Academic journal article Current Politics and Economics of South, Southeastern, and Central Asia

zCOPING WITH WATER SCARCITY IN RICE-BASED FARMS: DEVELOPMENT OF A CAPILLARY IRRIGATION SYSTEM FOR SMALL HOLDER FARMERS IN THE PHILIPPINES *

Academic journal article Current Politics and Economics of South, Southeastern, and Central Asia

zCOPING WITH WATER SCARCITY IN RICE-BASED FARMS: DEVELOPMENT OF A CAPILLARY IRRIGATION SYSTEM FOR SMALL HOLDER FARMERS IN THE PHILIPPINES *

Article excerpt

(ProQuest: ... denotes formula omitted.)

1.Introduction

Water is a basic necessity for plant growth and development. The manner in which water is applied to the plants is important especially now that it is predicted to become very limiting in the next years to come due to, among other things, the effects of climate change. A study conducted by the World Resources Institute predicts that the Philippines, together with other Southeast Asian Countries, will experience a "high" degree of water shortage in the year 2040 (Luo, Young, Reig, 2015). Moreover, extreme event like El Niňo comes every 2 to 7 years (Climate Prediction Center, 2005), causing significant losses in crop production due to its negative effect on irrigation water supply. Undoubtedly, there is an increasing need for efficient and affordable method of irrigating crops so as to help small holder and resource-challenged farmers during conditions where water supply is very limiting.

Commercial drip irrigation systems, although proven efficient (Goodwin, Murphy, Melville, Yiasoumi, 2003; Weatherspoon and Harrel, 1980), have high acquisition costs (Ali, 2011; Rowe, Kolp, Greer, Getter, 2014). Moreover, unless their operation is automatically controlled, the decision as to when to irrigate and how much water to apply relies on the judgment of the farmer which may not always be accurate. Even for the computer-controlled and tensiometer-triggered drip irrigation systems, there is still a possibility that the irrigation schedule is not effective to all plants in an irrigation zone (Million, Yeager, Larsen, 2007).

Irrigation using the capillarity wicks is labor-efficient and can substantially reduce water usage (Nalliah and Sri Ranjan, 2010). In capillary irrigation, water is applied beneath the root zone in such a manner that it wets the root zone by capillary rise (Ali, 2011). In this method, water, whether filtered or not, is made available to the plants all the time. There is no danger of flooding since the movement of water is governed by capillary action. It also conserves a significant amount of water because, among other things, water lost through evaporation from the soil surface is minimized since the water can be applied directly in the plants' root zone.

A lot of reports had been published regarding the use of capillary principle in irrigating plants (Bainbridge, 2002; Banko and Stefani, 1991; Gowda, 1974; Haydu, Beeson, Caron, 2004; Kinoshita and Masuda, 2011; Kinoshita and Masuda, 2012; Lee, So, Jeong, Huh, 2010; Schuch and Kelly, 2006; Yeager and Henley, 2004; Wells and Postlethwaite, 2015; Wesonga, Wainaina, Ombwara, Wasinde, Home, 2014) however, all of them are confined to nurseries and potted plants. As also observed by Million, Yeager and Larsen (2007), no advancements has been done yet for this technology to be applied in field crop production.

Generally, this study aimed to integrate the use of capillary wicks in a traditional drip irigation system and come up with a hybrid herein called as capillarigation system. Specifically, it aimed to: (a) identify suitable material to be used as capillary wick, (b) determine factors that affect the wicking flow rate (WFR) of the selected wick material, and (c) to test the performance of the capillary wicks in the actual field setup of the capillarigation system.

2.Materials and Methods

This study was conducted at the Philippine Rice Research Institute (PhilRice) - Central Experiment Station in Muňoz Science City, Nueva Ecija, Philippines, in January to December 2015.

2.1.The Capillarigation System's Design Concept

The development of the capillarigation system was benchmarked on the drip irrigation system with the main idea of replacing the dripper with capillary wicks, following a setup shown in Figure 1. As shown, irrigation water is contained in a tank which need not be placed in an elevated platform (as in the case of the drip irrigation system) since the capillarigation system operates at a much lower operating pressure than its counterpart. …

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