ABSTRACT The search for more sustainable systems of rice cultivation, especially in relation to water use, has included the evaluation of more-efficient irrigation systems in addition to alternative water sources. The aim of this study was to conduct a phytosociological survey of weeds in rice crops irrigated by subsurface drip with different concentrations of treated dairy effluent, maintaining the soil moisture at saturation or field capacity. A pilot scale experiment was carried out in a protected environment using a randomised block design in a 5 x 2 factorial scheme, with four replications. The IAC 301 cultivar (Arborio rice) was chosen. The phytosociological surveys were carried out on four different dates, and considered the composition as well as the distribution of plant species in each of the applied treatments, using the importance value index (IVI) to evaluate the influence of each treatment. The results showed that cultivating irrigated rice, giving priority to water management, altered the ecology of invasive plants. Fourteen weed species were identified, distributed over 10 families. The effluent dose did not alter the incidence of invasive plants, and only at the final evaluation was there a reduction in the IVI value at effluent concentrations of 50% and 75%. For soil moisture, the highest IVI values occurred on the first two days of the survey under saturated conditions; this result was reversed closer to plant maturity, when the IVI values were higher at field capacity. cultivation use moreefficient efficient sources capacity scheme replications 30 Arborio chosen dates treatments (IVI treatment management plants identified 1 families 50 75 75% conditions maturity 3 7

Abstract The research evaluated the effect of conventional management of irrigated rice on the physicochemical indicators of the soil, in the Mercedes and Pérez farms, in Yurimaguas, Peru. It is a comparative non-experimental investigation, with statistical adjustment of a completely randomized design, where the treatments are made up of the secondary forest (BS), the conventional rice management of one (A1), five (A5) and nine years (A9), evaluating physicochemical indicators of the soil in strata from 0.0 to 0.2 and 0.2 to 0.4 m. The results showed differences in the fractions, with initial reduction of sand, silt and clay increase and in time slight recovery of the sand, silt fraction and clay reduction. The chemical indicators according to treatments and strata show differences, except K; management significantly affects the beginning of the production process (A1) reducing the levels of pH, MO, N, P, , and and increasing , AC and SAl, and there is a recovery over time (A9), except in MO and N which decrease to very low levels. In conclusion, conventional management shows significant effects between treatments and indicators evaluated in both strata, negatively affecting the beginning (A1) and recovering over time (A9); however, there are long-term negative effects on OM and N levels.

Resumen La investigación evaluó el efecto del manejo convencional del arroz bajo riego en indicadores fisicoquímicos del suelo, en los fundos Mercedes y Pérez, en Yurimaguas, Perú. Es una investigación no experimental comparativa, con ajuste estadístico de diseño completamente aleatorizado, donde los tratamientos lo constituyen el bosque secundario (BS), el manejo convencional del arroz de: uno (A1), cinco (A5) y nueve años (A9); evaluándose indicadores fisicoquímicos del suelo en estratos de 0,0 a 0,2 y 0,2 a 0,4 m. Los resultados mostraron diferencias en las fracciones, con reducción inicial de arena, limo e incremento de arcilla y en el tiempo ligera recuperación de la fracción arena, limo y reducción de arcilla. Los indicadores químicos según tratamientos y estratos presentan diferencias, excepto el potasio (K); el manejo afecta significativamente al inicio del proceso productivo (A1) reduciendo los niveles del potencial de hidrogeno (pH), materia orgánica (MO), nitrógeno (N), fosforo (P), potasio ( ), calcio ( ) y magnesio ( ) e incrementando el aluminio ( ), acidez cambiable (AC) y saturación de aluminio (SAl); de igual forma, se observa la recuperación en el tiempo (A9), excepto en MO y N que descienden a niveles muy bajos. En conclusión, el manejo convencional muestra efectos significativos entre tratamientos e indicadores evaluados en ambos estratos, afectando negativamente al inicio (A1) y recuperándose con el tiempo (A9); sin embargo, se observan efectos negativos a largo plazo en los niveles de MO y N.

RESUMEN Burkholderia glumae es el principal agente causal del tizón bacteriano de panícula en el arroz (Oriza sativa), una enfermedad que genera pérdidas en la producción mundial. A pesar de su importancia económica, todavía no se dispone de medidas eficaces de control ni de variedades de arroz con resistencia total a la enfermedad. En este estudio se evaluó la actividad antimicrobiana de las nanopartículas de plata sintetizadas electroquímicamente (AgNPs) contra B. glumae. Para la síntesis de AgNPs se utilizó una fuente de alimentación DC (UNI-T®) regulada a 24 V, que se conectó a dos electrodos cilíndricos de plata de alta pureza (Aldrich-99,99%), utilizando agua destilada como electrolito.La concentración de AgNPs se determinó midiendo los sólidos disueltos totales (TDS) a través del multiparámetro HandyLab 680 FK. La actividad antibacteriana de estas nanopartículas contra B. glumae se determinó por el método de macrodilución de caldo, a diferentes concentraciones (1-10 mg L-1). La concentración mínima inhibitoria (CMI) se determinó en 5 mg L-1 de AgNPs. Los resultados de este estudio revelaron que las AgNPs podrían considerarse como nanoplaguicidas prometedores para controlar el tizón bacteriano de panícula en el arroz.

ABSTRACT Burkholderia glumae, is the main causal agent of bacterial panicle blight (BPB) in rice (Oriza sativa), a disease that generates production losses worldwide. Despite its economic importance, effective control measures and rice varieties with complete resistance to this disease have not yet been available.In this study, the antimicrobial activity of electrochemically synthesized silver nanoparticles (AgNPs) against B. glumae was evaluated. The AgNPs were synthesized with a DC power supply (UNI-T®) regulated at 24 V, which was connected to two cylindrical electrodes of high purity silver (Aldrich-99.99%) using distilled water as an electrolyte. The AgNPs concentration was determined by measuring the total dissolved solids (TDS) with a HandyLab 680 FK multiparameter. The antibacterial activity of these nanoparticles against B. glumae was determined by the broth macrodilution method at different concentrations (1-10 mg L-1).The minimum inhibitory concentration (MIC) was determined in 5 mg L-1 of AgNPs.The results revealed that AgNPs are a promising nanopesticide for controlling the BPB disease in rice.

Abstract In Ecuador, rice is one of the most important cereals in the diet of many families and, at the same time, a resource of economic, social, and environmental importance. The objective of this work was to characterize the rice production systems in Babahoyo canton. The information was obtained through surveys of 21 variables that included questions aimed at obtaining sociocultural, economic, and ecological information. Data collection techniques included surveys, interviews, workshops, and direct field observations. The study was based on cluster analysis. Three groups were defined: the largest brings together farmers with 53.70%, a medium with 27.58%, and small one with 18.51%, highlighting important variables in the groups such as a monoculture production system, the application of medium and high doses of fertilizers and pesticides, which reflects problems in the harvest due to low prices, and the chain of intermediaries when marketing their products.

Resumen En Ecuador, el arroz es uno de los cereales más importantes en la alimentación de muchas familias, al mismo tiempo, un recurso de importancia económica, social y ambiental. El objetivo de este trabajo fue caracterizar los sistemas de producción de arroz en el cantón Babahoyo, la información se obtuvo mediante encuestas a 21 variables que incluyó preguntas orientadas a obtener información sociocultural, económica y ecológica. Se utilizó como técnicas de recolección de datos, la encuesta, entrevistas, talleres, y observaciones directas en campo. El estudio se basó en un análisis de conglomerado, se definieron tres grupos, el más grande reúne agricultores con 53,70%, uno mediano con un 27,78% y uno pequeño de 18,51%, resaltando variables importantes en los grupos como un sistema de producción de monocultivo, la aplicación de medias y altas dosis de fertilizantes y pesticidas, lo que refleja problemas en la cosecha por los precios bajos y por la cadena de intermediarios al comercializar sus productos.

Resumen En México, ha sido un reto satisfacer la demanda nacional de arroz que superan las 850 000 toneladas anuales, por lo que en los últimos años se ha recurrido a la importación. Ante ello, a fin de contrarrestar esta situación, se ha incentivado el desarrollo de tecnologías propias a los sistemas de producción y la implementación de programas de mejoramiento genético orientados a la generación de genotipos y su adaptación a las zonas arroceras del país. A pesar de los esfuerzos, aun se carece de variedades de arroz de grano largo y delgado que son de buena calidad industrial del grano y competitivo con los arroces de importación; además, que son preferidos por el consumidor. En consecuencia, en la región arrocera de Michoacán se identificaron líneas de arroz avanzadas, donde surgió el genotipo Lombardía FLAR 13. Durante los ciclos 2017 a 2020 este material fue evaluado experimentalmente en comparación con el genotipo Milagro Filipino en Lombardía, municipio de Gabriel Zamora, Michoacán. Se registraron variables morfológicas y productivas. Con los datos obtenidos además de la verificación de las pruebas de normalidad y homogeneidad de varianzas, se analizaron con la prueba estadística t-student para muestras independientes. Los resultados mostraron superioridad del genotipo Lombardía FLAR 13 sobre el genotipo Milagro Filipino, ya que en la mayoría de las variables morfológicas evaluadas igualó, e incluso superó en las variables productivas, particularmente en esta última, los rendimientos fueron superiores a 9 t ha-1, además presentó estabilidad productiva durante los ciclos evaluados, por lo que es competitivo con la variedad convencional Milagro Filipino que se establece en la zona.

Abstract In Mexico, it has been a challenge to meet the national demand for rice, which exceeds 850 000 tons per year, so in recent years imports have been resorted to. Given this, in order to counteract this situation, the development of technologies specific to production systems and the implementation of genetic improvement programs aimed at the generation of genotypes and their adaptation to the rice-growing areas of the country have been encouraged. Despite the efforts, there is still a lack of long and thin grain rice varieties that are of good industrial grain quality and competitive with imported rice, in addition to being preferred by the consumer. Consequently, in the rice-growing region of Michoacán, advanced rice lines were identified, where the Lombardía FLAR 13 genotype emerged. During the 2017 to 2020 cycles, this material was experimentally evaluated in comparison with the Milagro Filipino genotype in Lombardía, municipality of Gabriel Zamora, Michoacán. Morphological and productive variables were recorded. With the data obtained, in addition to the verification of the tests of normality and homogeneity of variances, they were analyzed with the t-student statistical test for independent samples. The results showed superiority of the Lombardía FLAR 13 genotype over the Milagro Filipino genotype, since in most of the morphological variables evaluated, it equaled and even exceeded in the productive variables, particularly in the latter, the yields were greater than 9 t ha-1, it also showed productive stability during the evaluated cycles, so it is competitive with the conventional variety Milagro Filipino, which is established in the area.

Resumen La plaga que más problemas ha causado en los últimos años en el arroz (Oryza sativa L.) es el Caracol manzana (Pomacea canaliculata Lamarck), esta plaga está considerada entre las 100 peores especies invasoras del mundo. El presente trabajo es un ensayo experimental a nivel de campo donde se aplicaron diferentes dosis de quelato de cobre y agua ozonizada para el control del caracol manzana en el cultivo de arroz, para lo cual se utilizó un diseño de bloque completo al azar (DBCA), con cinco tratamientos incluido el testigo y cuatro repeticiones. El sitio experimental se ubicó en una finca del cantón Salitre, provincia del Guayas, Ecuador con clima tropical. Se evaluó el índice de mortalidad de los caracoles frente a los tratamientos propuestos. El tratamiento T4, que correspondía a la dosis de 2 L ha-1 de quelato de cobre mezclado con agua ozonizada con 2 ppm de concentración, fue el tratamiento que mejor control de caracol manzana se observó, dando como resultado 94% de mortalidad.

Abstract The pest that has caused the most problems in rice (Oriza sativa L.) in recent years is the apple snail, Pomacea canaliculata (Lamarck); this pest is considered among the 100 worst invasive species in the world. The present work is an experimental trial at the field level where different doses of copper chelate and ozonated water were applied to control the apple snail in rice cultivation; for which a randomized complete block design (RCBD) was used, with five treatments, including the control and four repetitions. The experimental site was located on a farm in the Salitre canton, in the Guayas province, Ecuador, with tropical climate. The mortality rate of the snails against the proposed treatments was evaluated. Treatment T4, which corresponded to the dose of 2 L ha-1 of copper chelate mixed with ozonated water with a concentration of 2 ppm, was the treatment were the best apple snail control was observed, resulting in 94% mortality.

El revestimiento de semillas de arroz con óxido de zinc microparticulado puede maximizar la absorción de este micronutriente por las plántulas y favorecer el vigor de las semillas en comparación con el sulfato de zinc. Este trabajo tuvo como objetivo evaluar las fuentes y dosis de zinc en la calidad de semillas y en la nutrición de plántulas de arroz. El experimento fue desarrollado en delineamiento completamente al azar con cuatro repeticiones, con un testigo sin aplicación de zinc, cuatro dosis de óxido de zinc (20, 40, 80 y 160 g kg-1 de Zn), y un tratamiento en la forma de sulfato de zinc, 40 g kg-1 de Zn. Se evaluaron los siguientes parámetros: germinación, velocidad de envejecimiento, emergencia de plántulas, índice de velocidad de emergencia, prueba fría de semillas, materia seca y acumulación de zinc en la raíz y parte aérea de las plántulas. La cobertura de semillas con zinc, independientemente de la fuente, mejoró la calidad fisiológica de las semillas y la nutrición de las plántulas de arroz. Las fuentes de zinc no alteraron la germinación; sin embargo, el óxido de zinc proporcionó un mejor vigor de las semillas, con la excepción de la mayor dosis, 160 g kg-1. El aumento en la dosis de óxido de zinc aumentó la acumulación de ese nutriente en la materia seca de las plántulas de arroz. El recubrimiento con zinc en semillas de arroz en forma de micropartículas, dependiendo de la dosis, puede maximizar el vigor de las semillas y aumentar la concentración de este micronutriente en las plántulas en comparación con el sulfato de zinc, que es la fuente tradicional utilizada por los productores.

Rice seeds coating with microparticulate zinc oxide can maximize the absorption of this micronutrient by the seedling and favor seeds vigor when compared with zinc sulfate. This work aimed to evaluate the sources and doses of zinc in seed quality and in the nutrition of rice seedlings. The experiment consisted of a completely randomized design with four replications, five doses of zinc in the form of oxide (0; 20; 40, 80 and 160 g kg-1), and a control treatment of zinc in the form of sulfate (40 g kg-1). The following parameters were evaluated: germination, accelerated aging, seedlings emergence, emergence speed index, cold test, dry matter, and zinc concentration in the root and shoot of the seedlings. Seed coating with zinc, regardless of the source, improved seed physiological quality and seedling nutrition. Zinc sources did not affect germination; however, the oxide form induced better seed vigor, except for the highest dose (160 g kg-1). Increasing doses of zinc oxide augmented the concentration of this nutrient in rice seedlings dry matter. Zinc coating of rice seeds in the form of microparticulate, depending on the dose, can maximize seed vigor and increase the concentration of this micronutrient in the seedlings when compared with zinc sulfate, the traditional source.

ABSTRACT: The objective of this study was to evaluate ruminal fermentation (i.e. pH, ammonia, and volatile fatty acid concentrations) and in situ degradability of diets in sheep fed sugarcane silage (SCS) supplemented with Tithonia diversifolia (Td) or alfalfa (Medicago sativa) hay (A), with or without rice (Oriza sativa) polishing (RP) as an energy source. Four Blackbelly sheep (35 kg average body weight) with rumen cannula were used. The experimental diets were (g/kg of dry matter): Diet 1) SCS (686) + Td (294), Diet 2) SCS (460) + Td (226) + RP (294), Diet 3) SCS (637) + A (343), and Diet 4) SCS (441) + A (245) + RP (294). The remainder (20 g/kg of dry matter) was composed by minerals supplement and salt. Samples of diets were incubated into rumen for 3, 6, 9, 12, 24, 30, 36, 48, and 72 h to determine in situ degradability. Data were analysed with a linear mixed model. The lamb, period and lamb nested in period*diet were considered as a random variable. The inclusion of RP improved the degradability of diets and ammonia production in the rumen. The acetic, propionic, and butyric acid concentrations (mmol/100 mL) in rumen increased (P<0.03) when diets with alfalfa and RP were provided. The degradability of diets based on sugarcane silage supplemented with either alfalfa or Tithonia diversifolia was improved (P<0.05) with the rice polishing inclusion, with no difference (P>0.05) between these forages. In conclusion, energy supplementation, not necessarily from starch, is important to improve rumen fermentation and degradability of diets based on sugarcane silage.

ABSTRACT The bioavailability of a nutrient in a food serves to determine the nutritional quality for human consumption. Rice is one of the most important foods in diet due to its caloric and nutritional contribution. The objective of this study was to analyze the in vitro bioavailability of zinc in rice by ultraviolet-visible spectrophotometry and flame atomic absorption spectrometry and its relationship with phytic acid content. The percentage of zinc bioaccessibility with respect to phytic acid percentage, showed an inverse proportional logarithmic relationship (r= −0.669; p<0.05). The percentage values of zinc bioavailability and phytic acid in the evaluated rice varieties had a range of 1.9-8.7% and 0.039-0.946%, respectively. Phytic acid affected the bioaccessibility of zinc and was not linked to the total concentration of zinc present in the rice lines evaluated. The techniques implemented to quantify zinc dialyzed presented significant differences. It was shown that the ultraviolet-visible technique was not suitable for this type of assay.

RESUMEN La bioaccesibilidad de un nutriente en un alimento sirve para determinar la calidad nutricional de éste para el consumo humano. El arroz es uno de los alimentos más importantes en la dieta por su gran aporte calórico y nutricional. El objetivo de este estudio fue analizar la bioaccesibilidad in vitro del zinc en arroz mediante espectrofotometría ultravioleta-visible y espectrometría de absorción atómica de llama y su relación con el contenido de ácido fítico. El porcentaje de bioaccesibilidad del zinc, respecto al porcentaje de ácido fítico, presentó una relación logarítmica inversamente proporcional (r= −0,669; p<0,05). Los valores porcentuales de bioaccesibilidad del zinc y ácido fítico en las líneas de arroz evaluadas se hallaron en un rango de 1,98,7% y 0,039-0,946% respectivamente. Se encontró que el ácido fítico afecta la bioaccesibilidad del zinc y que ésta no estuvo ligada a la concentración total del zinc presente en las líneas de arroz evaluadas. Las técnicas implementadas para cuantificar el zinc dializado presentaron diferencias significativas y se mostró que la técnica ultravioleta-visible no fue apta para este tipo de ensayos.

RESUMEN En la actualidad muchos recursos agrícolas no solo representan parte de la ingesta alimenticia de las personas, sino que además contribuyen al desarrollo agroindustrial y a la economía de los países, uno de esos recursos es el arroz (Oriza sativa) pero pese al gran potencial con el que se puede desarrollar este sector, presenta problemas como la escasez de inversión, modernización y comercialización, lo que impide incrementar su desarrollo en algunos países como el Ecuador. Se estudió la incidencia de la producción de arroz en el desarrollo socio económico de los agricultores del cantón Samborondón, para lo cual se estableció una investigación prospectiva-descriptiva con enfoque cualimétrico, se determinó una muestra de 63 productores asociados, se evaluó indicadores de calidad de vida, réditos obtenidos e interés y capacidad de producir subproductos elaborados a partir del arroz.

ABSTRACT Nowadays, so many agricultural resources represent not only part of the alimentary ingestion of people, but they contribute too, to the agricultural development and to the economy of countries and one of this resources is the rice but, with the great potential to develop this sector, it presents problems as poverty of inversion, modernization and commercialization, and do not improve the development in some countries as Ecuador. It was studied the incidence of the rice production in the socio-economic development of the agriculturalist in Cantón Samborondón, in where it was established a prospective-descriptive investigation with a qualimetric focus, and it was determine that a sample of 63 asociated agriculturalists, and they were evaluated with life quality indicators, interest and capacity to produce from the rice product.

ABSTRACT. This study presents self-organizing maps (SOM) as an alternative method to evaluate genetic diversity in plant breeding programs. Twenty-five genotypes were evaluated in two environments for 11 phenotypic traits. The genotypes were clustered according to the SOM technique, with variable topology and numbers of neurons. In addition to the SOM analysis, unweighted pair group method with arithmetic mean clustering (UPGMA) was performed to observe the behavior of the clustering when submitted to these techniques and to evaluate their complementarities. Genotype ordering according to SOM was consistent with UPGMA results, evidenced by the basic structure of UPGMA groups being preserved in each group of the maps. Regarding genotype arrangement and the group neighbors, maps involving five neurons presented inferior organization efficiency compared to the six-map arrangements in both environments. It was observed that the organization pattern among the rice genotypes evaluated by the maps was complementary to the UPGMA approach, as observed in all scenarios. It can be concluded that self-organizing maps have the potential to be useful for genetic diversity studies in breeding programs.

Resumen En la zona central de México se siembra el arroz (Oryza sativa L.) bajo trasplante y en siembra directa bajo riego; la mayoría de las variedades se han liberado para trasplante. En 2005 una de estas líneas se usó como progenitor y continuándose con el avance generacional hasta F5. En 2011 se realizó una prueba preliminar del rendimiento de varios grupos de líneas, alrededor de 256 materiales, de donde se identificó como sobresaliente a C14Za06 (actualmente, var. Morelos A-2016). En 2014 y 2015 se evaluaron diferentes líneas en ensayos de rendimiento en las localidades de Zacatepec, Jojutla, Emiliano Zapata, Mazatepec, Coatlán del Rio y Cuautla, estado de Morelos; además del testigo comercial Morelos A-2010. De los materiales evaluados sobresalió la C14Za06 por rendimiento superior a 10 t ha-1, moderada resistencia a pyricularia, alta tolerancia a manchado de grano, habito de crecimiento semierecto, altura de planta de 130 cm, resistentes al acame; rendimiento en industria de 57% de grano pulido entero; conservando la calidad Morelos (20% de centro blanco).

In the central zone of Mexico, rice (Oryza sativa L.) is planted under transplant and in direct sowing under irrigation; most varieties have been released for transplant. In 2005, one of these lines was used as a parent and continued with the generational advance to F5. In 2011, a preliminary performance test was carried out on several groups of lines, around 256 materials, from which C14Za06 was identified as outstanding (currently, Var. Morelos A-2016). In 2014 and 2015 different lines were evaluated in performance trials in the towns of Zacatepec, Jojutla, Emiliano Zapata, Mazatepec, Coatlan del Río and Cuautla, Morelos state; in addition to the commercial witness Morelos A-2010. Of the evaluated materials, C14Za06 stood out for its yield superior to 10 t ha-1, moderate resistance to pyricularia, high tolerance to grain staining, semi-erect growth habit, plant height of 130 cm, resistant to lodging; industry performance of 57% whole polished grain; conserving the Morelos quality (20% of white center).

Resumen En México el arroz largo y delgado es de mayor consumo, por lo que su abasto ha dependido principalmente de importaciones. Consecuentemente, el Consejo Mexicano del Arroz entregó al INIFAP líneas élite que generó el Fondo Latinoamericano de Arroz de Riego (FLAR) para evaluación y selección de materiales. Con el objetivo de validar líneas avanzadas de arroz de grano largo y delgado comparadas con el material convencional bajo las condiciones de la zona productora de Michoacán, trabajos experimentales fueron desarrollados en diferentes ciclos: otoño-invierno 2014-2015 (ensayo 1), primavera verano de los años 2015 (ensayo 2), 2016 (ensayo 3) y 2017 (ensayo 4) y diferentes genotipos: ensayo 1) INIFLAR RT, FL05601, “Milagro Filipino”; ensayo 2) FL06747, FL08224, INIFLA R, INIFLAR RT, Marfil, Lombardía, “Milagro Filipino”; ensayo 3) Lombardía, FL08224, “Milagro Filipino”; y ensayo 4) Marfil, Lombardía “Milagro Filipino”. Los datos registrados variaron en cada ensayo, pero se incluyeron aspectos fenológicos y productivos, incluido el rendimiento. Se realizaron análisis de varianza y comparación de medias. En el ensayo 1, los tratamientos superaron a la media regional, entre 8 000 a 8 500 kg ha-1. En el ensayo 2, los tratamientos FL06747, INIFLAR R y Lombardía sobresalieron significativamente en rendimiento. También la floración y madurez de grano, se presentó precozmente comparado con “Milagro Filipino”. En los ensayos 3 y 4, el tratamiento Lombardía presentó rendimientos superiores. Se concluye que las líneas avanzadas presentaron capacidad de adaptación a la zona productora de Michoacán. Estos materiales fueron superiores al material convencional, ya que mostraron consistencia en cada ensayo.

Abstract In Mexico, long and thin rice is the most consumed, so its supply has depended mainly on imports. Consequently, the Mexican Rice Council handed INIFAP the elite lines that generated the Latin American Rice Irrigation Fund (FLAR) for the evaluation and selection of materials. In order to validate advanced lines of long and thin grain rice compared to conventional material under the conditions of the Michoacán production area, experimental works were developed in different cycles: autumn-winter 2014-2015 (trial 1), spring summer from years 2015 (trial 2), 2016 (trial 3) and 2017 (trial 4) and different genotypes: trial 1) INIFLAR RT, FL05601, “Milagro Filipino”; test 2) FL06747, FL08224, INIFLA R, INIFLAR RT, Ivory, Lombardy, “Milagro Filipino”; essay 3) Lombardy, FL08224, “Milagro Filipino”; and essay 4) Ivory, Lombardy “Milagro Filipino 2. The data recorded varied in each trial, but phenological and productive aspects were included, including yield. Analysis of variance and comparison of means were performed. In trial 1, treatments exceeded the regional average, between 8,000 and 8,500 kg ha-1. In trial 2, the treatments FL06747, INIFLAR R and Lombardy stood out significantly in performance. Also, the flowering and maturity of grain, appeared early compared to “Milagro Filipino”. In trials 3 and 4, the Lombardy treatment showed higher yields. It is concluded that the advanced lines presented capacity to adapt to the production area of Michoacán. These materials were superior to the conventional material, since they showed consistency in each trial.

De acuerdo a la experiencia internacional, las pérdidas de granos debido a una deficiente regulación del molinete, presentan un peso importante (aproximadamente entre 33 y 73%) dentro de las pérdidas totales achacables a las máquinas cosechadoras de arroz, pudiendo alcanzar hasta un 23% del total del producto cosechado. La práctica nacional de regulación del molinete durante la cosecha mecanizada del arroz, no incluye la aplicación de principios científicos que están establecidos internacionalmente en la teoría de máquinas agrícolas, por lo que se hace necesario efectuar estudios donde se apliquen estos conceptos, de manera de perfeccionar el proceso de cosecha, minimizando las pérdidas achacables a una mala regulación de este órgano de trabajo. Como resultado de la aplicación y programación computarizada de estos modelos conceptuales, y tomando como datos de entrada los parámetros constructivos, de operación y de regulación del molinete de la combinada Claas-Crop Tiger 30, empleados en condiciones de producción (Empresa Agroindustrial de Granos de la localidad de Amarillas, provincia de Matanzas) y las propiedades del cultivo cosechado (Oriza sativa, variedad “Reforma”) se determinó que no se satisface la mayor parte de los requisitos exigidos para un buen funcionamiento del molinete, proponiéndose la corrección de los principales parámetros de operación y regulación, con vistas a minimizar las pérdidas achacables a la acción de este órgano de trabajo

According to international experience, grain losses due to poor regulation of the reel have a significant weight (approximately between 33 and 73%) within the total losses attributable to the rice harvesters, being able to reach up to 23% of the total harvested product. The national practice of regulating the windlass during the mechanized harvesting of rice does not include the application of scientific principles that are established internationally in the theory of agricultural machinery. Consequently, it is necessary to carry out studies where these concepts are applied, to perfect the harvesting process, minimizing the losses attributable to poor regulation of this body of work. These conceptual models were applied and computerized programmed. As input data they were taken: the construction, exploitation and regulation parameters of the windlass of the combined Claas-Crop Tiger 30, used in production conditions (Agro industrial Grain Company of Amarillas locality, Matanzas province) and the properties of the harvested crop (Oriza sativa, variety “Reforma”). As a result, it was determined that, most of the requirements for good windmill exploitation are not met. Correction of exploitation and regulation parameters is proposed to minimize the losses attributable to the action of this body of work

Resumo O objetivo deste trabalho foi determinar a influência da tensão de água e de atributos físicos e químicos do solo sobre a produtividade do arroz irrigado por aspersão, em terras baixas no Rio Grande do Sul. Na safra 2011/2012, foram avaliados os efeitos das tensões de água no solo de 20 e 40 kPa, durante todo o ciclo da cultura, bem como as de 40 e 20 kPa nas fases vegetativa e reprodutiva, respectivamente. Na safra 2012/2013, foram avaliadas as tensões de 10, 20 e 40 kPa, durante todo o ciclo da cultura, e as de 40 e 10 kPa nas fases vegetativa e reprodutiva, respectivamente. Em ambas as safras, utilizou-se a cultivar de arroz irrigado BRS Pampa. O gasto com água na irrigação por aspersão representou 48% do gasto com a irrigação por inundação. A produtividade do arroz correlacionou-se positivamente com a microporosidade e com os teores de fósforo e potássio disponíveis no solo; e negativamente com a macroporosidade e a saturação por alumínio. A avaliação conjunta da tensão de água e de atributos físicos e químicos do solo permite avaliar com mais propriedade a variabilidade na produtividade de arroz irrigado por aspersão em terras baixas no Rio Grande do Sul. A irrigação por aspersão possibilita melhor uso da água proveniente da precipitação pluvial, com efeitos positivos sobre a economia de água.

Abstract The objective of this work was to determine the effect of soil water tension and physicochemical soil attributes on sprinkler-irrigated rice yield in lowlands of the state of Rio Grande do Sul, Brazil. In the 2011/2012 crop season, the effects of 20 and 40 kPa soil water tensions throughout the crop cycle were evaluated, as well as of 40 and 20 kPa during the vegetative and reproductive phases, respectively. In the 2012/2013 crop season, soil water tensions of 10, 20, and 40 kPa were evaluated throughout the entire crop cycle, and the tensions of 40 and 10 kPa were evaluated during the vegetative and reproductive phases, respectively. In both crop seasons, the irrigated rice cultivar BRS Pampa was used. Water costs with sprinkler irrigation represented 48% of that with flood irrigation. Rice yield was positively correlated with soil microporosity and phosphorus and potassium availability; and negatively correlated with macroporosity and aluminum saturation. The joint evaluation of soil water tension and soil physicochemical attributes allow a better evaluation of the variability of sprinkler-irrigated rice yield in the lowland areas of the state of Rio Grande do Sul. Sprinkler irrigation allows better use of rainwater, revealing positive effects on water economy.