Application strategies of saline water and nitrogen doses in mini watermelon cultivation

Salt stress is highlighted as one of the limiting factors for the establishment of agriculture in the semiarid region of Northeastern Brazil. In this context, it is essential to look for new strategies aiming at minimizing the effects of salt stress on the crops. The present work aimed to evaluate the photochemical efficiency, photosynthetic pigments, and growth of the watermelon cv. Sugar Baby under different use strategies with saline waters and nitrogen fertilization. The experiment was conducted in a protected environment at the Center of Technology and Natural Resources of the Federal University of Campina Grande, municipality of Campina Grande, Paraíba. An experimental design in randomized blocks was adopted, arranged in a 6 x 2 factorial scheme, with six management strategies of water salinity and two nitrogen doses (corresponding to 50 and 100% of the recommendation), with five replications. Two salinity levels of the irrigation water were studied, one with low and another with a high level of electrical conductivity of the water (ECw = 0.8 and 3.2 dS m-1). The watermelon cv. Sugar Baby expressed higher sensitivity to salt stress in the flowering phase, with a decrease in the synthesis of chlorophyll b, chlorophyll total, and carotenoids. The 50% dose of N provided an increment in the initial fluorescence, stem diameter, and the number of leaves of the watermelon cv. Sugar Baby. The length of the main branch of the watermelon plants decreased with the salt stress applied in the fructification phase; however, the fertilization with 100% of N stimulated a higher growth when the irrigation with saline waters was performed at the vegetative and flowering phases.Salt stress is highlighted as one of the limiting factors for the establishment of agriculture in the semiarid region of Northeastern Brazil. In this context, it is essential to look for new strategies aiming at minimizing the effects of salt stress on the crops. The present work aimed to evaluate the photochemical efficiency, photosynthetic pigments, and growth of the watermelon cv. Sugar Baby under different use strategies with saline waters and nitrogen fertilization. The experiment was conducted in a protected environment at the Center of Technology and Natural Resources of the Federal University of Campina Grande, municipality of Campina Grande, Paraíba. An experimental design in randomized blocks was adopted, arranged in a 6 x 2 factorial scheme, with six management strategies of water salinity and two nitrogen doses (corresponding to 50 and 100% of the recommendation), with five replications. Two salinity levels of the irrigation water were studied, one with low and another with a high level of electrical conductivity of the water (ECw = 0.8 and 3.2 dS m-1). The watermelon cv. Sugar Baby expressed higher sensitivity to salt stress in the flowering phase, with a decrease in the synthesis of chlorophyll b, chlorophyll total, and carotenoids. The 50% dose of N provided an increment in the initial fluorescence, stem diameter, and the number of leaves of the watermelon cv. Sugar Baby. The length of the main branch of the watermelon plants decreased with the salt stress applied in the fructification phase; however, the fertilization with 100% of N stimulated a higher growth when the irrigation with saline waters was performed at the vegetative and flowering phases

Phytomass and quality of yellow passion fruit seedlings under salt stress and silicon fertilization

The semiarid region of Northeastern Brazil is characterized by long drought periods, and the use of saline waters appears as an alternative for the expansion of irrigated areas. Associated with the use of these waters, silicon fertilization constitutes an important attenuator of salt stress. In this perspective, this study aimed to evaluate the phytomass production and quality of the passion fruit cultivar ‘Gigante Amarelo’ grown with saline water and silicon fertilization. The experiment was conducted in a plant nursery belonging to the Center of Agrifood Science and Technology, in the municipality of Pombal-PB. A completely randomized block design in a 5 x 5 factorial scheme was used, referring to five levels of electrical conductivity of the irrigation water (0.3, 1.0, 1.7, 2.4, and 3.1 dS m-1) and five doses of silicon fertilization (0; 25; 50; 75, and 100 g of potassium silicate/plant), with four replications and two plants per plot. The phytomass accumulation (leaves, stem, and roots), as well as the total dry phytomass, shoot dry phytomass, root/shoot ratio, and the quality index of Dickson were evaluated. The data obtained were subjected to the F-test at 0.01 and 0.05 level of probability. The electrical conductivity of water from 0.3 dS m-1 caused the decrease of phytomass production in seedlings of the passion fruit cultivar ‘Gigante Amarelo’, although it is possible to produce good quality passion fruit seedlings with water salinity up to 3.1 dS m-1. The doses of silicon fertilization mitigated the effect of salt stress on the root/shoot ratio of plants of the passion fruit cultivar ‘Gigante Amarelo’.The semiarid region of Northeastern Brazil is characterized by long drought periods, and the use of saline waters appears as an alternative for the expansion of irrigated areas. Associated with the use of these waters, silicon fertilization constitutes an important attenuator of salt stress. In this perspective, this study aimed to evaluate the phytomass production and quality of the passion fruit cultivar ‘Gigante Amarelo’ grown with saline water and silicon fertilization. The experiment was conducted in a plant nursery belonging to the Center of Agrifood Science and Technology, in the municipality of Pombal-PB. A completely randomized block design in a 5 x 5 factorial scheme was used, referring to five levels of electrical conductivity of the irrigation water (0.3, 1.0, 1.7, 2.4, and 3.1 dS m-1) and five doses of silicon fertilization (0; 25; 50; 75, and 100 g of potassium silicate/plant), with four replications and two plants per plot. The phytomass accumulation (leaves, stem, and roots), as well as the total dry phytomass, shoot dry phytomass, root/shoot ratio, and the quality index of Dickson were evaluated. The data obtained were subjected to the F-test at 0.01 and 0.05 level of probability. The electrical conductivity of water from 0.3 dS m-1 caused the decrease of phytomass production in seedlings of the passion fruit cultivar ‘Gigante Amarelo’, although it is possible to produce good quality passion fruit seedlings with water salinity up to 3.1 dS m-1. The doses of silicon fertilization mitigated the effect of salt stress on the root/shoot ratio of plants of the passion fruit cultivar ‘Gigante Amarelo’

Gas exchange and photosynthetic pigments of West Indian cherry under salinity stress and salicylic acid

A aceroleira é uma fruteira que se destaca pela sua importância socioeconômica no semiárido do Nordeste brasileiro, devido sua utilização na indústria alimentícia e farmacêutica. Neste contexto, objetivou-se com esse trabalho avaliar as trocas gasosas e os pigmentos fotossintéticos da aceroleira cv. BRS Jaburu em função da irrigação com águas salinas e procedimentos de ácido salicílico. O trabalho foi conduzido em casa de vegetação em Campina Grande-PB. O delineamento estatístico de blocos casualizados, em esquema fatorial 5 x 4, combinados os tratamentos consistiram de cinco níveis de condutividade elétrica da água de irrigação - CEa (0,8; 1,6; 2,4; 3,2 e 4 , 0 dS m -1 ) e quatro especialidades de ácido salicílico - AS (0; 1,0; 2,0 e 4,0 mM), com 3 repetições. A salinidade de água a partir de 0,8 dS m-1 reduziu a transpiração, a taxa de assimilação de CO 2 e a eficiência instantânea do uso da água das plantas de aceroleira. O ácido salicílico não amenizou os efeitos deletérios do estresse salino sobre as trocas gasosas e clorofila a sob salinidade da água superior a 0,8 dS m -1 . A concentração de ácido salicílico de 4,0 mM promoveu incremento no teor de clorofila total das plantas de aceroleira.A aceroleira é uma fruteira que se destaca pela sua importância socioeconômica no semiárido do Nordeste brasileiro, devido sua utilização na indústria alimentícia e farmacêutica. Neste contexto, objetivou-se com esse trabalho avaliar as trocas gasosas e os pigmentos fotossintéticos da aceroleira cv. BRS Jaburu em função da irrigação com águas salinas e procedimentos de ácido salicílico. O trabalho foi conduzido em casa de vegetação em Campina Grande-PB. O delineamento estatístico de blocos casualizados, em esquema fatorial 5 x 4, combinados os tratamentos consistiram de cinco níveis de condutividade elétrica da água de irrigação - CEa (0,8; 1,6; 2,4; 3,2 e 4 , 0 dS m -1 ) e quatro especialidades de ácido salicílico - AS (0; 1,0; 2,0 e 4,0 mM), com 3 repetições. A salinidade de água a partir de 0,8 dS m-1 reduziu a transpiração, a taxa de assimilação de CO 2 e a eficiência instantânea do uso da água das plantas de aceroleira. O ácido salicílico não amenizou os efeitos deletérios do estresse salino sobre as trocas gasosas e clorofila a sob salinidade da água superior a 0,8 dS m -1 . A concentração de ácido salicílico de 4,0 mM promoveu incremento no teor de clorofila total das plantas de aceroleira. A aceroleira é uma fruteira que se destaca pela sua importância socioeconômica no semiárido do Nordeste brasileiro, devido sua utilização na indústria alimentícia e farmacêutica. Neste contexto, objetivou-se com esse trabalho avaliar as trocas gasosas e os pigmentos fotossintéticos da aceroleira cv. BRS Jaburu em função da irrigação com águas salinas e procedimentos de ácido salicílico. O trabalho foi conduzido em casa de vegetação em Campina Grande-PB. O delineamento estatístico de blocos casualizados, em esquema fatorial 5 x 4, combinados os tratamentos consistiram de cinco níveis de condutividade elétrica da água de irrigação - CEa (0,8; 1,6; 2,4; 3,2 e 4 , 0 dS m -1 ) e quatro especialidades de ácido salicílico - AS (0; 1,0; 2,0 e 4,0 mM), com 3 repetições. A salinidade de água a partir de 0,8 dS m-1 reduziu a transpiração, a taxa de assimilação de CO 2 e a eficiência instantânea do uso da água das plantas de aceroleira. O ácido salicílico não amenizou os efeitos deletérios do estresse salino sobre as trocas gasosas e clorofila a sob salinidade da água superior a 0,8 dS m -1 . A concentração de ácido salicílico de 4,0 mM promoveu incremento no teor de clorofila total das plantas de aceroleira

Saline water and nitrogen doses in the cultivation of West Indian cherry in the post-grafting phase

This study aimed to evaluate the photosynthetic pigments and growth of the West Indian cherry cv. BRS 366 Jaburu in the post-grafting phase as a function of the salinity levels of the irrigation water and nitrogen fertilization under greenhouse conditions, in the municipality of Campina Grande-PB. The study was performed in randomized blocks, consisting of two levels of electrical conductivity of irrigation water - ECw (0.8 and 4.5 dS m-1) and four nitrogen doses (70, 85, 100, and 115% of the recommended dose for the crop), with three replications. The synthesis of chlorophyll a and carotenoids in the West Indian cherry plants was inhibited with ECw of 4.5 dS m-1. Nitrogen fertilization in the estimated doses of 92 and 80% of N reduced the effects of salt stress on the contents of chlorophyll a and b in West Indian cherry plants, at 630 days after transplanting. The increment in nitrogen fertilization increases quadratically the absolute and relative growth rate of the diameter in the rootstock of the West Indian cherry plants under irrigation with saline waters.This study aimed to evaluate the photosynthetic pigments and growth of the West Indian cherry cv. BRS 366 Jaburu in the post-grafting phase as a function of the salinity levels of the irrigation water and nitrogen fertilization under greenhouse conditions, in the municipality of Campina Grande-PB. The study was performed in randomized blocks, consisting of two levels of electrical conductivity of irrigation water - ECw (0.8 and 4.5 dS m-1) and four nitrogen doses (70, 85, 100, and 115% of the recommended dose for the crop), with three replications. The synthesis of chlorophyll a and carotenoids in the West Indian cherry plants was inhibited with ECw of 4.5 dS m-1. Nitrogen fertilization in the estimated doses of 92 and 80% of N reduced the effects of salt stress on the contents of chlorophyll a and b in West Indian cherry plants, at 630 days after transplanting. The increment in nitrogen fertilization increases quadratically the absolute and relative growth rate of the diameter in the rootstock of the West Indian cherry plants under irrigation with saline waters

Physiological indices and phytomass partition in precocious dwarf cashew clones irrigated with saline waters

This research aimed to evaluate the physiological indices and the accumulation of phytomass in clones of precocious dwarf cashew under salt stress during rootstock formation. The experiment was conducted in greenhouse in the municipality of Pombal-PB. The experimental design was in randomized blocks, and the treatments were organized in a 5 x 3 factorial arrangement, constituting the levels of electrical conductivity of the irrigation water - ECw (0.4 -Control; 1.2; 2.0; 2.8, and 3.6 dS m-1) and the clones of precocious dwarf cashew (Faga 11, Embrapa 51, CCP 76), with three replications and two plants per plot. Water salinity higher than 0.4 dS m-1 resulted in a decrease of the relative growth in plant height, leaf area, and phytomass accumulation in the cashew plant. The cashew clones are sensitive to water salinity from 0.4 dS m-1. Among the physiological indicators, the leaf area ratio, the sclerophylly index, and the root/shoot ratio of the precocious dwarf cashew are highlighted as salt stress indicators. The use of water with 0.4 dS m-1 of electrical conductivity is recommended for the formation of cashew rootstocks.This research aimed to evaluate the physiological indices and the accumulation of phytomass in clones of precocious dwarf cashew under salt stress during rootstock formation. The experiment was conducted in greenhouse in the municipality of Pombal-PB. The experimental design was in randomized blocks, and the treatments were organized in a 5 x 3 factorial arrangement, constituting the levels of electrical conductivity of the irrigation water - ECw (0.4 -Control; 1.2; 2.0; 2.8, and 3.6 dS m-1) and the clones of precocious dwarf cashew (Faga 11, Embrapa 51, CCP 76), with three replications and two plants per plot. Water salinity higher than 0.4 dS m-1 resulted in a decrease of the relative growth in plant height, leaf area, and phytomass accumulation in the cashew plant. The cashew clones are sensitive to water salinity from 0.4 dS m-1. Among the physiological indicators, the leaf area ratio, the sclerophylly index, and the root/shoot ratio of the precocious dwarf cashew are highlighted as salt stress indicators. The use of water with 0.4 dS m-1 of electrical conductivity is recommended for the formation of cashew rootstocks

Morphophysiology of the passion fruit ‘BRS Rubi do Cerrado’ irrigated with saline waters and nitrogen fertilization

This study aimed to evaluate the gas exchanges and growth of the purple passion fruit cultivar ‘BRS Rubi do Cerrado’ as a function of the salinity levels of the irrigation water and nitrogen fertilization. The research was conducted in pots adapted as drainage lysimeters, placed within a plant nursery, using a Regolithic Neosol of sandy texture, in the municipality of Pombal-PB, Brazil. A randomized block design was used, testing five levels of electrical conductivity of irrigation water (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1) associated with four doses of nitrogen (50, 75, 100, and 125% of the recommendation). The irrigation water salinity above 0.3 dS m-1 compromised the leaf area and the relative water content of the purple passion fruit ‘BRS Rubi do Cerrado’. High doses of nitrogen enhance the deleterious effects of irrigation water salinity on stomatal conductance, transpiration, internal CO2 concentration, CO2 assimilation rate, number of leaves, stem diameter, and height of purple passion fruit plants. When waters with salinity levels of up to 1.3 dS m-1 are used, the dose of 125 mg of N kg-1 of soil is recommendation for providing increases in the CO2 assimilation rate of the purple passion fruit ‘BRS Rubi do Cerrado’ at 70 days after sowing (DAS). Water salinity increases electrolyte leakage, regardless of nitrogen doses.This study aimed to evaluate the gas exchanges and growth of the purple passion fruit cultivar ‘BRS Rubi do Cerrado’ as a function of the salinity levels of the irrigation water and nitrogen fertilization. The research was conducted in pots adapted as drainage lysimeters, placed within a plant nursery, using a Regolithic Neosol of sandy texture, in the municipality of Pombal-PB, Brazil. A randomized block design was used, testing five levels of electrical conductivity of irrigation water (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1) associated with four doses of nitrogen (50, 75, 100, and 125% of the recommendation). The irrigation water salinity above 0.3 dS m-1 compromised the leaf area and the relative water content of the purple passion fruit ‘BRS Rubi do Cerrado’. High doses of nitrogen enhance the deleterious effects of irrigation water salinity on stomatal conductance, transpiration, internal CO2 concentration, CO2 assimilation rate, number of leaves, stem diameter, and height of purple passion fruit plants. When waters with salinity levels of up to 1.3 dS m-1 are used, the dose of 125 mg of N kg-1 of soil is recommendation for providing increases in the CO2 assimilation rate of the purple passion fruit ‘BRS Rubi do Cerrado’ at 70 days after sowing (DAS). Water salinity increases electrolyte leakage, regardless of nitrogen doses

Nitrate and ammonium proportions in sesame cultivation under irrigation with saline waters

This research was conducted with the aim of evaluating the water relations, growth and the production components of the sesame cv. CNPA G3, in function of the irrigation with waters of different salinities and fertilization with different proportions of nitrate (N-NO3-) and ammonium (N-NH4+). The study was performed in drainage lysimeters in conditions of greenhouse, in the municipality of Campina Grande, PB, Brazil. The adopted design was in randomized blocks, in a factorial scheme of 5x5 with three repetitions, whose treatments were constituted of five levels of electrical conductivity of the irrigation water - ECw (0.6; 1.2; 1.8; 2.4 and 3.0 dS m-1) and five proportions of nitrate and ammonium (200:0; 150:50; 100:100; 50:150; 0:200 mg kg-1 of soil). The irrigation with ECw superior to 0.6 dS m-1 negatively affected the growth and production of the sesame; the fertilization with N-NH4+ and N-NO3- in the proportion 200:0 resulted in a higher percentage of cell membrane damage; the utilization of N-NH4+ and N-NO3- in the proportion 50:150 provided increase in the relative water content in the leaf blade and in the mass of a hundred seeds; N-NO3 and N-NH4+ proportions of 200:0 and 150:50 and water with ECw of 0.6 dS m-1 promoted the highest values for the content of chlorophyll a and total number of sesame seeds.This research was conducted with the aim of evaluating the water relations, growth and the production components of the sesame cv. CNPA G3, in function of the irrigation with waters of different salinities and fertilization with different proportions of nitrate (N-NO3-) and ammonium (N-NH4+). The study was performed in drainage lysimeters in conditions of greenhouse, in the municipality of Campina Grande, PB, Brazil. The adopted design was in randomized blocks, in a factorial scheme of 5x5 with three repetitions, whose treatments were constituted of five levels of electrical conductivity of the irrigation water - ECw (0.6; 1.2; 1.8; 2.4 and 3.0 dS m-1) and five proportions of nitrate and ammonium (200:0; 150:50; 100:100; 50:150; 0:200 mg kg-1 of soil). The irrigation with ECw superior to 0.6 dS m-1 negatively affected the growth and production of the sesame; the fertilization with N-NH4+ and N-NO3- in the proportion 200:0 resulted in a higher percentage of cell membrane damage; the utilization of N-NH4+ and N-NO3- in the proportion 50:150 provided increase in the relative water content in the leaf blade and in the mass of a hundred seeds; N-NO3 and N-NH4+ proportions of 200:0 and 150:50 and water with ECw of 0.6 dS m-1 promoted the highest values for the content of chlorophyll a and total number of sesame seeds

Summer squash morphophysiology under salt stress and exogenous application of H2O2 in hydroponic cultivation

Summer squash is a vegetable of significant acceptance in the market due to its economic and nutritionalimportance, with the potential for expansion in the food industry. In this context, this study aimed to evaluate the gas exchange and growth of summer squash plants subjected to a saline nutrient solution and exogenous application of hydrogen peroxide. The study was conducted in a greenhouse in Pombal – PB. The cultivation system used was the Nutrient Film Technique (NFT) hydroponic system. The experimental design was completely randomized, in a 4 x 4 factorial arrangement, whose treatments consisted of four levels of electrical conductivityof the nutrient solution - ECns (2.1, 3.1, 4.1, and 5.1 dS m-1) and four concentrations of  hydrogen peroxide – H2O2 (0, 20, 40, and 60 μM), with three replications. The increase in the nutrient solution salinity from 2.1 dS m-1 reduced the leaf area and transpiration of the summer squash plants. Hydrogen peroxide at a concentration of 40 μM increased the root length, the instantaneous carboxylation efficiency, and the CO2 assimilation rate when the plants were subjected to the saline solution of 2.1 dS m-1. Also, the application of 60 μM H2O2 mitigated the effect of salt stress on the internal CO2 concentration and stomatal conductance of the summer squash plants.A abobrinha italiana é uma hortaliça de grande aceitação no mercado, por apresentar importância econômica e nutricional, com potencial para expansão na indústria alimentar. Nesse contexto, objetiva-se nessa pesquisa avaliar como trocas gasosas e o crescimento da abobrinha italiana submetida a solução nutritiva salina e aplicação exógena de peróxido de hidrogênio. O trabalho foi conduzido em casa de vegetação, em Pombal - PB. O sistema de cultivo utilizado foi o hidropônico tipo Técnica de Fluxo Laminar de Nutriente - NFT. O delineamento experimental foi casualizado, sem esquema fatorial 4 x 4, utilizado consistindo de quatro níveis salinos de solução nutritiva - CEsn (2,1; 3,1; 4,1 e 5,1 dS m 2 S 2 -1 ), e de peróxido de hidrogênio - H (0; 20; 40 e 60 μM), com 3 repetições. O aumento da salinidade da solução nutritiva a partir de 2,1 dS m -1 reduz a área foliar e a respiração das plantas de abobrinha. O peróxido de hidrogênio com concentração de 40 μM de incremento ou comprimento de raiz, uma eficiência instantânea de carboxilação e os índices de assimilação de CO 2 quando submetido a uma solução salina de 2,1 dS m -1 , como também uma aplicação de 60 μM possui o efeito de estresse salino sobre a concentração interna de CO 2 e a condutância estomática das plantas

Características morfológicas e produtivas da mamoneira em cultivo com águas salinas e adubação nitrogenada

Objetivou-se com esta pesquisa avaliar variáveis morfológicas e produtivas da mamoneira cv. BRS Energia sob diferentes níveis de salinidade da água de irrigação e doses de adubação nitrogenada, em experimento conduzido sob condições de campo em área experimental pertencente ao Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande (UFCG). Usou-se o delineamento estatístico em blocos inteiramente casualizado em esquema fatorial 5 x 4, sendo os tratamentos compostos por cinco níveis de condutividade elétrica da água de irrigação - CEa (0,3; 1,2; 2,1; 3,0 e 3,9 dS m-1) e quatro doses de adubação nitrogenada (70; 100; 130 e 160% da dose indicada para ensaio em vaso), e três repetições. O aumento da salinidade da água de irrigação resulta em redução no número de folhas, na área foliar, no diâmetro de caule, na altura de plantas, na fitomassa fresca das folhas, no número de frutos e de sementes totais, sendo a área foliar a variável mais afetada. A aplicação de doses crescentes de nitrogênio aumenta o número de folhas, a área foliar, a fitomassa fresca das folhas e o número de frutos total. A salinidade afeta de forma linear e decrescente a fitomassa fresca do caule, independentemente da dose de nitrogênio aplicada

Insecticide Potential of Botanic Extracts Obtained from the Flora of the Brazilian North East Region

This article provides a literature review pointing out the relevance of plant extracts as an economically possible and ecologically sustainable alternative to the use of chemical compounds in the management and control of the insects in agriculture. The methodology was constituted in a literature review, through researches in Scielo and Lilacs, from 1990 to 2018. Organic farming is gaining importance in the Brazilian economy. The consumers are more and more conscious and demanding, choosing healthy foods, free from chemical residuals, deemed as harmful to the health. Botanic extracts can control insects and pathogens, providing no contamination for the soil, for the drinkable water sources, and leaving no toxic residuals in the environment. Studies focused on production and testing of these natural products deserve to be highlighted in the scientific literature. Only through the spreading of these studies, small producers and family farmers will access these informations