Site-specific nutrient recommendations

Generating effective fertilizer recommendations is arguably the single most important task for an oil palm agronomist. This is because fertilizers form one of the biggest cost factors in an oil palm plantation, and at the same time nutrient deficiency is often the most important yield-inhibiting factor that can be affected by plantation managers.
It is clear that rough “blanket” approaches to fertilizer application, where the same fertilizer doses are applied to large portions of the plantation, are neither agronomically nor economically effective. On the other hand, every agronomist knows that generating site-specific detailed fertilizer recommendations is typically a difficult and time-consuming task. In many cases it is very important to take into account site-specific knowledge and personal experience from previous years when creating fertilizer recommendations. At the same time it is obvious that at least conceptually a block’s fertilizer requirements should be calculable from measurable parameters including site specific details like soil type and topography, environmental parameters and limitations as well as measurements of plant and soil nutrients. Various scientific studies over the years have uncovered statistically significant correlations that can be used to derive fertilizer requirement indicators, and I believe this type of scientific approach to fertilizer recommendations will only become more important in the future.

A data-driven approach to generating nutrition programmes

The key to generating block-specific fertilizer recommendations using a scientific approach as outlined above is of course the availability of the relevant background data. In this respect OMP users are at a unique advantage as the OMP database already includes a huge amount of information that can flow into the generation of fertilizer recommendations. The logical next step is therefore the inclusion of a tool into the OMP-AMIS software suite which can be used to generate fertilizer recommendations based on the available OMP data. In the shape of the OMP Fertilizer Planner, Agrisoft Systems have now begun developing exactly such a tool, which will be described in more detail in the following. In this development project we are collaborating closely with Tropical Crop Consultants Ltd., led by the well-known agronomist Dr. Thomas Fairhurst.
The OMP Fertilizer Planner Add-In will help users in creating planning fertilizer application in two largely distinct steps. In the first step, the application will generate nutrient recommendations for each block and nutrient using scientific criteria evaluated on the OMP agronomic data set. In the second step, the application will run an optimization routine to find the least costly combination of fertilizers that can be used to fulfill these nutrient recommendations. The program is explicitly designed to give users the option to work with and compare various different recommendation scenarios, making it possible to evaluate different options before deciding on the final fertilizer recommendation for the coming year.

Support for site-specific nutrient rules

Although some scientific relationships between plant tissue nutrient levels and potential yield response have recently emerged which seem to have quite broad applicability, these general rules must of course be supplemented with site-specific criteria to obtain truly realistic recommendations. To handle this, OMP Fertilizer Planner will give the user very extensive possibilities to edit and customize the assumptions and settings used in the generation of the nutrient and fertilizer recommendations. As a case in point, users will be able to define various possible doses for each relevant nutrient as well as a set of rules for when each dose should be applied. Sets of rules and doses can be saved for re-use in different scenarios, so that users will be able to quickly generate and compare several scenarios that have the same general underlying logic but differ slightly in the specific dosages and application rules. With regards to fertilizer recommendations, users will be able to enter location-specific information such as the fertilizer purchasing, transportation and application costs as well as various other settings including minimum amounts of fertilizer to apply and rounding of fertilizer doses.

Reviewing and editing recommendations

Owing to the enormous costs and importance associated with fertilizer applications, we strongly recommend that all recommendations generated by a computer algorithm should be reviewed and double-checked by agronomists before being applied in the field. Of course this applies also to the recommendations generated by the OMP Fertilizer Planner. To help with this, the program will include a variety of data analysis forms, reports and charts to show relevant information such as averaged nutrient and fertilizer recommendation rates by division, field, tree age etc. Based on this information, users should evaluate whether the current recommendations make sense or whether the assumptions used need to be reviewed and edited. Besides changing the underlying scenario assumptions, users will also have the option of manually editing recommendations for single blocks or groups of blocks, giving them full control over the resulting fertilizer recommendations.
In connection with the reviewing of recommendations mentioned above, it will be possible to flag blocks for particular attention depending on criteria defined by the user. This tool can be used to quickly highlight blocks which display certain characteristics that suggest that an agronomist should take a closer look before the program’s recommendations are blindly applied. Examples of such criteria could be wildly fluctuating yield gaps over the previous years, unrealistically high or low leaf nutrient levels, severe erosion scores or insufficient pruning.

We believe that with the features roughly outlined above the OMP Fertilizer Planner will prove to be a great addition to the OMP-AMIS software suite and will turn into an important tool for agronomists looking to generate effective site-specific nutrient and fertilizer recommendations.

First published September 2014