A basin’s hydrological services are becoming increasingly important due to the scarcity of water in many regions of the world. The aim of this research was to evaluate the impact of variations in climate patterns on runoff from the Sextín River basin using the Water Evaluation and Planning System (WEAP) hydrological model. The hydrological scheme was developed with vector and raster cartographic information, along with land-use, vegetation, climatological and hydrometric data of the study area. Model parameterization and   calibration covered the period from 1971 to 2004. The model’s predictive performance was evaluated by NSE (Nash-Sutcliffe coefficient of efficiency), % BIAS and R2, obtaining values of 0.81, 12.1 and 0.81, respectively. Future regionalized climate change scenarios were generated with the Long Ashton Research Station Weather Generator (LARS-WG) on the basis of the Intergovernmental Panel on Climate Change (IPCC) A1B (rapid economic growth) and A2 (continuously increasing population) climate change scenarios, for the years 2020s (2010-2039) and 2050s (2040-2069). A possible mean annual increase of 1 °C, both for the maximum and minimum temperature, was observed in both analyzed periods. Increased precipitation and basin runoff were also projected in the regionalized climate scenarios. The information generated in this study can be useful for hydrological planning and management of the basin.

Sun-drying is the most widely used method of preserving agricultural products; however, under hostile climatic conditions it leads to serious losses in product quantity and quality. The use of solar drying technology in developing countries can reduce postharvest losses and significantly improve product quality compared to other methods. The development of mathematical models of solar dryers is necessary to be able to design, control and optimize this type of system. The aim of this study is to provide an overview of the different approaches to modeling and simulating greenhouse solar dryers, both of natural and forced convection. In addition, models that have not been extensively used in this area, such as empirical and numerical ones, are discussed.

Leaf area index (LAI) is a useful variable to characterize crop dynamics, productivity and water requirements. The three-fold aim of this work was to estimate the LAI of poplano pepper (Capsicum annuum L.) with a ceptometer, compare the results with the destructive method and analyze the relationship between the LAI and crop yield. The experiment was carried out in a greenhouse at the Colegio de Postgraduados, Montecillo campus. The transplant date was April 21 and the harvest ended on November 11, 2014. Tezontle was used as substrate and drip irrigation was applied. The experiment consisted of three treatments (T): T1 (two stems), T2 (three stems) and T3 (without pruning). To estimate the LAI, a ceptometer was used to measure the radiation intercepted above and below the canopy. Leaf area was measured with the LI-3100C area meter. Results indicated that the maximum LAI occurred at flowering, corresponding to 2,096 growing degree days (GDD) with 0.93, 1.2 and 2.75 for T1, T2 and T3. Estimating LAI with a ceptometer proved to be a suitable and reliable method, since the linear correlation coefficient (R2) obtained between the two methods was 0.82, 0.94 and 0.99, for T1, T2 and T3, respectively. The yield obtained was 10.74, 8.28 and 5.49 kg∙m-2 for T3, T2 and T1, respectively. Increasing the number of stems per plant increased LAI, yield and number of fruits; however, fruit size decreased.