Gas exchange and millet phytomass under organic fertilization and graywater irrigation

ABSTRACT Graywater is an alternative method to increase the water supply for agricultural production in semi-arid regions. The objective of this study was to evaluate the effects of different irrigation depths of graywater on the gas exchanges and phytomass of millet plants with and without organic fertilization. The research was conducted under greenhouse conditions in Serra Talhada municipality in semiarid region of Brazil, in a randomized complete block design with a factorial (4 × 2 + 1) plot and three replicates. The first factor corresponded to graywater irrigation depth equivalent to 25, 50, 75 and 100% of the available water content of the soil, and the second factor was the addition of bovine manure as fertilizer (0 and 34 Mg ha-1), and a control (irrigation with low-salinity water). Irrigation with graywater effluent did not promote adverse effects on gas exchanges and phytomass accumulation; however, it also did not provide enough nutrients to promote increase in these variables. The reduction in irrigation depth caused a decrease in gas exchange from 45 days after the application of the treatments. The basal tiller mass was the most favored plant component due to organic fertilization.

Modeling Basin-Scale Impacts of Cultivation Practices on Cotton Yield and Water Conservation under Various Hydroclimatic Regimes

The SWAT model equipped with an improved auto-irrigation function was used to assess the impacts of cultivation practices on irrigated and dryland cotton yield and water conservation in the Texas Panhandle. Results showed the largest irrigation depth led to reductions in irrigation and crop evapotranspiration (ETc) with slightly increased cotton yields compared to the baseline scenarios under different hydroclimatic regimes. However, soil water content and surface runoff values were increased when using the largest irrigation depth. The opposite results were observed for the small irrigation depth. Early planting of cotton resulted in decreased irrigation and ETc, and increased cotton yields under both irrigated and dryland conditions, particularly in normal and wet years. By contrast, the late planting scenarios indicated the opposite for those variables. Simulated hydrologic variables were relatively stable using various maturity cultivars. Nevertheless, greater than 10% reductions in irrigated cotton yield under diverse hydroclimatic years and dryland yields during normal and wet years were identified in the long-season cotton. The opposite was determined for the short-season cotton. These outcomes suggest that a larger irrigation depth, earlier planting date, and short-season cultivar are promising cultivation practices for improving cotton yield and water conservation in the Texas Panhandle.

Production efficiency of ‘BRS Pujante’ cowpea using single and dual Kc for irrigation

ABSTRACT The objective of this study was to evaluate the production efficiency of cowpea (Vigna unguiculata L. Walp.), ‘BRS Pujante’, from the weather-based irrigation scheduling using single and dual Kc. The study was carried out in randomized block design with two treatments (single and dual crop coefficient) and 12 replicates. Chlorophyll a, chlorophyll b and total chlorophyll contents, soil matric tension, number of pods per plant, number of grains per pod, average 100 grains weight, total grain yield and water use efficiency were evaluated. Scheduling with single and dual Kc did not interfere with chlorophyll pigments. Single Kc promoted tension values closer to zero during cowpea development stages III and IV. Significant difference was observed only for the average 100 grains weight, with higher value for dual Kc. The irrigation depth with the single Kc was 360.8 mm and there was a 9.3% water saving when compared to dual Kc, without significantly affecting cowpea yield. It is possible to use irrigation scheduling with single Kc for the stages I and II and dual Kc for the stages III and IV of cowpea, ‘BRS Pujante’.

An Evaluation of a New Scheme for Determination of Irrigation Depths in the Egyptian Nile Delta

Innovative irrigation techniques should be implemented to improve irrigation management in dryland countries. In this regard, a new scheme, that uses three sets of irrigation depth and numerically simulated cumulative transpiration, was evaluated in the Egyptian Nile delta in 2020. Presuming that water is volumetrically priced, the proposed scheme can maximize net incomes at optimum irrigation depths considering quantitative weather forecasts. A field experiment was carried out with a randomized complete block design using a major crop, maize, to assess the feasibility of the proposed scheme in comparison to a sensor-based irrigation method under conditions of dry climate and clay loamy soil. The proposed scheme could increase the gross net income of farmers and conserve irrigation by 21% and 35%, respectively, compared to a sensor-based irrigation method, although the yield and its components were almost the same with no significant statistical differences. The model could accurately simulate soil water content in the topsoil layers with a RMSE of 0.02 cm3 cm−3. The proposed scheme could be a useful tool to spare the costs of expensive soil monitoring sensors while saving water and improving net income.

Effect of irrigation regime on yield and water productivity of maize (Zea mays) in the Lake Tana basin, North West Ethiopia

Background Proper scheduling gave water to the crop at the right time in the right quantity to optimize production and minimize adverse environmental impact. Therefore, the objective of this study is to quantify the effects of irrigation regimes on yield and yield components of Maize in the Lake Tana basin during 2016–2018. Methods CROPWAT 8.0 model was used to determine the crop water requirement. Almost all parameters were adopted the default value of CROPWAT 8.0. Field data including; field capacity (FC), permanent wilting point (PWP), initial soil moisture depletion (%), available water holding capacity (mm/meter), infiltration rates (mm/day), and local climate data were determined in the study area. The treatments were arranged in factorial combinations with five irrigation depths (50, 75, 100, 125 and 150% of ETc) and two irrigation intervals (14 and 21 days) laid out in a randomized complete block design with three replications. Results The result was analyzed using SAS 9 software and significant treatment means separated using least significant difference at 5%. The result showed that the interaction of irrigation depth and irrigation frequency has no significant effect on the average grain yield and water use efficiency of maize. At koga, the highest grain yield (7.3 t ha− 1) and water use efficiency (0.9 kg m-3) obtained from 100% ETc. while, at Ribb the highest grain yield (10.97 t ha− 1) and water use efficiency (1.9 kg m− 3) obtained from 21 days irrigation interval. Conclusion Therefore, for Koga and similar agro ecologies maize can irrigated with 562 mm net irrigation depth and 21-day irrigation interval and at Rib and similar agro ecologies maize can irrigated with 446.8 mm net irrigation depth and 21- days irrigation interval.

RESPOSTA DA CULTURA DO RABANETE SOB CULTIVO ORGÂNICO AOS FATORES DE PRODUÇÃO ÁGUA E COBERTURA DO SOLO

RESPOSTA DA CULTURA DO RABANETE SOB CULTIVO ORGÂNICO AOS FATORES DE PRODUÇÃO ÁGUA E COBERTURA DO SOLO ANTONIO VANKLANE DE ALMEIDA1; ALEXSANDRO OLIVEIRA DA SILVA1; JENYFFER DA SILVA GOMES SANTOS2; JANIQUELLE DA SILVA RABELO3; VALSERGIO BARROS DA SILVA1 E ALFREDO MENDONÇA DE SOUSA1 1 Departamento de Engenharia Agrícola, Universidade Federal do Ceará, UFC, Av. Mr. Hull, s/n, Pici, CEP:60356-001, bloco 804, Fortaleza, Ceará, Brasil. E-mail: [email protected], [email protected], [email protected], [email protected] 2 Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas, UNICAMP, Av. Cândido Rondon, 501 - Cidade Universitária, CEP: 13083-875, Campinas, São Paulo, Brasil. E-mail: [email protected] 3 Departamento de Fitotecnia, Universidade Federal do Ceará, UFC, Av. Mr. Hull, s/n, Pici, CEP:60356-001, bloco 805, Fortaleza, Ceará, Brasil. E-mail: [email protected] 1 RESUMO Em regiões com limitações de recursos hídricos, como semiárido cearense, o uso eficiente da água torna-se a cada dia imprescindível para a produção de hortaliças irrigadas nestas regiões. Neste sentido, a presente pesquisa teve como objetivo a avaliação técnica e econômica do efeito dos fatores de produção água e níveis de cobertura do solo da bagana de carnaúba sobre a produtividade da cultura do rabanete. A pesquisa foi conduzida no período de junho a agosto de 2018 em dois ciclos de produção em área pertencente ao Prece (Programa de Educação em Células Cooperativas), localizado no município de Pentecoste-CE. O experimento foi conduzido em um delineamento em blocos casualizados com quatro repetições. Os tratamentos foram constituídos por cinco lâminas de irrigação (50%; 75%; 100%; 125% e 150% da evapotranspiração das culturas localizada, ETcloc) e cinco diferentes níveis de cobertura morta constituída de bagana de carnaúba: 25%; 50%; 75% e 100% além da testemunha com o solo sem cobertura 0%, totalizando 100 parcelas experimentais. Os resultados permitiram concluir que a bagana de carnaúba apresentou potencial para utilização como cobertura morta no cultivo de rabanete, proporcionando incremento no rendimento da cultura em condições de estratégia de irrigação com déficit para o uso de 16 t ha-1 de cobertura morta. A cultura rabanete responde de forma crescente às diferentes lâminas de irrigação até a ETcloc de 100%, podendo-se obter ganhos econômicos quando associadas à utilização de cobertura morta no solo. Palavras-chave: Cobertura do solo. Manejo da irrigação. Função de produção. Raphanus sativus L. ALMEIDA, A. V.; SILVA, A. O.; SANTOS, J. S. G.; RABELO, J. R.; SILVA, V. B.; SOUSA, A. M. RESPONSE OF RABANET CULTURE UNDER ORGANIC CULTIVATION TO PRODUCTION FACTORS WATER AND SOIL COVERAGE 2 ABSTRACT In regions with limited water resources, such as the semi-arid region of Ceará, the efficient use of water becomes indispensable every day for the production of irrigated vegetables in this region. In this sense, this research had as objective the technical and economic evaluation of the effect of the factors of production water and levels of the cover of the soil of the bagana on the productivity of the radish culture. The research was conducted in the period from June to August 2018 in two production cycles in area belonging to Prece (Cooperative Cell Education Program), located in the municipality of Pentecoste-CE. The experiment was conducted in a randomized block design with four replicates. The treatments consisted of five irrigation depth (50%, 75%, 100%, 125% and 150% of crop localized evapotranspiration, ET cloc) and five levels of ground cover consisting of carnauba bagana: 25%; 50%; 75% and 100% beyond the control with the soil without 0% coverage, totalizing 100 experimental units. The results allowed to conclude that the carnauba bagana presented potential for use as ground cover in the cultivation of radish, providing an increase in the yield of the crop under conditions of deficit irrigation strategy to use 16 t ha-1 of ground cover. The radish crop significantly responds to the different irrigation depth, up to 100% ET cloc, and economics gains can be obtained when associated with the use of ground cover in soil. Keywords: Soil cover. Irrigation management. Production function. Raphanus sativus L.

Assessing yield and water use efficiency of Capsicum annuum L. cultivated in a greenhouse under different irrigation strategies

<p>Several methodologies and techniques are available for irrigation management in protected environments. Despite the cultivation of vegetables in the greenhouse is largely present in the northeastern region of Brazil, not many research has been aimed at supporting growers for accurate irrigation management.</p><p>The objective of this study is to evaluate yield and irrigation water use efficiency of Capsicum crop cultivated in a greenhouse under different methods to define the daily irrigation depth, based on the soil water status and the atmospheric evaporative demand. Moreover, two different strategies to apply the estimated irrigation depths (single or double daily application) were also examined.</p><p>The experiment was carried out in a greenhouse in the Federal Rural University of Pernambuco (UFRPE), northeastern of Brazil (8° 01’ 07” S and 34° 56’ 53” W, altitude 6.50 m). Based on a completely randomized design, the experimental units were distributed according to a 4 x 2 factorial scheme with eight replications, with a total of 64 experimental units. Four methods to estimate daily irrigation water requirement were evaluated: two based on soil sensors (soil water content sensors EC-5, SWS, and tensiometers, TS), whereas the other two were based on the atmospheric evaporative demand (weighing lysimeter, WL, and Piché evaporimeter, PE). Moreover, the daily irrigation depths were applied with a single watering (at 8:00 am) or split into two applications (the half at 8:00 am and the half at 4:30 pm). The commercial yield of the examined crop was calculated through the relationship between the weight of fresh fruit and the area occupied by the plant.</p><p>The statistical analysis showed that the water use efficiency, the total water volume applied and the commercial yield of capsicum were significantly influenced by the method used to estimate crop water requirement, as well as the irrigation strategies. The total irrigation depth applied during the entire crop cycle resulted in equal to 509 mm, 678 mm, 716 mm, and 790 mm for treatments with WL, PE, SWS, and TS, respectively. The seasonal applied irrigation depths corresponded to an average daily crop water requirement ranging, according to the treatments, from 5.4 to 8.3 mm day<sup>-1</sup>; these values are consistent for the examined crop cultivated under protected conditions. The highest yields of commercial fruits were obtained in the treatments in which the highest irrigation depth (SWS and TS) was applied. On the other hand, the highest values of water use efficiency were obtained in those treatments in which the irrigation depth was defined based on SWS and WL. Splitting the estimated daily irrigation depth in two applications promoted greater commercial productivity and water use efficiency (10.73 t ha<sup>-1</sup> and 1.60 kg m<sup>-3</sup>) compared to a single application (8.14 t ha<sup>-1</sup> and 1.22 kg m<sup>-3</sup>), with an increase of both variables of about 31%. These results evidenced that splitting the daily irrigation depth is a promising strategy to increase water use efficiency for vegetable crops in protected environments.</p>

Assessing the productivity of coriander under different irrigation depths and fertilizers applied with continuous and pulsed drip systems

In this study, the authors analyzed the consequences of irrigation management strategies as an essential factor to save water and maintain high crop yields. The present research aimed at comparing coriander (Coriandrum sativum L.), cv. Verdão, yields under fertigation via drip irrigation with a continuous application and in pulses, with 40, 60, 80, 100 and 120% of the crop evapotranspiration (ETc) being recovered. These treatments were distributed in randomized blocks in a 2 × 5 factorial scheme, with three replications, in a greenhouse located at the Federal Rural University of Pernambuco, northeast Brazil (08°01′6.50″ S and 34°56′46″ W, average elevation 6.5 m). The continuous irrigation consisted of the application of water depth in a single daily event, while pulsed irrigation comprised the application of the same irrigation depth split up into five events with a 1-hour interval between pulses. Crop evapotranspiration (ETc) was determined via the water balance by lysimetric drainage. The fertilizers were applied in every watering. The biometric and productivity crop pointed that pulsed irrigation to a mean depth of 58% of the ETc corresponds to the results obtained with the application of the depth equivalent to 100% of the ETc by continuous irrigation, consequently with reduced input costs.