ICID, under its policy to extend its knowledge dissemination wider, conducts regular Webinar Services for its members in particular and wider irrigation and drainage community in general. The Webinar is being divided into two series, namely, ‘Professional Series’ delivered by renowned water experts with 10+ years of experience and ‘Young Professional Series’ provided by young professionals in the water sector, particularly working on agricultural water management (AWM) and other related topics

Introduction

The webinar is on the use and performance of a new device which allows the positioning of an antifriction plastic tape below the pipe of hose reel machines when sliding over the field surface during both unrolling and rolling up. The device hosting the tape is a small drum positioned in the travelling cart supporting the water distribution element, either sprinkler or boom. The tape has to be connected to the irrigation machine. During cart pulling for positioning, pipe and tape unroll from the respective reel, the tape laying down on the ground under the hose. During irrigation, pipe and tape roll up in their respective reel.

Traction force applied to polyethylene pipes moving at a constant velocity along a sliding surface, increases with the weight and length of the unrolled pipe, at a rate depending on the friction coefficient. Modern hose reel irrigation machines are equipped with increasingly longer and larger pipes, in order to improve their irrigation potential. Under actual field conditions, tractive force can be inadequate or excessive both to completely unroll the pipe during positioning of the cart and rewind it on the reel. The consequence is that severe damages can occur both to the pipe (i.e., yield strength, replacement) and to the machine (i.e., stress to mechanical components and stability), together with increasing consumption of energy. By reducing the friction coefficient to a low and constant value, the increase in tractive force is limited. This leads to reduced energy consumption and GHG emissions, no damage to machine and pipe, safe use of long and large pipes. Compared to other field operations, energy used for water lifting during system economical lifetime (i.e., 15 years) is by far the greatest source of monetary cost and GHG emissions.

The dramatic reduction of the tractive force permitted by the device allows the use of thinner pipes, the same outside diameter given. In a reference irrigation scenario of North Italy, with 2,100 m3/ha of supplied water per season, the potential of the device in reducing both energy use (fuel consumption and GHG emissions) and operation cost resulted to be about 25%, with the same system performance and under the assumption that economic lifetime of pipe and machine was the same. It can be stated that both environment and farm economy will benefit from this effective and quite simple technology.