RESUMO
Salinity is a major abiotic stress that adversely affects several physiological and biochemical aspects of plants. Antioxidants can be used as a potential remediation mechanism to promote plant resilience. Therefore, the objective of the present study was to evaluate increasing doses of the antioxidant lycopene on the germination and initial growth of common bean seedlings under conditions of salt stress. Seeds were treated with the following lycopene concentrations: 0.018; 0.036; 0.072; 0.144; and 0.288 g L-1 and two controls (negative and positive) and evaluated under two growth conditions (without and with salt stress) for physiological quality and pigment content. Data were analyzed by completely randomized design, in 2 x 7 factorial (two growth conditions, with paper towel moistened with water or salt solution x seven treatments, including five lycopene doses and two controls), in four replicates of 50 seeds by concentration. With the results of the analysis of variance, growth conditions (without and with salt stress) were compared by the Tukey test (5%), and the effects of lycopene doses were analyzed by polynomial regression. Lycopene promoted tolerance of bean seeds to salt stress and had a positive influence on the attenuation of salt harmful effects to the initial growth of seedlings, mainly at the doses of 0.072 g L-1 and 0.144 g L-1.
Salinity is a major abiotic stress that adversely affects several physiological and biochemical aspects of plants. Antioxidants can be used as a potential remediation mechanism to promote plant resilience. Therefore, the objective of the present study was to evaluate increasing doses of the antioxidant lycopene on the germination and initial growth of common bean seedlings under conditions of salt stress. Seeds were treated with the following lycopene concentrations: 0.018; 0.036; 0.072; 0.144; and 0.288 g L-1 and two controls (negative and positive) and evaluated under two growth conditions (without and with salt stress) for physiological quality and pigment content. Data were analyzed by completely randomized design, in 2 x 7 factorial (two growth conditions, with paper towel moistened with water or salt solution x seven treatments, including five lycopene doses and two controls), in four replicates of 50 seeds by concentration. With the results of the analysis of variance, growth conditions (without and with salt stress) were compared by the Tukey test (5%), and the effects of lycopene doses were analyzed by polynomial regression. Lycopene promoted tolerance of bean seeds to salt stress and had a positive influence on the attenuation of salt harmful effects to the initial growth of seedlings, mainly at the doses of 0.072 g L-1 and 0.144 g L-1.
RESUMO
RESUMO Avaliou-se o crescimento vegetativo e a produção de milho em campo, fertirrigado com diferentes doses de água residuária da estação de tratamento de esgoto de Janaúba, Minas Gerais. Utilizou-se o delineamento em quatro blocos casualizados com parcelas subdivididas, sendo cinco tratamentos: água limpa + adubação mineral; e água residuária tratada equivalente a 50; 100; 150 e 200% da adubação com 60 kg.ha-1 de K2O em cobertura. Nas subparcelas, avaliaram-se as plantas aos 24, 38, 51 e 74 dias após a emergência. O fornecimento de doses de potássio via água residuária tratada além de 142% da dose recomendada do nutriente reduz o diâmetro transversal da copa. A produtividade do milho em grãos não é influenciada pela aplicação de água residuária tratada.
ABSTRACT We evaluated the growth and yield of maize field, fertigated with different wastewater rates coming from Janaúba sewage treatment plant (Minas Gerais State, Brazil). The split-plot on a randomized complete block design was used with five levels: mineral fertilizer + clean water, treated wastewater like to 50%, 100%, 150% and 200% fertilization with 60 kg.ha-1 K2O topdressing. As subplots, maize plants were evaluated at 24, 38, 51 and 74 days after emergence. Potassium supply 142% above the recommended level decrease the transversal canopy diameter. Maize grain yield is not affected by wastewater fertigation.
RESUMO
Objetivou-se com a realização deste trabalho avaliar os atributos físicos de solo e as principais características agronômicas do sorgo granífero no sistema de plantio direto em área com diferentes coberturas vegetais. O experimento foi conduzido durante dois anos agrícolas (2008/09 e 2009/10). No primeiro ano foram semeadas sete espécies de gramíneas em consórcio com o sorgo para formação de pastagem, além do sorgo solteiro definindo os oito tratamentos. As coberturas vegetais foram roçadas simulando um pastejo diferido. No segundo ano agrícola, por ocasião da semeadura direta do sorgo, as forragens existentes na área experimental foram previamente dessecadas com herbicida para o plantio direto do sorgo. As áreas que representavam o plantio convencional foram gradeadas novamente. Em relação aos atributos físicos do solo, o experimento foi conduzido sob um delineamento em blocos casualizados em esquema fatorial 8 (tratamentos) x 3 (profundidades) com quatro repetições. Para os dados relacionados às características agronômicas do sorgo o experimento foi conduzido em um delineamento em blocos casualizados com quatro repetições. Concluiu-se que as diferentes forrageiras usadas na formação de cobertura vegetal para o plantio direto afetam tanto os atributos físicos do solo como a produtividade de grãos do sorgo granífero. O sistema radicular das gramíneas forrageiras promove a melhoria da qualidade física do solo, principalmente a porosidade, sendo necessário manejo adequado da adubação nitrogenada no plantio direto, em função da grande produção de palhada e elevada relação C/N e caule/folha das forrageiras.
The objective of this work was evaluated the physical attributes of soil and the main agronomic characteristics of sorghum for grain in no-tillage under different vegetation cover. The experiment was conducted during two growing seasons. In the first years were sown seven grass species in intercropping with sorghum for pasture establishment and the sorghum single defining the eight treatments. In the second season, when direct sowing of sorghum, forages available in the trial were previously desiccated for no-till sorghum. The areas representing the tillage had been barred again. In relation to soil physical properties, experiments were conducted under a randomized block design in factorial 8 (treatments) x 3 (depths) with four replications. Data related to the agronomic characteristics of the sorghum experiment was conducted in a randomized block design with four replications. It concluded with the work that the various forages used in the formation of vegetation for no-tillage affects both soil physical properties such as grain yield of sorghum.