Response of bell pepper crop subjected to irrigation depths calculated by different methodologies

<div><p>ABSTRACT Water must be supplied to a crop in the proper amount and in a timely manner. Vegetables require a good water availability in soil during their entire cycle. Thus, it is very important the implementation of an irrigation management and accurate estimation of water requirement. The objective of this work was to evaluate the effect of five irrigation depths estimated by the dual-Kc and single-Kc methodologies on the characteristics of growth, production and water use efficiency in the pepper crop. A randomized block design was adopted in a split plot arrangement. The effect of five irrigation depths (50, 75, 100, 125 and 150% of crop evapotranspiration - ETc) was evaluated in the plots, and the methodologies were evaluated in the subplots. It was evaluated the root dry matter, total fruit production, leaf temperature, number of aborted flowers and water use efficiency. The interaction between both effects was not significant for any of the variables. The effect of methodology was observed only on the number of aborted flowers. The effect of the irrigation depths was significant on all variables. The irrigation depths that lead to the best agronomic characteristics were superior to 100% of ETc. The ratio between the irrigation depths estimated by single-Kc and dual-Kc methodologies was 1.14. Single-Kc methodology and irrigation depth of 143% ETc were more suitable for the horticulturist. The most efficient irrigation depth in the use of water was 105% ETc.</p></div

ESTIMATES OF MONTHLY AND ANNUAL EVAPORATION RATES AND EVAPORATED VOLUMES PER UNIT TIME IN THE TUCURUÍ-PA AND LAJEADO-TO HYDROELECTRIC POWER PLANT RESERVOIRS BASED ON DIFFERENT METHODS

<div><p>ABSTRACT Evaporation rates in reservoirs influence the volume of water available for multiple uses. Thus, the objective of this study was to estimate the evaporation rates and the evaporated volumes per unit time in the Tucuruí-PA and Lajeado-TO reservoirs based on the methods in Linacre (1993), Kohler et al. (1955), Morton (1983), Bruin & Keijman (1979) and Penman (1948) method was adopted as the standard. The mean annual evaporation rates in the Tucuruí and Lajeado reservoirs, estimated by the Penman method, were similar, with values of 1,784 mm and 1,882 mm, respectively. None of the alternative analyzed methods could be used to estimate the mean annual evaporation in the Tucuruí and Lajeado reservoirs and could not replace the Penman method. However, the Linacre (1993) and Bruin & Keijman (1979) methods could be used to estimate monthly evaporation during the dry season in Tucuruí. The mean evaporated volume per unit time and the mean net evaporated volume per unit time in the Tucuruí reservoir correspond to 120% and 50%, respectively, of the total water demand in the Tocantins-Araguaia region, while the mean evaporated volume per unit time and the mean net evaporated volume per unit time in the Lajeado reservoir correspond to 120% and 50%, respectively, of the total water demand in the basin.</p></div