Bifactorial Arrangement Research Articles

Agronomic Behavior of Peanut (Arachis hypogaea L.) Cultivars under Three Planting Densities in the Northeast of Peru

Factors such as the selection of cultivars and the planted density affect the development and yield of peanuts (Arachis hypogaea L.). This study’s objective was to evaluate peanut cultivars’ agronomic behavior under three planting densities in the northeast of Peru. The design used was randomized complete blocks (DBCAs) with a bifactorial arrangement 4A × 3B (factor A, peanut cultivars; factor B, planting densities), forming 12 treatments with three replications per block. The results revealed that T3 (Huayabamba cultivar + density of 30 × 50 cm) stood out, presenting the most favorable means in the number of pods (16 pods), number of seeds per pod (five seeds), height at 90 days (22.7 cm), and yield (1850 kg/ha). Empty pods did not show significant differences between treatments. T8 (Chivita cultivar + density of 20 × 50 cm) indicated the highest number of branches (six branches); in the weight of 100 seeds, the Rojo Tarapoto cultivar was the most encouraging, adapting optimally to the three densities. In addition, T7 (chivita cultivar + density of 10 × 50 cm) showed the shortest days at flowering and harvest, with 64 and 134 days. The study showed that T3 was the most efficient in pod and seed production, making it crucial to optimizing peanut yield.

Implicações da remoção dos parâmetros do modelo nas relações lineares de ensaios com a aveia

ABSTRACT: This study was conducted with the aim of analyzing the implications of removing the parameters from the mathematical model on the results of path analysis, with oats grown in different years and agricultural scenarios (with and without fungicide). For this, two field trials were conducted in southern Brazil, in five years of growth. The experimental design used in trial I (with fungicide application) was randomized complete blocks (RCB), in a 22 × 4 bifactorial arrangement, characterized by twenty-two oat cultivars and four fungicide applications. For trial II (without fungicide application) the RCB design was used, and the treatments were characterized by twenty-two oat cultivars, with three replications. The traits measured were panicle length, panicle mass, number of spikelets, number of grains, grain mass, and grain yield. For each year, data group, and scenario, the correlation coefficients between the explanatory variables and grain yield were calculated. The diagnosis of multicollinearity indicated violation of the statistical assumption, so it was necessary to proceed with a path analysis under multicollinearity (ridge). The removal of parameters from the mathematical model caused changes in the linear relationships between the oat yield traits, with the maintenance of the linear correlation coefficients in 3.30% and 20% of the situations, for the scenarios with and without fungicide application, respectively. Regarding the path coefficients, it was observed that the direct effects were maintained in 3.30% and 30% and indirect effects in 7.33% and 24.67% of the situations, for the scenarios with and without fungicide application, respectively.

Co-inoculation of Azospirillum with mycorrhizal fungi in the cultivation of wheat in soils contaminated with copper

Copper is a micronutrient essential for plant growth since it is part of the constitution of enzymes and proteins. However, it can become toxic to plants when in high concentrations in the soil. The association between microorganisms and plants is an alternative for reducing the negative effects of excess copper on plants. The objective of this work was to determine the influence of inoculation and co-inoculation of arbuscular mycorrhizal fungi and Azospirillum brasilense in a wheat crop grown on soil contaminated with copper. The experimental design used was entirely randomized in a bifactorial arrangement of 5 x 2, with five sources of inocula, (Azospirillum brasilense; Acaulospora colombiana; Gigaspora margarita; Acaulospora colombiana + Azospirillum brasilense; Gigaspora margarita + Azospirillum brasilense;), two doses of copper (0 = natural soil content and 400 mg kg-1), and eight replicates. We evaluated the height of plants, number of tillers, root length, root volume, dry root mass, specific surface area, average root diameter, copper content in the root, straw and grain, productivity, and percentage of mycorrhizal colonization. The inoculation with A. brasilense increases the number of tillers, plant height, and productivity compared to mycorrhizal fungi. The co-inoculation of these microorganisms does not contribute positively to these evaluated parameters, regardless of the dose of Cu applied to the soil. Co-inoculation of A. brasilense with mycorrhizal fungi does not reduce copper in the aerial part of wheat plants, regardless of the evaluated species, even in soil contaminated with copper.

Effect of dietary energy levels in Hy-Line Brown laying Hens during the last production phase

Diets with 2800 and 2900 kcal of ME/kg was evaluated to determine their effect on weight gain and egg quality parameters at the end of the production cycle in hy-Line Brown hens separated into two weight groups weights: <2200g and> 2200 g. A group of 960 hens with 75 weeks of age was employed distributed in a Random Complete Blocks Design with a bifactorial arrangement. Data were analyzed by analysis of variance and for the comparison of treatment means, the Duncan Significant Minimum Range test was used at a <0.05 and <0.01 probability both for the independent factors and for the bird weight interaction and diet energy level. Data about consumption, egg production, feed conversion and abdominal fat were collected. Egg quality was determined by weight records, albumen height, color, freshness, resistance, and thickness by using the digital method with laser irradiation in the digital Egg Tester DET-600. The results showed effects on hens weight upon consumption and weekly weights, lighter hens consumed less and resulted in lower weekly weights compared to heavier hens (P <0, 01), however, cumulative weight gain was not affected by the hen weight factor and energy level of diets (P> 0, 005). Heavier birds accumulated more abdominal fat at the end of the laying period than the less heavy birds (P <0.01). Egg production and feed conversion did not suffer variations due to the effect of both factors, although egg weight was affected only by bird weight (P <0.01). On the other hand, egg color shows variations depending on the energy level of the diet; while the freshness, resistance and thickness of the egg were not affected by any study factor (P> 0.05). it would be feasible to reduce the energy value of the diet without affecting the productive performance of the birds.

Space use and navigation ability of hens at housing in the aviary for the laying phase: effect of enrichment with additional perches and genotype

The present study tested the hypothesis that increased availability of perches could favor the adaptation and navigation ability of pullets of different genotypes at housing in a new aviary system for the laying phase. To this purpose, 900 Lohmann White-LSL and 900 Hy-line Brown were randomly allocated at 17 wk of age in 8 pens of an experimental aviary, according to a bifactorial arrangement with 2 genotypes (Brown vs. White)×2 types of pens (enriched or not enriched with additional perches besides those of the aviary). Data collected between 17 and 20 wk of age showed that the enrichment with additional perches decreased the use of the aviary perches while the rate of successful landings/take-offs was unaffected. As for the effect of genotype, during the night a lower rate of hens on the floor (0.15 vs. 6.63%) and a higher rate of hens on the additional perches (2.47 vs. 0.98%) was found in White compared to Brown hens (P < 0.001); the former hens also used the third tiers for sleeping on the aviary uppermost perches (P < 0.001). During the day, White hens used more the third tier (32.8 vs. 15.6%; P < 0.001) and the additional perches (3.88 vs. 0.91%; P < 0.01) compared to Brown hens, while they stood less on the floor (18.3 vs. 22.6%; P < 0.05). White hens performed a significantly higher number of landings (80.7 vs. 21.9; P < 0.001) and of take-offs (74.3 vs. 10.0; P < 0.001) per pen compared to Brown hens. The risk of unsuccessful landings was higher in Brown compared to White hens (odd ratio: 6.65; 95% confidence interval: 4.36-10.1; P < 0.001). In conclusion, the enrichment with additional perches played a major role in hen distribution and space use than in their navigation ability. At the same time, the significant differences between the 2 genotypes call for a careful evaluation of the aviary design and animal management to optimize welfare at housing and possibly productive results of laying hens.

Growth Performance, Digestive Efficiency, and Meat Quality of Two Commercial Crossbred Rabbits Fed Diets Differing in Energy and Protein Levels.

Simple SummaryThe nutritional composition of the diets for growing rabbits should be well-balanced, both to meet the requirements of the high-producing hybrids currently used and to avoid nutrient losses. The improvement of the feed conversion ratio represents a key point in increasing rabbit farmers’ profitability because of the high feeding costs. This study evaluated the growth performance, digestive efficiency and meat quality of growing rabbits belonging to the most diffused commercial crossbred rabbit breeds, Grimaud and Hyla, feeding them diets with different energy and protein levels. The two genotypes showed similar growth performance, but Grimaud rabbits achieved higher slaughter yield than Hyla rabbits. The administration of high-energy diets improved feed conversion and increased nutrient digestibility. Conversely, low dietary protein contents reduced nitrogen excretion without negative effects on growth, feed efficiency and carcass traits of fast-growing rabbits.The present study evaluated the effect of digestible energy (DE) and crude protein (CP) levels on growth, digestive efficiency, slaughter yield and meat quality in growing rabbits of two genotypes (Grimaud, G vs. Hyla, H). A total of 384 crossbred rabbits (192 G and 192 H), half males and half females, were divided into eight experimental groups according to a bi-factorial arrangement (2 genotypes × 4 diets; 48 animals/group) and reared in individual cages. From 33 to 64 days of age, rabbits were fed four diets obtained by combining two DE levels (high, HE—10.9 MJ/kg vs. low, LE—9.2 MJ/kg, on average) and two CP levels (high, HP—159 g/kg vs. low, LP—144 g/kg, on average). Then, all rabbits received the same fattening diet (10.7 MJ DE/kg; 156 g CP/kg) until slaughtering (77 days of age). Growth performance did not differ between genotypes for the entire trial (on average final live weight 3010 g; daily weight gain 50.5 g/d), but H rabbits showed a faster growth during the post-weaning period (p ≤ 0.01) compared to G rabbits, while exhibiting lower slaughter yield and lower carcass fatness (p ≤ 0.01). As DE level increased, feed intake decreased and feed conversion improved (p < 0.001), while caecal volatile fatty acid concentration increased and caecal pH and N-ammonia decreased (p ≤ 0.01). The reduction in the CP level did not affect performance and carcass traits. No significant interaction was detected between genotype and diet. In conclusion, G rabbits may have an advantage over H rabbits because of the higher slaughter yield. As for the nutritional characteristics of diets for high-producing crossbred rabbits, high energy levels are confirmed to enhance feed efficiency, whereas dietary CP can be reduced to 144 g/kg without negative effects on performance and carcass traits.

EFFECT OF THREE GREEN MANURES ON THE AGRONOMIC CHARACTERISTICS OF NATIVE X’MEJEN NAAL MAIZE IN CAMPECHE, MEXICO

In the agronomic management of maize (Zea mays L.), chemical fertilizers can be substituted for fertilizing techniques that reduce the pollutant effect of the excessive use of commercial fertilizers. The hypothesis was the green manure of legumes with or without the inoculation of microorganisms are capable of promoting agronomic characteristics of X’mejen Naal maize, comparable to conventional fertilization. In order to measure the effect in the agronomic characteristics of X´mejen Naal maize, an experiment was designed in complete randomized blocks in a bifactorial arrangement with four repetitions, in which three green manures were tested, with or without the inoculation of Fosfonat (endomycorrhizas, EM, plus nitrogen fixating bacteria, NFB). Treatments were Mucuna (Mucuna pruriens, T1=MUC), Xpelón (Vigna unguiculata, T2=PEL), Ibes (Phaseolus lunatus, T3=IBE), inoculated Mucuna (T4=MUCEM), inoculated Xpelón (T5=PELEM), inoculated Ibes (T6= IBEEM) and the control with the incorporated biomass of weeds plus the addition of 200 kg ha-1 of diammonium phosphate (T7=ARDAP). Results showed that there were only differences caused by the types of green manure and their interaction with the inoculated symbionts in the fresh weight or biomass in X´mejen Naal maize. IBE and ARDAP stood out in fresh weight (1162 and 1251 g), dry weight (168.6 and 163.6 g), 7.3 Mg ha-1 (Megagrams per hectare) in the dry aerial biomass in the maize plants, respectively. Despite the grain yield of maize was similar among treatments, it was noticeable that the higher average yields were also observed in IBE and ARDAP with 3.5 and 3.3 Mg ha-1 respectively. All yields (fodder and grain) managed to express the potential of the X´mejen Naal, which is relevant to recommend the use of green manures as an agro-environmental alternative to conventional fertilization in the Luvisol soils of Campeche.

Phenology and fruit set of peach trees cultivated in Dois Vizinhos, Paraná State, Brazil

Understanding the dormancy phases and dynamics of commercial cultivars in the regions where they are grown allows for the implementation of different cultural practices and aids in the understanding of the temperature requirements for collaboration with genetic improvement programs. The objective of this study was to determine the budding, flowering, and fruit set rates of peach trees cultivated in the municipality of Dois Vizinhos, Southwestern Paraná, Brazil. The present work was developed using the collection of peach trees in the fruit growing sector of the Universidade Tecnológica Federal do Paraná. Sixteen peach cultivars were evaluated: Rubimel, Leonense, Coral, Marli, Charme, Riograndense, Douradão, Chimarrita, Granada, BR-1, Bonão, and Eldorado (all planted in 2009), as well as Regalo, Kampai, Fascínio, and Zilli (planted in 2014). The experimental design was completely randomized with four replications of one plant each, in a 16 × 2 bifactorial arrangement (cultivars × year/harvest). Phenology evaluations were performed weekly by counting open (anthesis) and sprouted flower buds, and the fruit set rate was measured just before fruit thinning. Flowering (%), budding (%), and fruit set (%) rates were calculated. It was found that the year/harvest 2016 promoted the highest rates of sprouting and fruit set. The Bonão cultivar showed greater flowering intensity and regularity in the crop years evaluated (2016 and 2017). Coral and Kampai present fruit sets with greater intensities and regularities when compared to the other cultivars evaluated under the climatic condition of the municipality of Dois Vizinhos. The Riograndense cultivar showed greater irregularity in flowering and fruit production.

Tolerância ao déficit hídrico de cultivares de feijão

Abstract The objective of this work was to evaluate the response of the Garapiá, Triunfo, and BRS-FC104 bean (Phaseolus vulgaris) cultivars to the water deficit represented by the fraction of transpirable soil water (FTSW). The experimental design was completely randomized in a 3×2 bifactorial arrangement (cultivars × irrigation and no irrigation). Transpiration, growth, and yield were evaluated in the crop season and off-season. In the crop season, with a low atmospheric air demand (below 15 hPa in 55% of the days), 'Garapiá' presented early stomatal closure with the critical FTSW (FTSWc) of 0.36, but had the same yield as 'Triunfo', whose stomata closed late (FTSWc = 0.23). In the off-season, with a high atmospheric air demand (greater than 15 hPa in 83.3% of the days), 'Garapiá' presented an early stomatal closure (FTSWc = 0.17) and a higher yield (392.2 kg ha-1 more than 'Triunfo'). In the crop season and off-season, 'Garapiá' showed tolerance to water deficit in the reproductive period. Water deficit resulted in lower values of height, shoot dry mass, root dry mass, and leaf area. Both 'Garapiá' and 'Triunfo' showed a high yield in the crop season, but only 'Garapiá' in the off-season. 'Garapiá' presents tolerance to water deficit, with efficient stomatal control and high growth and yield.

Producción de plántulas de chile habanero con fertilización orgánica y biológica

Chemical fertilization needs to be replaced in cultivation systems. Thus, this study proposes the alternative of combining compost with liquid organic fertilizers and biofertilizers to obtain habanero pepper seedling quality. The objective is to evaluate two liquid organic fertilizers in combination with Purpureocillium lilacinum and Beauveria brongniartii in growth, nutritional concentration and quality of habanero pepper seedlings grown in peat moss/compost substrate to substitute chemistry fertilization. A completely randomized experimental design was used with a bifactorial arrangement: (1) liquid organic fertilizers (vermicompost leachate and the commercial product Pez Terra®, diluted in water in a 1:200 ratio); (2) biofertilizers (B. brongniartii and P. lilacinum) and a control (25% Steiner’s nutrient solution) group were also evaluated. The seedlings treated with the commercial product increased their growth, Soil Plant Analysis Development (SPAD) units, N, P and K concentrations, and quality with P. lilacinum inoculation; seedling height, stem diameter, leaf area, N concentration and slenderness index increased, with respect to B. brongniartii. The interaction of the commercial fertilizer and P. lilacinum, and use of peat moss/compost substrate 1:1 (v/v) increased seedling height by 10%, leaf area by 35%, N and P concentrations by 57% and 35%, respectively, and slenderness index by 8% compared to the seedlings that were produced with Steiner’s 25% nutrient solution and peat moss. Therefore, this combination was considered viable for the production of habanero pepper seedlings and may substitute chemistry fertilization.

Características y rendimiento de semillas básicas de papa nativa (Solanum goniocalyx) obtenidas en biorreactor de inmersión temporal en condiciones de invernadero

The characteristics and yield of basic seeds of two native Peruvian potato varieties "Peruanita" and "Amarilla Tumbay" (Solanum goniocalyx), obtained in temporary immersion bioreactors under greenhouse conditions, were evaluated in order to obtain quality seeds in a continuous and sustainable way to guarantee farmers' production and to meet national demand. For this purpose, microtubers and cuttings obtained by temporary immersion bioreactors (TIB) were cultivated in an area of 240 m2 at 3.201 masl, a completely randomized block design was applied with a bifactorial arrangement (varieties x propagules) of 4 treatments and 3 repetitions. The variables evaluated were: survival (SP) and plant height (AP) at 30 days, number of tubers per plant (NT), tuber diameter (DT), tuber weight (PT), tuber size (TT), tuber skin color (CP) and yield in kg per 14.05 m2 (R). Tubers produced from the microtubers stood out from the cuttings in yield for basic seed, presenting an R=26.89 ± 0,483 kg.14.05 m-2, PT= 0,12 ±0,0036 kg and a TD= 22.59 ±0,451 mm; being the variety "Peruanita" the most optimal in number and weight of tubers per plant for basic seed. The basic seed coming from microtubers was obtained in 5 months, being an alternative to guarantee a constant production, allowing to take care of the demand of farmers and to lower the costs of production.

EFECTO FISIOLÓGICO DE LA DISPONIBILIDAD DE AGUA Y NITRÓGENO EN PLANTAS DE GUAYABA

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; The water deficit and the low availability of nutrients are factors that limit the growth and productivity of cultivated plants. &lt;strong&gt;Objective:&lt;/strong&gt; To evaluate the effect of nitrogen and water availability on growth, chlorophyll concentration and photosynthetic efficiency of guava plants (&lt;em&gt;Psidium guajava&lt;/em&gt; L. var. cuban red dwarf). &lt;strong&gt;Methodology&lt;/strong&gt;: A completely randomized experiment with bifactorial arrangement was designed under greenhouse conditions. Factor A was composed by two levels of nitrogen availability (N1: 1.0 g of nitrogen per plant, N0: no nitrogen application) and factor B by two levels of water availability (A&lt;sub&gt;400&lt;/sub&gt;: 400 mL of water every three days and A&lt;sub&gt;200&lt;/sub&gt;: 200 mL of water every three days). &lt;strong&gt;Results:&lt;/strong&gt; Indicators of photosynthetic structure gain (leaves and branches per plant) were more sensitive to water and nitrogen availability from the early stages of plant development, showing the highest values in treatments with higher nitrogen supply, regardless of water availability. Stem growth was higher in the treatments with higher nitrogen and water supply at 80 ddt, similar to that observed in leaf growth and branch emission, regardless of water availability. &lt;strong&gt;Implications:&lt;/strong&gt; The findings found provide new knowledge about the plasticity of cuban red dwarf guava to the conditions of water and nitrogen availability contrasting with the conditions of the experimental site. &lt;strong&gt;Conclusions:&lt;/strong&gt; Guava plants respond to nitrogen and water limitations in the substrate, increasing root growth as a survival strategy in environments with scarce soil resources, while floods with higher water and nitrogen availability increase their assimilation capacity, proportionally to the chlorophyll&lt;strong&gt; &lt;/strong&gt;content.&lt;/p&gt;

Inclusión de compost de cama profunda porcina en alimentación de vaquillas mestizas de doble propósito

El objetivo de esta investigación fue evaluar la inclusión de compost de cama profunda (CP) de cascarilla de arroz y porquinaza en la alimentación de vaquillas cruzadas de doble propósito. Para ello se utilizaron 18 vaquillas alimentadas con CP procesada en 12 meses obtenidos de la Unidad de Docencia, Investigación y Vinculación Hato Porcino de la Escuela Superior Politécnica Agropecuaria de Manabí “Manuel Félix López”. Se aplicó un DCA con arreglo bifactorial [primer factor: edad (menor a 25 meses de edad y mayor a 25 meses de edad y preñadas de diferente tiempo de gestación); segundo factor: niveles de compost de cama profunda (0%, 10% y 20%)], se consideró como covariable al peso inicial. La composición nutricional del compost de cama fue determinada mediante un análisis proximal con 5,71% de proteína cruda. No se encontraron diferencias significativas (P&gt;0,05) en cada uno de los factores y en la interacción de estos, el grupo de animales menores a 25 meses de edad tuvo un mejor peso al final promedio de la investigación con 308,48 Kg (±2,24), a la vez que los animales que fueron alimentados con una dieta que incluyó 20% de CP tuvieron un peso medio de 310,18 Kg (±2,10) al final del experimento. Se concluye que el contenido nutricional encontrado en el compost de cama profunda no desfavoreció la ganancia de peso y conversión alimenticia, por lo que las dietas suministradas 20% de porquinaza podrán ser utilizadas para mejorar el rendimiento productivo en vaquillas mestizas.

MALTEADO Y VARIEDAD DE MAÍZ EN LAS CARACTERÍSTICAS FISICOQUÍMICAS Y SENSORIALES EN UNA BEBIDA REFRESCANTE

El objetivo de esta investigación fue determinar los efectos del malteado y las variedades de maíz sobre las características fisicoquímicas y sensoriales en una bebida refrescante. Se aplicó un diseño completamente al azar (DCA) en arreglo bifactorial A x B siendo el factor A tres variedades de maíz y el factor B la condición del maíz (malteado y sin maltear), obteniendo 6 tratamientos y se realizó tres repeticiones, resultando 18 unidades experimentales de 2000 ml de bebida refrescante. Las variables valoradas fueron: fisicoquímicas (pH, acidez, sólidos solubles y sólidos en suspensión) donde se detectaron diferencias significativas entre las bebidas con relación al pH, acidez y grados Brix, obteniéndose como mejores tratamientos al T1, T3 y T5, siendo éstas de condición malteado. En los análisis sensoriales (calidad general) realizado mediante la prueba de ordenamiento resultó como mejor tratamiento T5; En las pruebas microbiológicas realizadas a la bebida sobre Coliformes totales, Escherichia coli, mohos y levaduras reflejó ausencia. Palabras clave: Maltear; maíz malteado, macerar; enzimas; bebida refrescante.

Efecto del ácido salicílico sobre la germinación y crecimiento inicial del café (Coffea arabica L. var. Costa Rica 95)

The establishment of new coffee plantations requires vigorous and healthy seedlings that guarantee good growth and high yields; hence the importance of studying the effect of bio-stimulant substances in the early stages of the crop's ontogeny. In this sense, the combined effect of five concentrations of salicylic acid (0; 0.0125; 0.025; 0.05; 0.1 and 1 mM) and different times of imbibition of the seeds (1, 2, 3 and 4 h), on the germination and initial growth of coffee plants (Coffea arabica L.) variety Costa Rica 95 was studied. The experimental design was completely randomized with a bifactorial arrangement, with 24 treatments and 20 repetitions. The percentage and germination rate, height and diameter of the hypocotyl were evaluated. The results showed that the concentrations (0.0125; 0.025 and 0.05 mM) and imbibition times of the seeds of 3 and 4 h in salicylic acid promoted an early germination and a positive effect on the height and diameter of the hypocotyl. The findings show that salicylic acid applied in low concentrations can be used to accelerate the germination of coffee seeds and induce the initial growth of coffee plantlets, while it could be considered as a viable option for coffee producers, both for its easy application and the safety of the product.

Ideal nitrogen concentration in leaves for the production of high-quality grapes cv ‘Alicante Bouschet’ (Vitis vinifera L.) subjected to modes of application and nitrogen doses

The low N use efficiency of vines calls for more efficient fertilization processes, which must mitigate losses caused by volatilization. Thus, N dose applications through different methods, such as fertigation, can potentiate N harnessing by vines. The study aimed to determine ideal N concentration in leaves for the production of high-quality grapes cv ‘Alicante Bouschet’ (Vitis vinifera L.) subjected to modes of application and N doses. The experiment was carried out in a bifactorial arrangement (N dose x modes of application) in a vineyard implanted in 2011, in Southern Brazil. The N doses were 0, 20, 40, 60, 80, and 100 kg N ha−1 year−1. The modes of application were N application without irrigation (NAWI), N application followed by irrigation (NAFI), and N application via fertigation (Fert). The study lasted three crop seasons. Complete leaves were collected at flowering and veraison to determine total N concentration. Grape yield and yield components were determined. Total soluble solids, total anthocyanins, and total polyphenols in grape must be assessed. The maximal recovery rate in grapes was at 36 kg N ha−1, when N concentration was higher than 2.75 % in leaves at flowering, and higher than 2.25 % at veraison, regardless of the N application mode. The concentrations of total anthocyanins, total polyphenols, and total soluble solids in grape must have diminished at doses higher than 60 kg N ha−1. Thus, N concentration in leaves can be used as a reference for grape yield, the concentration of anthocyanins, and soluble solids as indicators of high-quality grape.

PHYSICAL QUALITY OF SOIL IN MECHANIZED THINNING OF Eucalyptus sp.

The traffic of machines is the main cause of compaction of forest soils, causing soil deformations, due to the pressures exerted by the machines, both at the time of cutting and in the transshipment of wood. In this sense, this work had as objective to evaluate soil compaction, caused by the traffic of machines, in the mechanized thinning operation of Eucalyptus saligna Smith. This study was carried out in forest stands, in the municipality of Butiá, RS. Changes in soil physical properties were evaluated in three treatments: with no traffic; after cutting; and after wood transshipment. The forest inventory and collection of undisturbed soil samples were carried out to determine microporosity, macroporosity and bulk density. The experimental design was the completely randomized, in a bifactorial arrangement, with subdivided plots. For the comparison of the physical attributes, the Tukey test (p≤0.05) of significance was used. The results evidenced increase in soil density values, mainly in the treatment after transshipment and decrease in macropores, with values close to and below the limit considerable as detrimental to the development of the plants. The knowledge of soil deformations caused by forest operations contributes to the improvement of future processes aiming to guide the physical quality of the soil, in order to offer beneficial conditions to the growth of the plants.

Photosynthetic activity and grape yield of 'Alicante Bouschet' (Vitis vinifera L.) grapevines submitted to nitrogen supply methods and doses

The great majority of sandy soils present low nitrogen availability, generally below vines physiological demand, and therefore nitrogen fertilizer application, such as urea, is necessary. However, when urea is applied on the soil surface, the vine can use only a small amount of N. Thus, management strategies such as fertigation can increase N utilization by vine, reflecting in a greater photosynthetic activity and grape yield. The objective of this study was to evaluate the influence of nitrogen supply methods and doses on photosynthetic activity and grape yield of 'Alicante Bouschet' grapevines cultivated in sandy soil. The experiment was carried out in Santana do Livramento, in the southern region of Brazil, in a vineyard planted in 2011. The cultivar was 'Alicante Bouschet' grafted on '1103 Paulsen'. The experimental design was of randomized blocks in a bifactorial arrangement (dose x method). The N source used was urea (45 % N). The 0, 20, 60 and 100 kg N·ha-1 doses were applied on the soil surface, without irrigation (NWI) and via fertigation (NF). Photosynthetic activity, N concentration in leaves and grape yield during two growing seasons were evaluated. The application of N doses in soil increased N concentration in grapevine leaves by up to 53 % in NF and 18 % in NWI methods but did not affect yield. Strong correlations between yield and water use efficiency were also observed, evidencing a certain synchronism between the physiological demand of the grapevine and the offer of the adequate N dose by a more efficient method.

La Homeopatía incrementa la tolerancia al estrés por NaCl en plantas de frijol común (Phaseolus vulgaris L.) variedad Quivicán

Currently, the international scientif ic community is increasingly promoting the use of alternatives eco-friendly to the environment to solve agricultural problems, such as soil salinization. The use of agricultural homeopathy, as one of these alternatives, has increased because of its safety and proven effectiveness. This study assessed the effect of attenuating salinity stress (NaCl) of the homeopathic medicine Natrum muriaticum (NaM) on photosynthetic rate (TF) and morphometric variables of the common bean plant (Phaseolus vulgaris L.) variety white testa Quivican in initial plant growth stage. A completely randomized experimental design was applied with bifactorial arrangement (2A × 4B) where A = salinity levels (0 and 75 mM) and B = homeopathic dynamizations (NaM-7CH, NaM-13CH, NaM-7+13CH and distilled water [AD] as homeopathic control) with f ive replicates per treatment. The TF measurements were done twice a week, and the morphometric variables were measured at the end of the experimental evaluation period (35 days). In general, the assessed morphometric variables were favored with the application of the homeopathic treatments NaM 7CH and NaM 7+13CH; the increase in root length (LR) and fresh leaf biomass (BFH) were greater even when the plants were in salinity stress conditions (75mM NaCl). The TF reached the highest value when the plants in saline medium were treated with NaM-7CH, and an increase greater than 50% in PR was observed with respect to the (AD) control treatment. These results demonstrated a great potential of agricultural homeopathy as a bio-safe and low-cost alternative to increase P. vulgaris L. tolerance to NaCl and achieve greater areas of this crop.

The effects of supplemental nitrogen and calcium on the quality and postharvest life of cut gerbera

Abstract The objective of the present work was to evaluate the effect of nitrogen (N) and calcium (Ca), complementary to the complete fertilization established, on production, quality and postharvest shelf life of floral stems of gerbera as cut flower harvested 117 days after transplant. The experiment consisted of a combination of three doses of N.L−1 substrate (0.07 g, 0.15 g and 0.2 g) and three doses of Ca.L−1 substrate (0.02 g; 0.03 g and 0.04 g) and was conducted in a greenhouse in a bifactorial arrangement with an additional control treatment. Control plants were not supplemented with N or Ca. Both elements were diluted in water and applied manually every 15 days. Highest flower yields were obtained with application 0.2 g de N.L−1 substrate and 0.04 g Ca.L−1 substrate. Stem length, stem diameter, flower diameter, and longevity, relative fresh weight and solution uptake were highest in gerbera fertilized with 0.2 g de N.L−1 substrate and 0.04 g Ca.L−1 substrate. Applying every 15 days, 0.2 g of N.L−1 substrate and 0.04 g of Ca.L−1 substrate resulted in higher yields, better quality and postharvest shelf life of floral stems of gerbera as cut flower harvested 117 days after transplant.