Complementary Irrigation Research Articles

Winter wheat source‐sink relationships under various planting modes, complementary irrigation, and planting densities

AbstractVarious agronomic practices can affect the processes of aboveground dry matter accumulation (source) and grain filling (sink), resulting in yield differences. Improved source‐sink relationships can facilitate the production and accumulation of assimilates to increase the productivity of winter wheat (Triticum aestivum L.). A two‐season field experiment was undertaken on winter wheat during 2020–2021 and 2021–2022. In a split‐split‐plot design with three replicates (randomized blocks), we compared two planting modes (ridge‐furrow planting with plastic mulching [RFPM]; traditional flat planting [TF]), two complementary irrigation levels (I30+30: 30+30 mm; I0: no irrigation), and three planting densities (D1, D2, and D3: 240, 360, and 480 plants m−2). The results showed that RFPMI30+30 significantly increased maximum yield by 28.5% compared with TFI0. Although D3 increased the number of effective spikes per unit area and duration of grain filling compared to D2, it reduced the number of grains per spike, 1000‐grain weight, and average filling rate. Compared to TF and I0, RFPM and I30+30 improved the sink/source ratio by 5.3% and 6.5%, respectively. Grain yield peaked at D2 in the RFPM and at D3 in the TF. Medium planting density (D2) and complementary irrigation (I30+30) during the wintering and reviving periods under RFPM can achieve better source‐sink balance relationships and the maximum grain yield of winter wheat. Overall, we believe that in most cases, wheat yields are source‐limited and can be improved by ridge‐furrow planting with plastic mulching, complementary irrigation, and planting density regulation.

Deficit Irrigation of Forage Cactus (Opuntia stricta) with Brackish Water: Impacts on Growth, Productivity, and Economic Viability under Evapotranspiration-Based Management

Climate change significantly impacts agriculture and forage production, requiring the implementation of strategies toward increased water and energy use efficiency. So, this study investigated the yield of forage cactus (Opuntia stricta (Haw.) Haw) under different irrigation depths using brackish groundwater (1.7 dS m−1), whose management was based on reference evapotranspiration (ETo) estimated by the Hargreave–Samani (HS) and Penman–Monteith (PM) equations. The research was conducted in Independência, Ceará, Brazil, under the tropical semi-arid climate. A randomized block design in a 2 × 5 factorial scheme was employed, varying the ET0 estimation equations (HS and PM) and irrigation levels (0; 20; 40; 70; and 100% of total required irrigation—TRI). Growth, productivity, and water use efficiency variables were evaluated at 6, 12, and 18 months after treatment initiation. The economic analysis focused on added value, farmer income, and social reproduction level. The results showed no isolated effect of the equations or their interaction with irrigation depths on the analyzed variables, suggesting that irrigation management can be effectively performed using the simpler HS equation. Furthermore, there was no statistical difference between the means of 100% and 70% TRI as well as between 70% and 40% TRI for most variables. This indicates satisfactory crop yield under deficit irrigation. Dry matter productivity and farmer income at 12 months resulting from complementary irrigation with depths between 40% and 70% of TRI were significantly higher than under rainfed conditions. The 70% depth resulted in yields equivalent to those at 100% TRI, with the social reproduction level being achieved on 0.65 hectares in the second year.

Exogenously applied 5-aminolevulinic acid modulates growth, yield, and physiological parameters in lentil (Lens culinaris Medik.) under rain-fed and supplemental irrigation conditions

Lentils are a significant source of plant protein and are cultivated across Asia, Europe, and North Africa. Plants are subjected to various environmental stresses, which can hinder growth, yield, and productivity. 5-aminolevulinic acid (ALA) is a compound that acts as a precursor in the biosynthesis of tetrapyrroles and can increase plant tolerance to different abiotic stressors. However, the effects of exogenously applied ALA on lentil growth, yield, and physiological parameters under rain-fed and supplemental irrigation conditions are not well-known. In this study, a split plot experiment was conducted to investigate the impact of ALA foliar application and supplemental irrigation on lentil (Lens culinaris Medik.). The experiment was designed based on a randomized complete block with three replications. The main plot included four levels of supplemental irrigation [(supplementary irrigation in the flowering and early seed-filling stages, supplementary irrigation in the flowering stage, supplementary irrigation in the early seed-filling along with rain-fed conditions (no irrigation)]. The subplot considered foliar application of ALA at varying levels [(0 (control), 50 and 100 ppm)]. The results showed that water regimes and foliar spray with ALA significantly (P ˂ 0.01) affected plant height, number of pods per plant, pod weight, number of seeds per pod and weight of 1000 seeds, biological yield, seed yield, and harvest index. The highest total chlorophyll content was observed in plants that were subjected to supplementary irrigation in flowering and early seed filling stages and foliar sprayed with 100 ppm ALA. The study also found that exogenous ALA improved drought tolerance in lentil plants under rain-fed conditions mainly by regulating antioxidant enzymes, which ultimately protected the cellular membranes against overproduction of H2O2. Furthermore, ALA application increased total carbohydrate contents at all supplemental irrigation levels, but the rate was higher in complementary irrigation conditions during flowering and early seed-filling stages. Malondialdehyde (MDA), H2O2, and proline contents were increased in field-grown plants under rain-fed conditions without exogenous ALA application. In conclusion, this study sheds light on the effects of ALA foliar spray and supplemental irrigation on lentil growth, yield, and physiological parameters. The findings suggest that exogenous ALA can improve plant tolerance to various abiotic stressors and enhance plant growth, yield, and physiological parameters.

Impact of complementary irrigation on soil properties in the Argentine Pampas

The growing application of complementary irrigation in extensive agricultural systems in the Pampas region (Argentina) has increased the frequency of disturbed soil cases. Irrigation management requires appropriate indicators for decision-making in order to avoid disturbance in soil quality. Among these indicators, the use of the sodium adsorption ratio adjusted by the dilution factor (SARdf), which considers the contributions of irrigation water and rainfall during the period projected, could be a sensitive tool. Based on studies conducted under extensive conditions of agricultural production, the objectives of this work were to (i) quantify the changes in the soil chemical and physical properties caused by the use of complementary irrigation with sodium bicarbonate water; (ii) establish relationships between the changes in the chemical and physical properties of the soil; (iii) validate the use of SARdf as a tool to help manage complementary irrigation; and (iv) identify the threshold values to be considered when monitoring and analyzing the evolution of soil properties in areas under complementary irrigation. Twenty-three sites under dryland and irrigated conditions were evaluated. With increasing SARdf, an increase was also recorded in surface bulk density (r = 0.59), subsurface bulk density (r = 0.50), electrical conductivity (r = 0.30; 0.41), pH (r = 0.56; 0.70) and exchangeable sodium ratio (ESR) (r = 0.45; 0.77), measured in the layers up to 0.10 m and up to 0.20 m in depth. The ESR was evaluated as a sensitive indicator of the effects of irrigation on the physical and chemical properties of soils. In the predominant Typic Argiudoll conditions of the Pampas region, it is advisable to avoid the complementary application of water with a SAR dilution factor greater than 3.0. This threshold value was associated with a > 60% reduction in basic infiltration. In climate change scenarios, the use of SARdf can help plan the proper management of complementary irrigation.

Morfometria e rendimento de palma forrageira 'Gigante' sob irrigação e diferentes densidades de plantio

ABSTRACT Growing forage cactus pear in semi-arid regions is an alternative when facing current climate changes, and improving its cropping systems is critical to increasing its yields. The objective was to evaluate morphometric characteristics and yield of ‘Gigante’ cactus pear under complementary irrigation with saline water and different planting densities. The research was carried out in the semiarid region of Bahia during the period from September 2017 to October 2019. A randomized block design was used with treatments arranged in split-split plots. Two irrigation intervals (7 and 14 days) were assigned to plots, four planting densities (20,000; 40,000; 60,000 and 80,000 plants per hectare) to subplots, and four irrigation levels (0, 11, 22 and 33% of ETo) to sub-subplots. High-salinity water (2.91 dS m-1), classified as C4S1, did not limit the growth and yield of ‘Gigante’ forage cactus pear for two crop cycles. Fresh matter and dry matter yields, fresh matter-based water use efficiency and dry matter-based water use efficiency were highest at planting densities of 61,465 and 67,786 plants ha-1, and 61,848 and 69,707 plants ha-1, respectively. The use of 33% ETo irrigation level increased morphometric characteristics, fresh matter yield in the first and second cycles, and dry matter yield in the first cycle. Applying increasing irrigation levels promotes reductions in fresh matterand dry matter-based water use efficiency.

Fog water harvesting potential and its use in supplementary irrigation of rainfed crops (winter wheat) in Abi-beyglu, Ardabil (Iran)

Abstract In arid and semi-arid areas where available water resources are very limited, the application of unconventional sources of water like the fog is of paramount importance. In this paper, the feasibility of using a standard fog collector (SFC) to collect fog water for complementary irrigation of rainfed wheat in the Abi-beyglu area was investigated. For this purpose, collected water volume was measured on a daily basis during fog time in 2021. The water demand of the winter wheat was estimated by the FAO Penman–Monteith equation under dry and normal conditions. Then the contribution of the collected water to supply the water demand of the wheat and the resultant increase in the yield under two different scenarios, namely complementary irrigation with 30 and 60 mm of collected water, was estimated using the AquaCrop model. Results showed that it is feasible to obtain an average water production of 3.6 L/m2/day over the studied period. Upon irrigation with 30 and 60 mm of collected water under dry and normal conditions, 26 and 34% of the water deficiency for wheat farming was supplied, leading to increased crop yields by 0.6 and 1.7 ton/ha, respectively.

Determination of complementary irrigation times for rainfed cultivation based on biomass optimization and soil erosion index in Yellow River Valley

Abstract Drought is the most important factor limiting the growth and production of wheat in China. Arid and semi-arid regions and high water consumption in the agricultural sector have led to various deficit irrigation strategies. The effect of the hydrological process on yield production has been evaluated in rainfed cultivation of wheat for the three climatic stations of Gansu Province, Yellow River Valley, China. A general framework was provided for rainfed cultivation of wheat in arid and semi-arid regions. Moreover, the best time and amount of complementary irrigation and its effect on increasing yield production have been evaluated using grey wolf optimization algorithm. The results showed that rainfed cultivation of wheat in a humid regime could be suggested without complementary irrigation. Conducting two complementary irrigations in semi-humid regime can increase the final yield of wheat by more than 150 kg/ha. The maximum yields in sustainable management were obtained 4,844, 4,510, and 4,408 kg/ha for Longnan, Tianshui, and Dingxi, respectively.

IRRIGATED AGRICULTURE MAPPING IN A SEMI-ARID REGION IN BRAZIL BASED ON THE USE OF SENTINEL-2 DATA AND RANDOM FOREST ALGORITHM

Abstract. Irrigation is important for agricultural production and is often decisive for this, especially in arid and semi-arid areas, where precipitation is insufficient. In Brazil, irrigated agriculture is responsible for 46% of withdrawals from water bodies and 67% of the consumption of the total volume of water collected, representing the highest consumptive use in the country. Remote sensing technologies have great potential for developing methods for monitoring irrigated areas. However, mapping irrigated areas is still a challenge, due to the complexity and diversity of irrigation methods and crops, especially in a country with continental dimensions like Brazil. Remote sensing techniques for mapping irrigated areas in Brazil have been applied mainly in areas with center pivot irrigation in the Cerrado, and with paddy rice in the south of Brazil. But few or no applications, involving mapping of crops irrigated by other irrigation methods, mainly in the semi-arid, have been carried out. The objective of this work was to investigate a method for classifying irrigated agriculture in a semiarid region of Brazil, based on the use of Sentinel 2 imagery and random forest algorithm. We proposed a novel and robust methodology showing with preliminary results that it's possible to identify irrigated agriculture in this region with a class-f1-score of 74% for complementary irrigation and 95% for center-pivots.

Evaluation of Relative Efficiency of Several Selection Indices for Prediction of Expected Genetic Advance in Bread Wheat Grain Yield (Triticum aestivum L)

This experiment was conducted with fifteen genotypes of bread wheat introduced from ICARDA and two local varieties (Sham6 and Abu-Graib3), using three rows spacing (15, 25 and 35 cm). All genotypes were grown in 7 December, 2017 at Field Crops farm (inside Mosul University) under rain fed conditions with complementary irrigation, using split plots in randomized complete block design with three replications, for evaluation through constructing several selection indices and calculation of the expected gains of grain yield. The analysis of variance results for studied traits (grain yield, plant height, number spikes, biological yield, number of grains per spike, 1000-grain weight and harvest index) showed that mean square of genotypes were highly significant for plant height, number of grains per spike and 1000 grain weight. The selection index constructed from number of grains per spike and harvest index had high increase in the efficiency as compared with direct selection for yield. This indicate of the importance of a selection index based on combination of characters. This index in the present study considered the superior due to its highest efficiency. Using this index for genotypes evaluation revealed that the higher mean of selection index was 109.961 for genotype REYNA-12 with significant difference over Abu-Graib3 and is not with others, followed in importance by Sham6, ATTILA-7, PASTOR-2/BOCRO-2 and HUBARA-5/3/SHA3/SERI//SHA4LLIRA. The local varieties of bread wheat included in this study, (Sham6 and Abu-Graib3) locates at the sequences 2 and 17 respectively.
 

Improving Energy Efficiency in Agronomical Systems

Increasing demand for agricultural products and production of resource constraints- especially the limitation of cultivable areas - have made the highest yield per unit area the main goal of agricultural producers. Agriculture is a system exhibiting high energy consumption and production. Since energy has a direct impact on the efficiency of crop production, a sustainable agricultural system needs to be analyzed in terms of its input and output energy to determine the total consumed energy of production per unit area. The difference between input and output energy determines energy efficiency of an agronomical system. Input energy requires being well analyzed to reduce energy consumption and increase energy efficiency. This paper reviews energy efficiency indices based on energy consumption during planting and harvesting. To enhance energy efficiency of agronomical systems, some strategies are discussed in detail, including using high quality seeds, minimum tillage systems, direct seeded rice, weeds control especially in irrigation canals and plant nutrition through agronomical management. Although some agronomical strategies -like complementary irrigation in dry land farming systems- increase input energy, they increase crop yield. However, when output energy, resulting from the rise in crop yield, is higher than input energy, the system energy efficiency improves. Still, some inputs cannot be altered according to regional conditions which are often related to harvest stages operations.

Effect of Forecast Climate Changes on Water Needs of Giant Miscanthus Cultivated in the Kuyavia Region in Poland

Giant miscanthus is a vigorously growing energy plant, popularly used for biofuels production. It is a grass with low soil and water requirements, although its productivity largely depends on complementary irrigation, especially in the first year of cultivation. The aim of the study was to assess the impact of the forecast climate changes, mainly air temperature increase, on the water needs of giant miscanthus during the growing season in 2021–2050 in the Kuyavia region (central Poland). The years 1981–2010 as the reference period were applied. The meteorological data was based on the regional climate change model RM5.1 with boundary conditions from the global ARPEGE model for the SRES A1B emission scenario. Crop evapotranspiration, calculated using the Penman-Monteith method and crop coefficients, was assumed as a measure of water needs. The study results showed that in view of the expected temperature changes, in the forecast period 2021–2050, the giant miscanthus water needs will increase by 10%. The highest monthly increase may occur in August (16%) and in September (23%). In the near future, the increase in water needs of giant miscanthus will necessitate the use of supplementary irrigation. Hence the results of this study may contribute to increasing the efficiency of water use, and thus to the rational management of irrigation treatments and plant energy resources in the Kuyavia region.

Local empowerment and irrigation devolution in Ethiopia

ABSTRACT This paper investigates the effect of devolved irrigation water management systems and complementary irrigation technologies on collective empowerment in Ethiopia. We find that households’ monetary, in-kind and labour contributions for irrigation water provision and appropriation are more common in farmer-managed gravity irrigation schemes compared with farmer-managed pump systems and jointly managed schemes. The most frequent conflict occurrence was observed in jointly managed gravity irrigation systems, followed by farmer-managed gravity systems. Our results indicate that irrigation users’ degree of participation, decision-making capacity and strength of local governance are also affected by several household, plot, village, scheme and climatic factors.

Study on phenotypic and genotypic variation and the effect of complementary irrigation on yield and yield components of flixweld (Descurainia sophia L.) populations.

To study the phenotypic and genotypic variation of Iranian flixweld (Descurainia sophia L.) populations and the effect of complementary irrigation on their yield and yield components, an experiment was conducted as a split-plot in a randomized complete block design with three replications in the research farm of Islamic Azad University, Naragh Branch, during 2017-2018 growing season. Irrigation at two levels of rainfed cultivation and cultivation with one complementary irrigation was considered as the main plot and flixweld populations at eight levels of Hamedan, Esfahan, Chadegan in Esfahan, Markazi, Abuzeid Abad in Kashan, Bashrouye, Nakhjiravan, and Khomein as sub-plots. The results showed that grain yield, biological yield, the number of siliqua, the number of grains per silique, 1000-grain weight, and the number of sub-stems increased by complementary irrigation. There was a high variation among flixweld populations in terms of different traits. The highest grain yield under complementary irrigation and rainfed conditions was observed in Chadegan and Khomein populations with 499.1 and 359.1 kg ha-1, respectively. Cluster analysis divided flixweld populations into four groups under rainfed conditions. Populations Hamedan, Esfahan, Boshrouyeh, and Khomein were placed in the first group, Nakhjiravan in the second group, Markazi and Abuzeid Abad in the third group, and Chadegan in the fourth one. The highest broad-sense heritability (68.4%) was obtained for grain yield and number of siliqua traits.

Intensificação de sistemas de produção de palma forrageira por meio de consorciação rotativa com gramíneas, leguminosas e oleaginosas: uma revisão

A baixa produtividade de forragem no semiárido brasileiro atrela-se a escassez hídrica e condições climáticas, estas perturbações abióticas afetam o desenvolvimento da pecuária e economia local. Buscando contornar a situação, são de suma importância à utilização de espécies forrageiras adaptadas às condições climáticas como a palma, planta rica em nutrientes, bastante apreciada pelos animais, porém é carente em fibra e proteína, tornando-se necessário a utilização de outras plantas forrageiras como o sorgo, milheto, feijão-guandu e girassol forrageiro, ambas as espécies possuem elevados teores de fibras e proteína, e com isso, complementam-se e possibilitam a produção de dietas mais balanceada para os rebanhos. Todavia, o maior rendimento das culturas é observado com a implantação de práticas resilientes como a irrigação, adoção de cobertura morta, consorciação, o que promove sistemas mais sustentáveis e com alto potencial forrageiro. Nesta revisão, objetivou-se avaliar a utilização de diferentes práticas agronômicas para aumentar a produtividade e sustentabilidades dos cultivos de palma forrageira e culturas de apelo regional para o semiárido brasileiro. Conclui-se que a intensificação sustentável dos cultivos agrícolas, por meio da irrigação complementar, cobertura morta, consórcio com palma forrageira e espécies vegetais adaptadas ao semiárido brasileiro, podem promover aumento na produção de forragem sem efeitos adversos aos ecossistemas.Intensification of forage cactus production systems by rotating intercropping with grasses, legumes, and oilseeds: A review A B S T R A C T The low forage productivity in the Brazilian semi-arid is linked to water scarcity and climatic conditions, these abiotic disturbances affect the development of livestock and the local economy. Seeking to circumvent the situation, the use of forage species adapted to climatic conditions is of paramount importance, such as forage cactus, a crop rich in nutrients, much appreciated by animals, but lacking in fiber and protein, making it necessary to use other forage plants like sorghum, millet, pigeon pea and forage sunflower, both species have high levels of fiber and protein, and with this, they complement each other and enable the production of more balanced diets for herds. However, the higher yield of crops is observed with the implementation of resilient practices such as irrigation, adoption of mulch, intercropping, which promotes more sustainable systems with high forage potential. In this review, the objective was to evaluate the use of different agronomic practices to increase the productivity and sustainability of forage cactus crops and crops of regional appeal to the Brazilian semi-arid region. It is concluded that the sustainable intensification of agricultural crops, through complementary irrigation, mulch, intercropping with forage cactus, and plant species adapted to the Brazilian semi-arid region, can promote an increase in forage production without adverse effects on ecosystems. Keywords: intercropping, sustainable intensification, irrigation, Opuntia.

Efecto de la densidad de siembra y riego complementario en la morfo-fenología, rendimiento, rentabilidad y eficiencia de la fertilización del plátano

Efecto de la densidad de siembra y riego complementario en la morfo-fenología, rendimiento, rentabilidad y eficiencia de la fertilización del plátano

Quantifying Focused Groundwater Recharge Induced by Irrigation Surface Water Reservoirs in Crystalline Basement Areas for Complementary Irrigation

Through the practice of irrigation, surface water reservoirs (SWRs) contribute to the socio-economic development and food production activities of populations in Sub-Saharan Africa (SSA). However, they tend to dry up prematurely. One solution to circumvent these irrigation water shortages is to ensure their conjunctive use with groundwater. The objective of this study is to better understand the contribution of SWRs to groundwater recharge and to determine if groundwater may be considered as a complementary local resource for irrigation. The study was carried out on two watersheds in Burkina Faso, Kierma and Mogtedo. The spatiotemporal analysis of piezometric and SWRs level records coupled with physico-chemical analyses of water was used to characterize exchanges between SWRs and groundwater. The regional groundwater recharge at the scale of the watersheds was assessed. At the SWRs scale, a water balance methodology was developed and used to estimate focused recharge. The results show that SWRs interact almost continuously with groundwater and contribute focused recharge. The magnitude of this recharge is a function of the geological context and the sediment texture of the SWRs. It is estimated at 5 mm/day in Kierma and 4 mm/day in Mogtédo. These values are higher than the natural recharge estimated at 0.2 mm/day in Kierma and 0.1 mm/day in Mogtédo. Additionally, the values of hydraulic conductivity are between 0.01 and 2 m/day in Kierma and between 1 × 10−4 and 0.2 m/day in Mogtédo. These conductivities could allow pumping in large-diameter hand-dug wells with a significant yield between 0.5 and 120 m3/day in Kierma and between 0 and 10 m3/day in Mogtédo to palliate the early drying up of the SWRs.

Evaluation of Remote Sensing-Based Irrigation Water Accounting at River Basin District Management Scale

The Water Framework Directive in Europe requires extending metering and water abstraction controls to accurately satisfy the necessary water resource requirements. However, in situ measurement instruments are inappropriate for large irrigation surface areas, considering the high investment and maintenance service costs. In this study, Remote Sensing-based Irrigation Water Accounting (RS-IWA) (previously evaluated for commercial plots, water user associations, and groundwater water management scales) was applied to over 11 Spanish river basin districts during the period of 2014–2018. Using the FAO56 methodology and incorporating remote sensing basal crop coefficient time series to simulate the Remote Sensing-based Soil Water Balance (RS-SWB), we were able to provide spatially and temporally distributed net irrigation requirements. The results were evaluated against the irrigation water demands estimated by the Hydrological Planning Offices and published in the River Basin Management Plans applying the same spatial (Agricultural Demand Units and Exploitation Systems) and temporal (annual and monthly) water management scales used by these public water managers, ultimately returning ranges of agreement (r2 and dr) (Willmott refined index) of 0.79 and 0.99, respectively. Thus, this paper presents an operational tool for providing updated spatio-temporal maps of RS-IWA over large and diverse irrigation surface areas, which is ready to serve as a complementary irrigation water monitoring and management tool.

Hydrogeological conceptual model of an irrigated agricultural area, Buenos Aires Province, Argentina

In Argentina, the complementary irrigation has increased in most agricultural regions, where it is necessary to minimize possible negative impacts on the quantity and quality of groundwater. Numerical modeling techniques are used to obtain projections of the aquifer dynamics, for which a conceptual model is needed that provides the input data in the numerical simulations.A hydrogeological conceptual model for a rural area of Buenos Aires Province (Argentina), where complementary irrigation has caused significant depletion of groundwater levels during the irrigation season, has been developed. It was based on available geophysical and hydrogeological information and measurements of piezometric levels and hydraulic parameters of the aquifer together with the geochemical analysis of groundwater. This model was imported to a numerical model and the hydrogeological parameters were adjusted by the calibration with static piezometric levels measured in the wells. The conceptual model was validated satisfactorily using a fitting criterion to reach a value of root mean square error less than 5%. Different simulations of the probable drawdowns of the levels due to pumping were performed in the study area.The main hydrogeological unit is semi-confined, mostly comprising of a multilayer unit with good quality of water. Its minimum and maximum thickness was 60 and 240 m, respectively. The groundwater flows northwards from the hilly area to the plains. The recharge was 4.6 mm.year−1, representing 5% of annual precipitation. Dynamic simulations show that the aquifer gets dried, which questions its sustainability. The alternating condition of the source or drain of the streams depends on the irrigation period or the dry season, respectively. Great drawdowns of piezometric levels in some areas might be the cause of changes in water classification. These results lead to the need of planning the use of groundwater as a complement to agricultural activity, considering sustainable employment of the resource.

Evaluating Supplementary Water Methodology with Saturated Soil Irrigation for Yield and Water Productivity Improvement in Semi-Arid Rainfed Rice System, Burkina Faso

Saturated soil irrigation (SSI) has been reported as a great technique that increases water productivity in fully irrigated rice cultivation. However, this technique should be employed in a dry prone area where rainfalls fail to fulfill rice water requirements and fill up reservoirs for sufficient irrigation. Therefore, an experiment was conducted to identify the most effective complementary irrigation that restores soil moisture to saturation and increases water productivity with fewer yield expenses. The study used a complete randomized blocks design with four replications and four soil saturation treatments: Sat200% (farmer practice), Sat160%, Sat120%, and Sat80%. In Sat160%, Sat120%, and Sat80% irrigation was applied once a week in the absence of rainfall. In Sat200%, water was daily applied except the day of rain. The results showed that reductions in soil saturation decreased plant height, tillers, and leaves number by 10%, 18%, and 14%, respectively. Yield and components were reduced between 26.09% and 4.8%. Weekly soil saturation at 120% exhibited greater irrigation productivity (0.69 kg/m3), rainwater productivity (1.02 kg/m3), and water-saving (90.53%) with less production penalty (5 × 10−3 kg/m3). We advocate that saturated soil irrigation should be recommended in the rainfed rice system as a drought mitigation measure in semi-arid conditions.

Desenvolvimento de amendoim submetido a adubação fosfatada e potássica e diferentes espaçamento entre plantas

Theobjective ofthisstudy wasto evaluatethecultivationofpeanutsasafunctionofphosphateandpotassiumfertilizationinsowingandspacingbetweenplants,indrylandanddripirrigationinCariri-CE.A randomized block design was used in a split-plot scheme with four replications. TheplotsconsistedofthefertilizationdoseswithKandPofsowing(0,50,100and150%oftherecommendeddose)andthesubplotsbytwospacingsbetweenplants(10and20cm).Thevariablesevaluatedwereinitialpopulation,finalpopulation,plantheight,grainmassperplant,numberofpodsperplant,podmassperplant,grainmassperpods,massof1000grainsandmassof100pods,podyield,grainyieldandpercentageofnon-commercialgrains.Theresultsshowedthatthedrysequeiroandirrigationsysteminfluencedtheproductionofpeanutsandfertilization inthenumberofpodsandthemassofpodsperplantweresignificant,obtainingthemaximumpointatdosesof82.58and80.37%,respectively.Thespacingof20cmincreasedgrainyieldbyplantsandthemassof1000grainsby10.77%and14.8%,respectively.