates various plant growth traits, favoring the production of seedlings.

The Influence of Logging-Related Soil Disturbance on Pioneer Tree Regeneration in Mixed Temperate Forests.

The recovery of soil properties and the proper growth of natural tree regeneration are key elements for maintaining forest productivity after selective logging operations. This study was conducted on the soil properties and natural growth of two pioneer seedling species of alder and maple which were on skid trails in the mixed beech forests of northern Iran. To examine the long-term effects, we randomly selected six skid trails, with two replicates established for each of three time periods since last use (10, 20, and 30 years ago). Random plots 4 m × 10 m in size, three plots on each skid trail and six plots on areas without soil compaction (control), were selected. Measurements included the physical and chemical properties of the soil and the growth, and the architectural and qualitative characteristics of the seedlings. The results showed that all the soil properties of the 10- and 20-year-old skid trails were significantly different from the control area (except for the soil moisture in the 20-year-old skid trail). The 30-year-old skid trail showed values of other soil properties which were not significantly different from the control area, except for the amounts of organic matter and soil nitrogen, which was less than the control. The skid trails had a negative effect on all of the growth, qualitative, and architectural indices of seedlings. The characteristics of seedlings were related to soil characteristics and had the highest correlation with the soil penetration resistance (R-value from -0.41 to -0.63 for stem growth, p < 0.05; -0.57 to -0.90 for root growth, p < 0.01; and -0.76 to -0.86 for biomass, p < 0.01). The correlation coefficient between soil penetration resistance and the Dickson quality index of alder and maple seedlings was, respectively, -0.74 and -0.72, p < 0.01. The negative effect of soil compaction on root growth (-27.69% for alder seedlings and -28.08% for maple seedlings) was greater than on stem growth (-24.11% for alder seedlings and -16.27% for maple seedlings). The amount of growth, qualitative, and architectural indices of alder seedlings were higher than that of maple seedlings. Although alder is a better choice as compared to maple seedling in the initial year, the results of our study show that it is recommended to plant both alder and maple on skid trails after logging operations.

QUALITY OF BRAZILIAN SPINACH SEEDLINGS (Alternanthera sessilis (L.) R.Rr. ex DC.) IN REGIONAL SUMMAÚMA SUBSTRATE

The use of unconventional food plants is an alternative for diversification and promotion of food sovereignty. The objective of this work was to evaluate the quality of spinach seedlings from the Amazon produced in samaúma substrate as conditioner. The experiment was carried out in a greenhouse in the experimental garden of the Federal University of Acre, from November to December 2022. The experimental design was completely randomized, with three treatments and 30 repetitions, totaling 90 experimental units. The treatments were 3 substrates, as follows: T1 - Commercial substrate; T2 -commercial substrate + samaúma substrate (1:1) and T3 – samaúma substrate. At 30 days of cultivation, the following variables were evaluated: leaf length, leaf width, seedling height, stem diameter, total number of shoots, total number of leaves, number of leaves per shoot, root length, fresh mass of the part aerial part, fresh mass of roots, dry mass of aerial part, dry mass of roots, total fresh mass, total dry mass and the Dickson quality index was calculated. The combination of the commercial substrate with the samaúma substrate (1:1) is an alternative for the production of spinach seedlings from the Amazon.

Protected cultivation and water salinity in the formation of Erythrina velutina Willd seedlings

Protected cultivation can reduce the harmful effects of salt stress on the development of plant species. The objective of this study was to evaluate the growth and morphophysiological responses of E. velutina seedlings grown under saline stress in two growing environments. The experiment was conducted in an experimental area belonging to the Federal University of Ceará, in Fortaleza, Ceará. The experimental design was entirely randomized in subdivided plots, where the plots were represented by the growing environments (closed-screen greenhouse - CSG and open-sided greenhouse chapel - OSG), the subplots by the irrigation waters (0.8 and 5.0 dS m-1) and in the subplots the collection seasons (20, 40, 60 and 80 DAS), with four replications. Saline stress inhibited the growth of E. velutina seedlings in terms of height, leaf area, number of leaves and dry mass of the aerial part, but provided greater root dry mass throughout the growing season. It also affected gas exchange after 50 days of cultivation. The seedlings grown in the open shade environment on the sides and with lower salinity water had a higher Dickson quality index.

Seedling development of Schizolobium parahyba var. amazonicum inoculated with Rhizoglomus clarum in different doses of phosphorus

This work aimed to evaluate the growth and phosphorus uptake of Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby (pinho-cuiabano) seedlings inoculated with Rhizoglomus clarum (T.H.Nicolson &amp; N.C.Schenck) Sieverd., G.A.Silva &amp; Oehl at different doses of phosphorus. The treatments consisted of five levels of phosphorus (0, 25, 50, 100 and 200 mg dm-³) and inoculation or not with R. clarum. After 45 days of seedling inoculation, we analyzed: height, root fresh and dry matter, shoot fresh and dry matter, number of leaves, survival, stem diameter, root volume, Dickson quality index, mycorrhizal colonization, relative water content, leaf tissue density, phosphorus content, efficiency of phosphorus uptake and efficiency of phosphorus utilization. Inoculation with R. clarum and the lowest doses of phosphorus resulted in lower seedling mortality rates. R. clarum did not increase the phosphorus content, efficiency of phosphorus uptake, efficiency of phosphorus utilization, relative water content and the Dickson quality index of the seedlings, but it was efficient in increasing the shoot fresh and dry matter as well as leaf tissue density. Inoculation with R. clarum and phosphate fertilization had a significant joint effect on seedling height and root fresh matter. Thus, it can be concluded that R. clarum may represent an important sustainable technology for the production of pinho-cuiabano seedlings, increasing seedling growth, even at low levels of phosphate fertilization.

Brackish water and organic matter in the substrate for the growth and quality of oiticica seedlings

Oiticica is a forest species endemic to the semi-arid regions of Brazil, where the salinity water has caused reductions in the quality of seedlings, including oiticica. The objective of this study was to evaluate the effects of the proportion of organic matter in the substrate on the growth and quality of oiticica seedlings irrigated with brackish water. The experiment was conducted in a randomized complete block design, in a 4 × 2 factorial, with four proportions: organic matter to mineral soil ratios of 0:1, 1:1, 2:1 and 3:1 and two irrigation treatments. non-saline (0.5 dS m-1) and brackish water (4.5 dS m-1) water. Biomass characteristics and Dickson Quality Index were evaluated. Elevated irrigation water salinity compromised the biometric growth, dry mass accumulation, and the quality of oiticica seedlings. The addition of organic compound to the substrate is limited to the formation of oiticica seedlings.

Production of high-quality seedlings of Handroanthus spongiosus (Bignoniaceae), native to a seasonally dry tropical forest

Studies of the use of alternative substrates have enabled producing seedlings of various species with high quality and low cost. The objective of this work was to evaluate the best cultivation conditions for production of Handroanthus spongiosus seedlings. The seeds were collected from five different populations in the state of Pernambuco, Brazil, and cultivated in six substrates: soil, sand, soil + vermiculite, soil + goat manure, soil + vermiculite + goat manure, and soil + goat manure + 30% biochar. We evaluated the emergence, shoot and root length, stem base diameter, shoot and root dry mass, and Dickson quality index. The substrates with addition of organic matter favored increased shoot length, stem diameter and dry mass. The incorporation of goat manure and biochar in the substrates favored the quality of the H. spongiosus seedlings.

Initial Growth of Red Tent Seedlings (Adenanthera Pavonina l.) In Soil Enriched with Different Doses and Nitrogenous Sources

Purpose: To evaluate the initial growth of red tent seedlings in different doses and sources of N. Theoretical framework: Based on scientific articles found on search engines and books in the area of soil fertility and plant nutrition. This is to support the explanation of how the morphological characteristics of seedlings, which explain their growth, are affected by nitrogen fertilization, depending on the dose and source of fertilizer applied. Method: The experiment was carried out in a completely randomized design with five doses of N and five replications, using urea and ammonium sulfate as sources, which were evaluated separately. The doses tested were: T0 – without addition of N; T1 – 50 mg dm-3; T2 – 100 mg dm-3; T3 – 150 mg dm-3; T4 – 200 mg dm-3, for each source tested. At the end of 90 days, the morphological characteristics of the seedlings were evaluated: height, diameter, height/diameter ratio, dry mass of the aerial part, dry mass of the root part, aerial dry mass/root dry mass ratio, height/aerial dry mass ratio and, Dickson quality index. Results and conclusion: Growth, dry mass production and seedling quality were greater at a dose of 200 mg dm-3 when using urea as a source of N. When the source was ammonium sulfate, the greatest growth in height occurred at a dose of 100 mg dm-3, however, the greatest growth in diameter, the greatest production of dry mass and quality, were observed at a dose of 200 mg dm-3. This is the recommended dose for the species studied. Research implications: These results indicate that nitrogen fertilization is essential for the quality growth of red seedlings, and the dose to be applied is essential for this to happen, since values lower than this dose may not allow the plant to perform at its maximum. growth potential. Meanwhile, higher doses do not guarantee greater growth and will result in unnecessary expenses and, probably, loss of growth due to toxicity. Originality/value: Using nitrogen fertilizers, in the correct dose for the species, increases its growth potential and guarantees the production of quality seedlings within the nursery.

Nursery Cultivation Strategies for a Widespread Mangrove (Kandelia obovata Sheue &amp; al.): Evaluating the Influence of Salinity, Growth Media, and Genealogy

Mangrove plant seedling cultivation is crucial for the protection, management, and restoration of the mangrove ecosystem. In this study, we focused on Kandelia obovata Sheue &amp; al., a typical mangrove, and evaluated nursery cultivation with different combinations of three salinity levels (S1: 0 ppt, S2: 10 ppt, and S3: 20 ppt), three genealogies (EZD, JX, and YZ), and five growth media (M1: 100% loess, M2: 100% sandy, M3: 50% loess + 50% sandy, M4: 40% loess + 40% sandy + 20% peat, and M5: 40% loess + 40% sandy + 20% coir), by measuring the growth parameters such as mortality rate, seedling height, seedling diameter, and biomass partition. These growth indexes were significantly affected by salinity and medium, and genealogies also had significant effects on mortality rate and biomass accumulation. S2 or S3 both had lower mortality and higher growth indexes than S1. M1 was the medium that increased seedling height, diameter, and biomass the most and had the lowest death rate. EZD and JX were also at higher levels than YZ in these indicators, but the difference between them was not obvious. S3, M1, and EZD consistently performed well in fuzzy evaluation and quality assessment (Dickson quality index: 1.179, 1.478, and 1.089, respectively). Furthermore, combinations involving these treatments also produced highly favorable results. This indicates that the quality of seedlings produced under these conditions was high. These results furnish both a theoretical and practical foundation for advancing nursery cultivation techniques and germplasm breeding of K. obovata in mangroves.

Effect of sowing density on performance and biometric features of pedunculate oak

Sowing density is one of the most important factors influencing seedling quality. In forest nurseries, to ensure full seeding, it is recommended to obtain approximately 200 seedlings from 1 m2 (ZHL 2012). The aim of the study was to assess the effect of sowing density on sowing efficiency and the morphological features of pedunculate oak seedlings. Acorns were sown directly by broadcast seeding on 20 test plots, each 4 m in length, in four replications. The following variants were used:- 250acorns capable of germination totaling 341 acorns per 1 linear meter (0.9 m2);- 300 acorns capable of germination totaling 410 acorns per 1 linear meter (0.9 m2);- 350 acorns capable of germination totaling 478 acorns per 1 linear meter (0.9 m2);- 400 acorns capable of germination totaling 546 acorns per 1 linear meter (0.9 m2);- 450 acorns capable of germination totaling 614 acorns per 1 linear meter (0.9 m2). At the end of the growing season, seedlings were counted per 1 m (0.9 m2) in the central part of each plot. Sowing efficiency was determined as a percentage of seedling yield from the sown seeds. For laboratory analysis, 30 seedlings from each plot (600 in total) were collected. Based on biometric features like shoot height, root collar diameter, and dry weights of shoots, roots, and leaves, quality indicators such as the sturdiness quotient (SQ) and the Dickson quality index (DQI) were calculated. Sowing efficiency at the end of the vegetation season ranged between 39.68% and 50.12% and was not statistically significant. The research revealed that sowing density influenced seedling biometric characteristics. Pearson’s correlation coefficients showed significant negative correlations between the number of seedlings obtained in an experimental plot and the dry weight of the root, number and dry mass of leaves, as well as the DQI. The seedlings from all sowing variants complied with the binding Polish standard, outlined in the Regulation of the Minister for the Environment of 18 February 2004 (Ministerstwo Środowiska 2004) by over 96%. Keywords: seeding density, sowing rate, seedling quality, sowing performance, sturdiness quotient (SQ), Dickson quality index (DQI), Quercus robur L.

Silicon Mitigates the Attack of Pests and Diseases on Ipê-Roxo (Handroanthus impetiginosus) Seedlings

Abstract Background Silicon in plants is a structuring element that promotes water and saline stress tolerance and decreases transpiration. The silica accumulated in the cuticle establishes a physical barrier and helps fight against pests and diseases. The present study aimed to evaluate the development of ipê-roxo (Handroanthus impetiginosus) seedlings in different environments, and the application of potassium silicate and its efficiency in mitigating the attack of pests and diseases. Methods The experiment was carried out in an agricultural greenhouse and under full sun with silicic doses of 0 and 7.15 mg per plant in a completely randomized design arranged in a 2 × 2 factorial scheme, with 6 replications of 4 seedlings per plot. Plant height, chlorophyll, stem diameter, number of leaves, shoot dry matter, root dry matter, total dry matter, height-diameter ratio, root-shoot ratio, root-plant ratio, Dickson quality index, disease severity, and pest intensity were evaluated. Results Silicon application did not confer biometric qualities to the seedlings. The application of silicon conferred 24.6% higher protection against disease severity at a 90% probability level. The protected environment promoted 48.8% more protection against the attack of pests on the seedlings. The silicon application decreases the intensity of pests in the protected environment by 36.3%. Seedlings in a protected environment increase the production of chlorophyll but are 29.6% more susceptible to the severity of diseases. The full sun promoted greater diameters, phytomass, and Dickson quality index by 18%, 73%, and 195%, respectively. Conclusions The bestHandroanthus impetiginosusseedlings were obtained under full sun. Silicon mitigated the attack of pests and diseases onHandroanthus impetiginosusseedlings.

Initial seedling development of Tectona grandis L. f. under different substrates and shading level

The management of nurseries poses a delicate task within a forest seedling production system, where quality is paramount for successful cultivation. Seedlings serve as the initiation point in the production process, exerting subsequent impacts on plant performance in the field. This study aimed to evaluate the production of Tectona grandis seedlings under varying shading levels and substrates. Six shading levels (0%, 18%, 35%, 50%, 70%, and 80%) and two substrates (Vivatto Slim Plus® and 50% Vivatto Slim Plus® + 50% sand) were stipulated. The experimental design was completely randomized with four replications of ten plants; each shading level was considered as one experiment. Seedling emergence, stem diameter, length of the largest root, height of aerial part, total length, fresh and dry biomass of aerial part and root systems, total dry biomass, and Dickson's quality index were evaluated. Direct exposure to sunlight negatively impacts the development of Tectona grandis seedlings, with 18% shading recommended. The commercial substrate Vivatto Slim Plus® proved suitable for the production of higher-quality seedlings.

Water depletion on substrate and soil conditioner doses in the yellow passion fruit seedling formation

The cultivation of passion fruit requires constantly updated technical information to achieve competitive results. In this context, a commonly discussed aspect is the development of vigorous seedlings. The aim of this study was to assess water depletion levels in a substrate (WDL) and TerraCottem® doses for the formation of yellow passion fruit seedlings. The experimental design used was split plots in a completely randomized design, with four replications. The treatments consisted of 5, 15, 25, 35% of NDA and 0, 2.5, 5.0, 7.5, and 10.0 kg m-3 of TerraCottem® doses. The following variables were measured: plant height (PH), stem diameter (SD), number of leaves (NL), dry biomass of the aerial part (DSB), root system (DRS), total dry biomass (TDM), and the Dickson Quality Index (DQI) was calculated. WDL treatments did not influence the evaluated variables. NL, PH, SD, DSB, DSR, TDM, and DQI showed increases of 12.3, 13.4, 10.0, 30.1, 28.1, 29.5, and 26.8%, respectively, when comparing the highest TerraCottem® dose to the control treatment. Sliced interaction showed double gains for the highest TerraCottem® dose for SD and PH. The plants responded to higher doses of TerraCottem®, indicating synergy of the water-retaining polymer in the plant's water supply, especially in the presence of higher WDL.

MORPHOPHYSIOLOGICAL CHANGES IN SEEDLINGS OF Eugenia uniflora L. AFTER CHEMICAL HARDENING

Using quality seedlings increases the chances of survival and development after planting. Hardening aims to modify the morphology of seedlings to acclimatize them to stressful field conditions. The objective of this study was to quantify the effects of chemical hardening with methyl jasmonate on the morphophysiology of Eugenia uniflora L. seedlings subjected to 12 days of water deficit. Seedlings were hardened with doses of 0, 50, 100, and 150 μmol L-1 of methyl jasmonate (MeJA). Afterward, they were transplanted into pots with soil and subjected to water deficit for 12 days. During that period, we assessed shoot height (H), stem diameter (SD), leaf area (LA), leaf dry mass (LDM), stem dry mass (SDM), root dry mass (RDM), total dry mass (TDM), relative water content (RWC), robustness index (RI), Dickson quality index (DQI), shoot/root ratio (S/R), stomatal conductance (Sc) and evapotranspiration (ET). The experiment was conducted in a randomized block design with five blocks. Variables RI, DQI, LA, RWC, and TDM values presented a quadratic trend, with promising results from the 50 and 100 µmol L-1 doses. Sc and ET values were influenced by water deficit. Under conditions of water restriction, application of MeJA in adequate doses promoted morphophysiological changes and induced defense strategies in E. uniflora seedlings. Doses of methyl jasmonate between 50 and 100 µmol L-1 resulted in seedlings with greater tolerance to water deficit for 12 days.

Composted Sewage Sludge as a Substrate for Commercial Seedlings of Peltophorum dubium (Spreng.) Taub.

Sewage sludge in natura is rich in nutrients, water, and organic matter and is essential for plant development. However, sewage sludge is diluted with water when composted, which could hamper plant growth. Therefore, supplementation with chemical fertilization may be necessary. This study evaluated the performance of composted sewage sludge (CSS) in producing Peltophorum dubium (Spreng.) Taub. seedlings with and without chemical fertilization via fertigation. The experiment was completely randomized in a 3 × 4 factorial scheme, with four fertigation (Ca(NO3)2(H2O)x: 0.87; (NH4)(H2PO4): 0.21; KCl: 0.47; (NH4)2SO4: 0.11; CH₄N₂O: 0.54; MgSO4: 0.52; Fe (13%): 0.03; B(OH)3: 6.00; CuSO4: 0.60; ZnSO4: 1.40; MnSO4: 6.00; Na2MoO4: 0.16 g L−1) doses: zero, standard, duplicate, and quadruplicate. In addition, three substrates were used: commercial substrate as the control, sewage sludge composted with sugarcane bagasse (LBC), and sewage sludge composted with Eucalyptus bark (LCE). The development of the seedlings was measured through the following variables: height, stem diameter, shoot/root ratio, leaf dry mass, root dry mass, total dry mass, green color index, the Dickson Quality Index, and the accumulation of nutrients in plant tissue. The seedlings produced with LCE that were subjected to the standard dose (1×) and the quadruplicate dose (4×) had the statistically highest mean values for most variables. Nevertheless, supplementation with chemical fertilization was necessary. Composted sewage sludge with eucalyptus bark, at the standard dosage, can be used for the commercial production of P. dubium seedlings, thus preventing the dangerous disposal of waste and strongly decreasing associated environmental hazards.

Efficiency of organomineral fertilizer and doses of Azospirillum brasilense on the morphophysiological quality of Mezilaurus itauba seedlings.

The present study was conducted to determine the efficiency of organomineral fertilizer from cupuaçu residues (ORFCup) and dose of maximum technical efficiency of Azospirillum brasilense on the initial growth and morphophysiological quality of Mezilaurus itauba seedlings in the northern Amazon. The variables evaluated were: shoot height (H, cm), stem diameter (SD, mm), shoot dry mass (SDM, g plant-1), root dry mass (RDM, g plant-1) total dry mass (TDM, g plant-1), Dickson quality index (DQI), net assimilation rate (NAR, g m-2 day-1), leaf relative growth rate (RGR, g m-2 day-1), leaf area ratio (LAR, m2 g-1), leaf relative growth rate (RGR, g m-2 day-1), leaf area ratio (LAR, m2 g-1), specific leaf area (SLA, cm2 g-1), and leaf mass ratio (LMR, g g-1). Organomineral fertilizer from cupuaçu residues promotes better quality and robustness in M. itauba seedlings at the dose of maximum technical efficiency of 0.45 mL. L-1 of A. brasilense.

Polímero hidroabsorvente na produção de mudas de sabiá sob diferentes turnos de rega

ABSTRACT Mimosa caesalpiniifolia Benth is an arboreous species native to the Caatinga commonly utilized for restoration of degraded areas. One factor that can affect its development is water shortage. This denotes the importance of searching for alternatives for improving these plant's tolerance to water shortage, such as the use of water-absorbing polymers known as hydrogels. In this context, the objective of this study was to evaluate the production of M. caesalpiniifolia seedlings under different hydrogel rates and water regimes. The experiment was conducted at the Forest Nursery of the Federal University of Campina Grande, Patos, PB, Brazil. Seeds were sown in 2-liter pots made from halved polyethylene terephthalate bottles, containing a substrate consisted of soil and cattle manure (2:1 v v-1). A completely randomized design with four replications was used, in a 4×2 factorial arrangement consisted of four hydrogel rates in the substrate (0, 1, 2, and 3 g L-1) and two water regimes (daily irrigation and irrigation every 2 days). The following parameters were evaluated at the end of the experiment (75 days after sowing): number of leaves per plant, stem base diameter, plant height, root length, shoot and root dry weights, water relative content, chlorophyll content, gas exchanges, and Dickson quality index. Most of parameters presented no statistically significant difference; however, the hydrogel rate of 2 g L-1 resulted in increased production of M. caesalpiniifolia seedlings, whereas the absence of hydrogel resulted in longer roots, regardless of the water regime.