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A temporal trend analysis of weather variables is needed for developing mitigation and adaptation strategies to climate change. The objective of this work was to study temporal trends of 17 extreme temperature indices in North-Central Mexico (NCM). We used daily observations of maximum and minimum temperatures from 127 weather stations for 34 years (1980–2013). The extreme temperature indices were calculated with the RClimDex v1.9 package. Analysis of trend indices was carried out with the Mann–Kendall technique and the rate of change with the Theil–Sen estimator. Except for the growing season length, all-temperature indices showed statistically significant positive trends (SSPT) (p≤0.05$p\leq\nobreak 0.05$) between 1 and 62; except for the cold spell duration indicator, all indices showed statistically significant negative trends (SSNT) between 3 and 62. The SSPT of all indices varied between 0.246 °C decade−1 (TMINMEAN) and 48 days decade−1 (SU25), while the SSNT varied between −55.238 days decade−1 (SU25) and −0.181 °C decade−1 (TMINMEAN). In NCM, the increase in some indices could be causing an increase in crop water requirements and poorly meeting some crop's chilling requirements. In crops, such as grapevine, peach, and apple, an excellent short-term strategy to adapt to the decrease in cold winter and to compensate for the satisfaction of poor chilling hours using biostimulant of sprouting should be considered. New varieties/hybrids of corn and beans for dealing with the increase in warm days (TX90p), summer days (SU25), warm nights (TN90p), and tropical nights must be available; also, these new varieties should have shorter cycle and should be cold resistant. The results of this work constitute a reliable tool for generating answers for measures of adaptation to the onslaught of climate change in NCM.

Accurate estimation of radiation use efficiency (RUE) at variable timed sowing dates will enhance the prediction of plant dry matter accumulation. The objectives of this study were to (1) determine the impact of three sowing dates on the productivity, performance, and economic feasibility of three biomass sorghum hybrids and (2) evaluate the variability of RUE in the production of biomass sorghum under the effects of variable timed sowing dates. Over a two-year experiment, biomass sorghum hybrids were grown and monitored at different sowing seasons under optimal growth conditions. Average dry biomass (DB) productivity at harvest ranged from 22.71 to 32.77 Mg ha−1. Higher leaf area index (LAI) values (>4.0) represented an intercept of over 95% of incident photosynthetically active radiation (PAR). RUE obtained from the slope of the linear relationship between DB produced and accumulated intercepted photosynthetically active radiation (IPAR) ranged from 2.92 to 4.157 g MJ−1 across growing seasons. Higher RUE values were observed for the energy hybrids in the early and mid-season. They converted IPAR efficiently into DB. Lastly, the economic feasibility of each sorghum hybrid and sowing date was evaluated in terms of their expected net returns. Economic results suggest that the sorghum hybrids considered could be a viable source of biomass season long, with net returns ranging from USD 560.55 ha−1 to USD 1255.06 ha−1.

One simple way to estimate the relationship between air temperature and the energy needed for heating and cooling is to use the concept of degree day. Cooling degree days (CDD) and heating degree days (HDD) are indicators of the energy required to reach comfort levels and are related directly to energy demands. Therefore, using a novel approach, we examine the current conditions and future projections in degree days over Mexico using observations (Livneh and CPC), ERA5 reanalysis, and simulations from the Regional Climate Model (RegCM4). The RegCM4 experiments were driven by different General Circulation Models for two Representative Concentration Pathways scenarios. We consider three 20-year periods as “present conditions” (1995–2014), “near-future conditions” (2041–2060), and “far-future conditions” (2080–2099). The results suggest that in the future, under the lowest radiative forcing scenario there will be a smaller increase (decrease) in CDD (HDD) for the far-future, as compared to the near-future. This could represent the model’s response to the peak of radiative forcing at mid-century and its subsequent decline. For the highest radiative forcing scenario, we found a greater increase (decrease) in CDD (HDD) for the far-future, which could be explained by the response of the RegCM4 to the warming increase projected for 2100.

Abstract Precipitation and its distribution greatly influence the evolution of ecosystems and the development of society. The objective was to analyse trends in extreme precipitation indices at 25 weather stations of Aguascalientes State. Eleven extreme precipitation indices were obtained. The time series of these indices were analysed with the non‐parametric Mann–Kendall test. The number of days above 50 mm, consecutive wet days, and extremely wet days did not have significant trends at any of the weather stations. Each of the indices maximum 1 day precipitation amount, maximum 5 day precipitation amount and number of very heavy precipitation days showed a significant positive trend at 12% of the weather stations; both the number of heavy precipitation days and the number of very wet days had significant positive trends at 8% of the weather stations; the simple daily intensity index, consecutive dry days and annual total wet‐day precipitation showed significant positive trends at 20%, 36% and 4% of weather stations, respectively. The intensity index was the only one that showed a significant negative trend, which happened at 4% of the weather stations. In a small part of Aguascalientes, the precipitation intensity, the number of rainy days and the accumulated total increased in short periods. Also, in a reduced region, daily precipitation intensity decreased; and in another very small area the number of dry days increased. For mitigating the effects of these phenomena, it is suggested that water be used more efficiently for sustained agricultural production systems and ecosystem management. The results of the present study will be of great importance in future economic planning in the Aguascalientes State.

Abstract The formation of artificial lake due construction of a hydroelectric plant causes irreversible environmental impacts. Studies associated with these artificial lakes for the Brazilian semiarid region are still insufficient. Thus, the objective of this study is to provide new information on the trends of climatic extremes, dependent on rainfall and air temperature, for the Sobradinho Hydroelectric Power Plant (SHPP) lake region, through the analysis of climate change indices. This study is particularly important for the SHPP region because microclimate changes have significant impacts on the natural, social and economic sectors. For the two analyzed stations (Bebedouro-PE and Mandacaru-BA), it is not possible to affirm that the construction of the SHPP artificial lake altered the local microclimate. Trends of increase in maximum temperature, the number of hot days and diurnal temperature range were noticed. However, the rise of these indices cannot be attributed to the formation of the SHPP lake. The influence of the SST of Tropical Oceans on the temporal behavior of some of the indices used in this study may have contributed to increases in hot days and nights, maximum temperature, diurnal temperature range and consecutive dry days over the region.

La alta temperatura ambiental afecta de manera negativa el crecimiento de la planta y el rendimiento del cultivo. El objetivo fue evaluar el efecto de temperatura máxima estacional sobre el rendimiento y la eficiencia en el uso del agua en maíz forrajero con riego por goteo subsuperficial y riego superficial por melgas en cinco ciclos consecutivos (primavera y verano) en la Comarca Lagunera. El estudio se llevó a cabo en el Campo Experimental La Laguna, del Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP) en Matamoros, Coahuila. La investigación se realizó durante los ciclos: verano 2019, primavera 2020, verano 2020, primavera 2022 y verano 2022. Las variables fueron: temperatura ambiental máxima, altura de planta, forraje seco, lámina de riego y eficiencia en el uso del agua. Las mayores temperaturas se registraron en la primavera de 2022 y las menores en el ciclo de verano del mismo año. En general las mayores alturas de planta se presentaron en el ciclo más fresco (verano 2022). Se observó mayor rendimiento de forraje seco (19 Mg ha-1) en el ciclo de verano 2022. La mayor lámina de riego fue en el ciclo de primavera 2022 (71 cm) y la menor en verano 2020 (55 cm). Esto dio como resultado que la eficiencia en el uso del agua fuera mayor en verano. Esta variación de eficiencia en el uso del agua entre ciclos se debió a mayores temperaturas en primavera. En conclusión, la eficiencia en el uso del agua tendió a disminuir en 19% al incrementarse la temperatura de 30 a 38 grados centígrados.

Landsat images combined with the METRIC model have been used in applications such as EEFlux to estimate actual evapotranspiration (ETa) in irrigated areas, with uncertainty as to whether the results are sufficiently accurate at local scales. This work compares temporally and spatially ETa estimates using Landsat imagery and the METRIC model with LOCAL measured weather data and EEFlux for an irrigated area in northern Sinaloa, Mexico, from 1995 to 2018. A regression analysis and error metrics such as coefficient of determination (R2), mean absolute error (MAE), root mean square error (RMSE) and slope were used to compare both models. The temporal analysis results confirm that ETa differences are closely related to crop growth and that the daily mean absolute error was 1.17 mm/day. Spatial analysis showed that when using only cropland pixels without non-cropland pixels in EEFlux, the R2 increases from 0.36 to 0.73, and the RMSE decreases from 2.52 to 1.98 mm/day. Therefore, EEFlux should be limited to cropland areas, and it is suggested to exclude Landsat images close to the planting and harvesting season to reduce the differences.

La programación del riego es un factor clave para el manejo eficiente del agua en la agricultura. El objetivo del estudio fue programar los riegos con el uso del atmómetro y el coeficiente de cultivo (Kc) en maíz (Zea mays L.) forrajero para evaluar su efecto en la altura de planta, índice de área foliar, rendimiento de materia seca (MS) y eficiencia en el uso del agua (EUA) bajo diferentes tratamientos de riego. El estudio se realizó en el Campo Experimental la Laguna del INIFAP ubicado en Matamoros, Coahuila, México. Se utilizaron tres híbridos de maíz (H-431, H-383 y SB-302) con un sistema de riego por goteo subsuperficial, donde se aplicaron los tratamientos del 60, 80 y 100% de la evapotranspiración (ET) y un testigo (riego por gravedad). El diseño experimental fue bloques completamente al azar con parcelas divididas y cuatro repeticiones. La programación del riego con el atmómetro y el Kc del maíz propiciaron un mayor rendimiento de MS (18.83 t ha−1) y EUA (3.66 kg de MS m−3) en los tres híbridos con el 100% de ET. La EUA en el 100% de ET fue 1.36, 1.63 y 40% mayor con respecto al 60%, 80% de ET y riego por gravedad, respectivamente. Por lo tanto, programar el riego mediante el uso del atmómetro y el Kc del cultivo en un sistema de riego por goteo subsuperficial ayuda a obtener un mayor uso eficiente del agua en maíz forrajero.