Content:
Drip irrigation, originating from Israel, involves the use of hoses crisscrossing fields, punctuated with small openings from which water drips, irrigating crops in a drip-like manner.
Benefits:
- Water Conservation.
Drawbacks:
- Implementation plans may be restrictive.
Drip irrigation technology involves slow water dripping from emitters on mainlines, sub-mainlines, and lateral lines into the soil under low pressure. It directly supplies filtered water, fertilizers, or other chemicals to the soil. Unlike overhead or furrow irrigation, it allows water to gradually drip into the soil, entering through gravity and capillary action, providing moisture near the crop roots to maintain optimal soil moisture conditions. This is an advanced irrigation method.
I. Characteristics of Drip Irrigation Technology:
- Water and Labor Saving, Increased Yield and Income. Drip irrigation reduces water loss from evaporation and deep percolation, resulting in significant water savings compared to sprinkler irrigation (35–75%). It also reduces weed growth, minimizing competition for nutrients, and thus decreases the need for manual weeding, leading to increased crop yields.
- Higher System Costs. Issues such as emitter clogging due to impurities and mineral deposits can occur, making drip irrigation less straightforward. Currently, it is mainly used for economic crops such as tea and flowers.
II. Classification of Drip Irrigation Systems:
- Fixed Drip Irrigation Systems. Emitters and drip lines remain stationary throughout the irrigation period, requiring significant equipment investment, especially for densely planted crops.
- Mobile Drip Irrigation Systems. Plastic pipes are fixed on supports and moved using specific equipment. Another type involves rotating lateral pipes supported by towers. Manual mobile drip irrigation involves manually moving lateral lines and drip tapes, offering lower initial investment but requiring more labor.
III. Components of Drip Irrigation Systems:
- Mainline: Includes water pumps (and power units), fertilizer tanks, filters, control, and measurement devices.
- Pipelines: Comprise mainlines, sub-mainlines, laterals, and necessary control devices (such as pressure gauges, gate valves, flow regulators, etc.).
- Emitters: These devices regulate water flow through fine channels, dissipating energy and delivering water to the soil in a drip manner. Emitters are typically placed on the soil surface or buried slightly for protection.
Micro-sprinkler irrigation is a method where low-pressure water or chemical agents are sprayed onto foliage or the ground through micro-sprinkler heads. Unlike drip irrigation, which uses emitters, micro-sprinkler heads dispense water through a spraying mechanism. While it covers a larger wetted area compared to drip irrigation, facilitating moisture absorption by the soil, it may lead to increased humidity, making it less suitable for greenhouse applications compared to drip and seepage irrigation.
The composition and classification of micro-sprinkler irrigation systems are similar to drip irrigation systems, including water sources, mainline connections, distribution networks, equipment selection, construction, and operational maintenance.
Seepage irrigation is another water-saving irrigation technology following sprinkler and drip irrigation. It is a subsurface irrigation method where water is supplied to crops through buried seepage pipes (micro-perforated irrigation pipes) under low pressure, according to crop water demand.
Clogging is a major challenge faced by seepage irrigation, including sediment and biological clogging. Seepage pipes manufactured in the United States utilize patented technologies such as foaming, UV resistance, and insect bite resistance to mitigate these issues. However, China has yet to fully master the critical technology for seepage pipe production, making cleaning and repair difficult in case of blockages. Additionally, since the pipelines are buried underground, water and nutrients may not reach the soil layers where crop roots are located, leading to inefficient nutrient utilization. Therefore, the widespread application of seepage irrigation is currently constrained.
What are the primary water-saving irrigation technologies at present? What are their characteristics?
Agricultural irrigation is a major water consumer. Water-saving irrigation, under the premise of fully utilizing natural precipitation to meet crop water needs and minimizing or eliminating artificial irrigation, optimizes the allocation, development, and utilization of various water resources available for irrigation, reduces losses during field water distribution, and improves irrigation water efficiency. Water-saving irrigation is not only an indispensable part of agricultural modernization but also of great strategic significance for alleviating increasingly severe water shortages. Water-saving irrigation technologies include:
- Water System Water Conservation. This involves reducing ineffective water consumption by adopting measures such as leakage prevention and low-pressure pipeline water delivery.
- Field Water Conservation Technology. This includes rainwater harvesting, improvement, and promotion of surface irrigation technologies (such as furrow irrigation, ridge irrigation, surge irrigation, membrane irrigation, etc.), sprinkler irrigation, micro-irrigation, drip irrigation, as well as chemical, agronomic, and biological water conservation techniques.
- Optimization of Water Resources Allocation. This includes irrigation forecasting, irrigation area water allocation, water-saving irrigation standards, irrigation quotas, and irrigation frequency.
