Successful fruit growers regularly monitor their crops nutrition status in order to proactively manage their crops nutrition. But where to begin ? We look at the full system of testing and explain the what is needed and why.
All the nutrients in the system must be balanced
The fruit grower must consider a system in balance, if he or she is to understand where all the nutrients are going. We will look at the full system of testing and explain at each point why it is necessary to check and what kind of problems can be experienced at each stage.
Water is often very varied from location to location. There are three main sources of water, and a fourth which is rarely used on mass. In order of most used: bore holes, rivers & streams, mains water and rain water. Rain water does supply water to rivers and indirectly mains and bore holes, however if collected it can be considered a fourth source.
Regardless of the type of initial irrigation water, a first water sample must be taken for a nutrient and pH. Your agronomist or nutrient adviser can then work out what should be applied to the water to both buffer it and feed the crops, depending on crop stage. It is essential to know the pH as most UK water is alkaline and most soft fruit programmes are acidic, by contrast most top fruit and vines are neutral to alkaline.
An agronomist or nutrient adviser can help work out your nutrition programme
Once past the fertigation shed a second water sample should be taken, this sample will tell the grower if the fertigation equipment is working correctly. The equipment is normally computer controlled though it should be checked at least once per season to be sure it is calibrated correctly. Other issues which may arise include how well blended the fertigation mixture is. Mixing Calcium with Iron can be problematic as they can react to make gloopy blobs, which block the irrigation system. Using a high quality fertiliser mitigates this issue, but awareness of the potential issue means it can be monitored and managed.
A water into bag sample is recommended to be taken more often, such as bi-weekly or monthly. At this point the irrigation water has passed through a full system of plastic pipes and valves. The pipes can, on occasion, cause issues from debris during use, contamination of cleaning products. or if new, contamination of manufacturer products. An example of this is the use of chlorine to clean through pipes after manufacture. Should chlorine enter the fertigation system it bleaches the leaf of the crop while at the same time interfere with the E.C. readings. All growers are recommended to flush the irrigation lines at regular intervals to mitigate this issue, unless the lines are just used for the one set of crops.
The fertigation water should be set up to run out of the bag to the tune of 12% of the volume going into the bag. Water out will most likely contain NPK, though more N than anything else as its highly mobile in water. It may contain Chlorine which is a sign to soil sample the bags and attempt to trace where the contaminate is getting in to the system. Water out, if measured over time with water in, will allow the grower to see how the crop is responding to the fertigation mixture and what improvements or savings can be made against the mixture for future years.
The balanced sum of all nutrients should be zero
If the grower has all the information, a calculation can be made to show that the balanced sum of the data is zero. That means all the nutrients in the system have been accounted for. As the mixture is changed from vegetative mixture to flowering mixture, the change in E.C. and water/out measurements should define the change, in addition to looking at the crop and tasting the fruit.
Yara Analyical Services are able to conduct a complete range of analyses. For more information on any of these analyses or services please click the link below