With the objectives of analyzing N recovery and potential N losses in the warm-season hybrid bermudagrass 'Tifgreen' [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy], two greenhouse studies were conducted. Plugs were planted in PVC cylinders filled with a modified sandy growing medium. Urea (URE), sulfur-coated urea (SCU), and Hydroform (HYD) (Hydro Agri San Francisco, Redwood City, CA) were broadcast at rates of 100 and 200 kg N ha-1 every 20 and 40 d. The grass was clipped three times every 10 d and analyzed for N concentration and N yield. In addition, leachates were analyzed for NO3-N. Use of the least soluble source, HYD, resulted in the lowest average clipping N concentration and N yield, as compared with SCU and URE. Clipping N concentration and N yield showed a cyclic pattern through time, particularly under long-day (> 12 h) conditions. When the photoperiod decreased below 12 h, leachate NO3-N concentration exceeded the standard limit for drinking water (10 mg L-1) by 10 to 19 times with the high SCU and URE application rate and frequency. However, leaching N losses represented a minimal fraction (< 1%) of the total applied N. More applied N was recovered in plant tissues using SCU and URE (89.5%) than using HYD (64.1%), with more than 52% of applied N accumulating in clipping. Highly insoluble N sources such as HYD decrease N leaching losses but may limit bermudagrass growth and quality. Risks of NO3-N losses in bermudagrass can be avoided by proper fertilization and irrigation programs, even when a highly soluble N source is used.

The sowing method of spring-type canola (Brassica napus L. var. oleifera) for forage has a major influence on its productivity and agronomic management. A field experiment was conducted in Matamoros, Coahuila, Mexico, during two growing seasons (to determine dry matter (DM), crude protein (CP) and net energy for lactation (NE L ) yields, as well as canola forage chemical composition as a function of six sowing methods. The treatments assessed were broadcast sowing and five different row spacings: 0Á19, 0Á38, 0Á57, 0Á76 and 0Á95 m (double row, 0Á20 m apart). In the first year, with a mean growing season temperature of 17Á2°C, sowing methods did not affect DM yield, but CP and NE L content and yield were higher in 0Á19-m row spacing. The mean temperature in the second year (13Á5°C) was slightly lower than the long-term mean (14Á8°C) in the region, resulting in the highest DM (8840 kg ha À1 ), CP (2486 kg ha À1 ) and NE L yields (51 103 MJ ha À1 ) with 0Á19-m row spacing. In rowsowing methods with over 0Á19-m row spacing, DM, CP and NE L yields decreased by 19Á3-39Á7, 20Á4-42Á1 and 21Á2-42Á7% respectively. Results indicate that sowing methods significantly affected canola forage productivity.

ADDITIONAL INDEX WORDS. Turfgrass nutrition, Cynodon dactylon 'Tifgreen', photoperiod, irradiance, temperature ABSTRACT. Two greenhouse studies were conducted to trace the fate of fertilizer N in hybrid bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy 'Tifgreen'], and to estimate total plant N recovery and losses. The first experiment was performed during winter, with artificial light supplementing natural light to provide a photoperiod of 13.6 to 13.8 hours. The second experiment was conducted during summer and fall under only natural light conditions, with a progressively decreasing photoperiod of 13.7 to 11.1 hours. Urea (UR), ammonium sulfate (AS), and ammonium nitrate (AN) were labeled at 2 atom% 15 N, and applied at N rates of 100 or 200 kg·ha -1 for 84 days (divided into six equal fractions and applied every 14 days). Fertilizer N source did not affect total dry matter (DM) accumulation by the plant components, but the high N rate increased clipping DM production under the longer photoperiod. Under the decreasing photoperiod, overall DM production was reduced, and clipping DM production was unaffected by increased N rate. Average N concentration of clippings varied between N sources, ranging from a high of 38.6 g·kg -1 DM with AS to a low of 34.7 g·kg -1 for UR. In Expt. 1, the greatest total plant N recovery [clippings, verdure (shoot material remaining after mowing), and thatch plus roots] occurred with AS (78.5%) and the lowest with UR (65.9%). In Expt. 2, these values declined to 53.0% and 38.0%, respectively. Urea fertilization resulted in the greatest N losses as a fraction of the N applied (33.6% to 61.5%) and AS fertilization the lowest (20.7% to 46.3%). In view of the greater N losses, UR may be a less suitable soluble N source for bermudagrass fertilization within the conditions of this study. In addition, late-season N fertilization may result in a significant waste of fertilizer N as bermudagrass progresses into autumnal dormancy when temperature, photoperiod, and irradiance decline and cause reduction in growth and N uptake.

T he demand for nixtamalized products has broadened the industrialization of maize. The nejayote is a product of the alkaline cooking of grain, and unfortunately contributes to environmental deterioration after being dumped into the public sewer system. There is evidence that adequate treatment of this byproduct not only reduces pollution, but it is also a source of compounds with high added value with potential for technological applications. The objective of this review was to provide an overview of the main methodologies and technological developments which have been implemented to explore the physicochemical properties of nejayote and to assign a treatment or an application to it. With the work performed it was possible to detect that the recovery of materials with high added value (polyphenols, carbohydrates, sugars, gums and calcium components) can be used in various areas such as the food, pharmaceutical and biotechnological sectors. In addition, it was identified that the obtaining of these components can be carried out through the coupling of various bioprocesses (fermentation, filtration, centrifugation and decantation).Resumen L a demanda de productos nixtamalizados ha incrementado la industrialización del maíz. El nejayote surge de la cocción alcalina del grano, y desafortunadamente contribuye en el deterioro ambiental tras ser vertido al alcantarillado público. Existe evidencia de que el tratamiento adecuado de este subproducto no sólo disminuye la contaminación, también es fuente de compuestos de valor agregado alto con potencial para aplicaciones tecnológicas. El objetivo de esta revisión fue proveer un panorama sobre las principales metodologías y desarrollos tecnológicos que se han implementado para explorar las propiedades físico-químicas del nejayote y proveerle un tratamiento o aplicación. Con el trabajo realizado se pudo detectar que la recuperación de materiales con valor agregado alto (polifenoles, carbohidratos, azúcares, gomas y componentes de calcio) puede ser utilizada en diversas áreas como la alimenticia, farmacéutica y biotecnológica. Además, se identificó que la obtención de dichos componentes se puede llevar a cabo mediante el acoplamiento de diversos bioprocesos (fermentación, filtración, centrifugación y decantación).

El aumento en la densidad de población en canola (Brassica napus L. var. oleifera) para forraje puede incrementar los rendimientos de materia seca (MS) y nutrientes. Se realizaron dos experimentos para evaluar el efecto de la densidad de población sobre la composición química del forraje y los rendimientos de MS, proteína cruda (PC) y energía neta para lactancia (ENL) en canola. Los experimentos se hicieron en Matamoros, Coahuila, México durante los ciclos 2011-2012 y 2012-2013. Las densidades de población a la cosecha fluctuaron entre 19.1 y 248 plantas m-2. La asociación entre la densidad de población y las variables de respuesta se analizó mediante regresión lineal simple (P ≤ 0.05). El aumento en la densidad de plantas incrementó la concentración de PC y ENL en el primer ciclo, mientras que en el segundo la composición química no fue afectada. En las bajas densidades, la plasticidad de la canola no compensó el rendimiento de MS, PC y ENL por hectárea, ya que estas variables mostraron una relación lineal positiva (P ≤ 0.05) con la densidad de población. El rendimiento de MS fluctuó de 6,067 a 9,356 kg ha-1. Los rendimientos de PC y ENL se ajustaron a una función lineal (P ≤ 0.05). En el segundo año, los rendimientos de PC (1,398 a 2,260 kg ha-1) y ENL (29,248 a 54,487 MJ ha-1) fueron mayores que los del primero, con 842 a 2,159 kg ha-1 en PC y 17,533 a 44,617 MJ ha-1 en ENL. Losresultados indican que los rendimientos de MS y nutrientes en canola para forraje se incrementaron al aumentar la densidad de población, sin afectar la composición química del forraje.

La adecuada selección del tipo y cultivar de canola (Brassica napus L.) para forraje puede incrementar los rendimientos de materia seca (MS) y nutrientes. El objetivo del estudio fue evaluar el potencial forrajero de cultivares de canola tipo primaveral e invernal en la Comarca Lagunera, México. Dos experimentos se realizaron en Matamoros, Coahuila, México, durante los ciclos agrícolas 2012-2013 y 2013-2014. Se evaluaron seis cultivares primaverales y tres invernales, la variedad IMC 205 y el híbrido Hyola 401 fueron utilizados como testigos. El diseño experimental fue de bloques completos al azar con cuatro repeticiones. Los cultivares sobresalientes con mayor rendimiento de MS y nutrientes (P ≤ 0.05) fueron los testigos, y los nuevos cultivares Monty, Claremore y especialmente Ortegón, que presentó la ventaja adicional de una mayor precocidad a la cosecha (de 6 a 16 d) respecto a los testigos. El rendimiento en los cultivares primaverales sobresalientes fue de 7216 a 8480 kg ha-1 de MS, de 1270 a 1456 kg ha-1 de proteína cruda (PC) y de 39,663 a 47,928 MJ ha-1 en energía neta para lactancia (ENL). El mejor cultivar invernal fue Claremore, con un rendimiento de MS inferior (P ≤ 0.05) a los cultivares primaverales (6215 kg ha-1); sin embargo, debido a su mayor contenido de nutrientes, sus rendimientos de PC (1431 kg ha-1) y ENL (42,625 MJ ha-1) fueron similares a los obtenidos por los mejores cultivares primaverales. En conclusión, es posible incluir al menos tres nuevos cultivares de canola para la producción de forraje en la región.

Total plant biomass, shoot growth rate, and the periodicity in shoot growth and color of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy `Tifgreen'] in response to slow-release fertilizer N sources, rates, and application frequencies were studied in two, 120-day greenhouse studies. Plugs were planted in plastic cylinders filled with a growing medium of 93 sand: 7 peat moss (w/w). The first experiment was completed under progressively increasing photoperiod (13.1 to 14.9 hours) typical of the long-day requirements for bermudagrass growth. The second experiment occurred under progressively decreasing photoperiod (13.7 to 10.7 hours) representative of autumnal growing conditions and declining growth and N demand. Urea (URE), sulfur-coated urea (SCU), and hydroform (HYD, methylene urea polymers) were broadcast at N rates of 100 or 200 kg·ha-1 and at frequencies of 20 or 40 days. Bermudagrass was clipped at 3-day intervals and the average daily clipping growth rate (increase in shoot dry matter; DM) reached a maximum of 11.5 g·m-2 per day. Use of the least soluble source, HYD, produced the lowest total clipping DM, and at low HYD rate and frequency, leaf color intensity was frequently below the accepted standard of 7, in the scale from 1 “tan” to 9 “dark green”. A greater responsiveness of bermudagrass to N rate and application frequency (increased clipping growth rate and color intensification upon N application) occurred under increasing photoperiodic conditions as compared to decreasing photoperiodic conditions. Both clipping growth and color changed cyclically through time and mainly under long-day photoperiod (>12 hours), with greater oscillation at longer fertilization interval (40 days). With either SCU or URE, at low N rate and frequency (total N application of 0.25 g·m-2 per day), clipping growth rates were above 4 g·m-2 per day, and turf color was at or above the minimum quality standard through most of the growing period. Higher total SCU and URE application rates, previously shown to increase N leaching losses in these experimental conditions, produced significantly more clipping growth and did not appear to intensify color sufficient to warrant the increased risk of N loss.