Increasing Yield & Fruit Size in Oranges with Potassium

Introduction

Many factors influence the availability of potassium in the soil. Helena supplies a number of products designed to increase the availability of potassium in the soil. Hydra-Hume is a nutrient efficiency tool that chemically binds with K and other nutrients. This significantly reduces the amount of K lost to fixation or other competitive interactions. Helena's line of Nucleus products with potassium includes liquid formulations with ingredients specifically aimed at holding K in an available form. They also increase the exchangeable K in the soil solution to increase uptake by plant root systems.

Trial Design

In 2012 a two year trial was initiated to study the effects of different sources of potassium on Washington navel oranges. One treatment consisted of a broadcast application of 300 lbs per acre of potassium sulfate 0-0-50 (SOP). SOP was applied alone in one treatment and blended with 40 lbs per acre of Hydra-Hume DG Coated in another. These treatments were applied in early April, before flowering and before the spring growth flush in the orange trees. Additional treatments of KTS 0-0-25 and Nucleus 0-0-21 went on through the drip system in mid-May and mid-June. All of the trees received the industry standard nitrogen applications.

Trial Results

The oranges were harvested in early February 2013. The addition of 40 lbs/acre of Hydra-Hume DG Coated to the SOP treatment of 300 lbs/acre (150 lbs of K2O/acre) increased the yield of fruit by 30%.

Both Nucleus 0-0-21 treatments provided higher yields of oranges compared with KTS. This was even though the rates of potassium applied as Nucleus 0-0-21 were much lower than the amount of K applied as KTS.

Nucleus 0-0-21 also promoted larger size fruit (data not shown). Larger fruit brings higher prices in the marketplace. In addition, potassium has been shown to enhance the color and flavor of fruit. Nucleus 0-0-21 can greatly increase the value of the crop and the returns to the grower.

Conclusion

Potassium fertilizer applications should be based on recommendations from soil test results. Your Helena Agronomist can help you interpret soil test results and recommend the appropriate fertilizer and rate for your crops. The addition of Hydra-Hume to either liquid or dry fertilizers can greatly enhance the performance of these applications.

Nucleus 0-0-21 can be applied in the irrigation water at any time during the season. Crop stages, such as fruit sizing or ripening, can set up a demand for K that is greater than the soil can supply. Applications of Nucleus potassium fertilizers can help to fill the elevated K demand at these critical stages. The results are greater yields and higher quality fruit.

Contact your Helena Product Manager for additional information on how Hydra-Hume and Nucleus products can be used to improve the benefit of potassium applications on your crops.

- Kevin Dickinson, CPAg, Helena Technical Service Manager

KTS is a registered trademark of Tessenderlo Kerley, Inc. Nucleus and Hydra-Hume are registered trademarks of Helena Holding Company. To comply with varying state regulations, Hydra-Hume may be registered for specific purposes in certain states.