Nitrogen fertigation influence on nitrate concentration of nitrates on extract cellular of petiole, yield and quality of greenhouse tomato

El nitrógeno es el macronutriente que más afecta el rendimiento y la calidad de los productos hortícolas cosechados. Sin embargo, es importante conocer la respuesta de cada cultivo y ambiente en particular a fin de obtener el mayor uso eficiente del nutriente aplicado. El cultivo de tomate (Lycopersicon esculentum Mill.) "Beatrice" fue cultivado bajo condiciones de invernadero con cubierta plástica sobre un suelo árido del desierto sonorense en el noroeste de México. Se evaluó la concentración de nitratos en el extracto celular de peciolo (ECP), el rendimiento de fruta (total y comercial), así como parámetros de calidad (sólidos solubles totales: TSS, acidez titulable: AT, relación TSS/AT) en relación con cuatro dosis de fertilización nitrogenada (250, 500, 750 y 1000 kg N ha-1). Durante nueve fechas, se midió la concentración de nitratos en el ECP y los valores obtenidos se relacionaron con el rendimiento comercial. Las dosis de nitrógeno tuvieron efecto positivo en el rendimiento (P < 0,05) mientras que la calidad y el tamaño de la fruta no resultaron afectadas por ninguno de los tratamientos aplicados (P ˃ 0,05). De la misma manera, la concentraciones de nitratos en ECP estuvieron asociadas al rendimiento de la fruta en ocho de las nueve fechas evaluadas (P < 0,05). De acuerdo con los resultados obtenidos, se concluye que bajo las condiciones de suelo y clima en que se desarrolló el experimento, el cultivo de tomate responde a altas dosis de nitrógeno (750 kg ha-1) sin afectar su calidad. Así mismo, debido a la relación encontrada entre la concentración de nitratos en ECP y el rendimiento de fruta, podría ser posible utilizar los rangos de suficiencia en nitratos en ECP obtenidos en este estudio.Nitrogen is the macronutrient that most affect the yield and quality of harvested horticultural products. However it is important to know the response of each environment and horticultural crop in order to get a most efficient use of nutrient applied. Tomato crop (Lycopersicon esculentum Mill.) "Beatrice" was cultivated under plastic greenhouse conditions on arid soil of Sonoran desert of Mexico Northwest. Nitrates in extract cellular of petiole, fruit yield (total and marketable) and quality parameters (total soluble solids: TSS, titratable acidity: AT and soluble solids titratable acidity ratio: TSS/AT) were evaluated in relation of four nitrogen fertilization rates (250, 500, 750 and 1000 kg N ha-1). During nine dates, nitrate concentrations in extract cellular of petiole (ECP) were determined and the relationship with marketable yield was considered. Significant differences were found in total and marketable yield (P < 0.05) but not with quality attributes by any nitrogen rates applied at crop (P > 0.05). Size fruit resulted not affected by any nitrogen rates. On the other hand, when nitrate concentrations on ECP were related at nitrogen rates applied, a significantly response was found (P < 0.05). Similarly, nitrate in ECP concentrations were associated with marketable yield on eight of nine dates tested (P<0.05). Under this environment soil and climate conditions, greenhouse tomato respond at high nitrogen rates with high yields, with none effect on quality. On the other hand, because nitrate concentrations in ECP were in relation with fruit yield, it could be possible to identify preliminary sufficiency nitrates ranges.Fil: Núñez Ramírez, Fidel. Universidad Autónoma de Baja California Sur (México)Fil: Grijalva Contreras, Raúl Leonel. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (México)Fil: Robles Contreras, Fabián. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (México)Fil: Macías Duarte, Rubén. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (México)Fil: Escobosa García, María Isabel. Universidad Autónoma de Baja California Sur (México)Fil: Cázares Santillano, Jesús. Universidad Autónoma de Baja California Sur (México

La fertilidad del suelo afecta el crecimiento, nutrición y rendimiento de algodón cultivado en dos sistemas de riego y diferentes dosis de nitrógeno

La fertilidad intrínseca del suelo y la forma de riego podrían afectar la eficiencia de la fertilización con nitrógeno (N), modificar la meta de rendimiento, el crecimiento y el estado nutrimental de los cultivos. Se realizó un estudio con el objetivo de conocer el rendimiento, crecimiento, eficiencia en el uso del agua (EUA), eficiencia agronómica del N (EAN), además de medir la concentración de NO3- en el extracto celular de peciolo (ECP) y el índice de clorofila (SPAD) en el cultivo de algodón por efecto de diferentes dosis de N y dos formas de aplicar el riego. El estudio consistió en dos experimentos establecidos en suelos considerados de alta fertilidad [˃13.0 g kg-1 materia orgánica (MO) y N-NO3- ˃ 30 mg kg-1], variando la dosis de fertilización nitrogenada en cada uno de ellos: a) riego rodado (FRR; 11 y 220 kg N ha-1) y b) riego por goteo (FRG; 11 a 440 kg N ha-1). La altura y número de nudos en las plantas no se afectaron por los tratamientos aplicados. Los valores encontrados en el SPAD y la concentración de NO3- en ECP se relacionaron en forma cúbica con el rendimiento del cultivo. El mayor rendimiento y la EUA se obtuvo en el experimento manejado con riego goteo. En el experimento FRR no se encontró respuesta a los tratamientos de fertilización nitrogenada. En el experimento FRG la aplicación de 440 kg N ha-1, redujo en un 43% el rendimiento en comparación con el resto de las dosis evaluadas. La EAN fue estadísticamente mayor (P < 0.001) en los tratamientos fertilizados con 11 kg N ha-1. La disminuida respuesta en rendimiento en el cultivo de algodón debido a la aplicación de N fue atribuida a las altas concentraciones de N-NO3- y MO que estuvo presente en los suelos en donde se realizaron los experimentos

Assessment of Fertilizer Management Strategies Aiming to Increase Nitrogen Use Efficiency of Wheat Grown Under Conservation Agriculture

Sustainable crop production systems can be attained by using inputs efficiently and nitrogen use efficiency (NUE) parameters are indirect measurements of sustainability of production systems. The objective of this study was to investigate the effect of selected nitrogen (N) management treatments on wheat yields, grain and straw N concentration, and NUE parameters, under conservation agriculture (CA). The present study was conducted at the International Maize and Wheat Improvement Center (CIMMYT), in northwest, Mexico. Seventeen treatments were tested which included urea sources, timing, and methods of fertilizer application. Orthogonal contrasts were used to compare groups of treatments and correlation and regression analyses were used to look at the relationships between wheat yields and NUE parameters. Contrasts run to compare wheat yields or agronomic efficiency of N (AEN) performed similarly. Sources of urea or timing of fertilizer application had a significant effect on yields or AEN (p &gt; 0.050). However, methods of application resulted in a highly significant (p &lt; 0.0001) difference on wheat yields and agronomic efficiency of N. NUE parameters recorded in this study were average but the productivity associated to NUE levels was high. Results in this study indicate that wheat grew under non-critically limiting N supply levels, suggesting that N mineralization and reduced N losses from the soil under CA contributed to this favorable nutritional condition, thus minimizing the importance of N management practices under stable, mature CA systems

Assessment of Intercropping and Plastic Mulch as Tools to Manage Heat Stress, Productivity and Quality of Jalapeño Pepper

Under a global warming scenario, it is important to adopt practices that favor soil water conservation, such as plant intercropping systems and the use of plastic mulching. The objective of this study was to determine how microenvironment, morphology, productivity and quality of jalape&#241;o peppers were affected by corn intercropping and the use of plastic mulching. Two experiments were conducted during 2015 and 2016 in the Valley of Mexicali, Mexico, a region characterized by its extreme aridity, soil salinity, hot temperatures and high radiation during the summer. Four treatments were tested: jalape&#241;o peppers grown on bare soil (BS); on bare soil intercropped with corn (BS+IC); on plastic mulch (PMu); and on plastic mulch intercropped with corn (PMu+IC). The response variables measured were yield, fruit quality attributes, microclimatic variables, and morphology of the pepper crop. PMu treatment produced the tallest pepper plants and yields, while the BS+IC treatment produced the smallest plants and the lowest yields. A possible explanation for the higher biomass and crop yield of the PMu treatment is the lack of competition from corn and the effect of plastic mulching in reducing soil salinity. It is concluded that competition from corn on jalape&#241;o pepper dramatically affected the pepper&#8217;s productivity, particularly under high soil salinity and extremely high temperature conditions

Productivity, Morphology and Chemical Composition of Brachiaria spp. Ecotypes, under Two Solar Illumination Intensities, in Yucatan, Mexico

There are mixed reports about the advantages and disadvantages of the presence of shade produced by trees over the understory-growing grasses; thus, it is urgent to test grass species and cultivars with potential to develop in shaded conditions associated with trees that occur in silvopastoral systems. The objective of the present study was to identify Brachiaria spp. ecotypes adapted for cultivation under tree shade, typical of silvopastoral systems. The study was conducted at Kampepen ranch, located 14 km south of Merida, Yucatan, Mexico. A factorial 6 (ecotypes) x 2 (sunlight intensities) treatment structure was used, arranged in split-plot design; with sunlight intensity levels being the plots and ecotypes the subplots, with three replications. The ecotypes were T1: Brachiaria hybrid cv. Mulato II, T2: Brachiaria hybrid cv. Cayman Blend, T3: Brachiaria hybrid cv. Talisman (BR05/1467), T4: Brachiaria hybrid cv. Camello Blend, T5: Brachiaria brizantha cv. Marandu and T6 (the control): M. maximus cv. Mombasa, while the two sunlight intensity levels were higher and lower sunlight reductions with respect to full sunlight (25% and 50% light transmission with respect to full sunlight, respectively). Variables were plant height, forage yield and chemical composition; leaf, stem and dead material fractions and leaf:stem ratio; plant canopy cover, plant maturity, and growth rate. Significant (p &lt; 0.050) ecotype x sunlight intensity interactions were recorded for most of the studied variables. Independent of the shading levels, ecotype Talisman showed superior performance compared with the other assessed ecotypes, yielding up to 20 ton ha&minus;1 under the highest light intensity, means across light intensities for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of 11.8%, 59.7%, and 34.7%, respectively, and more than 90% plant canopy cover. It is concluded that Talisman has promising characteristics for cultivation under silvopastoral systems, where tree shading is common, in the dry tropics of Yucatan, Mexico

Can Biofertilizers Reduce Synthetic Fertilizer Application Rates in Cereal Production in Mexico?

Biofertilizers are considered as potential supplements or alternatives to fertilizers. The objective of the present study is to evaluate different biofertilizers in combination with synthetic fertilizers on the yields of maize and wheat in several states in Mexico. Fourteen biofertilizer treatments plus a treatment with 100% the locally recommended fertilizer rate (RFR), another with 50% RFR (the control treatment), and one without any fertilizer (for a total of 17 treatments) were tested on maize and wheat in five states across Mexico. Field experiments were established in five states and several years for a total of 14 experiments in Mexico. In general, except for the experiments conducted in moderately low soil P conditions, Chiapas and Sonora (maize), no response to biofertilizers was observed in the remaining locations, through the years in wheat and maize. We conclude that in high input production systems, the biofertilizer response is more an exception than a rule with only 21% of the experiments showing a significant difference in favor of biofertilizers and only 4 of 15 products tested produced a yield response in more nitrogen deficient environments. Some products containing AMF may be beneficial in maize production systems with phosphorus deficient environments

Identification of Sorghum (<i>Sorghum bicolor</i> (L.) Moench) Genotypes with Potential for Hydric and Heat Stress Tolerance in Northeastern Mexico

Sorghum (Sorghum bicolor (L.) Moench) is cultivated in regions with frequent drought periods and high temperatures, conditions that have intensified in the last decades. One of the most important photosynthetic components, sensible to hydric stress, is maximum quantum yield for photosystem II (PSII, or Fv/Fm). The objective of the present study was to identify sorghum genotypes with tolerance to hydric and heat stress. The treatments were hydric status (hydric stress or non-hydric stress (irrigation)), the plant’s developmental stages (pre or post-anthesis), and six genotypes. The response variables were Fv/Fm; photosynthetic rate (PN); stomatal conductance (gs); transpiration rate (E); relative water content (RWC); damage to cell membrane (DCM) at temperatures of 40 and 45 °C; and agronomic variables. The experiment was conducted in pots in open sky in Marín, N.L., in the dry and hot northeast Mexico. The treatment design was a split–split plot design, with three factors. Hydric stress diminished the functioning of the photosynthetic apparatus by 63%, due to damage caused to PSII. Pre-anthesis was the most vulnerable stage to hydric stress as it decreased the weight of grains per panicle (85%), number of grains per panicle (69%), and weight of 100 grains (46%). Genotypes LER 1 and LER 2 were identified as tolerant to hydric stress, as they had lower damage to PSII; LER 1 and LEB 2 for their superior RWC; and LER 1 as a thermo tolerant genotype, due to its lower DCM at 45 °C. It was concluded that LER 1 could have the potential for both hydric and heat stress tolerance in the arid northeast Mexico