"Under low K and Zn soil conditions, 3 foliar applications with Speedfol® Rice SP or 3 with Ultrasol® K on Japonica rice, grown under 3 different soil K application levels of the recommended KCL dose rate, increased crop yield by 9 to 17% and raised the farmer's net income by 9 to 16%" reports Sissi Ji, Agronomist at SQM China.
Speedfol® Rice SP outperformed Ultrasol® K, while Ultrasol® K surpassed the control treatment with respect to crop height, panicle length, number of panicles per hill, percentage of effective panicle, percentage of grains filled, 1.000-grain weight and the percentage of brown rice, calculated as an average of the 3 soil K input levels per foliar treatment. When soil K input levels were reduced from 100% to 50% of the recommended dose, the 1.000 grain-weight dropped from 26,0 to 25,1 grams, whereas the number of grains per panicle dropped from 133 to 120, also calculated as an average of the 3 foliar treatments per soil K input level.
The trial was set up in a Japonica rice field in Dandong, Liaoning province in China. The soil was medium fertile sandy loam with 42 mg exchangeable K/kg (low level), 0,7 mg available Zn/kg (low level) and 1,46 mg available B/kg soil (adequate level). All plots received equal amounts of 25 MT farmyard manure/ha, 160 kg N/ha and 69 kg P2O5/ha in the base and side dressings. The trial design consisted of a completely randomized block design with 36 plots in total: 3 soil K levels, 3 foliar treatments and 4 replicates.
- Foliar applied Speedfol® Rice SP and Ultrasol® K, on top of the current standard practice of 150 kg KCL/ha in the base dressing, increased crop yield by 9 to 17% and raised the farmer's net income by 9 to 16%.
- Lower soil K input levels of 75% and 50% resulted in respectively 3,5% and 6% less crop yield and respectively 3% and 5% less net farmer's income.
- 5 to 10% higher crop yields and 6 to 8% extra net income can be obtained with only 50% or 75% of the recommended KCL dose rate in combination with 3 foliar applications of Speedfol® Rice SP or Ultrasol® K, compared to the current standard of 100% KCL and no foliar applications.