Frequently Asked Questions  

Drip irrigation systems provide 100% coverage regardless of field shape and terrain, allowing for effective watering in various conditions. In contrast, pivot irrigation systems typically achieve about 80% coverage of square-shaped areas due to limitations imposed by the circular pattern of water application (unless a corner pivot sprinkler is used). While pivots can efficiently irrigate large, uniform fields, they often struggle in irregularly shaped areas, leading to underutilized land potential. Overall, drip irrigation offers more consistent and complete coverage, making it a more versatile choice for diverse agricultural landscapes.

The cost implications of drip irrigation compared to pivot irrigation systems can vary significantly. Sub-surface drip irrigation generally involves a higher initial investment due to the cost of the system and installation. This system is designed for long-term use, which can justify the upfront costs over time through benefits like reduced water usage and increased crop yields and quality. Surface drip irrigation systems cost less to install than SDI systems, with options of annual laterals and retrieval, and this cost should be considered in the long-term analysis. Although pivot irrigation systems are more expensive than Surface to set-up, they usually have a lower initial setup cost than SDI, making them more accessible for some conditions and farmers. However, their efficiency and overhead method of watering can lead to water waste and increased plant disease risk due to wet foliage potentially increasing operational expenses over time. Ultimately, while Surface and sub-surface drip irrigation has a higher upfront cost, it can lead to significant long-term savings through improved efficiency, lower water usage, and higher yields. In some applications, especially on leased land and for allowing different rotation crops, a surface drip system is more suited. In contrast, pivot systems may appear less expensive initially but can be more costly in the long run due to potentially lower crop yields and input inefficiency.

Drip irrigation systems, including Subsurface Drip Irrigation (SDI), generally reduce weed growth. By delivering water directly to the root zone, drip irrigation keeps the soil surface between the crop plant rows drier, which helps minimize weed germination and growth. This targeted watering approach makes crop management easier and can lead to healthier plants with less competition from weeds. In contrast, pivot irrigation systems water the entire field, including the areas between the plant rows, which can create more favourable conditions for weed growth. This widespread application can increase the need for herbicides and other protective measures to manage weeds.

Fertigation and chemigation in drip irrigation are highly efficient compared to pivot systems. Drip irrigation allows for the precise application of fertilizers and chemicals directly to the active root zone, ensuring that plants receive the nutrients they need exactly when they need them. This on-demand capability enhances nutrient uptake and minimizes waste. In contrast, pivot irrigation typically applies fertilizers and chemicals over a larger area and foliage spraying, which can lead in some cases to crop damage or to uneven distribution and less efficient nutrient use. Additionally, because the application is broader, there’s a higher risk of nutrient runoff and leaching, especially in wet conditions. While both methods can face challenges – such as weather dependencies affecting efficiency and the potential for nutrient leaching – drip irrigation generally offers a more controlled and effective approach to fertigation and chemigation. This leads to better nutrient management and can contribute to healthier crop yields.

One of the most significant advantages is water savings. Drip systems significantly reduce evaporation and runoff, allowing for more efficient water use. This can lead to lower water costs and a more sustainable use of this vital resource, particularly in areas where water is scarce. Additionally, drip irrigation enables precise application of water and nutrients directly to the root zone. This targeted approach not only enhances crop yields and quality but also improves nutrient uptake, leading to healthier plants. Another benefit is the reduction of weed growth and disease pressure. By keeping the soil surface drier between the plant rows, sub-surface and on-surface drip irrigation minimizes the conditions that promote weed germination and growth, making crop management easier. It also reduces the likelihood of diseases that thrive in moist environments.

Below is an overview of the key steps involved in installing a deep burial subsurface drip irrigation (SDI) system are as follows. More information in Module 3 of the Drip Guides available in the Rivulis Knowledge Hub.

1. Conduct a thorough assessment of the site to analyze soil type, crop type, crop rotations, water analysis, topography, and historical rotations and practices. This information is essential for designing the system effectively.
2. Based on the site evaluation, develop a detailed design plan that includes the layout of the drip line, submains, mainlines and pump station. This is usually done with a hydraulic designer, such as those provided by Rivulis.
3. Prepare for installation by either engaging a contractor knowledgable in SDI installation, or by procuring the equipment required, including specialized machinery for installing the drip line, such as an injection tool.
4. Install the drip tape with a GPS guided tractor below the tillage depth and in the root zone. Using GPS ensures that you can plant the crop in direct correlation to the buried drip lines.
5. A reliable water source, ensuring that it can provide sufficient flow and pressure with the right filtration for optimal operation must be used. Meanwhile, the installed pump station, main lines, and sub mains should be prepared for connection and first system operation.
6. Flush the system to remove any debris or contaminants that may have entered during installation.
7. Conduct a thorough testing of the system to ensure it operates correctly, checking for leaks, and pressure and flow according to the original hydraulic design.
8. After installation, establish a plan for regular monitoring and maintenance to ensure the system continues to function efficiently over time.

The above is only a brief overview of the steps required. For more information, consult the Rivulis Knowledge Hub.

From the water analysis, determine if any specific maintenance program is required to mitigate clogging risks by chemical or biological contaminants. Regularly flush the lines to prevent clogging. This helps remove any debris or mineral buildup that can obstruct water flow. Monitor for leaks and pressure changes throughout the system. Early detection of leaks or clogging can prevent water loss and damage. Conduct periodic inspections of filters and other components to ensure they are functioning properly. Use soil moisture sensors or other irrigation schedule methodology to optimize irrigation scheduling. These methods help ensure that water is applied only when necessary, preventing overwatering and promoting healthy root growth. Implement a maintenance schedule to regularly check the entire system. This includes inspecting flow and pressure and major system components. By following these practices, a drip irrigation system can remain effective and efficient over time, maximizing its benefits for crop production. For more detail view Module 4 of the Drip Guides in the Rivulis Knowledge Hub.

SDI and Surface drip irrigation are suitable for a variety of crops, particularly those that benefit from precise water application. Common crops that thrive with on-surface drip and SDI irrigation include field crops like corn, cotton, tomatoes, and many others as well as semi-permanent crops like sugarcane. These crops benefit from the efficient water delivery and nutrient application that drip systems provide, leading to improved yields and quality. SDI and Surface Drip Irrigation are effective where consistent control of moisture and nutrition is crucial for crop development and quality. Certain types of pasture can also benefit from SDI specifically, as drip irrigation helps maintain soil moisture without saturating the surface, reducing weed growth and disease pressures. Overall, the ability of drip systems to provide targeted irrigation makes them ideal for a wide range of crops.

In comparison to pivot irrigation, Sub-surface (SDI) and Surface Drip Irrigation are known to result in higher yields and quality. This is primarily due to the precise application of water and nutrients directly to the root zone, which optimizes plant growth and minimizes water stress. Drip irrigation systems can maintain consistent soil moisture levels, allowing crops to receive the necessary water at the right times. This provides a frequent ‘topping-up’ of moisture in the soil. In contrast, the duration for a pivot to make a full rotation can lead to an inability for the pivot to ‘catch-up’ in peak water requirement periods.

Drip irrigation systems are suitable for almost all soil types, making them versatile for various agricultural settings. The various types of drip lines and emitters allow for customization based on soil characteristics with dripper flow and dripper spacing, pressure compensated and anti-siphon, and other features, ensuring that water is delivered effectively to meet the needs of different crops. In contrast, pivot irrigation and furrow systems may face limitations depending on soil type. Their effectiveness can be reduced in soils with high variability, such as heavy clay or sandy soils, where water distribution may be uneven.

Subsurface Drip Irrigation (SDI) works by delivering water directly to the root zone through a network of buried pipes and drip lines. Unlike traditional drip systems, which are above ground, SDI is installed underground, minimizing evaporation and surface runoff. The water is slowly released through drip lines buried beneath the soil surface, providing consistent moisture, by capillary movement, directly to plant roots. This method is highly efficient, reduces weed growth, and minimizes the need for surface-level irrigation infrastructure or interference.

Both Surface Drip and Sub-surface (SDI) systems need proper maintenance to prevent clogging. It’s crucial to install good filtration systems to remove debris and particles from the water. Regular maintenance, such as cleaning filters, flushing the system, and chemical treatment, is also essential for long-term performance. With proper care, including using clean water and periodic system inspections, your SDI system can provide efficient irrigation for many years without significant clogging issues. For on-surface drip systems, as the drip lines are either replaced each year or retrieved, the maintenance requirement is subsequently lower.

SDI systems are not affected by above-ground animals but may be vulnerable to underground pests like rodents. SDI systems in some regions can be susceptible to animal damage. However, this can often be mitigated by farm hygiene and other preventative measures. More detail for mitigation techniques are provided in Module 4 of Rivulis Drip Guide in Knowledge Hub.

Your employees will need some training to effectively operate a drip irrigation system, as they would with any system. Understanding proper maintenance, operation, and troubleshooting is essential. Companies like Rivulis provide comprehensive guides for both Surface and SDI systems, ensuring your team has the necessary knowledge to manage and maintain the system. With proper training and reference materials, your employees can efficiently operate the system, ensuring optimal performance and long-term reliability.