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The use of treated wastewater (TWW) for crop irrigation is how many governments are looking to feed their large population due to urbanisation. Here, we outline and analyse the benefits of using TWW and the drawbacks of such practices in line with existing regulations. The review begins by highlighting the history of wastewater reuse in agriculture. The approach used in the write-up is outlined after the background. There is an in-depth look at three main areas: the uptake of heavy metals and pharmaceuticals on crop irrigation, plant yield, and the impact of regulations on these practices. Results demonstrate the presence of several pharmaceuticals, triclosan, acetaminophen, diazepam in lettuce, meprobamate, atenolol in celery, and carbamazepine, triclosan, and triclocarbon in soybean. Trace metals (Cd, Pb) are present in the edible part of the vegetable and arsenic is found in the ryegrass roots and maise. Some benefits derived from using TWW in crop irrigation include nutrient supply, water resource protection and food security, whereas the drawbacks are exposure of contaminants to food and humans.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A sensibilidade à salinidade varia com o estÃdio de desenvolvimento da cultura. O feijÃo-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiÃes semi-Ãridas do mundo. Avaliou-se o efeito da irrigaÃÃo com Ãgua salina, aplicada em diferentes estÃdios de desenvolvimento de plantas de feijÃo-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetiÃÃes. O feijÃo-de-corda foi cultivado no espaÃamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com Ãgua do poÃo (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Ãgua salina com CEa de 5,0 dS m-1, com aplicaÃÃo iniciada apÃs a germinaÃÃo e permanecendo atà o final do ciclo; T3 - Ãgua salina com CEa de 5,0 dS m-1, da semeadura atà 22 dias apÃs o plantio (DAP), correspondendo Ãs fases de germinaÃÃo e crescimento inicial, e Ãgua do poÃo no restante do ciclo; T4 - Ãgua salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo atà a prÃ-floraÃÃo), e Ãgua do poÃo nas demais fases do ciclo; T5 - Ãgua do poÃo da semeadura atà 42 DAP e Ãgua salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floraÃÃo e frutificaÃÃo). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossÃntese, transpiraÃÃo, condutÃncia estomÃtica, produtividade, partiÃÃo de matÃria seca, os teores, os totais extraÃdos e a distribuiÃÃo dos nutrientes na planta, a eficiÃncia nutricional, eficiÃncia no uso da Ãgua e o acÃmulo de sais no solo. A irrigaÃÃo com a combinaÃÃo de Ãgua do poÃo com Ãgua salina reduziu o acÃmulo de sais no solo, em relaÃÃo ao T2. O T2 reduziu as taxas de fotossÃntese e transpiraÃÃo, em relaÃÃo ao T1. O T3 provocou reduÃÃo das trocas gasosas somente na primeira mediÃÃo, enquanto, que similar aplicaÃÃo nos outros estÃdios (T4 e T5) nÃo provocou reduÃÃes significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduÃÃes significativas no nÃmero de vagens e na produÃÃo de sementes por planta, em relaÃÃo aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 nÃo afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleraÃÃo no ciclo reprodutivo da cultura. Os minerais foram extraÃdos pelo feijÃo-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extraÃÃo da maioria dos elementos analisados, com exceÃÃo do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporÃÃes pelos frutos. O T3 reduziu a eficiÃncia de utilizaÃÃo da maioria dos nutrientes. O T2 reduziu a eficiÃncia agronÃmica de utilizaÃÃo de N, P e K, entretanto nÃo afetou a eficiÃncia de utilizaÃÃo dos nutrientes extraÃdos pelas plantas. / The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants.

NEVES, Antônia Leila Rocha. Irrigation of cowpea with saline water at different growth stages and their effects on the plant and soil. 2008. 119 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola. 2008 / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-13T14:53:10Z No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-13T14:57:22Z (GMT) No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) / Made available in DSpace on 2016-06-13T14:57:22Z (GMT). No. of bitstreams: 1 2008_dis_alrneves.pdf: 903212 bytes, checksum: 4298d42aacb4a0815d2c06c72d764de8 (MD5) Previous issue date: 2008 / The sensitivity of crops to salinity often changes from one growth stage to another. Cowpea [Vigna unguiculata (L.) Walp.] is an important crop specie cultivated in different semi-arid regions of the world. The objective of this work was to evaluate the effect of the irrigation with saline water, applied at different growth development stages of cowpea. The experiment was set up in the field, during the dry season. A completely randomized block design, with five treatments (T1, T2, T3, T4 and T5) and five repetitions, was adopted. The distance between lines and plants were 0.8 m and 0.3 m, respectively, with two plants per hole. The treatments studied were: T1 - Groundwater with electrical conductivity (ECw) of 0.8 dS m-1 during the whole crop cycle; T2 - Saline water (ECw = 5.0 dS m-1) during the whole crop cycle, starting after germination; T3 - Saline water (ECw = 5.0 dS m-1) from sowing until the 22th day after sowing (germination and initial growth) and groundwater in remaining stages of the crop cycle; T4 - Saline water (ECw = 5.0 dS m-1) from the 23th to the 42nd day after germination (intense growth and pre-flowering), and groundwater irrigation for the remaining growth stages. T5 - Groundwater from sowing to the 42nd day after sowing and saline water (ECw = 5.0 dS m-1) during flowering and pod-filling stages. Soil coverage, gas exchange, vegetative growth and crop yield were measured. The mineral concentration and quantity of nutrient removed from the soil, as well as the nutrient use efficiency and salt accumulation in soil were also determined. The irrigation with combination of groundwater and saline water reduced the salt accumulation in soil, in relation to continuous use of saline water. The continuous application of water with ECw of 5.0 dS m-1 (T2) reduced the rates of photosynthesis and transpiration, in relation to the well water (T1). Plants of the treatment 3 showed reduction in gas exchanges only in the first measurement, while the saline water application in other growth stages (T 4 and T5) did not provoke significant reductions in leaf in the gas exchanges of the plants. It was found that the continuous use of saline water inhibits plant growth, while the irrigation with saline water during germination and initial growth causes retardation in plant development. For treatments 2 and 3, reduction in the number of pods and in seed production was verified. Irrigation with saline water from the 23rd to the 42nd day (T4) and from the 43rd to the 63rd (T5) day after sowing did not affect reproductive and vegetative growth, but the saline water application in the pre-flowering (T4) caused anticipation of reproductive cycle. Cowpea plants removed the minerals analyzed in the following decreasing sequence: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, but the continuous use of saline water (T2) reduced the total extracted for the most nutrients, except for Na e Cl. The minerals Na, Cl, K, Ca, Fe and Mn were distributed preferentially to vegetative plant parts, while the most of N and P were exported in the pods. The irrigation with saline water during germination and initial growth stage (T3) reduced the mineral use efficiency of most of analyzed nutrients. The continuous application of saline water (T2) reduced the agronomic efficiency of the fertilizer application (N, P and K), but it did not affect the nutrient use efficiency by the plants. / A sensibilidade à salinidade varia com o estádio de desenvolvimento da cultura. O feijão-de-corda [Vigna unguiculata (L.) Walp.] constitui uma das principais culturas, em diversas regiões semi-áridas do mundo. Avaliou-se o efeito da irrigação com água salina, aplicada em diferentes estádios de desenvolvimento de plantas de feijão-de-corda. O experimento foi conduzido no campo, e obedeceu ao delineamento em blocos ao acaso, com cinco tratamentos (T1, T2, T3, T4 e T5) e cinco repetições. O feijão-de-corda foi cultivado no espaçamento de 0,8 m entre linhas e 0,3 m entre plantas, com duas plantas por cova. Os tratamentos utilizados foram: T1 - plantas irrigadas com água do poço (CEa de 0,8 dS m-1) durante todo o ciclo; T2 - Água salina com CEa de 5,0 dS m-1, com aplicação iniciada após a germinação e permanecendo até o final do ciclo; T3 - Água salina com CEa de 5,0 dS m-1, da semeadura até 22 dias após o plantio (DAP), correspondendo às fases de germinação e crescimento inicial, e água do poço no restante do ciclo; T4 - Água salina com CEa de 5,0 dS m-1, aplicada de 23 a 42 DAP (fase de intenso crescimento vegetativo até a pré-floração), e água do poço nas demais fases do ciclo; T5 - Água do poço da semeadura até 42 DAP e água salina (CEa de 5,0 dS m- 1) aplicada a partir dos 43 DAP (floração e frutificação). Foram avaliadas a cobertura vegetal do solo, crescimento vegetativo, fotossíntese, transpiração, condutância estomática, produtividade, partição de matéria seca, os teores, os totais extraídos e a distribuição dos nutrientes na planta, a eficiência nutricional, eficiência no uso da água e o acúmulo de sais no solo. A irrigação com a combinação de água do poço com água salina reduziu o acúmulo de sais no solo, em relação ao T2. O T2 reduziu as taxas de fotossíntese e transpiração, em relação ao T1. O T3 provocou redução das trocas gasosas somente na primeira medição, enquanto, que similar aplicação nos outros estádios (T4 e T5) não provocou reduções significativas nas trocas gasosas das plantas. O T2 inibiu o crescimento vegetativo da planta, enquanto o T3 provocou retardo no desenvolvimento da planta. Os tratamentos T2 e T3 provocaram reduções significativas no número de vagens e na produção de sementes por planta, em relação aos demais tratamentos. Por outro lado, os tratamentos T4 e T5 não afetaram o crescimento e a produtividade da cultura, sendo que o T4 causou aceleração no ciclo reprodutivo da cultura. Os minerais foram extraídos pelo feijão-de-corda na seguinte ordem decrescente: N > K > Cl > Ca > Na > P > Fe > Zn > Mn > Cu, no entanto, o T2 reduziu a extração da maioria dos elementos analisados, com exceção do Na e Cl. Os minerais Na, Cl, K, Ca, Fe e Mn permaneceram preferencialmente nas partes vegetativas enquanto N e P foram exportados em maiores proporções pelos frutos. O T3 reduziu a eficiência de utilização da maioria dos nutrientes. O T2 reduziu a eficiência agronômica de utilização de N, P e K, entretanto não afetou a eficiência de utilização dos nutrientes extraídos pelas plantas.