Now that we are into the full swing of citrus harvest…let’s talk citrus crop nutrition
The 2022 citrus harvest is underway with many growers eager to have their fruit picked before more chilly weather. There have been several nights of temperatures dropping as low as 28 degrees in many parts of the Central Valley. It seems that there is a lot of smaller fruit this year, but larger-sized fruit is desired and getting the better prices at the moment.
The environmental weather conditions during bloom, cell division and cell expansion have a great role in quality fruit which is beyond our control. Our job is to anticipate and react with these conditions with essential nutrient elements to best meet or slightly exceed crop demand. Supplying citrus trees with the right amount of nutrition is critical to prepare the tree for getting optimum quality fruit. Did you take a fall tissue analysis? This analysis is both a snapshot of what has happened, as well as what we can anticipate to happen come springtime.
The goal of balanced nutrition is one of the most important factors that affect quality, set, size and yield, and storage potential of citrus fruit. A solid citrus crop fertilizer program that provides all essential nutrients when the crop demands them is critical.
Winter Pre-bloom Fertilizer Applications
From about mid-December to mid-February is the best time to apply foliar nitrogen to citrus. Foliar applications of lo-bi urea made during this time have been shown to increase fruit set, ultimately yield. Based on Dr. Carol Lovett’s research, just 0.35 lb N/tree has been shown to increase yield (set and size) in mature navel orange trees.
A combination of lo-bi urea and other essential nutrients and crop protection products applied via foliar can be more effective than just applying a single nutrient. Remember the ‘Law of the Minimum”. Elements in least supply dictate success rather than those in greatest supply. This is a great way to get ahead and stay ahead of any deficiencies that might be present and also to boost tree health before flowering. There are several nutrients that are critical during the citrus growing season, but especially early on. Getting the trees off to a strong start with lo-bi urea and a balanced foliar product.
Magnesium is needed for many processes in the citrus tree, particularly chlorophyll production. Magnesium applications have been proven to increase yield in trials with navel oranges. Magnesium deficiency is sometimes referred to as “bronzing”. Carbohydrate production is strongly linked to optimum photosynthesis.
Copper acts as a catalyst in photosynthesis and respiration. It affects protein production and pollen viability. Deficiencies in citrus cause limb die-back and bark gumming. A catalyst improves a reaction/process rate, duration and intensity.
Manganese supports photosynthesis, enzyme activation, and plant protein metabolism. Deficiencies in citrus cause mottled leaf. This chlorosis will decrease optimum photosynthesis.
Zinc is another catalyst element in many of the enzyme and hormone systems used for protein synthesis and carbohydrate metabolism. Deficiencies in citrus cause chlorotic mottling of leaf and reduced leaf size and stunted shoot growth (rosetting).
How to Supply These NutrientsHere are some of the options for supplying these nutrients through foliar nutrition.
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Contact your local Yara representative to find a distributor near you.
Vanessa Vicencio
Sales Agronomist at Yara North America - South Central Valley, California
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