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ABSTRACT The objective, in this research, was to evaluate the agricultural productivity and the financial performance of levels of irrigation in the cassava. For this, experiment was carried out, under a randomized block design, with six irrigation levels, as a function of crop evapotranspiration (L0 = 0% (rainfed), L1 = 40%, L2 = 80%, L3 = 120%, L4 = 160% and L5 = 200% of ETC) and four repetitions. Was evaluated: length and mass of roots, productivity of maximum physical and economic efficiency of roots and productivity of the aerial part. The irrigation level L5 or total useful water of 1,023 mm, got greatest productivity of the aerial part, 57 Mg ha-1. With a total useful water of 926 mm, this irrigation level, generated the greatest length and mass of roots per plant and the maximum physical productivity, 94 Mg ha-1. As well as the root yield of maximum economic efficiency, which is achieved with a total usable water, 914 mm. Among the irrigation levels studied, L3 (963 mm) is the one that provides the greatest productivity of roots, 90 Mg ha-1, and gross revenue 167% higher than in areas cultivated under rainfed conditions. Therefore, irrigation of cassava is economically viable.

Weeds are a serious threat to agriculture because they compete with crops, thereby interfering in production. As such, this study aimed to assess weed control using soil solarization and mulching on the growth and yield of cowpea. A completely randomized design was used, with eight treatments and four repetitions. The treatments consisted of a combination of two management practices, namely soil solarization (with and without) and three mulches (castor bean, rattlepod and spontaneous vegetation), as well as no mulching. Non-solarized soil and without mulch increased the number and dry weight of weeds, while the main stem length of the cowpea plants decreased. Mulching increased the pod length and number of seeds per pod regardless of solarization, as well as shoot dry weight and moisture content. By contrast, root dry weight increased in the absence of mulching, particularly in non-solarized soil. Soil solarization reduces weed infestation in cowpea crops, especially when associated with mulching.

O objetivo dessa pesquisa foi avaliar o crescimento, produtividade e as respostas fisiológicas da mandioca sob níveis de irrigação na Zona da Mata de Alagoas. O delineamento estatístico utilizado foi blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. Os tratamentos foram seis níveis de irrigação, em função da evapotranspiração da cultura – ETC (L0 = 0% (sequeiro), L1 = 40%, L2 = 80%, L3 = 120%, L4 = 160% e L5 = 200% da ETC). As variáveis foram divididas em grupos: crescimento e produção (avaliadas em seis períodos bimestrais – 1 ano) e as fisiológicas (taxa fotossintética líquida e transpiratória, temperatura foliar, condutância estomática, eficiência instantânea do uso de água, rendimento quântico potencial, eficiência quântica efetiva do fotossistema II (ΦPSII) e índice SPAD foram avaliadas em cinco períodos bimestrais – 10 meses). O balanço hídrico dos níveis de irrigação, foi realizado em escala decendial. A evapotranspiração anual da cultura da mandioca estimada foi 1.030 mm, e nas áreas de sequeiro, a chuva efetiva somou apenas 522 mm, o que gerou déficit hídrico de 508 mm, e isso torna evidente a importância de utilização da irrigação em cultivos na região. De maneira geral, crescimento, produtividade e as respostas fisiológicas da mandioca são superiores em áreas irrigadas quando comparadas com cultivos de sequeiro e a irrigação proporciona as produtividades de raízes e biomassa total de 97 e 155 t ha-1, sob os níveis de irrigação de 129 e 136% da ETC, respectivamente, na região estudada.

ABSTRACT: This research evaluated the effects of the irrigation on growth and productivity of irrigated cassava in the Coastal Plateaus of Alagoas. The planting was done in randomized blocks, with six treatments and four replications. The treatments were irrigation levels in function of crop evapotranspiration - ETC (L0 = 0% (rainfed), L1 = 40%, L2 = 80%, L3 = 120%, L4 = 160% and L5 = 200% of ETC). The total water applied was defined as the total irrigation plus the effective rain. The annual evapotranspiration of the cassava plantations in the Costal Plateaus of Alagoas, was 1,030 mm. Plant growth increased significantly with irrigation and the maximum values of the following variables are: leaf area index = 7.6, length of commercial roots = 49 cm, maximum productivity (physical and economic) of commercial roots = 94 Mg ha-1 and total biomass = 149 Mg ha-1 and the harvest index = 0.66, all obtained with total irrigation depths (effective rain plus irrigation) between 817 and 963 mm. Finally, it is ratified that understanding the growth, the agricultural and economically viable productivity of irrigated cassava, is an indispensable factor for good management of the crop, especially in regions with irregular rainfall such as the Northeast of Brazil.

A pimenta malagueta possui grande importância econômica e social para produtores devido sua crescente procura por agroindústrias que confeccionam molhos. Apesar disso, estudos sobre o manejo nutricional da pimenta malagueta são escassos, logo a adubação em cultivos é realizada, principalmente, de forma empírica. Diante disso, este trabalho objetivou verificar a influência de doses de nitrogênio na produtividade de pimenta malagueta. O experimento foi conduzido entre agosto de 2016 e maio de 2017 na área experimental do Campus Arapiraca, da Universidade Federal de Alagoas, Arapiraca, AL. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições, e seis doses de nitrogênio (0, 100, 200, 300, 400 e 500 kg ha-1 N). A aplicação do N ocorreu de forma parcelada aos 108, 142, 172 e 202 dias após o plantio (DAP), utilizou-se ureia como fonte de N. A colheita de frutos iniciou-se 90 DAP, sendo realizada em uma frequência semanal. As variáveis avaliadas foram: altura de planta (m), diâmetro do dossel (cm), índice SPAD, número de frutos e produtividade (t ha-1). As doses não influenciaram na altura de plantas e diâmetro do dossel. O maior índice SPAD (53,11), maior produção de frutos totais ao final do período de colheita (2.773 frutos por planta-1) e maior produtividade (26,25 t ha-1) foram verificados com 500 kg ha-1 de N.

The salinization process at the mouth of the São Francisco River has been caused serious damage to the ecosystem and the quality of life among riverine populations. This study aimed to assess the perception of the riverine populations regarding the effects of water salinization at the mouth of the São Francisco River, and also to analyze the quality of water that is provided to the Potengi community in Piaçabuçu, Alagoas, Brazil. For data collection, semi- tructured interviews were conducted with 22 riverine residents. The analyses of water samples were carried out at four places in the community, in which analyzes of pH, electrical conductivity, determination of salinity, and turbidity of the water were made. It was possible to identify, during the performance of this study, the inefficiency of the public authorities, both concerning the informative and mitigating actions, as the exposure of the population to high levels of sodium and turbid water, leading to changes in the parameters concerning data established by the World Health Organization (WHO). The results revealed that one of the samples analyzed presented a saline level 17 times higher than the limit established by the WHO, and a turbidity index was 15.6 times higher than the technical limit established. Therefore, these changes have affected the health of the community, directly compromising the use of water and the composition of the biota in the region.