By 2010 Mexico quantified 12,000 ha using protected agriculture with tomato, bell pepper, cucumber and habanero pepper, being this last the most profitable in the domestic and export market.The states producing habanero pepper are located in the Yucatan Peninsula; Campeche, Yucatan and Quintana Roo. Open field yields range from 10 to40 tons of pepper, and Quintana Roo has developed the technology of production under greenhouse conditions, specifically in the social enterprise “Hidroponia Maya”,located in Carrillo Puerto, working with medium scale technology, having 40 ha of greenhouses and coordinating at the same time the project “Social greenhouses” that is formed by 44 individual modules of 3,600 square meters. Yields per square meter vary from 7 to 12 kilograms in both production systems; the production is channeled to Mexico including Mexico City for fresh consumption and to the U.S.A. and Canada for industrialization. The description of this production system is based substantially on the experiences of the project “Social greenhouses”, which can be an alternative of production for the arid areas of northern Mexico.

As a mega diverse country, Mexico is home to many plant and animal species, whose habitats are diverse ecosystems that have been formed. This mega diversity is being threatened because national studies have confirmed the loss of vegetative cover as a process of land use change to develop activities that represent a greater satisfaction for growing society. The aim of this study was to know the current state of vegetation of the basin of San Cristóbal de las Casas, in response to the land use change in the period 1976 to 2002. In this regard, changes observed are similar to what happens in the overall picture, where the loss of plant cover is evident since increments above 5000 ha (the sixth part of the basin, with an area of 29,730 ha) were quantified for rainfed agriculture, related to the reduction of forest areas and grasslands. On the other hand, urban areas increased more than 10 times its surface (from 149 to 1,903 ha) during the same period.

The objective of the present work was to evaluate the effect of sowing system by changing the number of plants per hectare, and the distance between rows, on the grain yield of 10 dry bean varieties of different growth habit and earliness. The varieties used were: Pinto Bravo, Pinto Centauro, Pinto Coloso, Pinto Saltillo, Pinto Centenario, Pinto Libertad, Flor de Mayo Bajío, Flor de Mayo Dolores, Flor de Mayo Eugenia and Azufrado 2. Sowing date was 30 July 2011 under three planting systems: a) 0.76 m furrow planted in single row, b) beds of 1.52 m at triple row and c) beds 1.52 m with six rows. The experimental unit consisted of 8, 6 and 12 rows of 30 m in length with a gap of 0.76, 0.40 and 0.20 m for the single sowing, triple and six rows respectively. The higher grain yields were obtained with the treatment in beds of 1.52 m with six rows for most of the varieties. This determines that the variety Pinto Saltillo was superior to other varieties and had the highest yields in beds of 1.52 with six rows and close spacing.

Pico de Tancítaro National Park is the most important source of water for the collection and recharge cycle of the aquifers located in western region of the state of Michoacán. Understanding the precipitation variability throughout time is crucial. Nonetheless, there is a lack of extensive and quality series on climatic data. For this reason, this work established the following objectives: 1) to reconstruct the precipitation variability for Pico de Tancítaro National Park based on the Abies religiosa growth rings, and 2) to analyze the drought frequency during the XXth century and the first decade of the XXIst century. Thus, some A. religiosa samples were taken and dated using standardized dendrochronological techniques. The quality of the dating as well as the quality of its climatic response were verified with the COFECHA software. These series presented a significant correlation (r=0.473; P < 0.01), which indicates their potential to generate dendroclimatic series. The precipitation of the last 127 years (1884-2010) was reconstructed. The severest droughts were reconstructed for the 1890-1896, 1948-1956, 1967-1971, 1982-1989, and 1998-2004 periods. It was also found that the Paricutín volcano eruption (1943) had a significant effect on regional climate.

Salinas Grandes is an endorheic basin with different environments, defined by soil, salinity and topography, and related to water and wind dynamics. The main productive activity is extensive livestock raising, which has been undertaken poorly and thus generated degradation associated with loss of productivity and biodiversity. Therefore, the aim of this study was to assess the dynamics of vegetation recovery and changes in forage yield by fencing off areas with wire (enclosures) and leaving adjacent areas open (control), both in Lowland (187 masl) and Highland (192 masl) environments within the basin. The study area is located in the north-central region of Argentina. We determined the floristic diversity, plant cover and forage production by using the Point Quadrat and modified Braun Blanquet methods in the dry and rainy seasons. After three years, increases in floristic diversity (ΔH = +0.8; +3.03), plant cover (Δ% = +4.83; +13.55) and forage yield (Δkg·ha-1 DM (dry matter) = +23.84, +35.4) were observed for the Lowland and Highland zones, respectively. The enclosure technique was efficient for the vegetation recovery process.

Hydraulic conductivity is a property that refers to the degree to which water moves in the soil; its measurement and estimation is a constant research topic. In the procedures for measuring it, there are theoretical models which describe the behavior of the parameter of interest through mathematical relationships between variables. This study was conducted in two sites representative of the Central Valleys of Oaxaca; it consisted of analyzing the main soil fertility and salinity properties, in order to determine their relationship to saturated hydraulic conductivity. A total of 63 composite soil samples were taken at a depth of 30 cm, in agricultural plots; they were analyzed at a laboratory and 17 parameters were identified. They were subjected to multiple correlation analysis to see their influence on conductivity. The correlation results showed that calcium, magnesium and CEC determine 50 % of the conductivity behavior. Using these variables, a multiple linear regression was performed to define the second-order polynomial equation with which the saturated hydraulic conductivity can be estimated.

The heat pulse method is used for determining transpiration based on the amount of water flowing within the stem of perennial crops such as cacao. The objectives of this study were to determine hourly transpiration from a sap flow meter and estimate crop coefficients (Kc) at different stages of development in order to determine crop water requirements. It is concluded that the heat pulse method and sap flow reasonably estimate the transpiration of cacao trees and properly detect flow direction. Transpiration in cacao varies from 10 to 40 liters per day, in a 10-year-old tree during the irrigation requirement period. The Kc values estimated with shade trees during their growth and development vary from 0.6 to 0.7 in the months of February to May, when irrigation is required due to the water deficit that occurs according to the crop water balance.