**2.1. Water-use evaluation**

**1. Introduction**

78 Soil Moisture

financial loss to farmers [1].

replenishment in soils agricultural systems.

parks, public squares, schools and community gardens.

Small-scale family-based farmers oftentimes suffer considerable decreases in agricultural production during prolonged periods of soil water stress. Irrigation technology using clay pots buried in the soil is promoted as being an effective, accessible, and environmentally sustainable option for small-scale family-based farmers to be able to cultivate fruit trees and vegetables, and that can promote food security [1, 2]. Irrigation technology using clay pots buried in the soil has been used in important agricultural regions in the world [1, 3, 4] such as Burkina Faso, Zambia, the USA and Pakistan. Clay pots buried in the soil have been shown to be effective in the cultivation of fruit trees and in reforestation projects [1, 3]. This technique minimizes water losses due to evapotranspiration and soil drainage during irrigation in rural areas [5], improves seed germination and crop establishment [3], thus reducing crop loss and

This technology aims to provide solutions that are able to supply a crop's water needs during long dry periods [6], especially in rural areas that require irrigation to guarantee agricultural production [7]. Adopting a holistic vision of water security in regions that have an increasing demand for water in order to produce food, this technology presents indicators that point to sustainability for food security as well as for the responsible use of water resources. Therefore, locally accessible innovations that improve the efficiency of irrigation systems are necessary in order to minimize undesirable losses due to evapotranspiration and soil drainage. Such practices aim to mitigate impacts on current analyses being conducted to study the climate as well as scenarios of global climate change. Quantification of evapotranspiration rates is fundamental to the evaluation of environmental sustainability indicators. In this context, the objective of this project is to strengthen research activities and share knowledge of technology that is low-cost and that has a small water footprint that uses rainfall water for hydrologic

There is a great need to increase research and extension actions that make viable the diffusion of the technology of the use of rainfall water to fill clay pots buried in the soil to maintain the production of agricultural crops during prolonged periods of soil water stress under actual climate conditions and those of future scenarios influenced by climate change, and to disseminate the results in order to amplify the adoption of this technology. In the course of using the technique, new strategies of low-cost irrigation can be adapted to different production systems and also in urban environments to increase sustainability in green spaces such as

Managing irrigation water is among the critical issues to address food insecurity under the changing climate. Rainfall variability has been reported to significantly impact the economies of many countries as natural rainfall is the major source of water for agriculture. Clay pot technology has been proven to significantly improve crop water productivity in dry land areas but has not been promoted or used due to the lack of a suitable cropspecific standard design. In this context, the objective of this publication is to strengthen *2.1.1. Measuring evapotranspiration using the surface renewal technique*

$$\text{LE} = \text{Rn} - \text{G} - \text{H} \tag{1}$$

where, LE is latent heat flux, Rn is net radiation, G is soil heat flux, and H is sensible heat flux.
