It mainly uses the capillary drip trickle irrigation system and low-pressure pipelines to gradually and evenly drip the nutrient solution required by crops into the root zone of crops based on their actual water and fertilizer requirements. The frequent irrigation and slow application of a small amount of water and fertilizer to the roots of crops in drip trickle irrigation integrated with water and fertilizer technology ensures that crops maintain optimal water and fertilizer conditions, and prevents the periodic occurrence of excessive or insufficient water and nutrient conditions that can occur with other irrigation methods.
However, compared with ordinary ditch irrigation, there are significant differences in the entire nutrition absorption process and transport mechanism of crops due to the common water and fertilizer supply methods and irrigation amounts of drip trickle irrigation integrated with water and fertilizer.
Therefore, compared with ordinary ditch irrigation, drip trickle irrigation integrated with water and fertilizer is different in soil temperature, water and fertilizer distribution, and salt transport, and shallow water and fertilizer supply and increased membrane salt accumulation restrict the downward growth of crop roots, which spread close to the soil surface.
Roots are the main organs for crops to absorb nutrients and water, and the shape and structure of roots determine the spatial scale and resource competition ability of root systems for accessing water and nutrients from roots adjacent to them.
Therefore, root positioning is one way to prevent excessive irrigation. There are two main methods of root positioning: digging (digging a profile to see the root situation in the soil) and observation (direct investigation: using professional equipment to scan the root distribution state with a lower root tube regularly; indirect investigation: using a water meter to indirectly reflect the depth of the root system based on the water absorption characteristics of the root system).
After the root distribution depth is confirmed, controlling the irrigation depth is the second step in preventing over-irrigation. The relative water content can intuitively reflect the initial water content of the irrigation, and is often used as a basis for determining whether irrigation is needed and calculating the amount of irrigation water.
There are also two main methods to confirm the irrigation amount based on the relative water content: experience (based on soil moisture characteristics such as field water-holding capacity and relative water content, combined with irrigation depth to determine the ideal irrigation volume for a single cycle) and equipment (embedded water monitoring device in the soil based on the root distribution characteristics, using the set limit to control the start and stop of irrigation equipment).
In summary, drip trickle irrigation of fertilizer only irrigates the root system and provides fertilizer to the root system, so it is necessary to understand the depth of the crop root system's distribution, control the irrigation amount per cycle based on the root system's distribution characteristics, and then control the irrigation amount based on the soil moisture diffusion characteristics.