How to Find the Best Fertilizer for Potatoes
Researchers seek the best program for fertilizing potatoes
Maintaining a healthy leaf canopy is critical to potato production. In short, healthy leaves last longer and the longer they last, the better the yields. Fertilizing potatoes properly not only promotes healthy leaves, it also influences overall plant health and promotes resistance to insects and diseases. This translates to better quality crops and optimum yields.
Choosing a fertility program
When trying to find the best fertilizer for potatoes, start with a good soil test. Soil test results indicate soil salinity, acidity (pH) and fertility. Choosing the right fertilizer blend is much easier when you know the nutrient requirements of your planting site.
Once you know your site’s nutrient needs, consider what fertilizer will be the best fit. This step is important because nutrients play such a critical role in maintaining healthy potatoes. Phosphorus, for example, influences metabolic processes such as the transportation of sugars through potato leaves and the conversion of sugars into starch. Potatoes also require higher amounts of nitrogen and potassium prior to and during tuber bulking.
Research comparisons of fertility programs
In 2011 researchers at the North Central Research Station, owned by Agro-Culture Liquid Fertilizers, compared the marketable yields from multiple potato fertility programs. Their goal was to determine if programs or individual fertility components have a greater impact on total yield and size of potatoes. To do this, they evaluated the performance of various combinations of Agro-Liquid products with that of conventional fertilizers. (See Figure 1)
Preparations and methods
Growers broadcast the dry fertilizers into their treatment areas in early May. They split the liquid fertilizer planter treatment into two bands; placement was two inches above and two inches to each side of the seed piece. The potato cultivar used for the experiment was Russet Norkota.
Two side-dress nitrogen applications took place throughout the growing season. The first application occurred at hilling, the second one ten days afterward. Harvest took place in early September. Researchers used potatoes larger than 1.5 inches for evaluations. They sorted them according to size/shape and then weighed each grade to determine yields.
The Agro-Liquid based programs performed well and their yields were higher than the conventional fertility programs. (See Figure 2). Sometimes changing one part of a particular program had a positive impact on yields. This was the case with treatment three, which was a combination of conventional sources of nitrogen and potassium, but Pro-Germinator replaced 10-34-0 at time of planting. Among the conventional-based fertilizer programs, this treatment had the highest yields.
Treatment seven was a mix of S-Calate with Agro-Liquid base products. This modification worked well as treatment seven had the highest yields overall. In addition, the quantity of potatoes in both grade categories increased over the Agro-Liquid base (Trt #4). Data from treatments two, six and seven shows the value of adding sulfur to the blend, but “inert” ingredients can be just as important.
Research results provide some valuable insights for growers who are trying to find the right fertility program for their potatoes. Generally, the Agro-Culture Liquid Fertilizers’ programs proved to be a better option for increasing yields than the conventional fertilizer programs. To see the full research results, refer to the 2011 Research Report, Fresh market potato (Russet Norkota) soil fertility program comparisons (NCRS 11-201).