- Fertigation is the application of fertilisers in irrigation water.
- Trickle tape (drip tape), sprinkler and boom irrigation systems may be used.
- Trickle tape avoids risks of crop damage due to nutrient deposition on foliage.
- Some nutrients are more suitable for fertigation than others:
- nitrogen may be applied in fertigation provided that the required amount has been applied by the onset of bulking
- potassium may be applied in fertigation
- phosphorus should be incorporated into soil
- micro-nutrients should be applied as foliar sprays
Incorporation or placement of fertiliser
- In general, fertilisers should be evenly distributed in soil and not concentrated in ridges. More …
- Placement of fertilisers such as potassium and nitrogen can be damaging if there is a high concentration of salts close to developing sprouts, stolons and tubers (see below).
- Phosphate has very low mobility in soil but is important for root growth and may influence the number of tubers produced.
- Placement of phosphate may therefore be of some benefit if:
- competition with other nutrients restricts availability
- there is little available water early in the season, e.g. unirrigated sands
- there is poor soil structure which may restrict root growth
- there may be mechanical damage to roots, e.g. by nematodes
- More …
Influence of soil pH
- Soil pH influences the availability of nutrients.
- A suitable pH range for growth of potatoes is suggested to be about 5.3 – 6.0 (University of Maine).
- Higher pH increases the risk of common scab.
Potash Development Association (2011), Leaflet 24.
Notes on application of nutrients
Nutrition 2021 (Includes timing of nutrient applications in relation to crop physiology)
Phosphorus update 2018 (Placement may be beneficial in some situations)
Fertiliser placement 2010 (Placement may have an advantage if sub-optimal rates are applied or if availability in soil is restricted)
Fertigation 2007 (Sufficient concentrations of nutrients must be available at the appropriate time)
Fertiliser placement 1996 (High concentrations of salts should be avoided)
Nutrients in slurry 1996 (Tests of nutrients in slurry)
Palintest soil analysis 1996 (Soil test kit shown to be difficult to use in practice)
Organic manures 1995 (Availability of nitrogen in different types of manure)
Palintest soil analysis 1995 (Principles of a DIY soil test kit)