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Plot size related to numbers of treatments, repetitions, and the experimental precision in flax
Get PDFThe aim of this study was determining the optimum plot size to evaluate the fresh matter of aerial part in flax (Linum usitatissimum L.), in scenarios formed by combinations of numbers of treatments, number of repetitions, and precision levels. The fresh matter of aerial part was weighed on 144 basic experimental units of 1.00 m × 1.00 m in uniformity trial with size of 12 m × 12 m (144 m2). It was estimated the soil heterogeneity index of Smith (1938). Also, the optimum plot size was determined by the Hatheway’s method (1961) in scenarios formed by combinations of i treatments (i = 5, 10, 15, and 20), r repetitions (r = 3, 4, 5, 6, 7 8, 9, and 10), and d precision levels (d = 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, and 40%). In experiments planned on randomized block design, with 5 to 20 treatments and four repetitions, plots with 7 m2 are sufficient to identify significant differences between treatments regarding fresh matter of aerial part in flax, at 5% probability, of 34% of the experiment overall mean.The aim of this study was determining the optimum plot size to evaluate the fresh matter of aerial part in flax (Linum usitatissimum L.), in scenarios formed by combinations of numbers of treatments, number of repetitions, and precision levels. The fresh matter of aerial part was weighed on 144 basic experimental units of 1.00 m × 1.00 m in uniformity trial with size of 12 m × 12 m (144 m2). It was estimated the soil heterogeneity index of Smith (1938). Also, the optimum plot size was determined by the Hatheway’s method (1961) in scenarios formed by combinations of i treatments (i = 5, 10, 15, and 20), r repetitions (r = 3, 4, 5, 6, 7 8, 9, and 10), and d precision levels (d = 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, and 40%). In experiments planned on randomized block design, with 5 to 20 treatments and four repetitions, plots with 7 m2 are sufficient to identify significant differences between treatments regarding fresh matter of aerial part in flax, at 5% probability, of 34% of the experiment overall mean
Changes in temperature of a Plinthosol cultivated with sugarcane under straw levels
Get PDFSoil temperature is affected by its coverage and influences sugarcane productivity. Changes in temperature were assessed in a Plinthosol cultivated with sugarcane under different straw levels, as well as its reflection in stalk productivity, aiming at determining the maximum amount of straw to be removed for other purposes without damaging soil thermal conditions necessary for the crop. The experimental design was a split-plot randomized block design with four replications, with assessment periods of soil temperature arranged in the main plots, straw levels (0, 4.2, 9.5, 13.0, and 18.4 Mg ha−1) arranged in the subplots, and two measuring depths of soil temperature (0.05 and 0.10 m) arranged in the sub-subplots. Soil temperature was obtained by T-type thermocouples (copper/constantan). Soil thermal amplitude underwent oscillations as a function of straw levels, especially at a depth of 0.05 m. The maintenance of 9.5 Mg ha−1 of straw provided an increase of 11.1% in stalk productivity. Values above 9.5 Mg ha−1 of straw can be removed from the field for other purposes without impairing soil thermal conditions required for the crop.Soil temperature is affected by its coverage and influences sugarcane productivity. Changes in temperature were assessed in a Plinthosol cultivated with sugarcane under different straw levels, as well as its reflection in stalk productivity, aiming at determining the maximum amount of straw to be removed for other purposes without damaging soil thermal conditions necessary for the crop. The experimental design was a split-plot randomized block design with four replications, with assessment periods of soil temperature arranged in the main plots, straw levels (0, 4.2, 9.5, 13.0, and 18.4 Mg ha−1) arranged in the subplots, and two measuring depths of soil temperature (0.05 and 0.10 m) arranged in the sub-subplots. Soil temperature was obtained by T-type thermocouples (copper/constantan). Soil thermal amplitude underwent oscillations as a function of straw levels, especially at a depth of 0.05 m. The maintenance of 9.5 Mg ha−1 of straw provided an increase of 11.1% in stalk productivity. Values above 9.5 Mg ha−1 of straw can be removed from the field for other purposes without impairing soil thermal conditions required for the crop
Potential predation and fecundity of Amblyseius aerialis fed two-spotted spider mite
Get PDFThe mites of the Phytoseiidae family stand out for the biological control of pest mites. The species Amblyseius aerialis (Muma, 1955) is a generalist mite, which can contribute to the natural regulation of pest mites. The objective of this study was to evaluate the potential for predation and fecundity of A. aerialis on the different phases of Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae). A female of A. aerialis was confined on dish (3.0 cm in diameter) of jack bean leaves, Canavalia ensiformis (L.) DC. The discs were left in petri dish with water. Each T. urticae phase was offered individually to A. aerialis at densities: 2, 5, 10, 15, 20 and 30 mites / arena. The number of prey consumed and eggs laid by A. aerialis were evaluated every 24 hours for seven days, with removal of laid eggs by phytoseiid and dead prey and replacement of prey in the initial amount. The data were submitted to analysis of variance and the means were compared by Tukey test, applying the factorial (4x6). It was observed that with the increase of the density of T. urticae offered there was an increase in the predation of A. aerialis. When offered the nymph and adult the average number of eggs per day was higher, differing from egg and larva. Thus, A. aerialis can be a biological control agent of the T. urticae, reducing the population of the pest and maintaining its fecundity in all phases and densities offered.The mites of the Phytoseiidae family stand out for the biological control of pest mites. The species Amblyseius aerialis (Muma, 1955) is a generalist mite, which can contribute to the natural regulation of pest mites. The objective of this study was to evaluate the potential for predation and fecundity of A. aerialis on the different phases of Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae). A female of A. aerialis was confined on dish (3.0 cm in diameter) of jack bean leaves, Canavalia ensiformis (L.) DC. The discs were left in petri dish with water. Each T. urticae phase was offered individually to A. aerialis at densities: 2, 5, 10, 15, 20 and 30 mites / arena. The number of prey consumed and eggs laid by A. aerialis were evaluated every 24 hours for seven days, with removal of laid eggs by phytoseiid and dead prey and replacement of prey in the initial amount. The data were submitted to analysis of variance and the means were compared by Tukey test, applying the factorial (4x6). It was observed that with the increase of the density of T. urticae offered there was an increase in the predation of A. aerialis. When offered the nymph and adult the average number of eggs per day was higher, differing from egg and larva. Thus, A. aerialis can be a biological control agent of the T. urticae, reducing the population of the pest and maintaining its fecundity in all phases and densities offered
Partition and macronutrients accumulation in pineapple under nitrogen doses and plant density
Get PDFStudies related to the absorption and exportation capacity of macronutrients by irrigated pineapple are essential for the definition of adequate doses and fertilization management. The objective of this study was to evaluate the accumulation of biomass and macronutrients in the compartments (leaves, shoot, root, seedlings/slip, crown/top, and fruit) of ‘Vitória’ pineapple irrigated in the semiarid region after the use of nitrogen doses and population densities. The treatments, arranged in randomized blocks with three replicates, arranged in a 5x4 factorial scheme, consisted of five nitrogen doses (0, 5, 10, 15 and 20 g per plant) and four population densities (51,282, 76,923, 90,909, and 126,984 plants ha-1). The accumulation of biomass and macronutrients in the pineapple compartments was evaluated at the end of the growing cycle. The increase of N doses combined with the increase of the plant population promoted a linear increase in the accumulation of biomass and macronutrients by the pineapple plants. The leaves presented greater accumulation of macronutrients, followed by the seedlings, shoot, fruit, crown, and roots. The pineapple presented the following decreasing order of macronutrient absorption: K> N> Ca> P> Mg>S. At the dose of 20 g per plant of N and population of 126,984 plants ha-1 were exported from the area by fruits, 1,311 (12%), 150 (9%), 144 (11%), 52 (11%), 46 (12%) and 36 (12%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively; and by the shoots, 2,426 (22%), 480 (29%), 147 (11%), 101 (21%), 67 (18%), and 45 (15%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively.Studies related to the absorption and exportation capacity of macronutrients by irrigated pineapple are essential for the definition of adequate doses and fertilization management. The objective of this study was to evaluate the accumulation of biomass and macronutrients in the compartments (leaves, shoot, root, seedlings/slip, crown/top, and fruit) of ‘Vitória’ pineapple irrigated in the semiarid region after the use of nitrogen doses and population densities. The treatments, arranged in randomized blocks with three replicates, arranged in a 5x4 factorial scheme, consisted of five nitrogen doses (0, 5, 10, 15 and 20 g per plant) and four population densities (51,282, 76,923, 90,909, and 126,984 plants ha-1). The accumulation of biomass and macronutrients in the pineapple compartments was evaluated at the end of the growing cycle. The increase of N doses combined with the increase of the plant population promoted a linear increase in the accumulation of biomass and macronutrients by the pineapple plants. The leaves presented greater accumulation of macronutrients, followed by the seedlings, shoot, fruit, crown, and roots. The pineapple presented the following decreasing order of macronutrient absorption: K> N> Ca> P> Mg>S. At the dose of 20 g per plant of N and population of 126,984 plants ha-1 were exported from the area by fruits, 1,311 (12%), 150 (9%), 144 (11%), 52 (11%), 46 (12%) and 36 (12%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively; and by the shoots, 2,426 (22%), 480 (29%), 147 (11%), 101 (21%), 67 (18%), and 45 (15%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively
Selectivity of pre-and post-emergence herbicides to very-early maturing soybean cultivars
Get PDFThe combination of pre- and post-emergence herbicides may affect their selectivity to soybean plants, especially to short-cycle cultivars. The objective of this work was to evaluate the selectivity of pre- and post-emergence herbicides to very-early maturing soybean cultivars. Two field experiments were conducted, one in Mandaguaçu, Paraná (E1) and other in Rio Verde, Goiás (E2), Brazil, using a 4×7 factorial arrangement. The treatments consisted of four pre-emergence herbicide managements (S-metolachlor at 1440 g ha-1, diclosulam at 25.2 g ha-1, sulfentrazone at 300 g ha-1, and no herbicide application); and seven post-emergence herbicide managements (lactofen at 120 g ha-1, chlorimuron-ethyl at 12.5 g ha-1, bentazon at 720 g ha-1, lactofen at 120 g ha-1 + chlorimuron-ethyl at 12.5 g ha-1, glyphosate at 900 g a. e. ha-1, two sequential glyphosate applications at 720 g a. e. ha-1 each, and no herbicide application). The early-maturing soybean cultivars evaluated showed sensitivity to the herbicides used. The combined use of pre- and post-emergence herbicides increased the occurrence of injuries in the plants. Diclosulam and sulfentrazone were the least selective pre-emergence herbicides. All herbicide combinations used affected soybean grain yield in E1; lactofen, chlorimuron, and bentazon presented the least selectivity in E2.The combination of pre- and post-emergence herbicides may affect their selectivity to soybean plants, especially to short-cycle cultivars. The objective of this work was to evaluate the selectivity of pre- and post-emergence herbicides to very-early maturing soybean cultivars. Two field experiments were conducted, one in Mandaguaçu, Paraná (E1) and other in Rio Verde, Goiás (E2), Brazil, using a 4×7 factorial arrangement. The treatments consisted of four pre-emergence herbicide managements (S-metolachlor at 1440 g ha-1, diclosulam at 25.2 g ha-1, sulfentrazone at 300 g ha-1, and no herbicide application); and seven post-emergence herbicide managements (lactofen at 120 g ha-1, chlorimuron-ethyl at 12.5 g ha-1, bentazon at 720 g ha-1, lactofen at 120 g ha-1 + chlorimuron-ethyl at 12.5 g ha-1, glyphosate at 900 g a. e. ha-1, two sequential glyphosate applications at 720 g a. e. ha-1 each, and no herbicide application). The early-maturing soybean cultivars evaluated showed sensitivity to the herbicides used. The combined use of pre- and post-emergence herbicides increased the occurrence of injuries in the plants. Diclosulam and sulfentrazone were the least selective pre-emergence herbicides. All herbicide combinations used affected soybean grain yield in E1; lactofen, chlorimuron, and bentazon presented the least selectivity in E2
Determination of the soil water repellency of the Mediterranean climate by the use of the mini disk infiltrometer. Case of the micro basin of Tifiles, Tenes, Algeria.
Get PDFThe soil repellency is one of some soil propriety that can be use to indicate the quality of the soil and give a number of information for the soil conservation and the water management. This study show an example of the determination of this parameter in three sites (forest site, after fire forest site and mixed site) by the use of the mini disk infiltrometer test (MDIT) in the small watershed of wadi Tifiles situated in the North West of Algeria that is characterized by a Mediterranean climate. The result show that the water repellency affect namely the after fire forest site which can be equal to 100% of the measured sample flowed by the mixed soil by 93% and the forest site by 80%.The soil repellency is one of some soil propriety that can be use to indicate the quality of the soil and give a number of information for the soil conservation and the water management. This study show an example of the determination of this parameter in three sites (forest site, after fire forest site and mixed site) by the use of the mini disk infiltrometer test (MDIT) in the small watershed of wadi Tifiles situated in the North West of Algeria that is characterized by a Mediterranean climate. The result show that the water repellency affect namely the after fire forest site which can be equal to 100% of the measured sample flowed by the mixed soil by 93% and the forest site by 80%
Performance and carcass traits of heifers Rubia Gallega x Nellore supplemented with chromium picolinate
Get PDFThe objective was to evaluate the productive performance and the carcass traits of Nellore (NEL) and Rubia Gallega x Nellore F1 (NRG) heifers, subjected to energy-protein supplementation with chromium picolinate (CrP). Sixty heifers (30 NEL and 30 NRG) with a mean initial adjusted body weight (BW) of 214.50 kg and mean age of 201 days were distributed into a completely randomized design, in a 2 x 2 factorial (2 genetic groups x 2 supplementation groups). The experimental period lasted 320 days. There was no interaction (p>0.05) between the genetic groups and the supplements. The addition of CrP to the supplement did not alter the performance and carcass characteristics evaluated (p>0.05). However, the NRG genetic group was better than the NEL in the performance characteristics as final live weight, mean daily gain and carcass yield as carcass yield, Muscularity (p≤0.05).The use of the Rubia Gallega genotype in crossbreeding provides an increase in production of heavier carcasses with lower fat percentages and higher yields when compared to the use of Nellore heifers.The objective was to evaluate the productive performance and the carcass traits of Nellore (NEL) and Rubia Gallega x Nellore F1 (NRG) heifers, subjected to energy-protein supplementation with chromium picolinate (CrP). Sixty heifers (30 NEL and 30 NRG) with a mean initial adjusted body weight (BW) of 214.50 kg and mean age of 201 days were distributed into a completely randomized design, in a 2 x 2 factorial (2 genetic groups x 2 supplementation groups). The experimental period lasted 320 days. There was no interaction (p>0.05) between the genetic groups and the supplements. The addition of CrP to the supplement did not alter the performance and carcass characteristics evaluated (p>0.05). However, the NRG genetic group was better than the NEL in the performance characteristics as final live weight, mean daily gain and carcass yield as carcass yield, Muscularity (p≤0.05).The use of the Rubia Gallega genotype in crossbreeding provides an increase in production of heavier carcasses with lower fat percentages and higher yields when compared to the use of Nellore heifers
Health parameters and antioxidant response in Black Sea whiting Merlangius merlangus euxinus (Nordmann, 1840) parasitized by nematode Hysterothylacium aduncum (Rud., 1802)
Get PDFBiometrical and biochemical parameters in healthy and parasitized by nematode Hysterothylacium aduncum Black Sea whiting Merlangius merlangus euxinus were studied. The increase of hepatosomatic index and decrease of spleen index in infected fish were found, while condition factor was similar in both groups. Antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), peroxidase (PER), glutathione reductase (GR) and glutathione-S-transferase (GST)) were higher in red blood cells in the parasitized fish as compared with the healthy animals. In the liver, the antioxidant response was not uniform: activities of SOD and GST decreased and activities of PER, GR and CAT increased in the infected individuals. The obtained results reflect host defense against oxidative stress caused parasitic infection. The tissue specific fluctuations of antioxidant response in parasitized and healthy fish are discussed. Data in this study can be used for understanding the defense mechanisms of fish against parasites.Biometrical and biochemical parameters in healthy and parasitized by nematode Hysterothylacium aduncum Black Sea whiting Merlangius merlangus euxinus were studied. The increase of hepatosomatic index and decrease of spleen index in infected fish were found, while condition factor was similar in both groups. Antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT), peroxidase (PER), glutathione reductase (GR) and glutathione-S-transferase (GST)) were higher in red blood cells in the parasitized fish as compared with the healthy animals. In the liver, the antioxidant response was not uniform: activities of SOD and GST decreased and activities of PER, GR and CAT increased in the infected individuals. The obtained results reflect host defense against oxidative stress caused parasitic infection. The tissue specific fluctuations of antioxidant response in parasitized and healthy fish are discussed. Data in this study can be used for understanding the defense mechanisms of fish against parasites
Evaporative cooling efficiency of pads consisting of vegetable loofah
Get PDFBrazilian agroindustry has presented constant innovations in the use of equipment and materials, among which are those that generate artificial thermal conditioning inside the zootechnical facilities, through a direct evaporative cooling system (DEC). In order to mitigate the effects of high temperatures associated with low air humidity in buildings in the northeastern region of Brazil, the use of DEC systems is evident. Therefore, DEC’s built with evaporative pads constituted of alternative materials, prove to be an interesting and viable alternative. The aim of this work was to evaluate the cooling efficiency of the evaporative pads constituted of vegetable loofah. The experiment was performed at the Campus de Ciências Agrárias, Federal University of the São Francisco Valley (UNIVASF) in Petrolina, Pernambuco state. The experimental design was in randomized blocks, in a 4x4 factorial scheme, with 13 replicates. Air temperature and relative humidity values were collected before and after the passage through the pad for different flow velocities and pad thicknesses, in order to calculate the evaporative efficiency. The variance analysis was significant at 5% probability for the sources of variation of the pad thickness (0.05, 0.075, 0.1 and 0.125 m) and the air flow rate (0.076, 0.264, 0.459 and 0.773 m s-1), and the interactions. The highest efficiency, 57.0% was observed for the interaction between the thickness of 0.125 m and the speed of 0.773 ms-1 as adjusted model.Brazilian agroindustry has presented constant innovations in the use of equipment and materials, among which are those that generate artificial thermal conditioning inside the zootechnical facilities, through a direct evaporative cooling system (DEC). In order to mitigate the effects of high temperatures associated with low air humidity in buildings in the northeastern region of Brazil, the use of DEC systems is evident. Therefore, DEC’s built with evaporative pads constituted of alternative materials, prove to be an interesting and viable alternative. The aim of this work was to evaluate the cooling efficiency of the evaporative pads constituted of vegetable loofah. The experiment was performed at the Campus de Ciências Agrárias, Federal University of the São Francisco Valley (UNIVASF) in Petrolina, Pernambuco state. The experimental design was in randomized blocks, in a 4x4 factorial scheme, with 13 replicates. Air temperature and relative humidity values were collected before and after the passage through the pad for different flow velocities and pad thicknesses, in order to calculate the evaporative efficiency. The variance analysis was significant at 5% probability for the sources of variation of the pad thickness (0.05, 0.075, 0.1 and 0.125 m) and the air flow rate (0.076, 0.264, 0.459 and 0.773 m s-1), and the interactions. The highest efficiency, 57.0% was observed for the interaction between the thickness of 0.125 m and the speed of 0.773 ms-1 as adjusted model
Biofertilizers in horticultural crops
Get PDFBovine manure biofertilizers can exert physical, chemical, and biological effects on the soil and the phytoprotective, physiological, and productive actions in horticultural crops. The literature review was performed to compile information on the production, uses, and effects of bovine manure biofertilizers on soil properties and plants. Biofertilizers are produced by organic components, minerals, and inoculants. Among the organic sources, the bovine manure is the most used. The fermentation of the bovine manure in water constitutes the Vairo biofertilizer, the most employed in Brazilian horticulture. With the chemical enrichment of this preparation came the Supermagro, Agrobio, and Agrobom biofertilizers. In the soil, it can act in the improvement of soil fertility, physical properties, and in the diversity and abundance of the biota. Also, it can act in control of pests and diseases, leaf composition concerning macro and micronutrients, and in the production and post-harvest quality of horticultural crops. Therefore, this review describes the preparation, chemical composition, and utilization of bovine manure biofertilizers in both soil and plants, offering perspectives of research on the formulations, application, and effects of these inputs on horticultural species.Bovine manure biofertilizers can exert physical, chemical, and biological effects on the soil and the phytoprotective, physiological, and productive actions in horticultural crops. The literature review was performed to compile information on the production, uses, and effects of bovine manure biofertilizers on soil properties and plants. Biofertilizers are produced by organic components, minerals, and inoculants. Among the organic sources, the bovine manure is the most used. The fermentation of the bovine manure in water constitutes the Vairo biofertilizer, the most employed in Brazilian horticulture. With the chemical enrichment of this preparation came the Supermagro, Agrobio, and Agrobom biofertilizers. In the soil, it can act in the improvement of soil fertility, physical properties, and in the diversity and abundance of the biota. Also, it can act in control of pests and diseases, leaf composition concerning macro and micronutrients, and in the production and post-harvest quality of horticultural crops. Therefore, this review describes the preparation, chemical composition, and utilization of bovine manure biofertilizers in both soil and plants, offering perspectives of research on the formulations, application, and effects of these inputs on horticultural species