Biostimulants and Their Role in Improving Plant Growth under Abiotic Stresses

Biostimulants are products that reduce the need for fertilizers and increase plant growth, resistance to water and abiotic stresses. In small concentrations, these substances are efficient, favoring the good performance of the plant’s vital processes, and allowing high yields and good quality products. In addition, biostimulants applied to plants enhance nutrition efficiency, abiotic stress tolerance and/or plant quality traits, regardless of its nutrient contents. Several researches have been developed in order to evaluate the biostimulants in improving plant development subjected to stresses, saline environment, and development of seedlings, among others. Furthermore, various raw materials have been used in biostimulant compositions, such as humic acids, hormones, algae extracts, and plant growth-promoting bacteria. In this sense, this chapter aims to approach the use of biostimulants in plant growth according to the raw material used in their compositions as well as their effects on plants subjected to abiotic stresses

Organic fertilizer and irrigation in changes the chemical properties of a Fluvent and okra production

The objective of this experiment was to evaluate the effect of organic fertilization on changes of chemical properties of a “Neossolo Flúvico Eutrófico” (Fluvent) and okra production, cultivated with and without mulching and irrigation depths. The experiment was installed in the Agroecology sector at Universidade Estadual da Paraíba. The treatments were designed in a randomized blocks using the 2 x 5 x 2 factorial, which  corresponding to two irrigation depths (100 and 50% of the crop evapotranspiration - ETc), five doses of cattle manure to increase the level from 1.8 % to 2.8; 3.8; 4.8 and 5.8%, in soil with and without mulching (plant residues), with four replications, totaling 80 plots with 27 plants per plot. 140 days after planting okra, soil samples were collected at each plot and chemical analyses were performed. The okra production was evaluated based on the number of green fruits and crop yield. The data were submitted to analysis of variance. The application of cattle manures to the soil between 4.8 and 5.8% and irrigation with 100% of crop evapotranspiration - Etc, with and without mulching, was suitable for the cultivation of okra under semi-arid climatic conditions, which provided increases in the chemical attributes of a Fluvent and in the okra production.The objective of this experiment was to evaluate the effect of organic fertilization on changes of chemical properties of a “Neossolo Flúvico Eutrófico” (Fluvent) and okra production, cultivated with and without mulching and irrigation depths. The experiment was installed in the Agroecology sector at Universidade Estadual da Paraíba. The treatments were designed in a randomized blocks using the 2 x 5 x 2 factorial, which corresponding to two irrigation depths (100 and 50% of the crop evapotranspiration - ETc), five doses of cattle manure to increase the level from 1.8 % to 2.8; 3.8; 4.8 and 5.8%, in soil with and without mulching (plant residues), with four replications, totaling 80 plots with 27 plants per plot. 140 days after planting okra, soil samples were collected at each plot and chemical analyses were performed. The okra production was evaluated based on the number of green fruits and crop yield. The data were submitted to analysis of variance. The application of cattle manures to the soil between 4.8 and 5.8% and irrigation with 100% of crop evapotranspiration - Etc, with and without mulching, was suitable for the cultivation of okra under semi-arid climatic conditions, which provided increases in the chemical attributes of a Fluvent and in the okra production

Quantity/intensity relation of potassium in soils of brazilian tropical semi-arid region

Neste trabalho, procurou-se estudar, através de isotermas de adsorção de potássio e da relação Quantidade/Intensidade (Q/I), a relação entre a concentração de potássio da solução do solo e o potássio trocável, e a influência de algumas propriedades do solo nessa relação. As amostras de terra utilizadas foram coletadas dos horizontes A e C do Vertissol e dos horizontes A e B dos solos Bruno Não Cálcico, Bruno Não Cálcico-vértico, Planossol Solódico e Solonetz Solodizado, localizados no Estado da Paraíba. No estudo de adsorção de potássio, as amostras de 3,0 g de TFSA foram tratadas com soluções de potássio de concentração variando de 0,0 a 9,687 mmol/1. A solução de equilíbrio foi analisada para se determinar as quantidades de potássio adsorvido e de cálcio, magnésio e sódio dessorvidos. Para a determinação das relações Quantidade/Intensidade dos solos, foram analisados o potássio, cálcio e magnésio das soluções de equilíbrio das amostras de 0,3; 0,8; 1,5 e 3,0 g de TFSA, tratadas com soluções contendo 2 mmol/1 de cálcio e quantidades de potássio variando de 0,0 a 4,357 mmol/1. Através das curvas representativas das relações Q/I, determinou-se os parâmetros quociente de atividade de potássio em equilíbrio (QAKe), atividade de equilíbrio de potássio (Ke) e poder tampão de potássio (PTK). Nas condições do experimento, verificou-se que a adsorção de potássio aumenta com a elevação de sua concentração nas soluções de tratamento e que os solos que adsorvem mais potássio são os que apresentam valores mais elevados de CTC. O sódio do complexo soroativo dos solos influencia de maneira direta e proporcional a adsorção preferencial de potássio. O maior e o menor valor de PTK foram apresentados pelo Vertissol e Solonetz Solodizado, respectivamente. O parâmetro que melhor se relaciona com a concentração de potássio na solução de equilíbrio é a porcentagem de saturação em potássio. Com base na relação Q/I, concluiu-se que os solos que apresentam potássio trocável adsorvido na posição planar, são os que mantêm maior concentração do elemento na solução. Os parâmetros QAKe e Ke correlacionam-se de manei ra significativa com a porcentagem de saturação em potássio e com a relaçao K+ trocável (Ca2+ + Mg) trocáveis. O PTK dos solos está diretamente relacionado à CTC dos mesmos. O horizonte A de todos os solos, com exceção do Vertissol, apresenta baixos valores de PTK e mantem altos níveis de Ke.Potassium adsorption isotherms and quantity/intensity (Q/I) curves were determined in order to study potassium concentration of the soil solution in relation to the exchangeable potassium and some soil properties affecting such relation. Soil samples were collected from Vertisol, Planosol Solódico, Bruno Não Cálcico, Bruno Não Cálcico-vértico, and Solonetz Solodizado located in the state of Paraíba. The potassium adsorption isotherrns were obtained by equilibrating 3.0 g of soil with solutions containing potassium, the concentration of which varied from 0.0 to 9.687 mmol/1. The equilibrium solution was analyzed to determine the amount of potassiurn adsorbed and the amount of calcium, magnesium and sodium desorbed. For the Q/I curves, soil samples weighting from 0.3 to 3.0 g, were equilibrated with solutions containing 2 mmol/1 of calcium and amounts of potassium varying from 0,0 to 4.357 mmol/1; the equilibrium solution was then analyzed for potassium, calcium and magnesium. Equilibrium activity ratio (ARKe), equilibrium potassium actvity (Ke) and potential buffer capacity (PBCK) were obtained from the Q/I curves. The potassium adsorption, under the experimental conditions, increased with its concentration in the equilibrium solution, and the soils with higher cation exchange capacities tended to adsorb more potassium. Exchangeable sodium affected in the diret and proportional way the preferencial adsorption of potassium. The highest and lowest PBCK values were observed in the Vertisol and in the Solonetz Solodizado, respectively. The parameter which showed the best correlation with the potassium concentration of the equilibrium solution was the base saturation percentage. Based on the Q/I relation, it was concluded that soils having the exchangeable potassium adsorbed in the planar position maintain the best concentration of the element in the solution. The parameter ARKe and Ke were significantly correlated with the potassium saturation percentage and the exchangeable K+ / (Ca2+ + Mg2+) ratio. The PBCk of the soils was directly related to their cation exchange capacity. The A horizon of all soils except the Vertisol had low values of PBC and maintained higher levels of Ke

Efeito da incorporação de xisto retortado ao solo sobre o parasitismo de Meloidogyne incognita em tomateiro

A greenhouse experiment was carried out to study the effect of schist incorporated into the soil for the control of Meloidogyne incógnita in tomato. The treatments consisted of five rates of schist processing waste (0, 3, 6, 9 and 12 t ha-1) and a completely randomized experimental design with three replications was used. The schist was applied and incorporated in the soil in each experimental unit, constituted by pot with 3 dm3 of soil, and incubated during 10 days with its respective treatment. After this period the tomato was sown and after 90 days of the plantation the plant height, the fresh matter of the shoots and fruit, the roots weight and the number of the gall were evaluated. In the soil samples taken from each experimental unit after the tomato plantation was evaluated the number of nematode. The evaluated parameters were not significantly influenced by treatments with schist.Avaliou-se, em condições de casa de vegetação, o efeito da aplicação de xisto retortado ao solo sobre o parasitismo de Meloidogyne incognita em tomateiro (Lycopersicon esculentum). Os tratamentos foram constituídos por cinco doses xisto retortado (0, 3, 6, 9 e 12 t ha-1) sendo o delineamento experimental inteiramente casualizado, com três repetições. O xisto foi incorporado ao solo em cada unidade experimental, constituída por vasos com 3 dm3 de solo, as quais permaneceram incubadas por 10 dias. Após este período semeou-se o tomate e após 90 dias da semeadura, foram avaliados: a altura da planta, peso verde da parte aérea e do fruto, peso total das raízes e número de galhas. Nas amostras de solo das unidades experimentais, coletadas no final do experimento, foi feita a contagem de nematóides. Os parâmetros avaliados não foram influenciados pelas doses de xisto retortado utilizadas

Cadmium and copper adsorption on bentonite: effects of pH and particle size Adsorção de cádmio e cobre em bentonita: efeito do pH e da granulometria

Reactions of heavy metals with clay minerals are important in determining metal fates in the environment. However, the adsorption process of these metals by the bentonite has been extensively investigated. The objectives of this work were to assess the ability of bentonite clay to adsorb cadmium and copper and to study the effects of pH and particle size upon these metals adsorption. Adsorption isotherms were obtained from batch adsorption experiments, with increasing cadmium and copper concentrations (5-200 mg L-1). To find out the effects of pH and particle size on adsorption, the experiments were conducted at pH 4; 5 and 6 using particles sizes of < 0.5 mm and 0.5 to 2.0 mm . The difference between initial and final cadmium and copper concentrations was assumed to be the amount adsorbed by bentonite. The bentonite adsorbed more copper than cadmium, both metals adsorption increased with increasing pH for both particle sizes. No effect of particle size was observed. Experimental data were best fitted to Langmuir model.<br>As reações dos metais pesados com os minerais de argila são importantes para determinar o destino dos mesmos no meio ambiente. Assim, o processo de adsorção destes metais pela bentonita tem sido muito investigado. Objetivou-se com este trabalho avaliar a capacidade da argila bentonita em adsorver cádmio e cobre e os efeitos do pH e de sua granulometria na adsorção dos mesmos. A partir de experimentos tipo "batch", foram elaboradas isotermas de adsorção com quantidades crescentes de Cd e Cu (5-200 mg L-1). Para determinar o efeito do pH e da granulometria sobre a adsorção, os experimentos foram conduzidos a pH 4; 5 e 6, utilizando bentonita com granulometria < 0,5 mm e entre 0,5 a 2,0 mm. As quantidades de Cd e Cu adsorvidas pela bentonita foram determinadas pela diferença entre as concentrações inicial e final dos elementos na solução de equilíbrio. A bentonita adsorveu mais Cu do que Cd, entretanto a adsorção dos dois metais aumentaram com o aumento do pH independentemente da granulometria. Nenhum efeito da granulometria sobre a adsorção foi observada. Os dados experimentais foram bem ajustados ao modelo de Langmuir. A capacidade máxima de adsorção diminuiu e a energia de ligação aumentou em função do aumento do pH

Doses de fósforo e potássio no desenvolvimento da cultura de Crambe abyssinica

Mineral nutrients have essential and specific roles in plant metabolism. The application of mineral fertilizers is made to replenish its loss, for every cycle of the plant extract soil nutrients. The crambe culture is an alternative for the production of biodiesel getting this approach for its rusticity, precocity, high oil content and adaptability. Proper management of fertilizer use in crambe cultivation is little known and no specific recommendations for fertilizer. Therefore, the objective of this research was to study the effects of mineral fertilizers on the elements phosphorus and potassium on growth and production of crambe. The experiment was installed in a greenhouse, with a completely randomized design in a factorial 4 x 4 + 1, with three repetitions, totaling 51 experimental units. Phosphorus and potassium levels the used were 50; 75; 100 and 125 kg ha-1. The use of these elements caused no significant effect on the growth and production of crambe. Sixty days after sowing (DAS) plant height, stem diameter and number of branches were analyzed. Plants were harvested at maturity stage at 90 DAS, when the total dry weight of plants, number of grains per plant and thousand grain weights were evaluated. The growth and production of crambe, these conditions were little influenced by the application of phosphorus and potassium, probably because culture was hampered by a lack of nitrogen fertilization.A cultura do crambe (Crambe abyssinica) é uma alternativa para produção de biodisel recebendo este enfoque por sua rusticidade, precocidade, alto teor de óleo e adaptabilidade. Os nutrientes minerais possuem funções essenciais e específicas no metabolismo das plantas. A aplicação de fertilizantes minerais é feita para repor sua perda, pois a cada ciclo as plantas extraem nutrientes dos solos. O manejo adequado do uso de fertilizantes no cultivo do crambe é pouco conhecido, não havendo recomendações específicas para a adubação. Portanto, objetivou-se estudar os efeitos da adubação mineral relativa aos elementos fósforo e potássio, no crescimento e na produção do crambe. O experimento foi instalado em casa de vegetação, com delineamento inteiramente casualizado em esquema fatorial 4 x 4 + 1, com três repetições, totalizando 51 unidades experimentais. As doses de fósforo e potássio utilizadas foram 50; 75; 100 e 125 kg ha-1. Aos 60 dias após o semeio (DAS) foram analisadas altura das plantas, diâmetro caulinar e número de ramificações. As plantas foram colhidas em fase de maturação aos 90 DAS, quando foram avaliadas a massa seca total das plantas, número de grãos por planta e massa de mil grãos. O crescimento e a produção do crambe, nestas condições, foram pouco influenciados pela aplicação de fósforo e potássio, provavelmente, porque a cultura foi prejudicada pela falta de adubação nitrogenada

ESCÓRIA DE SIDERURGIA E CALCÁRIO NA CORREÇÃO DA ACIDEZ DO SOLO E NA DISPONIBILIDADE DE CÁLCIO, MAGNÉSIO E FÓSFORO

The slag represent an alternative recommended to replace the traditional source of corrective or fertilizers. This study evaluated different base saturation levels, comparing basic slag to dolomitic limestone as soil acidity corrective agents and in the availability of calcium, magnesium and phosphorus. Thus, one experiment involving soil incubation was conducted in laboratory, during 60 days. The treatments consisted of two corrective agents: dolomitic limestone and basic slag, evaluated by the base saturation method, with eight correction levels (V%) (56, 58, 60, 62, 65, 67, 69 e 71 %) and two replicates. After the incubation period the soil samples was analyzed chemically. The application of the corrective agents promoted efficient neutralization of acidity in soil, especially when basic slag was used. The Ca + Mg level increased depending on the increasing amounts of correctives, reducing the K (Ca2+ + Mg2+)-0,5 ratio. The neutralization of acidity in soil reaction was fast when the slag was used. The soil available P did not increase with increasing levels of soil acidity correctives

Análise do crescimento de mudas de cacau CCN-51

This study aimed to evaluate the growth parameters of seedlings of cocoa (Theobroma cacao L.), specifically the clone CCN-51, subjected to irrigation. The experimental design was a randomized block design, where 256 seedlings were used, divided into 16 blocks and in each block there were 16 plants per block. Three evaluations were performed in the growth parameters: leaf number, plant height and stem diameter. Regression analysis showed a linear increase in these parameters with coefficients of determination (R2 ), equal to 0.98; 0.99 and 0.99, respectively.Objetivou-se com este trabalho avaliar parâmetros de crescimento de mudas de cacau (Theobroma cacao L.), especificamente o clone CCN-51, submetida à irrigação. O delineamento experimental utilizado foi o de blocos casualizados, onde se utilizou 256 mudas, distribuídas em 16 blocos sendo que em cada bloco existiam 16 plantas por bloco. Foram realizadas três avaliações nos parâmetros de crescimento: número de folhas, altura da planta e o diâmetro do caule. Pela análise de regressão verificou-se um crescimento linear nestes parâmetros com coeficientes de determinação (R2 ), iguais a 0,98; 0,99 e 0,99, respectivamente

QUALIDADE DE ÁGUAS PARA FINS DE IRRIGAÇÃO DA REGIÃO DO CONGO, PB

The research was carried out to evaluate the quality of waters used in the irrigation of agricultural areas of Congo region, Paraíba State, Brazil. The water samples were collected in Cordeiro dam, in wells and in river, in two periods of the year, rainy (May/2006) and dry period (December/2006) and analyzed under the qualitative aspects of salinity, sodicity and toxicity of ions. For the studied conditions and in agreement with the evaluated parameters in both periods, most of the samples of water, as for the salinity, were considered normal for the use in the irrigation since special practical of soil and water management are adopted; as the toxicity of the ion sodium, more than 40% didn't present restriction to the use. In relation to the toxicity of the ion chloride, in the rainy period, 61% of the samples didn't indicate restriction to the use for irrigation and in the dry period, 44% presented restriction varying from low to moderate

ADSORÇÃO DE FÓSFORO EM MATERIAIS DE LATOSSOLO E ARGISSOLO

The objective of this paper was to determine the phosphorus adsorption characteristics using the Langmuir isotherm. The study was carried out in the Laboratório de Irrigação e Salinidade, of Universidade Federal de Campina Grande, PB, Brazil, with surface (0-20 cm) samples from two soils of Paraiba State. The soil samples (2,5 g) were mixed with a CaCl2 0.01M (25 mL), with addition to 0; 35; 45; 55; 70; 85 and 100 mg L-1 of P as KH2PO4 and maintained in contact for 24 hours. The phosphorus was analyzed from the supernatant in order to determine the amount of P adsorbed by the soils. The maximum P adsorption capacity (MPAC) was determined for all soil through the linear model of the Langmuir equation. The Ultisol showed the highest values of the MPAC and PmCF and the Oxisol showed the highest adsorption energy. The results showed that the soil attributes that had influenced on soil MPAC were soil organic matter and clay content and the base saturation