To assess the response of cotton to foliar fertilizations with Speedfol® Kali SP (12,2% N-NO3 -, 42,5% K2O, 0,9% B) a field test was held in order to evaluate the effect of three doses of Speedfol™ Kali SP on cotton yields. The test was performed in Block 1401 of the locality Valle del Yaqui, Sonora State, Mexico. The tested cotton cultivar was Stonville, sown on 15/03/2011.
The irrigations, moments of fertilization and applied quantities of fertilizers were similar for all treatments (Table 1). To assess the soil characteristics, a soil fertility analysis was performed before sowing (Table 2). The actual treatments and the application dates are described in Table 3.
Table 1. Irrigations and applied fertilisers to the cotton crop.
Table 2. Soil fertility analysis (0-30 cm).
Table 3. Treatments and application dates.
The studied foliar fertilization variants consisted of 4 treatments arranged in a completely randomized block design with 5 replications. The plots were 5 meters long by 0.9 meters wide. The treatments were manually applied with a knapsack sprayer with a capacity of 15 liters. The applications of the treatments started at first bloom with an interval of approximately 7 days, and ended at the formation of the first bolls growth stage. Manual harvesting of the test field took place on 07/09/2011 after applying the desiccant to the crop.
Agronomic analysis and economic results:
ANOVA statistically significantly showed an increase of the cotton lint yield (P = 0.01) as a result of foliar treatments with Speedfol™ Kali SP as compared to the control treatment.
The regression formula in Figure 1 clearly shows that the maximum cotton lint yield of 1.357 kg/ha was obtained by applying 15 kg of Speedfol™ Kali SP/ha. On average, the non-treated plots generated 1.062 kg/ha; the difference between the maximum yield and the non-treated plot being 295 kg/ha (28% more lint yield).