Low-pressure Drip Irrigation Research Articles

IRRIGATION PROCEDURE (MODE) OF TOMATO GROWN BY THE LOW PRESSURE DRIP IRRIGATION METHOD

Presently, the Republic of Kazakhstan, particularly the Kyzylorda region, grapples with a significant water scarcity issue. In light of this, the utilization of the drip irrigation method plays a crucial role in the judicious management of water resources. In regions like Kyzylorda, characterized by pronounced drought conditions, the efficacy of employing a low-pressure drip irrigation system is notably high. This approach results in an augmented land utilization coefficient, savings in material and labor costs, and an enhanced efficiency in the utilization of irrigation water. The implementation of a drip irrigation system contributes to the improvement of soil nutrition, air circulation, and water-physical properties. It mitigates soil erosion risks, ensures optimal water utilization by supplying irrigation water directly to the roots of each plant, and thereby maximizes the plants' water utilization efficiency. The likelihood of achieving abundant, excellent, and consistent harvests from agricultural crops rises. This method offers several advantages compared to alternative irrigation techniques, including reduced labor costs, preservation of the soil's fundamental structure, prevention of surface soil folds, the ability to concurrently apply fertilizers to the root system area, a potential 30-100% increase in crop productivity, a 50-60% decrease in irrigation water usage, and suitability for use in areas with high slopes.

Mathematical modeling of moisture infiltration in the soil during drip irrigation of a garden

This article presents long-term data of theoretical and field experimental studies using a low-pressure drip irrigation system for the apple variety the “Golden” in the Chirchik-Akhangaran valley for the first time. In the development of irrigation regimes for equipment and technology for drip irrigation of a garden, there is a great importance to determine amount of water infiltration into the soils of the active layer of the irrigated area. As a result of current research work, a mathematical modeling of the process of moisture inflation in the soil during drip irrigation of the garden has been developed.

How Non-Governmental-Organization-Built Small-Scale Irrigation Systems Are a Failure in Africa

Every year, millions of dollars are invested in irrigation development in Sahelian African countries. After shifting from governmental organizations to non-governmental organizations (NGOs), the vulnerability of local populations has not changed much over the last 60 years in Africa. In this study, ten 1 ha small-scale irrigation systems—spread over the two driest climatic zones—were investigated in Burkina Faso. The soils and subsoils were characterized using double-ring infiltration measurements and two soil databases. The irrigation systems’ operability was assessed by sampling 10–12 farmers per system. A total of eight pumping tests were performed on a sample of wells. To assess the yield of cultivated onion, 5 to 7 squares were followed up in each of the 10 systems. Results indicated that water availability was ensured nowhere. The 32 wells were dug in clayey subsoils. Six of them yielded available water Ve flows ranging from 0.0 to 6.1 m3/day, far below the 80 m3/(ha·day) required by onion. To solve this issue, the NGOs shifted to a low-pressure drip irrigation solution, but the too-low pressure of 0.1 bar led to clogging. Ultimately, all 10 systems (except Louda) broke down a few months after the project’s end.

Simple ETo-Based Rules for Irrigation Scheduling by Smallholder Vegetable Farmers in Laos and Cambodia

Hand-held hoses and watering cans are widely used by smallholder farmers to irrigate vegetables in Cambodia and Laos. Overwatering is common. Technology change (e.g., low-pressure drip irrigation) has been used to improve irrigation efficiency but can be unaffordable for many smallholder farmers. The purpose of this study was to identify an appropriate method of predicting crop water demand, develop and field-test improved irrigation schedules for smallholder leafy vegetable farming based on that method, and then develop extension tools to communicate the schedules to smallholder farmers. Improved irrigation schedules for leafy vegetables were developed based on a crop water use prediction technique that is well established (the Penman–Monteith method) but beyond the capacity of smallholder farmers to implement without access to simple aids. Compared to conventional practice, the method approximately halved water and labour use and improved irrigation water productivity 2–3 fold in field research and demonstration trials. Simplified extension tools to assist smallholder farmers with practice change were developed. This work showed that significant efficiencies could be gained through improved irrigation scheduling without changing application technology.

Технология возделывания риса при низконапорном капельном способе полива в условиях Кызылординской области

The article explores the method of drip irrigation of agricultural crops, which provides a high coefficient of irrigation water (80–95%) and land (95%) use. This method helps to significantly save irrigation water by reducing losses for evaporation and filtration outside the root system zone, which eliminates surface runoff, unevenness of irrigation and creates the ability to maximize the use of irrigated areas for agricultural crops. The use of drip irrigation in vegetable production in the south of Kazakhstan since 2000 has radically changed the approach to the “water – soil – plant” complex. The authors believe that a metered feeding regimen would form a new approach to irrigation of agricultural crops, such as rice. Rice (Oryza sativa L.) as a food culture serves as one of the products consumed in food. It is grown in 120 countries on the area of more than 165 million hectares. Rice, unlike other agricultural crops, has a high biological plasticity and adaptive ability, which in modern agriculture allows it to be cultivated in a wide range of climatic conditions and irrigation methods, such as flooding, periodic irrigation and dry conditions. In world practice a continuous flooding of checks was the most widespread method of watering. This technology consumes about 50% of the total volume of irrigation water or 30% of the world’s fresh water reserves. The irrigation rate of rice cultivated with the use of this technology is in the range of 20–25 thousand m3/ha, which significantly exceeds the biological water consumption of rice agrocenosis. A significant part of the irrigation water is lost for filtration, discharges and lateral outflows. Currently, the use of drip irrigation method in rice fields is poorly studied. The research is aimed at substantiating the technology of rice cultivation using a low-pressure drip irrigation method in the conditions of Kyzylorda region

Development and Evaluation of an Emitter with a Low-Pressure Drip-Irrigation System for Sustainable Eggplant Production

Drip-irrigation can improve uniformity in water distribution, water use efficiency, and crop productivity in the saline and nonsaline regions of South Asia and in Bangladesh where the availability and quality of water resources are scare for sustainable crop production. However, the currently available drip-irrigation systems (DIS) have limitations especially in the design and field performance of emitters. A new type of emitter with low pressure (gravity) was developed, installed and evaluated using the locally produced materials in two locations (nonsaline and saline zones) of Bangladesh. The emitter discharge rate was measured for the variable operating heads of 1.5, 2, and 2.5 meter (m) with 0%, 1%, and 1.5% slopes with eggplant (Solanum melongena L.), a commonly grown vegetable in the region. The tested parameters of the emitter were manufacturer coefficient of variation (CVm), emission uniformity (EU), coefficient of uniformity (CU), and the statistical uniformity (Us) of water application. Our results reveal that the discharge rates of the emitter varied from 3 to 5 L h−1 under the operating head of 1.5 to 2.5 m with the slope of 0–1.5%, with better performance of the DIS at 2 m operating pressure head and for slopes of 0% and 1%. The CU of all the test parameters was more than 80%, implying that the DIS was designed and installed with appropriate dimensions for the efficient application and distribution of water to the individual plants, with the emitter performance classified as fair to excellent considering water application and distribution, as well as crop yield. The new emitter used for DIS in field conditions showed that the eggplant yield, water use, and water productivity were greater by 4.6%, 38%, and 70%, respectively, compared to farmers’ irrigation practice. We conclude that the DIS has a great prospect to save water, and could be a convenient irrigation water application method for sustainable crop production in saline and nonsaline regions of Bangladesh and similar soil and climatic conditions in South Asia.

Optimal water use on low pressure drip irrigation system for tomato cultivation in Uganda

Optimal water use on low pressure drip irrigation system for tomato cultivation in Uganda

Influence of protected environments and irrigation methods on plant growth and seed yield of coriander (Coriandrum sativum)

A field experiment to study the effect of different protected environments and irrigation methods on growth and yield of coriander (Coriandrum sativum L.) was conducted at NRCSS, Tabiji, Ajmer, Rajasthan during rabi season of the year 2008-09 to 2010-11. The experiment comprising four treatments of protected environments, viz. plastic covered walk in tunnel, insect proof net covered walk in tunnel, shade net covered walk in tunnel, plastic low tunnel and control (open conditions) in main plots and three irrigation method treatments (pressurized drip irrigation, low pressure drip irrigation and surface irrigation) in subplots was conducted with three replications in split plot design. The soil of the experimental plot was sandy loam, with low organic carbon and nitrogen, medium in available phosphorus and sufficient in available potassium. Impact of protected environment and methods of irrigation was recorded with respect to plant growth, yield attributes and seed yield. The plastic covered walk in tunnel protection resulted highest plant height, maximum branches/plant at harvest, maximum number of umbels/plant, maximum number of seeds/umbel and highest seed yield. Among irrigation methods, low pressure drip irrigation exhibited significantly higher plant height at 60 days after sowing (DAS) as well as at harvest with maximum number of umbels per plant, maximum number of umbellates/umbel and maximum seed yield. On the basis of above study it is concluded that plastic covered walk in tunnel with low pressure drip method of irrigation is best for realizing better plant growth and seed yield of coriander as compared to all other treatments.

Design, Introduction, and Extension of Low-Pressure Drip Irrigation in Myanmar

Drip irrigation is used extensively by both large and small commercial horticultural crop growers in most developed countries where benefits include not only high water use efficiency, but also higher yields, improved product quality, and reduced incidence of foliar disease. Drip systems are still relatively new and expensive in Southeast Asia, and it is primarily wealthier farmers who currently enjoy its benefits. There are also significant perceptual barriers to adoption as many farmers are accustomed to applying copious amounts of water to horticultural crops and are unfamiliar with drip or their crops’ actual water requirements. As a nongovernmental organization whose mission is to help boost small farm incomes, International Development Enterprises (IDE) began experimenting with low-pressure, low-cost gravity-fed drip systems in Myanmar (Burma) in 2006. While the basic design was similar to microtube drip systems of the 1960s, local improvements included filters designed for low pressures, easy-to-use fittings, and inexpensive collapsible header tanks. Our system was optimized for operation on small but commercial-scale plots using pressures as low as 1 psi or only ≈1/10th of that used for conventional drip irrigation. Extension support materials included illustrated installation guides, system design software, videos, testing/filtering of dissolved iron, and easy-to-use water requirement calculators. After hundreds of controlled and farmers’ field tests, our locally manufactured drip sets were offered for sale by private dealers throughout Myanmar in 2009. Incremental system improvements coupled with a strong on-farm demonstration and farmer education program resulted in the successful introduction and widespread adoption of drip irrigation in Myanmar.

English

Characteristics of emitters under low pressure are essential for the design of low pressure drip irrigation systems. Few data is provided by the manufacturers for drip emitter operating under low pressures. No guidelines regarding the optimum combination of operating pressure head and lateral length available either. A laboratory test was conducted to evaluate the effects of pressure head and lateral length on water distribution uniformity of a PVC drip irrigation system. Five different lengths of lateral were considered under a pressure head of 55 kPa (8.21 psi / 5.6 m). The five lengths were 20, 40, 60, 80 and 100 m. Drip tape tested in this study is a non-pressure compensating (NPC) emiiter with 3.00 L/h discharge rate, 16 mm diameter and 35 cm emitter distance. Evaluation of 10 sampled emitters from the 20 m lateral showed a flow variation (Qvar) of 5%, uniformity coefficient (UC) of 99%, with a coefficient of variation (Cv) of 0.016. The 40 m lateral length showed a flow variation (Qvar) of 9%, UC of 98% with a Cv of 0.024. The 60 m lateral length also showed an average flow variation (Qvar) of 16%, UC of 95% with a Cv of 0.060. The 80 m lateral length showed a flow variation (Qvar) of 23%, UC of 93% with Cv of 0.08 and the 100 m lateral length showed a flow variation (Qvar) of 39%, UC of 89% with a Cv of 0.138. EU for 20, 40, 60, 80 and 100 m were 92, 90, 80, 75 and 58% respectively. Flow discharge vs. sampled emitter points (Q-E curves) was also developed for each length. Q-E curves were fitted to the data resulting in R2 values of 0.1566, 0.1202, 0.8607, 0.7904 and 0.8998 respectively for 20, 40, 60, 80 and 100m. The operating pressure was 55 kPa (8.21 psi / 5.6 m) for all the tested length. From the statistical analysis, it was observed that as the lateral length increase invariably decreases the average discharge (Qvar). It is therefore recommended to use the 60 m lateral length with a low pressure head of 55 kPa (8.21 psi / 5.6 m), since the 60 m length satisfied the uniformity distribution criteria under a low pressure. Key words: Pressure head, lateral length, irrigation uniformity.

LEAF NUTRIENT CONTENT AND TOMATO FRUIT YIELD AS AFFECTED BY SINGLE SUPER PHOSPHATE RATES APPLIED BY DRIP IRRIGATION

A drip fertigation system should use low-cost phosphorus fertilizer available in small markets to smallholders such as especially Brazilian tomato growers. A study was conducted in an unheated greenhouse to establish an optimum rate of single superphosphate (SS) to formulate an aqueous solution that can be applied to tomato plants through a low-pressure drip irrigation system. Five rates of SS [18% phosphorus pentoxide (P2O5)] 0, 25, 50, 100, and 200 g·plant−1, were evaluated in a randomized block design with four replications. Each rate was subdivided into 15 equal parts. Each part was dissolved in water (210 mL for each plant) and the mixture left to settle for 24 hours. The supernatant was applied by drip irrigation every week for 15 weeks. The tomato plants were grown in 9 dm3 plastic bags containing fertilized substrate in an unheated greenhouse. The leaf contents of nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), and zinc (Zn) were not affected by the treatments. The highest phosphorus (P), manganese (Mn), and iron (Fe) leaf contents were obtained from plants fertilized with SS at 79; 0; 0 g·plant−1, respectively. The marketable tomato fruit yield, measured up to 123 days after transplanting, increased with the increasing SS up to 54 g·plant−1, resulting in a yield of 6.16 kg·plant−1, corresponding to 10.3 kg·m−2. A settled aqueous solution of SS (54 g·210 mL−1 of water) can be applied weekly to tomato plant through a low-pressure drip irrigation system during the plant cycle.

On-farm evaluation of low-pressure drip irrigation system for smallholders

The aim of this paper was to evaluate the performance of a low-pressure drip system (LPS) for three years of service, to calculate the consumptive working time and costs of maintenance and laterals retrieving before harvesting and to determine benefits and problems with drip irrigation. Drip irrigation provides the opportunity to save water and the potential to increase net income by applying water at the right quantity and at the right time. Small to medium fields would benefit from the LPS irrigation system which has the ability to distribute the amount of water applied. LPS is a well-researched system for drip irrigation, typically that available for furrow irrigated crops. There are significant agronomic advantages of using a low-pressure, low-flow drip system. These advantages translate into measured improved distribution uniformity when compared to flood irrigated crops and energy savings compared to flood and sprinkler irrigated crops. The old (reused) drip line leads to a decrease in distribution uniformity and an increase in costs, when the distribution uniformity decreased by 10.5 and 21.6% for reusing the laterals in the second and third year, respectively. Moreover, the cost of repairing laterals was more than 5 and 6.5 times higher for both the 2<sup>nd</sup> and 3<sup>rd</sup> season. Many disadvantages of drip lines retrieval can be observed, because labour and maintenance are more intensive; there is a risk of mechanical damage to laterals especially if they are reused; increased management skills and experience are needed; and increased retrieval costs arise season after season.

FARMERS' EXPERIENCES WITH LOW-PRESSURE DRIP IRRIGATION FOR VEGETABLE PRODUCTION IN SOUTHEAST ASIA AND THE PACIFIC

Low-pressure drip irrigation has been introduced to small-scale vegetable farmers in several countries in Asia and Africa for almost two decades, but adoption and impact of the technology have been limited due to several factors. This paper evaluates the performance of low-pressure and affordable drip irrigation kits developed and promoted by International Development Enterprises for vegetable production based on farmers’ experiences in Cambodia, Philippines, Indonesia, Vietnam, and Solomon Islands. On-farm, farmer-participatory demonstration trials were conducted using low-pressure drum and bucket kits with 1 m pressure head. In Cambodia, drip irrigation resulted in significant increase in water use efficiency (43%), yield (15%) and labor productivity (38%) in cucumber, eggplant, and yard-long bean. In the Philippines, drip irrigation increased average yields of vegetables by 35% despite unusually high rainfall in the dry season. Similar results were obtained from Indonesia, where there was no significant yield response of five vegetable crops to drip irrigation during the wet season but in the dry season drip irrigation improved yield and quality of chili pepper and reduced disease incidence. In Vietnam, drip irrigation increased average yield of vegetables by 8-11% and reduced labor input by 33%. In the Solomon Islands, unusual rainfall patterns even during the dry season negated the benefits of drip irrigation on vegetable production, but farmers claimed that drip irrigation reduced labor spent in watering the plots. A trial on tomato demonstrated the advantage of drip irrigation as shown in improved yield of 19%. Based on farmers’ experiences, the adoption and impact of affordable drip irrigation technology in Asia and Pacific is mainly determined by climate, particularly the rainfall pattern and growing season in addition to other related technical and socioeconomic factors.

The economics of low pressure drip irrigation and hand watering for vegetable production in the Sahel

Low pressure drip irrigation is being promoted in Sub Saharan Africa as an alternative to traditional methods of small scale irrigation of vegetables. The African Market Garden (AMG) is a horticultural production system for smallholders based on low-pressure drip irrigation combined with an improved crop management package. The agronomic and economic performance of the AMG is compared to two gardens irrigated manually with watering cans. One of these gardens is managed according to the same improved crop management package as in the AMG, this treatment is called Improved Management (IM). The other garden is managed according to common practices of vegetable producers in the area, this treatment is called the Farmer Practice (FP). Crop productivity, labor and water use were monitored for two vegetable species (okra and eggplants). The experiment was performed on-station in Niger on three adjacent 500 m2 plots in a sandy acid soil. It was found that improved crop management practices greatly enhance crop productivity over traditional methods at comparable production costs. The AMG gave higher crop yields and higher returns to investment than the treatments irrigated with watering cans. Labor accounts for up to 45% of the production cost in vegetable gardens irrigated by hand, where 80% of the producer time is spent on irrigation. The total labor requirement for the drip irrigated AMG was on average 1.1 man hours per day against 4.7 man hours per day for the Farmers Practice on a 500 m2 garden. Returns on labor are at least double for the AMG against the other treatments. The returns on land from eggplant were found to be US$ 1.7, 0.8 and 0.1 per m2 for the AMG, IM and FP respectively. The returns on water for the cultivation of eggplant are around US$ 2 per m3 in the AMG, against US$ 0.1 in the Farmers Practice. This experiment showed the strong positive impact of drip irrigation and improved crop management practices on profits at minimal environmental costs, indicating that transformation of existing practices poses a considerable potential towards sustainable agricultural development.

Experimental Determination of the Hydraulic Properties of Low-Pressure, Lay-Flat Drip Irrigation Systems

The hydraulics of IDEal low-pressure drip irrigation system components were analyzed under controlled laboratory conditions. The hydraulic loss coefficient for the lateral-submain connector valves ...