cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14320329
title: Numerical-experimental comparison of radial fans applied in pneumatic transport of agricultural fertilizer spreaders

description: ABSTRACT This study presents a numerical and experimental comparison of two different types of radial fans used in an agricultural fertilizer spreader at a rotation of 4000 rpm. The numerical analysis was validated through experiments conducted on a test bench using a hot-wire anemometer for velocity measurements and a Pitot tube for pressure readings. A simulation of the agricultural fertilizer spreader was carried out after the experimental validation of the mathematical models of the radial fans on the test bench to evaluate the air distribution behavior along the application nozzles, which was compared to the experimental results. A turbulent mean-field was obtained using the Reynolds Averaged Navier Stokes (RANS) and the k-Epsilon turbulence model was used for two equations. The computational fluid dynamics software CFX 18.1 was used to solve the transport equations. Unstructured tetrahedral meshes generated by the ICEM CFD 18.1 software were used in all models. The applied method is adequate and able to reproduce the fluid-dynamic behavior of airflow in pneumatic systems of agricultural fertilizer spreaders, avoiding the need for prototypes.
DOI: 10.6084/m9.figshare.14320330
title: Nutritional balance and recovery rate of macronutrients by ‘Gigante’ cactus pear under different fertilizations

description: ABSTRACT The objective of this study was to evaluate nutrient export, nutritional balance and macronutrient recovery rate in ‘Gigante cactus pear under different fertilization doses, spacings and configurations during three production cycles. The 72 treatments were arranged in a randomized block design with three repetitions, two configurations in the plots (triple and quadruple row), three spacings in the subplots (3.00 x 1.00 x 0.25 m; 3.00 x 1.00 x 0.16 m and 3.00 x 1.00 x 0.125 m); and 12 types of fertilization in the sub-subplots (with organic, organomineral and mineral sources). Exports of nutrients are higher under fertilizers with higher nutrient supplies, regardless of source. The order of export was K &gt; Ca &gt; N &gt; Mg &gt; S &gt; P for mineral fertilization, organic fertilization with 30 Mg ha-1 year-1 and organomineral fertilization with 30 and 60 Mg ha-1 year-1 plus NPK and PK, and it changed to K &gt; Ca &gt; N &gt; Mg &gt; P &gt; S under organic fertilization with 60 and 90 Mg ha-1 year-1 and organomineral fertilization with 90 Mg ha-1 year-1 plus K. The nutrient balance after three production cycles was positive for N, P and S, negative for Ca and Mg in all fertilizations, and positive for K under mineral fertilization with 600 kg ha-1 of K2O and organomineral fertilization with 30, 60 and 90 Mg ha-1 year-1 plus 600 kg ha-1 of K2O. The highest recovery rates of K and the lowest recovery rates of N occur under organic fertilization.
DOI: 10.6084/m9.figshare.14320330.v1
title: Nutritional balance and recovery rate of macronutrients by ‘Gigante’ cactus pear under different fertilizations

description: ABSTRACT The objective of this study was to evaluate nutrient export, nutritional balance and macronutrient recovery rate in ‘Gigante cactus pear under different fertilization doses, spacings and configurations during three production cycles. The 72 treatments were arranged in a randomized block design with three repetitions, two configurations in the plots (triple and quadruple row), three spacings in the subplots (3.00 x 1.00 x 0.25 m; 3.00 x 1.00 x 0.16 m and 3.00 x 1.00 x 0.125 m); and 12 types of fertilization in the sub-subplots (with organic, organomineral and mineral sources). Exports of nutrients are higher under fertilizers with higher nutrient supplies, regardless of source. The order of export was K &gt; Ca &gt; N &gt; Mg &gt; S &gt; P for mineral fertilization, organic fertilization with 30 Mg ha-1 year-1 and organomineral fertilization with 30 and 60 Mg ha-1 year-1 plus NPK and PK, and it changed to K &gt; Ca &gt; N &gt; Mg &gt; P &gt; S under organic fertilization with 60 and 90 Mg ha-1 year-1 and organomineral fertilization with 90 Mg ha-1 year-1 plus K. The nutrient balance after three production cycles was positive for N, P and S, negative for Ca and Mg in all fertilizations, and positive for K under mineral fertilization with 600 kg ha-1 of K2O and organomineral fertilization with 30, 60 and 90 Mg ha-1 year-1 plus 600 kg ha-1 of K2O. The highest recovery rates of K and the lowest recovery rates of N occur under organic fertilization.
DOI: 10.6084/m9.figshare.14320332
title: Reducing sugarcane irrigation demand through planting date adjustment in Alagoas State, Brazil

description: ABSTRACT Sugarcane is both an important crop for the Brazilian Northeast economy, which faces severe water scarcity, and a water-intensive crop. Thus, it is important to develop irrigation strategies to reduce irrigation water demand in the region. This study aims to determine the sugarcane planting date that results in the maximum rainwater availability to the crop in the growing cycle. The crop effective precipitation was estimated from a soil water balance performed during three planting cycles of sugarcane, cultivar ‘RB 92579’. The crop was planted under subsurface drip irrigation in five months: October, November, December, January, and February, corresponding to the dry season period of the region. The experiment was conducted at the Açúcar e Álcool Coruripe Mill, located in the Coruripe municipality, State of Alagoas, Brazil, during the years 2012 to 2016. For all planting dates and growing cycles studied, the average effective rainy precipitation was equal to 30% of the total rainfall under irrigated conditions and 54.5% without considering the irrigation component in the soil water balance. November was the planting date that resulted in the minimum irrigation depth for the sugarcane growing cycle, with the potential irrigation water saving ranging from 5 to 129 mm.
DOI: 10.6084/m9.figshare.14320332.v1
title: Reducing sugarcane irrigation demand through planting date adjustment in Alagoas State, Brazil

description: ABSTRACT Sugarcane is both an important crop for the Brazilian Northeast economy, which faces severe water scarcity, and a water-intensive crop. Thus, it is important to develop irrigation strategies to reduce irrigation water demand in the region. This study aims to determine the sugarcane planting date that results in the maximum rainwater availability to the crop in the growing cycle. The crop effective precipitation was estimated from a soil water balance performed during three planting cycles of sugarcane, cultivar ‘RB 92579’. The crop was planted under subsurface drip irrigation in five months: October, November, December, January, and February, corresponding to the dry season period of the region. The experiment was conducted at the Açúcar e Álcool Coruripe Mill, located in the Coruripe municipality, State of Alagoas, Brazil, during the years 2012 to 2016. For all planting dates and growing cycles studied, the average effective rainy precipitation was equal to 30% of the total rainfall under irrigated conditions and 54.5% without considering the irrigation component in the soil water balance. November was the planting date that resulted in the minimum irrigation depth for the sugarcane growing cycle, with the potential irrigation water saving ranging from 5 to 129 mm.
DOI: 10.6084/m9.figshare.14320333
title: Rhizobacteria inoculation in maize associated with nitrogen and zinc fertilization at sowing

description: ABSTRACT Rhizobacteria have a wide range of plant growth-promoting mechanisms of action, making them an alternative and/or complementary biological input for chemical fertilizers. In this respect, the present study aimed to assess growth and nitrogen accumulation in maize plants as a function of Azospirillum brasilense, Bacillus subtilis, zinc and nitrogen application at sowing. The experiment with the ‘AL Bandeirante’ maize variety was conducted in a greenhouse, using a completely randomized design. The treatments were arranged in a 2 x 2 x 2 x 2 factorial scheme, with six repetitions, considering the presence and absence of Azospirillum brasilense (5 g kg-1), Bacillus subtilis (5 mL kg-1) and zinc (20 g kg-1) in the seeds and addition or not of nitrogen (30 kg ha-1) to the soil. The variables assessed were plant height, stem diameter, leaf, stem, shoot, root and total dry weight, and shoot nitrogen content. Nitrogen fertilization in the absence of zinc increased shoot and total dry weight as well as shoot nitrogen content. Zinc applied to the seeds improved the total and stem dry weight of maize plants in the absence of Bacillus subtilis. Inoculation with Azospirillum brasilense and Bacillus subtilis increased the stem diameter and shoot nitrogen content of maize plants when nitrogen fertilization was not performed at sowing. There was no isolated or interaction effect between factors for plant height and root dry weight.
DOI: 10.6084/m9.figshare.14320333.v1
title: Rhizobacteria inoculation in maize associated with nitrogen and zinc fertilization at sowing

description: ABSTRACT Rhizobacteria have a wide range of plant growth-promoting mechanisms of action, making them an alternative and/or complementary biological input for chemical fertilizers. In this respect, the present study aimed to assess growth and nitrogen accumulation in maize plants as a function of Azospirillum brasilense, Bacillus subtilis, zinc and nitrogen application at sowing. The experiment with the ‘AL Bandeirante’ maize variety was conducted in a greenhouse, using a completely randomized design. The treatments were arranged in a 2 x 2 x 2 x 2 factorial scheme, with six repetitions, considering the presence and absence of Azospirillum brasilense (5 g kg-1), Bacillus subtilis (5 mL kg-1) and zinc (20 g kg-1) in the seeds and addition or not of nitrogen (30 kg ha-1) to the soil. The variables assessed were plant height, stem diameter, leaf, stem, shoot, root and total dry weight, and shoot nitrogen content. Nitrogen fertilization in the absence of zinc increased shoot and total dry weight as well as shoot nitrogen content. Zinc applied to the seeds improved the total and stem dry weight of maize plants in the absence of Bacillus subtilis. Inoculation with Azospirillum brasilense and Bacillus subtilis increased the stem diameter and shoot nitrogen content of maize plants when nitrogen fertilization was not performed at sowing. There was no isolated or interaction effect between factors for plant height and root dry weight.
DOI: 10.6084/m9.figshare.14320335.v1
title: Application of biostimulants in tomato subjected to water deficit: Physiological, enzymatic and production responses

description: ABSTRACT The objective of this study was to evaluate the effect of the application of the biostimulants Seed+ and Crop+ on physiological and production variables and on the activity of antioxidant enzymes (superoxide dismutase - SOD and guaiacol peroxidase - POD) in tomato plants subjected to two soil water conditions. The experiment was carried out in a greenhouse, in a 2 x 2 x 6 factorial scheme, with two times of application of the biostimulants (flowering and fruiting), two soil water conditions (50 and 100% of soil water holding capacity) and six biostimulants (control treatment; Seed+; Seed+ + Crop+ 1x; Seed+ + Crop+ 2x; Crop+ 1x; + Crop+ 2x). The exprimental design was completely randomized, with four repetitions. The biostimulants Seed+ and Crop+ increased the quantum yield of photosystem II (Fv/Fm), regardless of the time of application and water condition of the soil. The biostimulants Seed+ + Crop+ 2x and Crop+ 2x stood out in the pre-morning period, with an average Fv/Fm of 0.813, under the conditions tested. The highest SOD activity (372.12 U mg-1 of protein) was obtained with Crop+ 2x biostimulant in fruiting and under water deficit. For POD, when under water deficit, the best results were obtained with the biostimulants Seed+ + Crop+ 2x, Crop+ 1x and Crop+ 2x in flowering (810.94; 691.19 and 921.59 U mg-1 protein) and in fruiting (703.60; 800.00 and 972.62 U mg-1 protein). Thus, the use of Seed+ and Crop+ biostimulants can be an alternative to help mitigate the damage caused by water deficit in tomato crop.
DOI: 10.6084/m9.figshare.14320335
title: Application of biostimulants in tomato subjected to water deficit: Physiological, enzymatic and production responses

description: ABSTRACT The objective of this study was to evaluate the effect of the application of the biostimulants Seed+ and Crop+ on physiological and production variables and on the activity of antioxidant enzymes (superoxide dismutase - SOD and guaiacol peroxidase - POD) in tomato plants subjected to two soil water conditions. The experiment was carried out in a greenhouse, in a 2 x 2 x 6 factorial scheme, with two times of application of the biostimulants (flowering and fruiting), two soil water conditions (50 and 100% of soil water holding capacity) and six biostimulants (control treatment; Seed+; Seed+ + Crop+ 1x; Seed+ + Crop+ 2x; Crop+ 1x; + Crop+ 2x). The exprimental design was completely randomized, with four repetitions. The biostimulants Seed+ and Crop+ increased the quantum yield of photosystem II (Fv/Fm), regardless of the time of application and water condition of the soil. The biostimulants Seed+ + Crop+ 2x and Crop+ 2x stood out in the pre-morning period, with an average Fv/Fm of 0.813, under the conditions tested. The highest SOD activity (372.12 U mg-1 of protein) was obtained with Crop+ 2x biostimulant in fruiting and under water deficit. For POD, when under water deficit, the best results were obtained with the biostimulants Seed+ + Crop+ 2x, Crop+ 1x and Crop+ 2x in flowering (810.94; 691.19 and 921.59 U mg-1 protein) and in fruiting (703.60; 800.00 and 972.62 U mg-1 protein). Thus, the use of Seed+ and Crop+ biostimulants can be an alternative to help mitigate the damage caused by water deficit in tomato crop.
DOI: 10.6084/m9.figshare.14320336
title: Accumulation of humic substances in an Oxisol fertilized with pig slurry for 15 years

description: ABSTRACT The growth of swine production in Brazil has increased the amount of production and use of pig slurry (PS) as soil fertilizer. This product provides nutrients to plants, and a continuous application of this residue usually increases total soil organic carbon (SOC) content. The objective of this study was to determine the SOC content and its distribution into humic substance fractions (humic acids, fulvic acids, and humin) in an Oxisol annually fertilized with PS for 15 years. The experiment was implemented in 2001 with a maize and oat crop rotation under no-tillage system in Campos Novos, SC, Brazil. The treatments used were: PS at rates of 0 (Control), 25, 50, 100, and 200 m3 ha-1 year-1, mineral fertilizer, and PS combined with mineral fertilizer, applied on the soil surface once a year. The 0-2.5, 2.5-5, 5-10, 10-20, 20-40, and 40-60 cm soil layers were evaluated for SOC content in the fractions humic acid, fulvic acid, and humin, and E4/E6 ratio of humic substances. Increases in PS rates up to 100 m3 ha-1 increased the SOC content in the 5-10 cm soil layer; however, decreased the proportion of the soil fulvic acid and humic acid fractions, favoring the accumulation of organic carbon in the humin fraction. The E4/E6 ratio was higher when using the soil mineral fertilizer than that found in treatments with PS.
DOI: 10.6084/m9.figshare.14320336.v1
title: Accumulation of humic substances in an Oxisol fertilized with pig slurry for 15 years

description: ABSTRACT The growth of swine production in Brazil has increased the amount of production and use of pig slurry (PS) as soil fertilizer. This product provides nutrients to plants, and a continuous application of this residue usually increases total soil organic carbon (SOC) content. The objective of this study was to determine the SOC content and its distribution into humic substance fractions (humic acids, fulvic acids, and humin) in an Oxisol annually fertilized with PS for 15 years. The experiment was implemented in 2001 with a maize and oat crop rotation under no-tillage system in Campos Novos, SC, Brazil. The treatments used were: PS at rates of 0 (Control), 25, 50, 100, and 200 m3 ha-1 year-1, mineral fertilizer, and PS combined with mineral fertilizer, applied on the soil surface once a year. The 0-2.5, 2.5-5, 5-10, 10-20, 20-40, and 40-60 cm soil layers were evaluated for SOC content in the fractions humic acid, fulvic acid, and humin, and E4/E6 ratio of humic substances. Increases in PS rates up to 100 m3 ha-1 increased the SOC content in the 5-10 cm soil layer; however, decreased the proportion of the soil fulvic acid and humic acid fractions, favoring the accumulation of organic carbon in the humin fraction. The E4/E6 ratio was higher when using the soil mineral fertilizer than that found in treatments with PS.
DOI: 10.6084/m9.figshare.14320338.v1
title: Interaction between nitrogen, soil water condition and herbicides in Urochloa plantaginea control in irrigated rice crop

description: ABSTRACT The present study sought to verify the existence of interactions between the soil water conditions, nitrogen and herbicides commonly used to control alexandergrass in irrigated rice crop. The experimental design was completely randomized, arranged in a 2 x 3 x 4 factorial scheme, corresponding to two soil water conditions (5 cm water depth and 100% soil water holding capacity [WHC]), three nitrogen doses (0, 80 and 160 kg of N ha-1) and four doses of herbicides (0, 0.5, 1 and 2 times the registration dose). The herbicides evaluated were cyhalofop-butyl, imazapyr + imazapic and imazethapyr. The treatments were repeated four times. Phytotoxicity and dry mass were evaluated 28 days after application. For cyhalofop-butyl and imazapyr + imazapic, the phytotoxicity at 100% WHC and 5 cm water depth conditions was higher in treatments with nitrogen fertilization. However, for imazethapyr under the 100% WHC condition of soil increased phytotoxicity in the absence of nitrogen fertilization. For the flooded condition, from the dose of 35 g of a.i. ha-1, the result in the control for the herbicide imazethapyr was optimized under the conditions of fertilization with 80 and 160 kg of N ha-1. Cyhalofop-butyl and imazapyr + imazapic undergo synergistic interaction with nitrogen fertilization and water status in the control efficiency, yet with imazethapyr, the synergistic interaction only occurs under 100% of soil WHC.
DOI: 10.6084/m9.figshare.14320338
title: Interaction between nitrogen, soil water condition and herbicides in Urochloa plantaginea control in irrigated rice crop

description: ABSTRACT The present study sought to verify the existence of interactions between the soil water conditions, nitrogen and herbicides commonly used to control alexandergrass in irrigated rice crop. The experimental design was completely randomized, arranged in a 2 x 3 x 4 factorial scheme, corresponding to two soil water conditions (5 cm water depth and 100% soil water holding capacity [WHC]), three nitrogen doses (0, 80 and 160 kg of N ha-1) and four doses of herbicides (0, 0.5, 1 and 2 times the registration dose). The herbicides evaluated were cyhalofop-butyl, imazapyr + imazapic and imazethapyr. The treatments were repeated four times. Phytotoxicity and dry mass were evaluated 28 days after application. For cyhalofop-butyl and imazapyr + imazapic, the phytotoxicity at 100% WHC and 5 cm water depth conditions was higher in treatments with nitrogen fertilization. However, for imazethapyr under the 100% WHC condition of soil increased phytotoxicity in the absence of nitrogen fertilization. For the flooded condition, from the dose of 35 g of a.i. ha-1, the result in the control for the herbicide imazethapyr was optimized under the conditions of fertilization with 80 and 160 kg of N ha-1. Cyhalofop-butyl and imazapyr + imazapic undergo synergistic interaction with nitrogen fertilization and water status in the control efficiency, yet with imazethapyr, the synergistic interaction only occurs under 100% of soil WHC.
DOI: 10.6084/m9.figshare.14320341
title: Hydrogen peroxide in the acclimation of yellow passion fruit seedlings to salt stress

description: ABSTRACT The objective of the present study was to evaluate the effect of exogenous application of hydrogen peroxide on the emergence, growth and gas exchange of yellow passion fruit seedlings subjected to salt stress. The experiment was conducted in pots (Citropote®) under greenhouse conditions, in the municipality of Campina Grande, PB, Brazil. Treatments were distributed in a randomized block design, in a 4 x 4 factorial arrangement, with four levels of electrical conductivity of irrigation water (0.7, 1.4, 2.1 and 2.8 dS m-1) associated with four concentrations of hydrogen peroxide (0, 25, 50 and 75 μM), with four replicates and two plants per plot. Irrigation using water with electrical conductivity above 0.7 dS m-1 negatively affects the emergence and growth of passion fruit. Hydrogen peroxide concentrations between 10 and 30 μM induce the acclimation of passion fruit plants to salt stress, mitigating the deleterious effects of salinity on the relative growth rate in stem diameter and leaf area, stomatal conductance, transpiration, CO2 assimilation rate and instantaneous carboxylation efficiency. Irrigation water salinity combined with hydrogen peroxide concentrations above 30 μM causes reduction in passion fruit growth and physiology.
DOI: 10.6084/m9.figshare.14320341.v1
title: Hydrogen peroxide in the acclimation of yellow passion fruit seedlings to salt stress

description: ABSTRACT The objective of the present study was to evaluate the effect of exogenous application of hydrogen peroxide on the emergence, growth and gas exchange of yellow passion fruit seedlings subjected to salt stress. The experiment was conducted in pots (Citropote®) under greenhouse conditions, in the municipality of Campina Grande, PB, Brazil. Treatments were distributed in a randomized block design, in a 4 x 4 factorial arrangement, with four levels of electrical conductivity of irrigation water (0.7, 1.4, 2.1 and 2.8 dS m-1) associated with four concentrations of hydrogen peroxide (0, 25, 50 and 75 μM), with four replicates and two plants per plot. Irrigation using water with electrical conductivity above 0.7 dS m-1 negatively affects the emergence and growth of passion fruit. Hydrogen peroxide concentrations between 10 and 30 μM induce the acclimation of passion fruit plants to salt stress, mitigating the deleterious effects of salinity on the relative growth rate in stem diameter and leaf area, stomatal conductance, transpiration, CO2 assimilation rate and instantaneous carboxylation efficiency. Irrigation water salinity combined with hydrogen peroxide concentrations above 30 μM causes reduction in passion fruit growth and physiology.
DOI: 10.6084/m9.figshare.14320342.v1
title: The amazonian capim-açú is less nitrogen dependente than antelope grass to produce leaf dry matter

description: ABSTRACT The Maranhão floodplain is dominated by native grasses like capim-açú (Paspalum plicatulum, Mich.). Due to scarce information on nutrient demands of native species, farmers are replacing native pastures by exotic and potentially invasive species such as antelope grass (Echinochloa pyramidalis, Lam). The aim of this study was to compare the growth of capim-açú and antelope grass, under varying N and K doses, to better understand the potential of capim-açú to be used as forage. The experiment was carried out in pots, consisting of a 2 × 5 × 2 factorial scheme (2 species × 5 N doses × 2 K doses) with four repetitions, in a completely randomized design. The N doses of 0, 50, 100, 150 and 200 mg dm-3 were combined with 10 and 30 mg dm-3 K2O. The capim-açú produces higher leaf to stem ratio aboveground by using lower nitrogen and potassium doses than antelope grass. Leaf, stalk, and total dry matter production of both studied species do not respond to potassium doses.