Objetivou-se, neste trabalho, avaliar os efeitos de doses de N sobre os componentes de produção da cultura do milho cultivado em Sistema Plantio Direto. Utilizaram-se quatro doses de nitrogênio (0, 40, 80 e 120 kg ha-1) e cinco cultivares (AG-9010, TRACTOR, DOW-8550, DKB-395 e AL-34). Todos os tratamentos, exceto a testemunha, receberam 20, 115, 60 e 4 kg ha-1 de N, P(2)0(5) e K2O e Zn, respectivamente. O delineamento estatístico foi em blocos casualisados com quatro repetições em esquema de parcelas subdivididas. Os componentes da produção estudados, foram: população final de plantas por hectare, comprimento de espigas, número de fileira de grãos por espigas, número de espigas e massa de 100 grãos. As produtividades dos materiais utilizados no experimento variaram de 1.900 kg ha-1 na testemunha a 5.662 kg ha-1 para a maior dose de N (120 kg ha-1). Observou-se que, do ponto de vista de rentabilidade, as cultivares DOW-8550 e AG-9010 foram as mais promissoras; contudo, conclui-se que a utilização de 120 kg ha-1 de N permitirá ao agricultor retorno econômico da adubação nitrogenada. Os híbridos e a variedade utilizados mostraram alta eficiência na utilização do N aplicado, sendo os híbridos mais responsivos que a variedade.

A produtividade é definida pela interação entre a planta, ambiente e manejo. Dentre as práticas de manejo destacam-se a densidade de semeadura e o espaçamento entrelinhas. Objetivou-se com este trabalho avaliar o efeito de densidades e arranjos de plantas no desenvolvimento vegetativo e produtividade de grãos de soja. O delineamento experimental foi de blocos casualizados com quatro repetições em esquema de parcelas subdivididas. Nas parcelas foram alocados dois arranjos espaciais: convencional (45 cm entre fileiras) e fileira duplas (65 cm entre uma fileira dupla e outra e 25 cm entre as linhas dentro da fileira dupla). Nas subparcelas foram alocadas cinco densidades de semeadura (7, 10, 15, 19 e 22 sementes m-1). Cada subparcela foi composta por oito linhas com 5,0 m de comprimento. A cultivar utilizada foi a ANTA 82, com ciclo de aproximadamente 115 dias e hábito de crescimento semi-determinado. O arranjo espacial em fileiras duplas proporciona redução na altura das plantas, porém não interfere na produtividade de grãos de soja. O aumento da densidade de semeadura resulta em aumento da produtividade de grãos da soja independente do arranjo espacial entre plantas utilizado.

The use of mixed mineral fertilizers consisting of macro- and micronutrients, which are already routinely used for leaf fertilization, in the treatment of corn and soybean seeds would positively influence germination and vigor, consequently improving growth and seedling development. This study aimed to evaluate the physiological potential of corn and soybean seeds treated with mixed mineral fertilizers. The seed treatment efficiency test with mixed mineral fertilizers was conducted at the Federal University of Jataí—UFJ—using Vital^®, Lança^®, Ídolo^®, Massivo^®, and their combinations. The treatments consisted of two controls for soybean and three for corn. Analysis of variance was performed using the F-test (p ≤ 0.05), and when there was significance, the means were compared using the Scott–Knott test (p ≤ 0.05). The mixed mineral fertilizers Vital^® + Massivo^® (T6), Lança^® + Ídolo^® (T7), and Vital^® + Lança^® + Ídolo^® (T10) used in the seed treatment benefit the development of soybean (NS7667 IPRO) seeds. The treatments for corn (MG744 PWU) had little effect on germination and seedling development. The use of mixed mineral fertilizers in the seed treatments did not affect the physiological potential of the soybean and corn seeds, keeping the lots with germination values within commercialization standards.

The enzymatic activity of soil arylsulfatase and β-glucosidase enzymes are biological parameters used to measure the biological activity of soils, an important tool for identifying disturbances in agricultural systems, as they are more sensitive to differentiate changes in soil management when compared to physical and chemical attributes. Thus, the aim was to evaluate arylsulfatase and β-glucosidase levels in different succession systems. Soil samples were collected in agricultural areas with 5 years of experimentation, with four treatments: (1) soybean/corn + brachiaria (Urochloa ruzizienses), (2) soybean/corn, (3) soybean/brachiaria (Urochloa ruzizienses) and (4) soybean/millet. Routine chemical analyses were performed, and the determination of β-glucosidase and arylsulfatase was carried out according to the p-nitrophenyl colorimetric method. As a result, both enzymes presented higher average values in treatment 3. In the biological IQS, treatment 3 differed from treatments 1 and 2. Under the study circumstances, the use of soil with soybean, corn, millet and brachiaria crops provided adequate sustainability conditions, providing high arylsulfatase and β-glucosidase levels.

The Anacardium humile A. St.- Hil. fruit tree has productive potential, being their fruits appreciated in the Cerrado region for having characteristic flavor, however, this species is still exploited in an extractive way, being necessary studies for its domestication. The aim of this work was to estimate the leaf area of Anacardium humile. One hundred leaves were collected in the biological collection from a genetic resources field and evaluated for length, width and fresh weight, and scanned at resolution of 300 dpi to determine the leaf area with the aid of the ImageJ image analysis program. Subsequently, a leaf disc with a diameter of 22.27 mm was detached at the basal portion of each leaf, in which the fresh weight of the discs was obtained. Data were submitted to descriptive analysis and the relationship among the features explained by Pearson’s correlation with the software Rbio. The data were also subjected to regression analysis to explain the relationship between leaf area and measurements of width, length and leaf weight, and to fit the proper statistical model with the software Origin. It was concluded that leaf area can be determined by image analysis software and linear measurements are correlated to leaf area.