Allelopathy of Ricinus communis and light spectrum variation decrease emergence and growth of Cyperus rotundus

Weeds negatively influence agricultural production. However, those losses depend on weed specie, its time of emergence, and period of interference on agricultural crops. Synthetic herbicides are commonly used to control these plants species; however, they may cause damage to the environment, human beings and animals health, and this problem justify the need to develop alternative bioherbicides. To evaluate the allelopathic potential of Ricinus communis (Castor bean) and light spectrum variation on the emergence and growth of Cyperus rotundus L., a trial was carried out in a protected environment with 15% of brightness reduction at the Center for Agricultural and Environmental Sciences at the Paraíba State University. Four aqueous extract concentrations of R. communis leaves were tested (0, 5, 10, and 15%) and four light spectrums variations (white, purple, blue, and red lights). Variables such as emergence, length, dry matter accumulation and growth rates of shoots and root of C. rotundus seedlings were assessed. Data were analyzed by normality test, analysis of variance, polynomial regression, and averages test. Soot and root emergence, length, and dry matter accumulation of C. rotundus seedlings were reduced due to the allelopathy caused by R. communis aqueous extract leaves (15% concentration) and under purple or red light spectrum radiation.

Organic fertilization as an alternative to the chemical in cherry tomato growing under irrigation depths

Two experiments were carried out to evaluate the effects of organic fertilization as an alternative to the chemical on the yield and quality of cherry tomato grown under different irrigation depths in protected environment, in 2013 and 2014. The experimental design was in randomized blocks (5 x 3 factor), with five irrigation depths as the factors (70%, 85%, 100%, 115% and 130% of ETc) and three types of fertilization: no fertilized soil (control), NPK fertilized soil (Chemical) and earthworm humus fertilized soil (organic). The following were evaluated in this study: water use efficiency, number of aborted flowers, total soluble solid content, transverse and longitudinal diameter of the fruits, number of fruits and fruit yield per plant. Organic fertilization is an alternative to the chemical with no losses in yield and fruit quality. The increase in water depth enhanced yield and fruit diameters and reduced water use efficiency. Water use efficiency was more sensitive to the increments in water depth than to different types of fertilization. The values ​​of °Brix obtained in the experiment were classified as acceptable for the domestic and international market when submitted to organic fertilization.

Desenvolvimento vegetativo, rendimento da fruta e otimizacão do abacaxizeiro cv. Pérola em diferentes níveis de irrigacão / Vegetative development, fruits yield and optimization of pineapple cv. Pérola with different levels of irrigation

Apesar de ser uma planta com necessidades hídricas relativamente baixas, o abacaxizeiro tem demanda permanente de água, variável ao longo do ciclo e dependente do seu estádio de desenvolvimento. Assim, objetivou-se analisar volumes de irrigacão no desenvolvimento vegetativo, no rendimento da fruta e na otimizacão do abacaxizeiro cv. Pérola. O experimento foi realizado na Universidade Federal de Sergipe, município de São Cristóvão (11º01'S, 37º12'W), no delineamento em blocos ao acaso, com quatro tratamentos (lâminas de água) (100 por cento da evaporacão do tanque Classe A (523,7mm ano-1); 75 por cento da evaporacão do tanque Classe A (392,8mm ano-1), 50 por cento da evaporacão do tanque Classe A (261,8mm ano-1) e 0 por cento da evaporacão do tanque Classe A, seis repeticões e 12 plantas úteis por parcela. O sistema de irrigacão foi por aspersão convencional disposto em linha, com pressão de 20mca e vazão de 1,33m3 h-1. A área foliar (cmy) mínima atingida de 4552,6cmy foi observada no volume de água de 122,9mm ano-1, enquanto a massa seca das folhas (147,6g) foi constatada com 17mm ano-1. O máximo comprimento da folha D (88,9cm) foi estimado com 532,7 mm ano-1. Já o máximo comprimento do fruto (23cm) foi observado na lâmina de 296,9mm ano-1. A massa do fruto máxima estimado de 1.736g foi constatado na lâmina de 356,4mm ano-1. No contexto, a irrigacão contribui de forma positiva no desenvolvimento vegetativo e rendimento da fruta do abacaxizeiro. Ressalta-se remuneracão mensal líquida de R$ 1.161,17ha-1, quando se adota lâmina de irrigacão de 356,4mm ano-1.