RESUMOO reuso da água na agricultura é uma alternativa de minimização da degradação dos corpos hídricos receptores, além da possibilidade de fornecimento de água e nutrientes a produção vegetal. No entanto, a irrigação por gotejamento, sistema mais indicado ambientalmente, tem como maior vulnerabilidade a susceptibilidade ao entupimento dos emissores. Este trabalho objetivou analisar a qualidade do efluente de laticínios diluído, em relação ao risco de obstrução de emissores, bem como verificar a alteração de indicadores de desempenho hidráulico como vazão (Q) e coeficiente de variação da vazão (CVQ). O experimento foi conduzido no Laboratório de Poluição e Degradação do Solo da Universidade Federal Rural do Semi-Árido, em Mossoró-RN; a partir da montagem de uma bancada experimental com cinco subunidades gotejadoras tendo os emissores Netafim Streamline, Netafim Tiran, Netafim PCJ CNJ, NaanDanJain TalDrip e Netafim Super Typhoon; onde Q e CVQ foram determinados e avaliados a cada 40 h, até completar o tempo de funcionamento total de 200 h. Os resultados indicaram, conforme diretrizes internacionais, que os sólidos suspensos e pH foram os principais agentes ocasionadores de obstrução de gotejadores que operam com efluente de laticínios diluído. O entupimento dos gotejadores com biofilme acarretou redução de Q e aumento do CVQ, ao longo do tempo. Os menores níveis de obstrução ocorreram nas subunidades gotejadoras dotadas dos emissores Netafim Streamline e Netafim Super Typhoon.Palavras-chave: reuso da água; entupimento; variação da vazão; emissores. CLOGGING OF DRIPPERS OPERATING WITH DILUTED DAIRY WASTEWATER ABSTRACTThe reuse of water in agriculture is an alternative of minimizing the degradation of the water body, besides the possibility of supplying water and nutrients to the vegetal production.

Although cassava is an undemanding crop in terms of soil chemical fertility, the scarcity of nutrients affects crop productivity, and it is common to cultivate it in soils with low natural fertility, as occurs in Coastal Tablelands. In this context, the present study aimed to evaluate the physical and chemical attributes of soils cultivated with cassava under different managements. The study was carried out in the municipality of São Felipe, located in the landscape unit of Coastal Tablelands, Bahia state, Brazil. Fifteen properties were selected to evaluate the characteristics of soils cultivated with cassava under different types of management. Soil sampling was carried out during the months of October and November 2018, a dry period in the region. The medium-textured soil was predominant in the different areas of management of cassava cultivation. Most areas showed pH below the recommended range for cassava (5.5 to 6.5), base saturation below 50% and low phosphorus, potassium, calcium, and magnesium contents, according to the crop’s nutritional needs. The first two principal components explained 84.65% of the total variance. Thus, it was possible to verify that the diversity of management of cassava production areas results in high or very high variability of soil chemical attributes. The attributes pH, P, Al, H + Al, V, CEC and OM are the most representative in the distinction of soils of the cassava cultivation areas evaluated.

The use of resources derived from the agricultural property itself to meet the needs of producers promotes the reduction of costs with commercial inputs and recycling of by-products, among them the liquid waste from the cassava flour production, called cassava wastewater, which can be an important fertilization source. This study aimed to evaluate the growth and production of Capsicum chinense Jacq., as a function of cassava wastewater doses associated with mineral fertilizer proportions. The experiment was conducted in a greenhouse, in a completely randomized design, with treatments distributed in a 3 x 5 factorial scheme, corresponding to 3 doses (0, 50 and 100 %) of the mineral fertilization recommended for the crop and 5 doses (0, 25, 50, 100 and 150 m³ ha-1) of cassava wastewater, with 4 replicates. The cassava wastewater doses influenced the crop yield, showing a linear trend. The dose of 150 m3 ha-1 promoted a yield equivalent to that obtained with the application of 100 % of the mineral fertilization recommended for this crop, thus enabling the partial or total replacement of this fertilization by cassava wastewater.

The environmental pollution coming from dairies industries are the most hazardous of the economy sector due to the great amount of garbage produced. This work aimed it evaluating the dairies effluent on the morphometric, productive, bromatological, and nutritional effects of the thornless cactus. One trial was carried out it the Water Reuse Experimental Station during the period from April to December 2015. The experiment was carried out in randomized blocks design, with five treatments and five replications, totaling 25 experimental units. The treatments were irrigation with water of well (T1), irrigation with 10% of annual dose plus water of well (T2), irrigation with 20% of annual dose plus water of well (T3), irrigation with 30% of annual dose plus water of well (T4), and irrigation with 40% of annual dose plus water of well (T5). The growth parameteres determinations parameteres (production and quality) of thornless cactus were achieved at 240 days after planting. The highest productivity (28.2 Mg ha-1) was achieved with the treatment T4. The nitrogen concentrations were significative to thornless cactus, whereas the treatment T4 increased mostly the Nitrogen content in the plants. Then, the T4 treatment predominated, since it enhanced the crop productivity about crude protein and Nitrogen contents.

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