Optimization of gravity-fed surface drip irrigation system for small farm under varying head and length of laterals

Introduction

Drip irrigation is the latest irrigation technology; is also known as trickle irrigation. In this method, the daily required of water is applied to crop root zone, in the form of water droplets, as a result the loss of water due to evaporation, seepage, deep percolation, etc. gets minimized to a large extent. n Chhattisgarh, farmers usually have small bari/ kitchen garden in small area around 0.3 decibel to 0.5 ha, where farmers usually grow fruits & vegetables to meet their family needs. There was no test initiated for the Mungeli soil and climate which are favorable for growing fruits and vegetables, oil seeds and pulse crops at BRSM CAET & RS campus. A mango orchard in Chatarkhar of about 1 ha length is available on the right side of the college building, which has 28 varieties of mango plants (45 years old). So far, surface irrigation was being done in the orchard. Near Mungeli, many farmers have small orchard/ kitchen garden close to the house. Keeping this in view, we are working on "Optimization of Low Head Gravity fed surface drip irrigation system in mango orchard under varying head and length of laterals". So that the farmers can grow fruits & vegetables easily. Mungeli is located at an elevation of 281.8 meters (924.54 feet) above Mean Sea Level (MSL), Mungeli has a Tropical wet and dry or savanna climate (Classification: Aw). The district's yearly temperature is 30.13 °C (86.23ºF) and it is 4.16% higher than India's averages. Mungeli typically receives about 38.29 millimeters (1.51 inches) of precipitation and has 34.19 rainy days (9.37% of the time) annually.

Components & Methodology Study area

The work was carried out in the village of Chatarkhar, Block District Mungeli at college campus (BRSM CAET & RS). The distance of research field is about 11 m from BRSM CAET & RS. Study area was located at latitude of 22°03'59" N and longitude of 81°38'32" E. The experiment was conducted on mango orchard. The soil in the site of the experiment is black cotton soil.

Data collection

The tiny research area of 12 x 10 m2 was used for this investigation. Three emitter discharge points that were mounted on drip lines were the subject of the evaluation. The emitter positions on each dripline are designated as A, B, and C as shown in fig 1. Driplines are marked as L1, L2, L3, and L4. As a result, L1A, L1B, and L1C were determined to be the discharge points; this also applied to L2A to L2C and L4A to L4C. The water in the overhead tank is collected with the help of siphoning from higher elevation to lower elevation from water source situated www.extensionjournal.com above 10 m from the ground level. A 2 L container of specified size was utilized. A stopwatch was utilized to gather the water flow from each discharge point and it is also used to determine the drippers' chosen discharge rate. For analysis, the discharge rate was determined and noted at specific locations along each drip line. A constant height of 1 m, 1.5 m, 2 m is maintained by continuous flow water from the water source in such a way that inflow of water is more than outflow from a given head as shown in fig 2. The average value of the three sets of each data point was recorded as the data.

Parameter used to evaluate drip emitter discharge 1. Average Emitter Discharge Rate (qa)

The average emitter discharge rate (q) is the total amount of water emitted by all of the drippers in a given amount of time.

Equation it as:

where; qi = flow rate of the emitter i (m3/s) or (l/h) n = Total number of emitters

Uniformity Coefficient (UC)

Uniformity coefficient is defined as the factor which determines how uniformly the water is distributed in a given area. The equation is considered as:

where; UC = Uniformity Coefficient (%) n = number of emitters under consideration qa = mean flowrate of the emitter (l/h) qi = flowrate of the emitter i (l/h) When the head varies from 2 m to 1 m, the discharge also varies accordingly. Here, the number of laterals was kept constant as shown in fig 1. It can be observed from the Table No. 2 that as the length of lateral is increased the average emitter discharge also decreases and vice versa. Similarly, as the discharge head increases the average emitter discharge also increases and vice versa. The average emitter charge was observed to be maximum under operating of 2 m with 8 m length of lateral was minimum when head decreased to 1 m and length of lateral was 12 m with 4 number of laterals. Therefore, in order to obtain maximum discharge, the length of lateral should be kept minimum and the head should be kept at higher elevation. Also, it is observed that to obtain more discharge the head should be equal to or more than 2 m depending on the farm/ kitchen garden/bari size.

Results and Discussion

References

1. Bhatnagar P, Srivastava R. Gravity-fed drip irrigation system for hilly terraces of the northwest Himalayas. Irrigation Science. 2003;21(4):151-157.
2. Ayare BL, Thokal RT. Performance evaluation of gravity fed inline drip irrigation system. International Journal of Agricultural Engineering. 2018;11(1):79-83.
3. Raphael OD, Amodu MF, Okunade DA, Gbadamosi AA. Field evaluation of gravity fed drip irrigation system in a sloped greenhouse. International of Civil Engineering and Technology. 2018;9(10):536548.
4. AAU Farah, Abdi ASH. Evaluation of hydraulic performance of three different emitters in drip irrigation systems for small vegetable farms, Gezira state, Sudan. International Journal of Agriculture and Nutrition 2023;5(2):11-15. DOI: https://doi.org/10.33545/26646064.2023.v5.i2a.123
5. Rigve A, Bhardwaj A, Satpute S, Singh J, Garg S. Standardization of gravity-fed low head drip irrigation system under variable operational head for small farms. International Journal of Hill Farming. 2018;31(1):132140.
6. Kapupara PJ, Bhatu HM, Gohel J. Study of the hydraulic performance parameters of the drip irrigation system at various operating pressures. Agricultural Science Digest -A Research Journal. 2021;41(1):89-92.