Models for predicting coffee yield from chemical characteristics of soil and leaves using machine learning.

BACKGROUND: Coffee farming constitutes a substantial economic resource, representing a source of income for several countries due to the high consumption of coffee worldwide. Precise management of coffee crops involves collecting crop attributes (characteristics of the soil and the plant), mapping, and applying inputs according to the plants' needs. This differentiated management is precision coffee growing and it stands out for its increased yield and sustainability. RESULTS: This research aimed to predict yield in coffee plantations by applying machine learning methodologies to soil and plant attributes. The data were obtained in a field of 54.6 ha during two consecutive seasons, applying varied fertilization rates in accordance with the recommendations of soil attribute maps. Leaf analysis maps also were monitored with the aim of establishing a correlation between input parameters and yield prediction. The machine-learning models obtained from these data predicted coffee yield efficiently. The best model demonstrated predictive fit results with a Pearson correlation of 0.86. Soil chemical attributes did not interfere with the prediction models, indicating that this analysis can be dispensed with when applying these models. CONCLUSION: These findings have important implications for optimizing coffee management and cultivation, providing valuable insights for producers and researchers interested in maximizing yield using precision agriculture. © 2024 Society of Chemical Industry.

Yield, nutrition, and leaf gas exchange of lettuce plants in a hydroponic system in response to Bacillus subtilis inoculation.

Inoculation with Bacillus subtilis is a promising approach to increase plant yield and nutrient acquisition. In this context, this study aimed to estimate the B. subtilis concentration that increases yield, gas exchange, and nutrition of lettuce plants in a hydroponic system. The research was carried out in a greenhouse in Ilha Solteira, Brazil. A randomized block design with five replications was adopted. The treatments consisted of B. subtilis concentrations in nutrient solution [0 mL "non-inoculated", 7.8 × 103, 15.6 × 103, 31.2 × 103, and 62.4 × 103 colony forming units (CFU) mL-1 of nutrient solution]. There was an increase of 20% and 19% in number of leaves and 22% and 25% in shoot fresh mass with B. subtilis concentrations of 15.6 × 103 and 31.2 × 103 CFU mL-1 as compared to the non-inoculated plants, respectively. Also, B. subtilis concentration at 31.2 × 103 CFU mL-1 increased net photosynthesis rate by 95%, intercellular CO2 concentration by 30%, and water use efficiency by 67% as compared to the non-inoculated treatments. The concentration of 7.8 × 103 CFU mL-1 improved shoot accumulation of Ca, Mg, and S by 109%, 74%, and 69%, when compared with non-inoculated plants, respectively. Inoculation with B. subtilis at 15.6 × 103 CFU mL-1 provided the highest fresh leaves yield while inoculation at 15.6 × 103 and 31.2 × 103 CFU mL-1 increased shoot fresh mass and number of leaves. Concentrations of 7.8 × 103 and 15.6 × 103 increased shoot K accumulation. The concentrations of 7.8 × 103, 15.6 × 103, and 31.2 × 103 CFU mL-1 increased shoot N accumulation in hydroponic lettuce plants.

Inoculation with Azospirillum brasilense Strains AbV5 and AbV6 Increases Nutrition, Chlorophyll, and Leaf Yield of Hydroponic Lettuce.

Inoculation with Azospirillum brasilense has promisingly increased plant yield and nutrient acquisition. The study aimed to estimate the dose of A. brasilense that increases yield, gas exchange, nutrition, and foliar nitrate reduction. The research was carried out in a greenhouse at Ilha Solteira, in a hydroponic system in randomized blocks with four replicates. The treatments consisted of doses of inoculation with A. brasilense strains AbV5 and AbV6 via nutrient solution (0, 8, 16, 32, and 64 mL 100 L-1). Inoculation with A. brasilense at calculated doses between 20 and 44 mL provided the highest fresh and dry mass of shoots and roots, number of leaves, and leaf yield. In addition, the calculated doses of inoculation with A. brasilense increased the accumulation of N, P, K, Ca, Mg, S, B, Fe, Mn, and Zn in shoots and roots, except the accumulation of Ca in roots. It also increased cell membrane integrity index (15%), relative water content (13%), net photosynthesis rate (85%), intracellular CO2 concentration (15%), total chlorophyll (46%), stomatal conductance (56%), transpiration (15%), and water use efficiency (59%). Hence, inoculation with A. brasilense at doses between 20 and 44 mL 100 L-1 is considered the best approach for increasing the growth, yield, accumulation of nutrients, and gas exchange of hydroponically grown iceberg lettuce.

A site suitability analysis for castor (Ricinus communis L.) production during Brazil's second harvest incorporating disease prediction.

Castor (Ricinus communis L.) is an important industrial crop with a wide range of industrial and pharmaceutical applications. Brazil is among the largest castor-producing countries. Between 2004 and 2010, castor cultivation was stimulated with an emphasis towards biodiesel production. However, this was not enough to leverage the production of castor in Brazil, mainly due to the lack of structured trade and the competition with other cheaper raw materials for the production of biodiesel. Despite this failure, the species presents itself as an excellent alternative for crop rotation in the second crop among soybean, corn, beans, and cotton cultivation areas as the oil is highly valuable for other products. Moreover, it has drawn the attention of producers and researchers in Brazil for this potential rotation as it is considered a plant tolerant of water-deficiency and is highly susceptible to gray mold, a disease favored by high humidity in the final stages of the crop. For instance, its cultivation in the second crop in Cerrado regions, where rains occur in the early stages of the crop and cease when the plants reach the final stage of production, has been successful and shows great promise. The current study aimed to evaluate the suitability of environments throughout Brazil to grow castor, incorporating variables associated with the incidence of gray mold and confirm these findings based on existing castor trial data obtained from the literature. The site suitability analysis determined that 74.99 million hectares - 8.8% of Brazilian territory - are highly suitable for castor production during second harvest, mostly located in the Northeastern and Midwestern regions. These results are surprising since Brazil currently has around 7.8% (∼66.81 million hectares) of its territory occupied with agriculture (grains, fruits, vegetables, and perennial crops). The findings of this study provide a method to perform site suitability for crops using data associated with agronomic and disease characteristics, as is the case with gray mold that often results in significant losses in castor production. Also, this analysis provides evidence for the great potential of Brazil to increase castor production and meet the world demand for its oil through utilization of second-crop cultivation.

Jatropha curcas L. as a Plant Model for Studies on Vegetative Propagation of Native Forest Plants.

Even though it is a forest native plant, there are already several studies evaluating the small genome of Jatropha curcas L., which belongs to the Euphorbiaceae family, and may be an excellent representative model for the other plants from the same family. Jatropha curcas L. plant has fast growth, precocity, and great adaptability, facilitating silvicultural studies, allowing important information to be obtained quickly, and reducing labor costs. This information justifies the use of the species as a model plant in studies involving the reproduction of native plants. This study aimed to evaluate the possibility of using Jatropha curcas L. as a model plant for studies involving native forest plants and establish possible recommendations for the vegetative propagation of the species using hardwood cuttings. The information collected can be helpful to other native forest plant species, similar to Jatropha curcas L. To this end, the effects of hardwood cutting length (10, 20, and 30 cm) and the part of the hardwood cuttings (basal, middle, and apex) were evaluated. Moreover, the influence of immersing the hardwood cuttings in solutions containing micronutrients (boron or zinc) or plant regulators (2,4-D, GA3) and a biostimulant composed of kinetin (0.09 g L-1), gibberellic acid (0.05 g L-1), and 4-indole-3-butyric acid (0.05 g L-1). The experiments were carried out in duplicates. In one duplicate, sand was used as the substrate, and rooting evaluations were made 77 days after planting. In another duplicate, a substrate composed of 50% soil, 40% poultry litter, and 10% sand was used, and the evaluations of the saplings were performed 120 days after planting. The GA3 solutions inhibited the roots' and sprouts' emissions, while immersion in 2,4-D solution increased the number of primary roots at 77 days after planting. The hardwood cuttings from the basal part of the branch had the best results for producing saplings.

Adaptability and Stability of Safflower Genotypes for Oil Production.

The study aimed to analyze the agronomic performance of 11 safflower genotypes using adaptability and stability methods, while identifying safflower genotypes with stable behavior and a high grain yield in different environments of the Brazilian Cerrado. Ten lines and a cultivar of safflower were evaluated in four environments in the Brazilian conditions. Our results revealed the genotypes P30, P35, P9, P11, and P31 to be superior for grain yield and P43, P7, P11, and P31 to be superior for oil content. The lowest Wricke index, an indication of genotype stability, was observed for P9 (0.41%), which is considered the most stable genotype, followed by P35 (1.29%) and P31 (1.98%). For the predictability of the behavior of genotypes in the environments, P7 (80.85%), P35 (86.10%), P31 (85.90%), and P9 (97.42%) were considered predictable genotypes. The genotypes P11 (1045.6 kg ha-1 and 19.7%) and P21 (952.7 kg ha-1 and 20.6%) are recommended for cultivation in this region, considering both their grain yield and oil content. Safflower is viable to use out of season in the Brazilian Cerrado. The crop can generate profits for farmers and be used for oil production in periods of uncertain corn production.

Zinc - rooting cofactor in rubber tree mini-cuttings / Zinco - cofator de enraizamento em miniestacas de seringueira

The rubber tree (Hevea brasiliensis Müell. Arg.) is a species of significant economic interest in the natural rubber industry in Brazil and the world. This species presents recalcitrance to rooting, and its cuttings are difficult to propagate. This study aimed to evaluate the effect of the pre-conditioning of rubber tree mini-cuttings with zinc on the improvement of the adventitious rooting of rootstocks. Mini-cuttings were standardized with 45 mm length and submitted to preconditioning by immersion of the mini-cutting base in solutions containing 0.00; 0.04; 0.08; 0.16; 0.32 and 0.64 mg L-1 of Zn, for 24 hours. The experimental design was randomized blocks with six treatments and four replicates of 10 mini-cuttings. The rubber tree mini-cuttings were placed in a fitotron-type growth chamber, at 25 °C, with 12-hour photoperiod, 5,000 K intensity, and 95% of relative air humidity, for 60 days. The survival rate, number of buds, percentage of mini-cuttings that had leaf abscission, the percentage of mini-cuttings with callogenesis in the root meristem, the percentage of rooted mini-cuttings, the number of primary roots and root length were evaluated. The highest values of survival rate, the number of buds, the number of primary roots, the percentage of mini-cuttings with callogenesis in the root meristem, the percentage of rooted mini-cuttings and root length were observed with 0.16 to 0.26 Mg L-1 of Zn. The use of zinc in the mini-cuttings of rubber tree reduces linearly the percentage of mini-cuttings that had leaf abscission and the formation of callogenesis in the root meristem.

A seringueira (Hevea brasiliensis Müell. Arg.) é uma espécie de importância econômica para a indústria da borracha natural do Brasil e do mundo. Esta espécie apresenta recalcitrância ao enraizamento e suas estacas são difíceis de se propagar. Este trabalho objetivou avaliar o efeito do pré-condicionamento de miniestacas de seringueira com zinco na melhoria do enraizamento adventício de porta-enxertos. As miniestacas foram padronizadas com 45 mm de comprimento e submetidas ao pré-condicionamento por imersão da miniestaca em soluções contendo 0.00; 0,04; 0,08; 0,16; 0,32 e 0,64 mg L-1 de Zn, por 24 horas. O delineamento experimental foi em blocos ao acaso, com seis tratamentos e quatro repetições de 10 miniestacas. As miniestacas de seringueira foram colocadas em câmara de crescimento tipo fitotron, a 25 °C, com fotoperíodo de 12 horas, intensidade de 5.000 K e umidade relativa do ar de 95% por 60 dias. Foram avaliadas a taxa de sobrevivência, o número de gemas, a porcentagem de miniestacas que apresentaram abscisão foliar, o percentual de miniestacas com calogênese no meristema radicular, o percentual de miniestacas enraizadas, o número de raízes primárias e o comprimento das raízes. Os maiores valores de taxa de sobrevivência, o número de gemas, o número de raízes primárias, a porcentagem de miniestacas com calogênese no meristema radicular, o percentual de miniestacas enraizadas e o comprimento radicular foram verificados com 0,16 a 0,26 Mg L-1 de Zn. O uso de zinco nas miniestacas de seringueira reduz linearmente a porcentagem de miniestacas que tiveram abscisão foliar e a formação de calogênese no meristema radicular

Correlations and path analysis in agronomic traits of soybeans under defoliation / Correlações e análise de trilha em caracteres agronômicas de soja sob desfolha

Stress events or leaf damage can alter the redistribution of photoassimilates and modify the morphological traits directly related to grain yield. This study aimed to evaluate the influence of agronomic traits on grain yield in soybean crop in function of leaf defoliation. The experiment consisted of a randomized block design with three replications, arranged in a 6 x 3 + 1 factorial scheme. The factors were composed by six reprodutive stages (R1, R2, R3, R4, R5, and R6) and three defoliation levels (33%, 66%, and 99%), and one additional treatment without defoliation (control). The following traits were evaluated: plant height, number of pods per plant, number of grains per pod, thousand grain weight, and grain yield. The magnitudes of the correlations between the same traits showed high oscillation according to the defoliation level. Results revealed the potential for the indirect selection for grain yield by the traits plant height and number of grains per pods under 0% of defoliation and by the trait number of pods per plant under 33% of defoliation.

Ocorrências de estresse ou danos foliares podem levar a alteração na redistribuição de fotoassimilados e modificar os caracteres morfológicos envolvidos diretamente na produtividade dos grãos. Portanto, objetivou-se avaliar por meio da análise de trilha, a influência de caracteres agronômicos na produtividade de grãos na cultura da soja em função de níveis desfolha da planta. O delineamento experimental utilizado foi o de blocos casualizados com três repetições, dispostos em esquema fatorial 6 x 3 + 1. O primeiro fator foi composto por seis estádios reprodutivos de desfolha (R1, R2, R3, R4, R5, R6) x três níveis de desfolha (33%, 66%, 99%) e um tratamento adicional sem desfolha (controle). Os caracteres avaliados foram: altura de plantas, número de legumes por planta, número de grãos por legume, peso de mil grãos e produtividade de grãos. As magnitudes das correlações entre os mesmos caracteres apresentaram alta oscilação de acordo com o nível de desfolha, sendo que, que existe potencial da seleção indireta para produtividade de grãos por meio da altura de plantas e número de grãos por legumes sob 0% desfolha e do número de legumes por planta sob 33% de desfolha.

Potassium supplying capacity of some lowland soils under potassium fertilization and successive croppings / Capacidade de suprimento de potássio de alguns solos de várzea sob fertilização com potássio e plantações sucessivas

The effects of intense cropping and potassium fertilization on potassium (K) dynamics and non-exchangeable K release from three lowland soils of Paraná State, Brazil, were investigated in this study. Samples of three lowland soils were fertilized or not with K and subjected to six successive croppings (soybeans, pearl millet, wheat, common beans, soybeans, and maize). The crops were grown in 8-L pots for 45 days, and at the end of the sixth cropping, the soil from each pot was sampled to the determination of soil K pools. The lowland soils differ in the ability to K supply to the plants in the short to medium term due to the wide range of origin material and the concentration of K in solution, exchangeable K, non-exchangeable K, and structural K. When the soils were not fertilized with K, the successive cropping resulted in continuous depletion process of non-exchangeable and exchangeable K; however, this depletion was less pronounced in soils with a higher potential buffer capacity of K. Non-exchangeable and exchangeable K concentrations were increased with the addition of K fertilizer, indicating the occurrence of K fixation in soil. The non-exchangeable K contribution to K nutrition of plants ranged from 44 to 69% in the treatments without the addition of K fertilizer, reporting the importance of non-exchangeable K pools in the supply of this nutrient to plants in agricultural production systems.

Os efeitos dos cultivos sucessivos e da adubação potássica na dinâmica de potássio (K) do solo e na mobilização do K não-trocável para às plantas em três solos de varzea do Estado do Paraná, Brasil, foram investigados neste estudo. Amostras dos três solos de várzea foram submetidas à adição ou não de fertilizante potássico e a seis cultivos sucessivos de plantas (soja, milheto, trigo, feijão, soja e milho). As culturas foram cultivadas em vasos de 8-L por 45 dias e, ao final do sexto cultivo, foram coletadas amostras de solos para a deteminação das diferentes formas de K do solo. Os solos de vázea diferenciaram-se na capacidade de suprir K às plantas a curto e médio prazo, devido à ampla variação do material de origem e dos teores de K na solução, K trocável, K não-trocável e K estrutural. Quando os solos não foram adubados com K, o cultivo sucessivo de plantas resultou em um processo contínuo de esgotamento das formas de K não-trocável e K trocável, sendo menos acentuada nos solos com maior poder tampão de potássio. Os teores de K não-trocável e K trocável aumentaram com a adição de fertilizantes potássicos, indicando a ocorrência de fixação de K pelo solo. A contribuição do K não-trocável para a nutrição das plantas durante os seis cultivos variou de 44 a 69% no tratamento sem adição de fertilizante potássico. Estes resultados reportam a importância das formas de K não-trocável para o suprimento deste nutriente às plantas nos sistemas de produção agrícolas.

Can co-inoculation of Bradyrhizobium and Azospirillum alleviate adverse effects of drought stress on soybean (Glycine max L. Merrill.)?

Harnessing the beneficial potential of plant growth-promoting rhizobacteria may be an alternative strategy to improve plant tolerance to drought stress. The effect of inoculation with Bradyrhizobium japonicum and Azospirillum brasilense either alone or in combination on the plant growth and drought tolerance of soybean [Glycine max (L.) Merrill.] was investigated in this study in greenhouse conditions. Treatments were arranged in a randomized block design in a 3 × 4 factorial: three irrigation regimes [100% of pot capacity-PC (well-watered control), 50% of PC (moderate stress) and 25% of PC (severe stress)] and four inoculation treatments [control (non-inoculated), inoculation with B. japonicum, inoculation with A. brasilense, and co-inoculation with B. japonicum and A. brasilense]. Leaf relative water content, cell membrane stability, root nodulation, plant growth, and morphophysiological indexes were recorded. The inoculation of soybean plants with B. japonicum and A.brasilense either alone or in combination improved leaf membrane stability under drought stress conditions when compared to non-inoculated plants; however, this lower damage to cell membranes was not sufficient to maintain the leaf water content of the plant under drought stress. Plants co-inoculated with B. japonicum and A.brasilense improved the root nodulation under severe drought conditions. Inoculation of B. japonicum and A. brasilense either alone or in combination reduced the pod abortion rate under moderate drought stress, but had no effect under severe drought stress. In summary, the co-inoculation of A. brasilense and B. japonicum alleviate adverse effects limited by drought stress to the growth of soybeans.Author: Please check and confirm that the authors [Elijanara Raissa Silva, Carlos Eduardo Silva Oliveira, Alan Mario Zuffo, Eduardo Pradi Vendruscolo] and their initials have been correctly identified and amend if necessary.The authors were correctly identified.

Seed priming improves the germination and growth rate of melon seedlings under saline stress / Condicionamento de sementes melhora a germinação e a taxa de crescimento das plântulas de melão sob estresse salino

ABSTRACT: The germination and growth of melon (Cucumis melo L.) plants can be severely affected by excess salts in the soil or irrigation water; however, negative effects of salt stress can be attenuated using appropriate methods of seed priming. Thus, effects of osmopriming as inducer of salt stress tolerance in melon seeds exposed to salinity levels were investigated in this study. Seeds were soaked for 22 h at 25 °C in the dark in distilled water (hydropriming) or 0.5% KNO3 solution (osmopriming), and after drying, were distributed in plastic boxes with blotter paper containing different NaCl solutions prepared with osmotic pressure of 0.0 MPa (control), -0.3 MPa (mild stress), and -0.6 MPa (severe stress). Unprimed dry seeds were taken as control. The plastic boxes were kept into a seed germinator, at 25 °C for 14 days. A completely randomized design in a 3 × 3 factorial schemes with four replicates of 25 seeds was used. Results showed that the seed priming with water and KNO3 may be successfully applied on melon seeds to alleviate the adverse effects of saline stress in initial stages of plant growth. However, under severe salt stress conditions, hydropriming should be used because it results in higher germination and initial growth rate of the seedlings when compared to the osmopriming. Use of unprimed seeds should not be adopted in cultivation areas affected by salinity because they result in low germination rate and reduced initial plant growth.

RESUMO: A germinação e o crescimento de plantas de melão (Cucumis melo L.) podem ser severamente afetadas pelo excesso de sais no solo ou na água de irrigação. No entanto, os efeitos negativos do estresse salino podem ser amenizados com o uso de métodos adequados de condicionamento das sementes. Assim, este estudo objetivou investigar os efeitos do osmocondicionamento como indutor da tolerância ao estresse salino em sementes de melão expostas à níveis de salinidade. As sementes foram imersas por 22 h à 25 °C em água destilada (hidrocondicionamento) ou em solução de 0,5% de KNO3 (osmocondicionamento). Após secagem, as sementes foram distribuídas em caixas plásticas com papel mata-borrão contendo as diferentes soluções de NaCl preparadas com potencial osmótico de 0,0 MPa (controle), -0,3 MPa (estresse suave) e -0,6 MPa (estresse severo). Um tratamento com sementes secas não condicionadas foi utilizado como controle. As caixas plásticas foram mantidas em germinador de sementes, a 25 °C por 14 dias. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 3 × 3, com quatro repetições de 25 sementes. Os resultados mostraram que o condicionamento de sementes com água e KNO3 pode ser aplicado com sucesso em sementes de melão para amenizar os efeitos adversos do estresse salino durante o estágio inicial de crescimento das plantas. No entanto, sob estresse salino severo, o hidrocondicionamento deve ser utilizado por resultar em maior percentagem de germinação e maior taxa de crescimento inicial das plântulas quando comparado ao osmocondicionamento. O uso de sementes de melão sem condicionamento prévio não deve ser adotado em áreas de cultivo afetadas pela salinidade, pois resultam em baixa taxa de germinação e reduzido crescimento inicial das plantas.

Feeding preference of Spodoptera frugiperda on different sorghum genotypes / Preferência alimentar de Spodoptera frugiperda em diferentes genótipos de sorgo

The resistance of plants to pests is a feature of great importance for agriculture, as it reduces costs with insecticides and promotes increased yield resulting in higher profits. This work aimed to evaluate the feeding preference of the Spodoptera frugiperda caterpillar by different sorghum genotypes. The experiment was carried out at the Entomology Laboratory of Universidade Estadual de Mato Grosso do Sul, at University Unit of Cassilândia, from March to June 2016. The experimental design was completely randomized with ten replicates. The treatments were composed by seven sorghum genotypes: Agromen 50A40, Agromen 50A50, DOW 1G100, DOW 1G220, DOW 1G233, XB 6022 and LG 6310. Evaluations were performed with 1st instar caterpillars. The number of caterpillars that settled in the genotypes at 5, 10, 15, 20, 25, 30, 60 minutes and 24 hours after the infestation was recorded. The feeding preference index and the fresh leaf mass consumed were estimated. The Agromen 50A40 genotype showed lower attractiveness rating for the S. frugiperda among all evaluated sorghum genotypes.(AU)

A resistência das plantas às pragas é uma característica de grande importância para a agricultura, pois reduz os custos com inseticidas e promove o aumento da produtividade, resultando em maiores lucros. Este trabalho foi desenvolvido com o objetivo de avaliar a preferência alimentar da lagarta Spodoptera frugiperda por diferentes genótipos de sorgo. O experimento foi conduzido no Laboratório de Entomologia da Universidade Estadual de Mato Grosso do Sul, na Unidade Universitária de Cassilândia, no período de março a junho de 2016. O delineamento experimental foi inteiramente ao acaso, com 10 repetições. Os tratamentos foram compostos por sete genótipos de sorgo: Agromen 50A40, Agromen 50A50, DOW 1G100, DOW 1G220, DOW 1G233, XB 6022 e LG 6310. As avaliações foram realizadas com lagartas de 1° instar. Anotou-se o número de lagartas que se estabeleceram nos genótipos aos 5, 10, 15, 20, 25, 30, 60 minutos e 24 horas após a infestação. Foi estimado o índice de preferência e a massa fresca de folha consumida. O genótipo Agromen 50A40 apresentou menor atratividade para a S. frugiperda dentre todos os genótipos de sorgo avaliados.(AU)

Foliar application of calcium and boron improves the spike fertily and yield of wheat / Aplicação foliar de cálcio e boro melhora a fertilidade da espiga e produtividade do trigo

Foliar applications of calcium (Ca) and boron (B) could improve the fertilization of flowers and enhance the wheat yield. The effects of foliar spray of Ca and B on plant growth, grain yield and yield components of wheat were investigated in this study. Treatments consisted of 0, 1.8, 3.6, and 7.2 L ha­1 application of chelated fertilizer containing 125 g L­1 of Ca and 6 g L­1 of B (Omega Cabor II®), divided into two spray, the first one at tillering and the second at early bloom. The results revealed that foliar spray of Ca and B did not affect the stem diameter, peduncle length, spike length, hectoliter weight and thousand-grain mass of wheat. Maximum plant height and flag leaf insertion height was recorded with 4.0 L ha­1 application of foliar fertilizer (4% increase over control). The 7.2 L ha­1 application of foliar fertilizer increased significantly the number of spikelets per spike (9%), number of grains per spike (24%), grain mass per spike (28%), spike mass (14%), number of spikes m­2 (32%) and grain yield (30%) compared to the control. Foliar application of Ca and B improves growth, fertilization of flowers and the number of fertile tillers of wheat plants resulting in higher grain yield.

A aplicação foliar de cálcio (Ca) e boro (B) pode garantir a fertilização das flores e aumentar a produtividade do trigo. Este estudo teve como objetivo avaliar o efeito da aplicação foliar de Ca e B no crescimento, nos componentes de rendimento e na produtividade do trigo. Os tratamentos constituíram da aplicação de 0; 1,8; 3,6 e 7,2 L ha­1 de fertilizante foliar, na forma de quelato, contendo 125 g L­1 de Ca e 6 g L­1 de B (Omega Cabor II®), divididas em duas aplicações foliares, a primeira no início do afilhamento e a segunda no emborrachamento. Os resultados revelaram que a aplicação foliar de Ca e B não afetaram o diâmetro de colmo, comprimento do pedúnculo, comprimento da espiga, peso do hectolitro e massa de mil grãos de trigo. A maior altura de planta e altura de inserção da folha bandeira foram verificados com a aplicação de 4.0 L ha­1 de fertilizante foliar (aumento de 4% em relação ao controle). A aplicação de 7.2 L ha­1 de fertilizante foliar aumentou significativamente o número de espiguetas por espiga (9%), número de grãos por espiga (24%), massa de grãos por espiga (28%), massa de espiga (14%), número de espigas m­2 (32%) e produtividade de grãos (30%). A aplicação foliar de cálcio e boro melhora o crescimento, a fertilização das flores e o número de afilhos férteis das plantas de trigo resultando no aumento de produção de grãos.

Morphogenesis and production of tanzânia, mombaça and mulato grasses under nitrogen fertilization / Morfogênese e produção dos capins tanzânia, mombaça e mulato sob adubação nitrogenada

A field trial was conducted designed in a completely randomized block in a 4 x 3 factorial arrangement to evaluate the application of nitrogen doses (N) (0, 40, 80 and 160 kg/ha) on the morphogenical characteristics and dry matter partition of three forage grasses (Panicum maximum cvs. Mombasa and Tanzania and Brachiaria sp. Hybrid Mulato). The leaf appearance (LAR, leaf/day) and stretching (LER; mm/day) rates, the number of green leaves per tiller (NLT) and the average weight of tillers (MTW; g) presented s positive linear response to the N dose while the phyllochron (Phil; day/leaves) showed a negative linear response. The highest LER, IAL and final leaf length (FLL; cm) occurred in the Mombaça and Tanzania grasses, while the highest LAR occurred in the Mulato grass. There was a negative quadratic effect of the N dose on the stem elongation rate (SER; mm/day) and LF. The Mombaça and Tanzania grasses presented the highest SER; however, in just two forages. The production of total dry matter (TDM; kg/ha), leaves (LDM; kg/ha) and stems (SDM; kg/ha) increased linearly and quadratically with the N dose, respectively, for the Mombaça and Tanzania grasses. There was a high positive correlation among DM, LDM and SDM and the Mombaça grass MTW. The dry matter production and morphogenic characteristics were influenced by the nitrogen fertilization as a result of the substantial increase in the flow of tissues stimulated by fertilization, proving the importance of N for forage biomass accumulation.

O experimento foi conduzido sob o delineamento em blocos completos ao acaso em esquema fatorial 4x3 para avaliar a aplicação de doses de nitrogênio (N) (0, 40, 80 e 160 kg/ha) sobre as características morfogênicas e a partição de matéria seca (MS) de três gramíneas forrageiras (Panicum maximum cvs. Mombaça e Tanzânia e Brachiaria sp. híbrida Mulato). As taxas de aparecimento (TapF; folhas/dia) e alongamento de folhas (TalF; mm/folha), o número de folhas verdes por perfilho (NFVP) e o peso médio de perfilhos (PMP; g) apresentaram resposta linear positiva às doses de N enquanto o filocrono (Fil; dias/folha) apresentou resposta linear negativa. Os capins Tanzânia e Mombaça apresentaram maiores TalF, Fil e comprimento final de folhas (CFF; cm) enquanto o capim Mulato apresentou maior TapF. As produções de matéria seca total (PMST; kg/ha) de folhas (PMSF; kg/ha) e de colmos (PMSC; kg/ha) aumentaram de forma quadrática e linear com as doses de N, respectivamente, para os capins Mombaça e Tanzânia. Houve alta correlação positiva entre as PMST, PMSF e PMSC e o PMP da forrageira Mombaça. A produção de matéria seca e as características morfogênicas foram influenciadas pela adubação nitrogenada, como resultado do aumento substancial do fluxo de tecidos estimulado pela adubação, o que comprova a importância do N para o acúmulo de biomassa da forragem.

Cultivo consorciado de soja com braquiária / Intercropping of braquiária with soybean

Objetivou-se nesse trabalho estudar o cultivo consorciado da Brachiaria brizantha cv. Marandu com a soja. O experimento foi implantado em área sob sistema plantio direto vigente há 3 anos, em Latossolo Vermelho eutroférrico, no município de Maripá - PR. O delineamento experimental foi de blocos casualizados com cinco repetições. A produção e o valor nutricional do capim Marandú foram estudados em quatro tratamentos que consistiram de épocas de semeadura da braquiária em relação á semeadura da soja: antecipada (sete dias antes da semeadura da soja), conjunta (mesmo dia da semeadura da soja), e defasada (nos estádios V3 e R1 da soja). No estudo da produtivividade, teor de nitrogênio e teor de óleo nos grãos da cultura da soja foram adotados seis tratamentos que constaram de épocas de semeadura do capim Marandu, [antecipada (sete dias antes da semeadura da soja), conjunta (mesmo dia da semeadura da soja), após (estádio V3, R1 e R5 da soja) em relação à data de semeadura da soja, mais o cultivo exclusivo da leguminosa (solteira)]. A maior produtividade de massa seca pela forrageira ocorre com a semeadura antecipada, entretanto, nesse caso ocorre a maior redução de produtividade da soja. A época de semeadura da braquiária até o R5 da soja não tem influência sobre o valor nutricional da forrageira. O cultivo consorciado da soja com Brachiaria brizantha cv. Marandu não tem influência sobre o teor de nitrogênio foliar, teor de óleo e atividade de enzima peroxidase da soja. A maior produtividade da soja ocorre quando a mesma é cultivada solteira ou quando a braquiária for semeada no estádio R5. O teor de proteína bruta dos grãos da soja é reduzido quando a semeadura da braquiária ocorre antecipadamente ou em conjunto com a soja em relação ao cultivo solteiro.

The objective of this work was to study the intercropping of Brachiaria brizantha. Marandu with soybeans. The experiment has been planted in a 3 year prevailing area with no-tillage, in eutrophic Oxisol at Maripá ­ PR. The experimental design was a randomized block with five replications. For the forage study, four treatments were performed which consisted of seeding times brachiaria [early (seven days before planting soybeans) joint (same day of soybean planting) and after (at stages V3 and R1 culture)] intercropping with soybean. To study the yield and crude protein and oil levels of the grain were adopted six treatments, which consisted of sowing dates of "capim Marandu" [early (seven days before planting soybeans), joint (same day of soybean planting ) after (V3, R1 and R5 soybean) and in single culture (single)]. The forager higher productivity of dry matter occurs with early sowing, however, the greatest reduction in soybean yield also occurs in this case. The sowing of Brachiaria until R5 soy has no influence on the nutritional value of the forage. The intercropped of soybean with Brachiaria brizantha. Marandu has no impact on the leaf Nitrogen content, oil content and enzyme activity of soybean peroxidase. The highest yield of soybeans occurs when it is grown single or Brachiaria is sown in stage R5. The crude protein content of soybean grain is reduced when brachiaria seeding is early or together with soybeans compared to single culture.

Substituição da adubação nitrogenada mineral pela cama de frango na sucessão aveia/milho / Mineral nitrogen substitution by chicken litter in succession oat/corn

A busca constante pela sustentabilidade dos sistemas de produção têm direcionado as pesquisas a buscar alternativas aos problemas oriundos da intensificação dos sistemas produtivos. Nesse contexto o presente trabalho teve como objetivo estudar os efeitos da substituição da adubação nitrogenada mineral pela cama de frango sucessão aveia-milho e nas características químicas do solo. O trabalho foi desenvolvido durante o período de maio de 2009 a março de 2010 em área de Latossolo Vermelho eutroférrico. O delineamento foi de blocos ao acaso com quatro repetições. Os seis tratamentos foram obtidos com a combinação de diferentes quantidades de cama de frango (0, 1500, 3000, 4500, 6000 e 7500 kg ha-1) aplicadas 30 dias antes da semeadura da aveia combinadas com a adubação nitrogenada mineral de cobertura aplicada na cultura do milho (311,1; 257,8; 202,2; 148,9; 95,6; 42,2 kg ha-1 de uréia), visando o fornecimento total de 140 kg ha-1 de nitrogênio (N). A aplicação de cama de frango na cultura da aveia favorece o aumento da produção de massa seca, teor e acúmulo de N. A substituição da adubação nitrogenada mineral pela cama de frango eleva os índices de produtividade da cultura do milho. A utilização de cama de frango altera as propriedades químicas do solo, elevando os teores de matéria orgânica, alumínio trocável e a acidez potencial. Entretanto reduz o pH, K, Ca, Mg, soma de bases e saturação por bases.

The constant search for sustainability of production systems have driven research to find alternatives to the problems arising from the intensified use such systems. In this context the present work aimed study the effects of substitution of mineral nitrogen by chicken litter in oat and corn crop in succession and the chemical characteristics of soil. The study was conducted during the period May 2009 to March 2010 in area of Oxisol. The design was of randomized block with four replications. The six treatments were obtained by a combination of different amounts of chicken litter (0, 1500, 3000, 4500, 6000 and 7500 kg ha-1) applied 30 days before the sowing of oats combined with the mineral nitrogen applied in coverage in corn (311.1, 257.8, 202.2, 148.9, 95.6, 42.2 kg ha-1 of urea), for the total supply of 140 kg ha-1 of nitrogen (N). The application of poultry litter in oat promotes increased the production of dry matter, and content and accumulation of N. The mineral nitrogen substitution by chicken litter increases the yield of corn crop. The use of poultry litter alters the chemical properties of soil, increasing the levels of organic matter, exchangeable Al and acidity potential. However lowers the pH, K, Ca, Mg, sum of bases and base saturation.

Peroxidase activity as an indicator of water deficit tolerance in soybean cultivars / Atividade de peroxidase como indicativo de tolerância à deficiência hídrica em cultivares de soja

This study had as purpose to test the hypothesis that peroxidase enzyme activity could be used as an indicator of tolerance to water deficit in soybean cultivars. The experiment was carried out in pots containing 20-L of a Rhodic Hapludox soil in greenhouse conditions. Treatments were arranged in a randomized block design in a 2 × 4 factorial: two water regimes (with and without water deficit) and four soybean cultivars (CD 204, CD 215, CD 225RR and CD 226RR), with four replications. Soybean plants were grown until the beginning of flowering (R1-R2) with soil moisture content near at the field capacity, and then, it started the differentiation of treatments under water deficit by the suspension of water supply. Changes in relative water content (RWC) in leaves, protoplasmic tolerance, peroxidase activity, and plant growth were measured after four days of drought stress and 4-d recovery. The soybean cultivars used in this study have different responses under water deficit conditions. The CD 215 cultivar was the most sensitive to water deficit in the beginning of flowering stage. Soybean cultivars presented variable responses to the peroxidase enzyme activity, and this variable can be used in the selection of soybean genotypes with greater tolerance to drought.

Este estudo teve como objetivo testar a hipótese de que a atividade das enzimas peroxidase poderia ser utilizada como um indicativo de tolerância à deficiência hídrica em cultivares de soja. O experimento foi realizado em vasos contendo 20L de um Latossolo vermelho argiloso em condições de casa-de-vegetação. Os tratamentos foram dispostos no delineamento de blocos casualizados em esquema fatorial 2 × 4, constituído de dois regimes hídricos (sem e com déficit hídrico) e quatro cultivares de soja (CD 204, CD 215, CD 225RR and CD 226RR), com quatro repetições. A soja foi cultivada até o início do florescimento com teor de água no solo próximo a capacidade de campo, e então, iniciouse a diferenciação dos tratamentos com déficit hídrico, mediante a suspensão do fornecimento de água. Alteração no conteúdo relativo de águas nas folhas, tolerância protoplasmática, atividade das enzimas peroxidade e crescimento das plantas foram avaliados após quatro dias de exposição ao déficit hídrico e após quatro dias de recuperação das plantas em condições controle. As cultivares de soja utilizadas neste estudo apresentam respostas distintas em condições de déficit hídrico. A cultivar CD 215 foi mais sensível ao déficit hídrico imposto no inicio do florescimento. As cultivares de soja apresentaram respostas variáveis à atividade das enzimas peroxidase, e esta variável pode ser utilizada na seleção de genótipos de soja com maior tolerância à seca.

Tolerance of physic nut plants to aluminum activity in nutrient solution / Tolerância de plantas de pinhão-manso à atividade de alumínio, em solução nutritiva

Plants have different levels of tolerance to phytotoxic effects of aluminum and the exploitation of this characteristic is of significant importance to the use of acid soils. This research aimed to evaluate the effect of aluminum activity in nutrient solution on growth of physic nut young plant. After seven days of adaptation, plants were submitted to Al concentrations of 0; 200; 400; 600; 800 and 1,000 µmol L­1, corresponding to Al3+ activity solution, of: 14.5, 21.4; 46.6; 75.6; 108.3 e 144.8 µmol L­1, respectively. The increased activity of Al3+ decreased linearly the number of leaves, plant height, leaf area, shoot dry matter and root length of physic nut plant. Physic nut young plants are sensitive to high aluminum activity in solution. The root length, number of leaves, shoot dry matter and total dry matter were variables more affected by Al activity in solution, and can be used to discriminate the tolerance levels to aluminum in physic nut plants. The accumulation of aluminum increased in a activity-dependent manner; however, its translocation from root to shoot was low.

As plantas apresentam diferentes níveis de tolerância aos efeitos fitotóxicos do alumínio e a exploração dessa característica torna-se de relevante importância para a utilização dos solos ácidos. Objetivou-se com este trabalho avaliar o efeito da atividade de alumínio, em solução nutritiva, no crescimento inicial de plantas de pinhão-manso (Jatropha curcas L). As plantas foram cultivadas em vasos com capacidade para 1,5 L, contendo solução nutritiva. Após sete dias de adaptação, as plantas foram submetidas a concentrações de Al de 0, 200, 400, 600, 800 e 1.000 µmol L­1, que corresponderam a atividades de Al3+ em solução de: 14,5; 21,4; 46,6; 75,6; 108,3 e 144,8 µmol L­1, respectivamente. O aumento da atividade de Al3+ reduziu o número de folhas por planta, altura da planta, área foliar, matéria seca da parte aérea e comprimento da raiz principal das plantas de pinhão-manso. Plantas de pinhão-manso são sensíveis a elevada atividade de Al em solução. O comprimento da raiz, número de folhas e a produção de matéria seca da parte aérea e total foram as características mais afetadas pela atividade de Al em solução, e podem ser utilizadas para discriminar os níveis de tolerância ao alumínio em plantas de pinhão-manso. O acúmulo de alumínio aumentou de uma maneira dependente da atividade; no entanto, sua translocação das raízes para a parte aérea foi baixa.

Response of wheat to foliar application of zinc / Resposta do trigo à aplicação foliar de zinco

Wheat is grown in Brazil, mostly in no-till, a system in which the zinc can become potentially deficient, due to excessive application of acidity corrective and phosphate fertilizers in surface and, or at shallow depths. This study aimed to evaluate the effect of foliar application of zinc in agronomic characteristics and yield of wheat. The experimental design was randomized blocks with five replications. Treatments consisted of four doses of zinc (0, 54, 108 and 216g ha-1 Zn), divided into two foliar applications, the first at tillering (18 days after plant emergence) and the second at the boot stage (65 days after emergence). Foliar application of zinc increased the number of fertile tillers and yield of wheat, however, have little effect on the agronomic characteristics of no-tilled crop with high nutrient content in soil.

O trigo é cultivado, no Brasil, predominantemente, em semeadura direta, sistema em que o Zn pode tornar-se potencialmente deficiente, em decorrência da aplicação excessiva de corretivos da acidez e de fertilizantes fosfatados em superfície e/ou em pequenas profundidades. Este estudo teve como objetivo avaliar o efeito da aplicação foliar de zinco nas características agronômicas e produtividade do trigo. O delineamento experimental utilizado foi em blocos casualizados, com cinco repetições. Os tratamentos constituíram-se de quatro doses de zinco (0; 54; 108 e 216g ha-1 de Zn), divididas em duas aplicações foliares: a primeira no afilhamento (18 dias após a emergência das plantas) e a segunda no início do emborrachamento (65 dias após a emergência das plantas). A aplicação de Zn, via foliar, aumentou o número de afilhos férteis e a produtividade de trigo, porém tem pouco efeito nas características agronômicas da cultura em sistema de semeadura direta com teor alto de nutriente no solo.

Atributos físicos de latossolo vermelho sob pousio ou cultivado com forrageiras tropicais sob pastejo / Physical attributes of oxisol under fallow or cultivated with tropical forages under grazing

Objetivou-se estudar os atributos físicos de um Latossolo Vermelho sob pousio ou cultivado com gramíneas tropicais sob pastejo. O experimento foi conduzido sob o delineamento experimental em blocos casualizados, em esquema de parcelas subdivididas 5 x 2, sendo cinco tipos de uso do solo (Brachiaria ruziziensis, Panicum maximum cv. Áries, Brachiaria brizantha cv. MG5, Panicum maximum cv. Mombaça e pousio) e duas épocas de avaliação (após o primeiro e após o segundo pastejo), em quatro repetições. Foram avaliadas as características de densidade do solo, porosidade total, microporosidade e macroporosidade, após o primeiro e segundo pastejo, e a resistência do solo à penetração após o segundo pastejo. Na camada de 0,00-0,10 m, a macroporosidade foi afetada pela interação tipo de uso do solo e época de avaliação, enquanto a microporosidade e porosidade total foram reduzidas e a densidade foi aumentada da primeira para a segunda época de avaliação. Na camada subsuperficial (0,10-0,20 m), houve significância apenas para a macroporosidade, porosidade total e densidade. A macroporosidade e porosidade total sofreram redução, enquanto a densidade aumentou da primeira para a segunda época de avaliação. Não houve efeito significativo dos tipos de uso do solo sobre a resistência à penetração em todas as camadas estudadas. A manutenção de um Latossolo Vermelho sob pousio ou seu cultivo com gramíneas tropicais submetidas ao pastejo de bovinos ocasiona redução na porosidade total e aumento na densidade do solo nas camadas superficial (0-0,10 m) e sub-superficial (0,10-0,20 m), sem promover alterações sobre a resistência do solo à penetração mecânica.

The objective was to study the physical attributes of an Oxisol under fallow or planted with tropical grasses under grazing. The experiment was conducted under the experimental design of randomized blocks in split-plot 2 x 5, being five types of use of soil (Brachiaria ruziziensis, Panicum maximum cv. Aries, Brachiaria brizantha cv. MG5, Panicum maximum cv. Mombaça and fallow) and two evaluation periods (after the first and after the second grazing), with four replications. We evaluated the characteristics of soil bulk density, total porosity, microporosity and macroporosity, after the first and second grazing, and soil resistance to penetration after the second grazing. In layer of 0.00 to 0.10 m, the macroporosity was affected by the interaction between types of use and evaluation periods, while the microporosity and total porosity were reduced and the density was increased from first to second evaluation time. In the subsurface layer (0.10-0.20 m), there were significant effect only of evaluation time, on the macroporosity, total porosity and density. The porosity were reduced, while the density increased from first to second evaluation time. No significant effects of types of use of soil on penetration resistance in all layers studied. The maintenance of an Oxisol under fallow or cultivation with tropical grasses subjected to grazing cattle causes a reduction in total porosity and increased density of surface soil layers (0 to 0.10 m) and subsurface (0.10 - 0.20 m), without promoting changes on resistance to penetration mechanics.