Publication 360, Fruit Production Recommendations: Phosphorus

Excerpt from Publication 360, Fruit Production Recommendations, 2010-11
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Table of Contents

1. Introduction
2. Phosphorus in the environment
3. Sources of phosphorus
   • Mineral fertilizers
     • Table 3-10b. Fertilizer Materials: Primary Nutrients - Phosphates (PDF 73 kb)
   • Manure
     • Table 3-11. Average Fertilizer Replacement Values for Different Types of Manure (PDF 75 kb)
4. Phosphorus application methods
5. Phosphorus recommendations
• Table 3-13. Phosphorus Requirements for Berries, Tree Fruits and Grapes (PDF 73 kb)
6. Other topics in Soil Management, Fertilizer Use, Crop Nutrition and Cover Crops
   • Assessing Nutrient Needs
   • Soil Organic Matter
   • Soil pH and Liming
   • Nitrogen
   • Potassium
   • Calcium
   • Magnesium
   • Micronutrients
   • Cover Crops
7. Ch. 3, Soil Management, Fertilizer Use, Crop Nutrition & Cover Crops - PDF 189 kb
8. Related Links

Introduction

Like nitrogen, phosphorus is important to photosynthesis and the development of enzymes and protein. It also plays a major role in cell division and the creation and transport of sugars and starches.

Soil phosphorus levels across Ontario are variable. Because phosphorus tends to bind to soil particles, leaching through the soil profile is minimal. Many coarse sandy-loam soils often contain high phosphorus levels. Soils with a history of regular manure applications have high levels of phosphorus, and fruit crop yield will rarely respond to additional phosphorus fertilizer. Too much phosphorus can induce deficiencies of zinc and iron.

Phosphorus deficiency symptoms usually develop on the older leaves first. The leaves develop a purplish-red colour that may be more noticeable on the underside of the leaves. Severe deficiencies may also cause the leaf tips to die back. Cool, wet soil conditions often induce phosphorus deficiencies. During establishment of early-planted fruit crops, use a starter fertilizer to deliver the required phosphorus directly to the root zone.

Phosphorus in the environment

Surface runoff is the main route by which phosphorus leaves the field and contaminates the environment. It can be transported in solution with runoff water or through its attachment to eroded soil particles. When this water reaches open surface water, streams can become polluted.

Avoid additional phosphorus applications to soils that are rated Rare Response (RR) or No Response (NR). If phosphorus is required to promote early season growth, use low rates applied in a band close to the roots or as a starter fertilizer.

Farmers who are required to complete a nutrient management plan must establish a permanent vegetated buffer adjacent to any surface water, with a minimum width of 3 m, prior to any nutrient application. This practice is highly recommended even in situations where it is not a requirement. The grass will help reduce erosion and act as a natural filter for runoff entering the watercourse.

Where phosphorus soil tests are greater than 30 ppm, use the phosphorus index to determine separation distances from surface water sources. The phosphorus index uses five factors, which include field slope, length of slope, soil drainage class and soil texture, to determine an appropriate rate and separation distance for phosphorus application from surface water.

For details, see OMAFRA Factsheet, Determining the Phosphorus Index for a Field, Order No. 05-067.

Sources of phosphorus

Mineral fertilizers

The most common phosphate fertilizer sources are outlined in Table 3-10. Fertilizer Materials: Primary Nutrients.

Table 3-10b. Fertilizer Materials: Primary Nutrients (Phosphorus) (PDF 73 kb)

See also:

• Fertilizer Materials: Nitrogen
• Fertilizer Materials: Potassium

Manure

When properly applied, manure is an excellent, inexpensive phosphorus source. It also supplies the soil with valuable organic matter and micronutrients. Table 3-11. Average Fertilizer Replacement Values for Different Types of Manure, below, provides the approximate amount of crop-available phosphorus contained in manure.

Table 3-11. Average Fertilizer Replacement Values for Different Types of Manure (PDF 75 kb)

Nutrient values based on average analysis results for over 3,000 samples.There are large variations between manures, so a manure analysis is your best guide to nutrient availability.¹

Table 3-11a. Liquid Manure

Table 3-11b. Solid Manure

¹ Data from manure analysis provided from Ontario Labs collected between 1992 and 2007.
² Nitrogen based on spring application, incorporated within 24 hr. Unincorporated manure will have less N due to ammonia losses.
³ Phosphate from manure or biosolids is assumed to be 40% as available in the year of application as that in commercial fertilizer (another 40% of the phosphorus is available the following year).
⁴ Potassium from manure is assumed to be 90% as available in the year of application as that in commercial fertilizer.

Unlike nitrogen, the phosphorus in manure becomes available to crops over a considerable period of time. Regular manure applications may result in a buildup of soil phosphorus, which should be monitored with a soil-testing program.

Manure can pose a food safety risk on many fruit crops. Ensure at least 120 days between manure application and harvest.

Phosphorus application methods

Phosphorus is not mobile in the soil, therefore broadcasting and incorporating any required phosphorus prior to planting perennial fruit crops is crucial. Some phosphorus is often applied in a band or in transplant solution at planting to ensure good vigour of new plantings. On established perennial crops, it can be broadcast on the surface or banded near the roots. Do not rely on fertigation for phosphorus application.

Phosphorus recommendations

Use a soil test from an OMAFRA-accredited lab in conjunction with Table 3-13. Phosphorus Requirements for Berries, Tree Fruits and Grapes,below.

For crop specific details see:

• Apple Nutrition
• Berry Crop Nutrition
• Grape Nutrition
• Tender Fruit Nutrition

Table 3-13. Phosphorus Requirements for Berries, Tree Fruits and Grapes (PDF 73 kb)
Phosphate (P₂0₅) required (kg/ha)

Probabilities of profitable crop response to applied nutrient: HR = high probability, MR = medium probability, LR = low probability, RR = rare response, NR = no response
* 0.5 M sodium bicarbonate extract
† For established tree fruits and grapes, plant analysis is used to estimate requirements.

Related Links

• OMAFRA Publication 611, Soil Fertility Handbook
• Soil Management
• Soil Fertility & Crop Nutrition
• Soil Water Management
• Best Management Practices: Soil Management
• Cover Crops
• OMAFRA Publication 505: Ontario Weeds
• OMAFRA Publication 75: Guide To Weed Control