- MOISTURE DISTRIBUTION UNDER DRIP IRRIGATION

2013 ◽  
Vol 33 (2) ◽  
pp. 249-257 ◽  
Author(s):  
Alberto Colombo ◽  
Lívia A. Alvarenga ◽  
Myriane S. Scalco ◽  
Randal C. Ribeiro ◽  
Giselle F. Abreu

The increasing demand for water resources accentuates the need to reduce water waste through a more appropriate irrigation management. In the particular case of irrigated coffee planting, which in recent years presented growth with the predominance of drip irrigation, the improvement of drip irrigation management techniques is a necessity. The proper management of drip irrigation depends on the knowledge of the spatial pattern of soil moisture distribution inside the wetted strip formed under the irrigation lines. In this study, grids of 24 tensiometers were used to determine the water storage within the wetted strip formed under drippers, with a 3.78 L h-1 discharge, evenly spaced by 0.4 m, subjected to two different management criteria (fixed irrigation interval and 60 kPa tension). Estimates of storage based on a one-dimensional analysis, that only considers depth variations, were compared with two-dimensional estimates. The results indicate that for high-frequency irrigation the one-dimensional analysis is not appropriate. However, under less frequent irrigation, the two-dimensional analysis is dispensable, being the one-dimensional sufficient for calculating the water volume stored in the wetted strip.


Author(s):  
A. Selvaperumal ◽  
E. Sujitha ◽  
I. Muthuchamy

Drip irrigation system uniformity can preserve a higher crop yield and deplete the initial investment of cost. The experiment was conducted at precision farming development centre research farm, Tamil Nadu Agricultural University, Coimbatore, to evaluate the uniformity coefficient and soil moisture distribution under drip irrigation system. The experiment was designed under Factorial Randomized Block Design (FRBD) which included three fertigation levels 80%, 100% and 120% of Recommended Dose of fertilizers which were replicated thrice. The Coefficient of Variation (CV) was obtained as 0.0207 per cent kept at a constant pressure of 50.66 kPa, Statistical Uniformity (SU) as 97 per cent and Coefficient of Uniformity (CU) as 0.9518. As the elapsed time increased, the rate of increase of wetted zone diameter decreased. A high R2 value of 0.97 shows the goodness of fit for the horizontal movement. The mean soil moisture distribution 39.2 per cent was observed below the emitter at the depth of 10 cm immediately after irrigation.


2020 ◽  
Vol 20 (3) ◽  
pp. 761-772 ◽  
Author(s):  
Arpna Bajpai ◽  
Arun Kaushal

Abstract The wetting pattern of soil under trickle (drip) irrigation is governed by soil texture, structure, initial water content, emitter spacing, discharge rate and irrigation frequency. For efficient management of trickle irrigation moisture distribution plays an important role. The degree of soil wetted volume in an irrigation system determines the amount of water required to wet the root zone. This article helps in understanding moisture distribution for different lateral spacing, emitter spacing, emitter discharge rates and drip line installation depth for trickle irrigation under various soil conditions all over the world. This review reveals that soil moisture distribution and uniformity within the soil profile were affected by the distance between emitters rather than the distance between drip lines. In drip irrigation systems, the less the dripper spacing, the greater the moisture distribution as well as water use efficiency and crop yield. The radial spread of moisture was greater at lower water application rates, whereas the vertical spread was greater at higher water application rates. The vertical movement of soil moisture was greater than the horizontal movement under surface as well as subsurface drip irrigation systems. Deeper drip tape installations had a potential risk of not providing moisture to shallow rooted crops.


2021 ◽  
Vol 15 (2) ◽  
pp. 4-8
Author(s):  
F. U. Zhuraev ◽  
G. Kh. Karimov

Experience shows that for the irrigation of intensive gardens, various types of equipment and technologies are used, such as continuous irrigation (invasive), drip irrigation, subsurface irrigation and other methods. All irrigation options have some shortcomings, such as water evaporation, high water consumption, high consumption of mineral fertilizers and energy. (Research purpose) To develop an automated system for subsurface irrigation of intensive gardens with groundwater using electric pumps and solar panels, and to create a mathematical model of soil moisture distribution. (Materials and methods) Special devices shaped as pegs were designed to supply water with dissolved mineral fertilizers directly into the root system of intensive gardens. The authors investigated the pegs’ geometric parameters and the criteria for their placement in the soil, taking into account the consumption of water and nutrients. The authors examined soil mechanical composition and salinity as well as its physical and mechanical, technological properties. (Results and discussion) It was found out that the installation of the peg facilitates soil moisturizing through the central pipeline within the radius of 1.55-1.75 meters at the depth of 0.7-0.9 meters. Three-four pegs, being equidistant from each other and inclined in relation to the vertical axis by 20-30 degrees, were placed around a tree. Water consumption was determined for various irrigation methods: for furrow irrigation (control) – 1125.7 cubic meters per hectare, for continuous irrigation (invasive) – 1812.3 cubic meters per hectare, for drip irrigation – 618.6 and subsurface irrigation – 506.4 cubic meters per hectare. (Conclusions) Based on the results of the experimental study carried out in farms with intensive gardens using various irrigation methods, continuous irrigation (invasive), drip irrigation and subsurface irrigation were compared in terms of water consumption. The results show that drip irrigation and subsurface irrigation ensure less water consumption than flood irrigation, by 46 per cent and 57 per cent respectively. It was found out that subsurface irrigation ensures 57 per cent water and 25-35 per cent mineral fertilizer economy, in comparison with the other methods of providing trees with water and nutrients.


Author(s):  
A. Selvaperumal ◽  
E. Sujitha ◽  
I. Muthuchamy

Drip irrigation system uniformity can preserve a higher crop yield and deplete the initial investment of cost. The experiment was conducted at precision farming development centre research farm, Tamil Nadu Agricultural University, Coimbatore, to evaluate the uniformity coefficient and soil moisture distribution under drip irrigation system. The experiment was designed under Factorial Randomized Block Design (FRBD) which included three fertigation levels 80%, 100% and 120% of Recommended Dose of fertilizers which were replicated thrice. The Coefficient of Variation (CV) was obtained as 0.0207 per cent kept at a constant pressure of 50.66 kPa, Statistical Uniformity (SU) as 97 per cent and Coefficient of Uniformity (CU) as 0.9518. As the elapsed time increased, the rate of increase of wetted zone diameter decreased. A high R2 value of 0.97 shows the goodness of fit for the horizontal movement. The mean soil moisture distribution 39.2 per cent was observed below the emitter at the depth of 10 cm immediately after irrigation.


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