How to use water-soluble fertilizers for best results

Select Fertilizers Based on Irrigation Facilities
Water-soluble fertilizers feature an indicator called “water-insoluble matter content.” Typically, drip irrigation requires water-insoluble matter content below 0.2%, micro-sprinkler irrigation below 5%, and overhead sprinkler irrigation below 15%. Furrow and flood irrigation demand even lower levels. Generally, lower water-insoluble matter content indicates better fertilizer efficacy, though such fertilizers command higher prices.
Avoid Direct Flushing Application
Employ a two-step dilution method. This ensures uniform fertilizer distribution, enhances nutrient utilization, and minimizes leaching losses caused by single-dose heavy applications—a key consideration given crops' continuous nutrient uptake. Apply 3-6 kg of water-soluble fertilizer per mu per application.
Mastering Drip Irrigation Fertilization Details
When fertilizing via drip irrigation, first flush with clean water until pipes are fully saturated before initiating fertilizer delivery. Longer application durations yield better results. Immediately flush with clean water for 20-30 minutes after fertilization to completely remove residual fertilizer solution from the pipes.
In principle, slower application ensures more uniform distribution, especially for elements with poor soil mobility (e.g., phosphorus). Extending application time effectively improves nutrient utilization. During dry seasons, aim for a 2-3 hour completion time for drip irrigation fertilization.
Avoid excessive irrigation.
Generally, maintain moisture within the top 20-40 cm of soil.
Regarding mixing: Use alone or with non-alkaline pesticides whenever possible to prevent metal ion reactions that cause precipitation, leading to leaf fertilizer damage or pesticide damage.