Sistema de riego del Río Dulce, Santiago del Estero, Argentina. Brecha de rendimientos y productividad del agua en los cultivos de maíz y algodón

Autor: Angella, Gabriel Augusto
Přispěvatelé: Fereres Castiel, Gabriel Augusto, Fereres Castiel, Elías
Jazyk: Spanish; Castilian
Rok vydání: 2016
Předmět:
Zdroj: INTA Digital (INTA)
Instituto Nacional de Tecnología Agropecuaria
instacron:INTA
Helvia. Repositorio Institucional de la Universidad de Córdoba
instname
Popis: Seventy percent of the Planet Earth´surface is covered by water. However, only 2.5% isfresh water, the remaining 97.5% is salt water in oceans and seas. From 2.5% of freshwater,only 0.3% is available in rivers, lakes and reservoirs, 30% is located in underground aquifersand the rest is frozen in the poles and glaciers. It is clear that only a very small portion of thewater of the Earth is currently available to meet the needs of mankind: drinking water,agriculture and industry. It is estimated that worldwide there are around 1,500 millionhectares of farmland, of which 277 million are irrigated lands. Of the total freshwater deliveredto different uses, irrigation is the main user of the planet: approximately 70% of the totalfreshwater is used to irrigate crops (Molden et al 2010; Kassam et al 2007).It is estimated that by year 2050 the Earth will be inhabited by 9,000 million people,which will demand more and better food. It is important to know that such a scenario must beaddressed with a similar amount of arable land and fresh water. The agricultural sector shouldbe able to provide the necessary answers, for example by making more efficient use of waterand increasing their productivity. The concepts of "efficiency" and "productivity" of the waterhave been widely studied by the scientific and academic community. Both have differentapproaches, according to the scale of study, its objectives and the actors involved, whichdetermines the framework to use. To characterize the use of water in irrigation systems isrequired to understand the characteristics of the cultures involved, identify the factors thatrestrict the efficient use of water, determine the prevailing farmers´ irrigation practices, andthen be able to explore strategies of management within each particular technological,economic and social framework. One of the approaches to assess the water use andproductivity in agriculture is based on the use of simulation models, whose main function is toestimate the production of crops according to climate, soil, and technological management.The model AquaCrop (Steduto et al 2009) focuses on the crops response to water availability.In the Río Dulce Irrigation System (SRRD), located in the province of Santiago delEstero, Argentina, crop production is lower than attainable. The low irrigation frequency andstandard farmer´ practices expose crops to periods of water shortage, which have negativeimpact on yields, and also limit the efficient use of water.This thesis is aimed to characterize the use of irrigation water in maize and cottoncrops and to analyze irrigation strategies allowing increasing crops production and improvingwater use in the SRRD. For that purspose, the following specific objectives have been raised: tocalibrate and validate the AquaCrop model for maize and cotton crops; to evaluate the yieldsand water productivity gaps in those crops, and quantify the benefits of changing the systemof fixed shifts to one more flexible.Calibration and validation of maize in the agro-ecological conditions of Santiago delEstero is dealt with in Chapter 2. To do this, experiments set at INTA between 2007 and 2012were used. Their objectives were to determine the response of maize to various planting datesand deficit irrigation treatments. The model precisely simulated maize behavior. Statisticalindicators gave a degree of adjustment that can be described as very good; by way of example,in yields, values were as follows: coefficient of determination (R2)=0,985; Willmott index (d)=0,995; Mean absolute error (MAE)=0, 259; Root of the mean square error (RMSE)=0, 361 andaverage normalized quadratic error (NRMSE) root=3,6. To close this chapter, a meta-analysis ofAquaCrop ability to simulate the behavior of the corn in a wide range of climate, soil, geneticmaterials and agronomic management conditions was made, analyzing the existing literature.It showed the good response of the model in twelve places. The good behavior of the model inSantiago del Estero, Argentina, having different climate characteristics to the place where thexcrop parameters were defined (Davis, California, USA), strengthens the viability of AquaCrop tosimulate the production of maize.Calibration and validation of cotton is treated in Chapter 3. To this purpose,experiments set at INTA between 2007 and 2013 were used. Their objectives were todetermine the cotton response to deficit irrigation treatments and to different soil watercontents (without stress conditions). AquaCrop simulated very well the behavior of cotton. Thevalues of the statistical indicators were: R2=0.940; d=0.974; MAE=0,317; RMSE=0,413 andNRMSE=10.1. The varieties used in the experiments are very different to those used in originalcrop parameterization, so some conservative parameters were changed, among others:canopy growth coefficient, time to maximum canopy cover, time to flowering and harvestindex. It should be noted that the maximum yields observed in experiments and appropriatelysimulated by AquaCrop, quite exceed yields on which is based the original calibration. Finally,it is necessary to highlight the great adaptation of the model to different agronomic conditions(distance between lines, plant density and intensive use of growth regulators) with respect towhich were used for their original parameterization.It is emphasized the simplicity of AquaCrop and its capacity of adaptation to differentclimates and agronomic management. The model can be used in several applications: yieldestimation, analysis of production risks by impact of droughts, definition of irrigation strategiesat farm level to improve water use and as a tool in assessing irrigation performance.This thesis is the first approach to assess, at system level, yield and water productivitygaps in the Río Dulce Irrigation System (SRRD), located in Santiago del Estero, Argentina. This isdone in chapter 4 and the specific objectives were: characterize variations in maize and cottonwater use in the San Martín District (SRRD); determine the gaps in yield and water productivityin those crops; assess the benefits of changing the actual irrigation rotational system to a moreflexible water delivery, and evaluate how irrigation scheduling impact on water use. To achievethese objectives, AquaGIS (Lorite et al 2013) was used. AquaGIS is an interface that overcomesthe current limitations of AquaCROP when it is necessary to do many simulations over largeareas and for a large number of years. The use of AguaGIS was complemented with fieldsurveys and questionnaires, to adjust the information of the current productive situation.Various scenarios have been set, whit the following factors: climate (series 1988-2013), soil(four), crop (maize and cotton), production levels (potential, water limited and actual), andplanting date (two for each crop). The combination of variables resulted in 624 simulations percrop. Production levels were associated to irrigation strategies: potential production/ondemand irrigation; water limited production/improved irrigation scheduling within the presentrotational system; actual production/current farmers` irrigation management.For maize, the gap between potential and actual yield is estimated at 5900 kg ha-1 andthe gap between potential yield and achievable (limited by the irrigation rotational system)yield was estimated at 1100 kg ha-1. Current water productivity (WP) is 17 kg ha-1.mm-1,considered low considering the potential of hybrids currently used. The WP in potentialproduction is 25 kg ha-1.mm-1 and in water limited production, 23 kg ha-1.mm-1. The currentirrigation water productivity (IWP) is very low, 4.5 kg ha-1.mmIW-1. The IWP in potentialproduction is 27 kg ha-1.mmIW-1 and in water limited production 16 kg ha-1.mmIW-1. Simplechanges in farmers` irrigation practices would lead to significant increases in maize WP andIWP, even within the constraints imposed by the present rotational irrigation system.In cotton, the gap between potential and actual yield is estimated at 2000 kg ha-1 andbetween potential...
La Tierra recibe, entre otros, el apelativo de "Planeta Azul" debido a que el 70% de susuperficie está cubierta por agua. Sin embargo, sólo el 2.5% es agua dulce, el 97.5% restanteson mares y océanos de agua salada. Del 2.5% de agua dulce, sólo el 0.3% está disponible enríos, lagos y embalses, el 30% se encuentra en acuíferos subterráneos y el resto está congeladaen los casquetes polares y glaciares. Resulta claro que sólo una muy pequeña porción del aguade la Tierra está actualmente disponible para cubrir las necesidades de la humanidad: aguapotable, agricultura e industria. Se estima que en el mundo hay alrededor de 1,500 millones dehectáreas de tierras de cultivo, de las cuales 277 millones disponen de riego. Del total del aguadulce derivada para los distintos usos, el riego es el principal usuario del planeta, conaproximadamente el 70% del total se usa para el riego de los cultivos (Molden et al. 2010;Kassam et al 2007; FAO 2012).Se calcula que en el año 2050 el planeta Tierra estará habitado por 9,000 millones deseres humanos, que demandarán más y mejores alimentos. Se estima que los pilarespermitirán hacer frente a tal desafío serán las técnicas agronómicas, la biotecnología y elmanejo juicioso de los recursos naturales. Un aspecto clave a considerar es que ladisponibilidad de tierras cultivables y agua será similar que en el siglo pasado. El sector agrícoladeberá ser capaz de dar las respuestas necesarias, por ejemplo haciendo un uso más eficientedel agua e incrementando su productividad. Los conceptos de “uso eficiente” y“productividad” del agua han sido y son ampliamente estudiados por la comunidad científica yacadémica ligadas al uso del agua en la agricultura. Ambos tienen matices según la escala deestudio, sus objetivos y los actores involucrados, lo que determina el marco a utilizar. Paracaracterizar el uso del agua en los sistemas de riego se requiere conocer las características delos cultivos involucrados, identificar los factores que restringen el uso eficiente del agua,determinar los hábitos predominantes de riego de los agricultores, para luego poder explorarestrategias de manejo en cada marco tecnológico, económico y social particular. Uno de losenfoques para evaluar el uso y la productividad del agua en la agricultura se basa en el uso demodelos de simulación, cuya función principal es estimar la producción de los cultivos enfunción del clima, el suelo y el manejo tecnológico. El modelo AquaCrop (Steduto et al 2009) secentra en la respuesta de los cultivos a la disponibilidad de agua.En el Sistema de Riego del Río Dulce-Los Quiroga, ubicado en la provincia de Santiagodel Estero, Argentina, la producción de los cultivos es bastante menor que la que podríaobtenerse. La baja frecuencia del turno de riego y las prácticas habituales de manejo exponena los cultivos a períodos de déficit hídrico, que tienen impacto negativo en los rendimientos y,asimismo, limitan el uso eficiente del agua.La presente tesis tiene como finalidad, para el Sistema de Riego del Río Dulce-LosQuiroga, Santiago del Estero, Argentina, caracterizar el uso del agua de riego en los cultivos demaíz y algodón y analizar estrategias de riego que permitan aumentar su producción,mejorando el uso del agua. Para ello, se plantearon los siguientes objetivos específicos:calibrar y validar el modelo de simulación AquaCrop para los cultivos de maíz y algodón,evaluar la brecha de rendimientos en esos dos cultivos a nivel de productor y cuantificar losbeneficios productivos de cambiar el sistema de turno fijo a uno más flexible, que permitaacoplar el riego con las necesidades de agua de los cultivos.La calibración y validación del maíz para las condiciones agroecológicas de Santiago delEstero se aborda en el Capítulo 2. Para ello, se utilizaron experimentos realizados en INTAentre los años 2007 y 2012, que tuvieron como objetivos determinar la respuesta de híbridosde maíz a distintas fechas de siembra y a tratamientos de riego deficitario. El modelo simuló...
Databáze: OpenAIRE
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