PHOSPHITE FERTILISERS What are they?
CAMPEY Turfcare has introduced the Imants Sandcat, part of a new range designed by the Dutch manufacturer to offer golf courses the sophisticated maintenance machinery already prized on sports grounds. Matched to a 30hp tractor the Sandcat pads lightly over the turf, with 21 blades of 8mm thickness penetrating the sward to 150mm deep at 150mm centres. Sand can be applied from the 800 litre hopper into the slits to improve drainage and enhance the rootzone quality. It can also be used empty to act as a mini version of Imants Shockwave decompactor.
Making your life easy - and getting beautiful results - is what our business is all about. It is also all about consumer education, and the science behind our products. Here we offer a brief primer on phosphite and how it differs from phosphate. Phosphorous (P) is an essential element for plant photosynthesis, root growth, energy storage and protein formation. The most common form of P in fertilisers is phosphate, which is a chemically stable molecule with four oxygen atoms. Because of its rock-like nature, the phosphate in traditional granular fertilisers often becomes bound in soils and is not fully available to plants. Phosphite is also a form of P, but it has one less oxygen atom than phosphate. Being “lighter” by one oxygen atom than phosphate makes a tremendous difference. Since the fully oxidized phosphate is the most stable P form in the environment, phosphite undergoes a gradual transformation after addition to the soil. Micro organisms are able to assimilate phosphite and release phosphate, gaining energy and nutrients during biological conversion. Microbes will preferentially take up phosphate for their metabolism before taking up
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JOHN Deere’s new 5R and 5RN Series utility
tractors are rated at 80, 90 and 100hp. They replace the previous 5020 Series models and include the 80hp 5080R, the 90hp 5090R and the 100hp 5100R. In addition to these standard models, narrow (RN) versions have a maximum overall width of 1.86m and are particularly designed for horticultural use, working in row widths greater than 2.50m. The new full-frame chassis design allows a 20 percent higher payload compared with the 5020 Series. They can also be optionally equipped with a front hitch, front pto and various front loader packages. All three tractors are powered by a proven 4.5-litre PowerTechE turbocharged engine, which is certified according to Tier IIIa emission requirements.
HO - P - OH I
O H
Phosphoric Acid
significant amounts of phosphite. However, due to its greater solubility it is more readily available to these microbes and plant roots than phosphate. So, phosphite is less chemically stable, and therefore more agile than its staid cousin. It also has certain benefits that phosphate never dreamed of. Phosphite is highly water soluble, and when applied to plants is quickly absorbed by leaves, roots, and branches. Once in plants, it is extremely mobile, exhibiting "symplastic ambimobility," meaning that it is uniquely able to move in both xylem and phloem (1).
to
By Chris Hollow, Agronomist with Growth Products Years of use in agricultural and
horticultural settings have shown that foliar applications of phosphite improve seedling growth, bud formation, blossoming, fruit set, and plant vigour. On golf courses, phosphite improves turf quality and promotes overall growth. Applications of phosphite to turf also significantly reduce summer stress. Interestingly, phosphite ions, unlike elemental phosphate, have fungi toxic effects on several plant pathogens (1). When PSD approved fungicides with phosphite as an active ingredient are applied to grass, the phosphite moves quickly to the turf’s crowns and roots, where it works against root rots such as pythium and phytophthora (1, 2). Note: Many phosphite fungicides and phosphite fertilisers have the same active ingredient, but only those products with a PSD fungicide label can claim any fungicidal properties or benefits. This discusses published research on phosphite, and does not make any fungicidal claims for phosphite products. Scientists find phosphites both fascinating and a fertile source of on- going debate and research. The growth- stimulating and other beneficial effects of phosphite are well-documented, even if
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HO - P - OH I
H Phosphorous Acid
Phosphoric acid (phosphate) and phosphorous acid (phosphite) comparison; in phosphorous acid, the H is bonded directly to P and is always present.
they are not fully understood (1, 2). To summarise we can say: phosphite helps fungicides work better; quickly enters through the leaves, crown and roots; highly systemic via xylem and phloem; protection throughout the whole plant including new growth; does not contribute to phosphate build-up in soils; reduces summer stress.
References: 1. Understanding Phosphonate Products, prepared by Peter Landschoot, Professor and Joshua Cook, Dept. of Crop and Soil Sciences, The Pennsylvania State University. 2. Phosphite Fertilisers: What Are They? Can You Use Them? What Can They Do?, by C.J. Lovatt and R. L. Mikkelsen. Better Crops, vol. 90 (2006, No. 4)
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