Nov 9, 2016Study: New Potassium fertilizer increases tuber yield
Potassium fertilizer is comparable to nitrogen in the quantity needed for a successful potato crop production. Earlier studies conducted indicate that the source of potassium fertilizer applied can influence potato tuber yield and quality. A new potassium-based fertilizer, known as Bio-K has been introduced. Bio-K is a combination of an inorganic salt reacted with an organic acid to form potassium acetate fertilizer. A study was conducted at Colorado State University San Luis Valley Research Center, to evaluate the response of Russet potato to the timing of Bio-K application as source of K fertilizer.
The study was established in the field as a randomized complete block design, with each treatment replicated four times. Mesa Russet, a fresh market Russet potato, was used as the candidate potato cultivar.
In this study, the effect of Bio-K application timing was compared to application of muriate of potash (KCl), which is the more commonly used K fertilizer source. Experimental treatments included (i) pre-plant application of Bio-K (Bio-K pre-); (ii) pre-plant application of Bi0-K, followed by foliar application of Bio-K (Bio-K pre- + foliar); (iii) foliar application of Bio-K (Bio-K foliar); (iv) pre-plant application of KCl (KCl pre-); and (v) pre-plant application of KCl, followed by foliar application of Bio-K (KCl pre- + Bio-K foliar). The study also included a control treatment where no K fertilizer was applied. Forty pounds per acre (40 lb./A) KCl was applied in the KCl Pre-, treatment. Two gallons of Bio-K per acre was applied at each Bio-K application. One gallon of Bio-K contains 2.6 lbs. K2O/A. The ‘Bio-K foliar’ treatment received 4 gal./A of Bio-K.
At harvest, tubers from each plot were weighed for total yield. Harvested tubers were separated into various size distribution groups based on weight (> 4 oz., > 6 oz., > 10 oz., etc.). Treatment effects on tuber quality was also evaluated, but not reported in this article.
Results and discussion
Source and time of K fertilizer application did influence tuber yield and tuber size distribution of Mesa Russet. Treatments that included Bio-K application increased total and marketable tuber yield when compared to the control and KCl Pre-, treatments (Table 1). Pre-plant application of Bio-K increased total, marketable (> 4 oz.), and premium size (> 10 oz.) tuber yields by 12 percent, 22 percent, and 58 percent, respectively, when compared to the control treatment (Table 1). Yield increases observed for pre-plant Bio-K application treatments were not significantly different from total and marketable tuber yields observed for Bio-K pre- + foliar, Bio-K foliar, and KCl pre- + Bio-K foliar treatments. When compared to pre-plant application of KCl, Bio-K Pre- increased total, marketable, and premium size tuber yields by 9 percent, 13 percent, and 42 percent, respectively.
Yield increases obtained from pre-plant application of Bio-K did not significantly differ from yields obtained for Bio-K pre- + Bio-K foliar application and pre-plant application of KCl + foliar application of Bio-K treatments (Table 1). It should be noted that the application of Bio-K Pre-, Bio-K Pre- + foliar, and KCl Pre- + Bio-K foliar did increase the percentage of premium size tuber yield, compared to only foliar application of Bio-K, indicating that pre-plant application of Bio-K can be more effective in K uptake and utilization. It should also be noted that, application of KCl alone did not increase tuber yield, but addition of Bio-K as a foliar spray after pre-plant KCl application did increase total, marketable, and premium size tuber yields (Table 1).
Summary and conclusion
The purpose of this study was to evaluate the effect of potassium fertilizer source and time of application on Russet potato performance. Data from the study indicate that application of Bio-K as source of K fertilizer did increase total and marketable tuber yield of Mesa Russet. Even though pre-plant application of KCl did not increase marketable and premium size tuber yields, foliar application of Bio-K following pre-plant application of KCl significantly increased total, marketable, and premium size tuber yields. It can be concluded that pre-plant application of Bio-K significantly improves marketable and premium size tuber yields of Mesa Russet. The yield increases observed for Bio-K application was due to efficient uptake and utilization of K from the potassium acetate fertilizer.
— Samuel Y.C. Essah, Colorado State University
Source: Colorado Potato Administrative Committe