Identification of the potential use of sago midrib (Metroxylon sp.) as drip irrigation emitters for chili plants

Drip irrigation is an irrigation system that can save water by releasing a regulated amount of water and nutrients to the roots of plants using emitters. The use of emitters is one of the additional costs in the use of drip irrigation systems. Estimating the potential of fronds as emitters are done by measuring saturated hydraulic conductivity. The method used is falling head to determine the ability of emitter material made from sago fronds to pass water that can be used to meet the water needs of chili plants. The results showed that the average hydraulic conductivity value at the end sample was higher than the middle and base samples. The hydraulic conductivity values of the tip, middle and base are 0.0077 (m/s), 0.0022 (m/s), and 0.0020 (m/s), respectively. So that the tip-sample can be used as a drip irrigation emitter. The discharge produced by the emitters of tip samples 1 and 2 amounted to 1.252 and 1.424 l/day. Based on this discharge, the number of droppers for each phase of chili plant growth using sago frond emitters, namely at the base and center, requires two emitters in months 3 and 4. Meanwhile, the end frond emitter only requires two emitters in month three, and in other growth phases only requires one emitter.


Introduction
Drip Irrigation is an irrigation technology that releases a regulated amount of water and nutrients to the roots of plants.The delivery of irrigation water is done using emitters.Using emitters in drip irrigation for some farmers, especially small farmers is an additional cost of using drip irrigation systems.The use of drip irrigation can replace inefficient irrigation systems where drip irrigation can reduce the amount of water wasted by 20% to 76% and increase water productivity by 15%.The use of drip irrigation can increase crop productivity and save water [1].
Drip irrigation is the application of irrigation water by dripping water through pipes along the rows or around the plants.Installation of drip irrigation depends on the shape and characteristics of the soil.Ideally, the area between rows and individual plants should remain dry and receive moisture only from incidental rainfall.The irrigation system places emitters and laterals on the soil surface [2].The emitter is an essential part of the drip irrigation system, where the emitter functions to dispense water plants need.The emitter is often called the outlet of drip irrigation, where the emitter is the part that directly distributes water to the plant's roots.Emitters have several types in the process of use [3].
In selecting the emitter to be used, paying attention to several things is necessary before it is used as a dropper in drip irrigation.A good emitter is considered from the droplet discharge, wetting width, plant water needs, and the length of watering time [4].The parameters used in testing the characteristics of the dropper on the emitter are the dropper discharge, pressure or operating head, the relationship between the discharge and the operating head of the dropper known as the emission component, the coefficient of variation of the dropper, the diameter of the dropper and the wet volume of soil or plant water requirements are the determining factors for the success of the selection of emitter materials because the emitter functions according to plant water needs [5].
Based on research on the Identification of the Potential Use of Sago Fronds (Mitroxylon sp.) Drip Irrigation Emitters aims to determine the potential use of sago fronds (Mitroxylon sp.) as an emitter material in drip irrigation to meet the water needs of red chili plants.

Tools
The tools used are scaled pipes, calipers, stands and statives, cutters, stopwatches, butterfly clamps, scissors, funnels, smartphone cameras, and catch cans.The materials in the study were dried sago fronds, heat shrink, water, and rubber.

Hydraulic conductivity measurement.
Measurement of hydraulic conductivity to identify parts of sago fronds that can be used as emitter material.The conductivity of the emitter is measured by the falling head method.The hydraulic conductivity of the emitter material needs to be known to determine the ability of the material to pass water that can be used to fulfill the water supply in plant growth where the more significant the conductivity, the material has large pores or cavities so that the material's ability to seep or pass water is faster [6].
The frond parts used in making emitter samples (Table 1) made from sago fronds are the contents of the fronds at the base, middle, and end with various sizes, as follows; The sample that has been made is wrapped in insulation (Fig. 1).The piece that has been made is mounted on a scaled pipe which is then tied using rubber so that the water does not spill when filled with water.The scaled pipe is filled with 5 cm drop in water level.Measurement data is the length of time for each change in water level in a scaled pipe that is measured using a measuring device hydraulic conductivity (Fig. 2).The data is used to calculate the hydraulic conductivity using the following equation: where: h0 = initial water level (m), h = water level at time t (m), A = cross-sectional area of the sample (m 2 ), a = cross-sectional area of the burette (m 2 ), L = sample height (m), Ks = saturated hydraulic conductivity (m/s) t = time (s).
The determination of the number of emitters made from sago palm fronds is based on the hydraulic conductivity value and plant water requirements using the following equation: where: QE = Emitter discharge (l/day) Ks = Saturated hydraulic conductivity (m/s) A = Cross-sectional area of the sample (m 2 ).

Determination of the number of emitters for chili plant irrigation.
The plants used as samples are chili plants.Determination of the number of emitters to be given to chili plants is based on the amount of plant water needed for each phase of chili plant growth.Plant water requirements are obtained from the research conducted in Indonesia, namely in the Enrekang and Bima areas [7][8].Determination of the number of emitters for drip irrigation in chili plants is done using the equation: where: n = Number of emitters.

Hydraulic conductivity
The results of hydraulic conductivity calculations for each sample with different sizes are presented in Table 2.The hydraulic conductivity values show that the end samples have a higher average hydraulic conductivity than the middle and base samples.The end sample number 2 has the largest hydraulic conductivity value, which is 0.0077 m/s, and the smallest value is the base sample number 2, which is 0.0020 m/s.Based on previous research, if the conductivity value of an emitter material is higher, the material has large pores or cavities, so that the material's ability to pass water becomes greater [6].The discharge on the sample is calculated using equation 2. The discharge on the emitter sample made from sago fronds is one of the determinants of the emitter's success in meeting the plants' water needs.Based on Table 2 the discharge generated by the most significant emitter at the end sample is 1.252 and 1.424 l / day.The base and middle pieces have a smaller discharge value when compared to the end sample.The discharge value of the sago-based sample emitter is directly proportional to its hydraulic conductivity value.Based on previous research, the discharge value produced by the emitter is a general index used to evaluate the hydraulic performance of the emitter, which is influenced by the emitter material [7].

Number of emitters for drip irrigation in chili crops
Based on the results of research conducted [8][9] that the water needs of chili plants in the UTM 50s zone area vary greatly based on the age of the plant, namely 0.11 l/day for one month, 0.422 l/day for two months, 1.148 l/day for three months and 1.323 l/day for four months [8].The water requirement must be met by using the number of emitters as follows; Based on Table 3 determination of the number of droppers for each growth phase, namely at the base and center, requires two emitters in the 3rd and 4th-month phases.Meanwhile, the tip sample requires two emitters in month three, and in other growth phases only requires one emitter.This is because the daily discharge produced by emitters made from sago fronds at the base and center is lower than the plant water requirements.

Conclusion
The results showed that the average hydraulic conductivity value at the end sample is higher than the middle and base samples.The hydraulic conductivity values of the tip, middle, and base are 0.0077 (m/s), 0.0022 (m/s), and 0.0020 (m/s), respectively, so the tip-sample can be used as a drip irrigation emitter.The discharge produced by the emitters of tip samples 1 and 2 amounted to 1.252 and 1.424 l/day.Based on this discharge, the number of droppers for each phase of chili plant growth using sago frond emitters, namely at the base and center, requires two emitters in months 3 and 4. Meanwhile, the end frond emitter only requires two emitters in month three, and in other growth phases only requires one emitter.

Table 2 .
Calculation of conductivity and discharge.

Table 3 .
Determination of the number of emitters.