ABSTRACT: The quality of the sugarcane plantation affects the plantation longevity, yield and production costs. Therefore, this study aimed to evaluate the quality of sugarcane mechanized planting in day and night shifts. The mechanized planting was carried out in Ivinhema, MS, Brazil. For the evaluation of pre-planting seedlings, were collected 40 billets in the seedling area with 10 repetitions for each shift. For the other variables, it was held sampling, totaling 60 points, 30 points assessed for each shift. The variables evaluated were: total of natural damage and total of mechanized damage in pre-planting, shoot per meter, viable shoots per meter, total of unviable shoots, seedlings consumption and failures percentage. Data were analyzed with descriptive statistics and statistical quality control. The attributes showed stable mechanized planting process, that is, with quality, except only for the seedlings consumption and failures for the day shift that presented unstable process or outside the proposed standards to achieve quality. To achieve the specific limits for the number of viable shoots m−1, it is necessary to increase the seedlings consumption, and an alternative would be to start the operators training to align the expected goals and qualify labor.

Foram investigados a distribuição do fósforo, o pH e a umidade do solo no bulbo molhado em um Latossolo sem vegetação, após fertirrigação com ácido fosfórico, durante 21 dias. O experimento foi instalado na UNESP/Jaboticabal - SP, em blocos casualizados, com cinco repetições. Os tratamentos foram 0; 30; 60; 90 e 120 kg ha-1 de P2O5, dividindo-se as doses em quatro aplicações semanais, via fertirrigação. Após a última aplicação, foram abertas trincheiras nos bulbos molhados e coletadas amostras de solo em quadrículas de 100 cm². O ácido fosfórico provocou aumento da acidez e elevados teores de fósforo no bulbo, principalmente até 30 cm de distância lateral e até 40 cm de profundidade, em relação ao ponto de gotejamento. O aumento da dose de ácido fosfórico (90 e 120 kg ha-1 de P2O5) provocou maiores teores de fósforo e maior acidificação do solo até 30 cm de distância lateral e até 40 cm de profundidade. A distribuição do fósforo e seu efeito no pH no volume de solo molhado não seguiram a distribuição de umidade no mesmo.

The phosphorous distribution, pH and the water content in the wet bulb of a Latosol without vegetation fertigated along one month, were investigated. The experiment, with randomised blocks design was carried out in UNESP - São Paulo State University, Jaboticabal - Brazil. The treatments (0; 30; 60; 90 and 120 kg ha-1 of P2O5) were divided in four weekly applications, by fertigation, using phosphoric acid. After the last application, trenches in the bulbs were opened, and samples of the soil were collected in 100 cm² areas. The phosphoric acid increased the acidity and provoked high phosphorus contents in the fertigated bulbs, until 30 cm of lateral distance and until 40 cm of depth, in relation to the drip point. Increasing the rate of the phosphoric acid (90 and 120 kg ha-1 of P2O5) resulted in higher phosphorus concentration and soil acidity until 30 cm of lateral distance and until 40 cm of depth. The phosphorous distribution and its effect in the pH did not follow the moisture distribution in the bulb.

A aplicação de fertilizantes fosfatados por meio de fertirrigação com sistemas de irrigação localizada pode causar obstrução de emissores. Para evitar esse problema, pode ser utilizado o ácido fosfórico como fonte de fósforo às plantas. Porém, têm sido pouco investigados os efeitos da irrigação relacionados às perdas de CO2 do solo para a atmosfera, em conseqüência da decomposição do carbono orgânico e da infiltração de água no solo. Neste trabalho, investigou-se, no período de um mês, o efeito da fertirrigação com ácido fosfórico nas taxas de emissão de CO2 de um latossolo desprovido de vegetação, na Área Experimental de Irrigação da UNESP, Câmpus de Jaboticabal - SP. Utilizou-se de um sistema de irrigação por gotejamento, com delineamento experimental em blocos casualizados, constando de cinco repetições e cinco tratamentos (0; 30; 60; 90 e 120 kg ha-1de P2O5), aplicados via fertirrigação com ácido fosfórico. Verificou-se que as taxas de emissão de CO2 aumentaram significativamente após as fertirrigações, porém não houve efeito da dose do ácido fosfórico sobre as taxas. A umidade do solo mostrou-se um fator importante na relação entre as variações das taxas de emissão e a temperatura do solo ao longo do período estudado.

The application of phosphoric fertilizers through fertigation, with localized irrigation systems, can cause emitters obstruction. In order to avoid this problem, the phosphoric acid can be used as phosphorus source to the plants. However, it has been little investigations on the effects of the irrigation practices, related to the CO2 transference to the atmosphere, due to organic matter decomposition in the soil and its water infiltration. At this work, the rates of emissions of CO2 from a bare soil without vegetation, and fertigated along one month were investigated. The experiment was conducted with randomized blocks design in São Paulo State University - UNESP, Jaboticabal, Brazil. The drip irrigation system was used, with five treatments and five replications. The treatments were constituted by five rates (0; 30; 60; 90 and 120 kg ha-1 of P2O5), applied by fertigation using phosphoric acid. By the results, it is possible to verify that the emissions increased significantly after the fertigation events, however, no effect of phosphoric acid added to water was observed on emissions. Soil moisture was a relevant factor in the relationship among the variations of the emission rates and the temperature of the soil along the studied period.