Maintaining soil fertility on a farm is the key to superior crop growth, success, and yield.
Nitrogen is the most important nutrient that is added through fertilizers. The crucial question to ask is – how much should be added?
Finding the right amount of fertilizers to add begins with the correct soil testing technique, which can be done by resorting to drone imagery analysis of crop growth.
Soil fertility varies within a farm
Soil is not uniform. It differs between regions and between farms. Furthermore, any experienced farmer knows that there are also differences within a farm or any small plot of land.
Soil fertility is not just a result of soil types, salinity issues, and topography. Chemical and biological reactions also matter. Quantities of organic matter in the soil and thriving populations of soil microbes, earthworms, and small insects are also necessary to keep the land healthy.
So, when a farmer adds the same amount of fertilizers over their entire farms, they end up duplicating the old patterns of growth. The yield from the farm is not maximized, as nutrients are not spread effectively and do not bring the whole farm to the correct level of soil fertility.
How much nitrogen?
Of all nutrients added, nitrogen is the most important one. It is present in many essential plant compounds, such as genes, chlorophyll, proteins, enzymes, and hormones. The nutrient keeps the leaves green to produce food through photosynthesis and controls many other functions in plants.
Nitrogen deficiency in plants results in reduced crop growth and yield. On the other hand, when there is too much nitrogen, plants try to break it down by using their reserves. As a result, plants become tall but weak, roots get smaller, and flowering and fruiting are delayed. Also, when excessive fertilizers are added, their concentration in the runoff is very high.
Therefore, soil testing has been one of the standard procedures in farming. Farmers test their soil to decide how much fertilizer and manure they need to apply for their crop.
What farmers need
While any field soil testing is better than following blanket recommendations for fertilization for a region, the current practices are not good enough. Farmers still struggle with the fact that they get less than the optimum yield, even though they are using the recommended amounts of fertilizers.
If the farmers had a better idea of the soil differences in their farm, it would help them create a variable prescription map for fertilization for the next crop rotation. They would be able to apply the exact amounts of fertilizers where needed.
It is not possible to apply varying amounts of fertilizers following the traditional soil sampling method, where the whole farm is treated as a homogeneous area with similar fertility.
Following new suggestions, farmers have started to divide large fields into zones, varying from one to 20 acres, to get a more detailed soil map. Around 10-15 soil samples are taken from each zone and an average is calculated, to evaluate soil fertility within it.
However, the division of farms into various zones is random. In some cases, the farm is divided into grids with regularly spaced horizontal and vertical lines, and once again the soil conditions are assumed to be uniform within each grid.
In such sampling methods, soils within each zone can have large differences in fertility. Not only is this tedious and time consuming, but it provides no useful information in creating a variable prescription map for fertilization.
Hence, farmers need a reliable method of analysis to identify zones that are both accurate and swift.
Zoning based on plant growth
A more effective way to identify zones for soil sampling is to use crop growth. This is called directed sampling and it is the method used by Agremo.
Agremo provides software that is customized for zonal nitrogen analysis. Our solutions are based on precision farming methods, where drone imagery is analyzed to get a picture of the variations on a farm.
Pictures of the crop are taken when it is growing. Plant Vigor analysis categorizes the growth into four zones of vegetation:
- Excellent
- Good
- Poor
- No vegetation
Farmers can now take 10-15 soil cores within each of these four zones instead of several random areas. Each zone can consist of patches scattered in the field and be of various shapes and sizes. Software assigns a color to each zone and calculates the total area for each of them.
This kind of zoning is impossible for any farmer to achieve by normal scouting.
The averages for each zone are now meaningful, as each represents uniform soil conditions that are reflected by a similar growth of the standing crop.
The immediate benefit of nitrogen analysis is that the number of zones on a farm can be reduced. This makes soil testing faster and more economical than the traditional or grid zoning method.
How to use Plant Vigor analysis?
To be able to benefit from Plant Vigor Analysis, a farmer needs to follow three steps:
- Get images: High-resolution photos of the farm are required. Farmers can choose to use the services of drone operators in their area or invest in a drone and take the pictures themselves, as the procedure is quite straightforward – simply take several pictures of different parts of the farm with the help of the camera mounted on the drone.
- Stitch photos: The photos from the drones can be “stitched together” to give a seamless map of the whole farm. There are several online software providers, such as DroneDeploy, that can stitch farm images.
- Software analysis: Once the map is ready, upload it to the Agremo website. Choose Nitrogen Analysis and define your crop and its growth stage. You will receive the report within 48 hours. It will include the photo of the analyzed map, showing the four zones clearly demarcated, and an accompanying written document that provides details on the area under each zone in acres and percentages (of the total farm).
- Sampling map: Based on vegetation analysis soil samples will be taken across the designated zones on certain spots and in a determined number. With the sample insights, a highly accurate fertilization map can be created.
A farmer can easily understand and use the information, without the need for any further analysis on their part. Each report is also scrutinized by agronomists before sending, so it has the stamp of approval from an expert!
The Agremo analysis is based on algorithms developed by analyzing thousands of acres. It is based on several vegetation indices, going beyond the Normalized Difference Vegetation Index (NDVI), which takes into consideration the differences in structure, color, and growth stage of a crop. Even spectral data that tell us about internal plant characteristics specific to each crop are used. This means that weeds are not calculated while categorizing the crop.
Agremo has customized analysis for over 100 species and can cover crops ranging from grains and vegetables to perennial fruit trees.
Benefits of directed zonal soil sampling
Up until recently, because farmers lacked precise information, they were not making efficient use of their fertilizers, money, and time.
By using Agremo Plant Vigor Analysis, a farmer can optimize:
- Quantities: They can decide how much fertilizers to apply to each zone to build soil fertility and maintain them at optimum levels. Excellent vegetation zones can get less, while good, poor, to no vegetation zones,can benefit from increased amounts of nutrients in the current and succeeding crop cycles.
- Location: The farmer knows which areas need more and which portions of the farm need less fertilizers.
- Inputs’ use: By using the correct amounts of fertilizers at the right location, farmers reduce the cost of:
- Fertilizer, as they use less of it
- fuel and mechanization involved in using tractors and applicators
- Yields: By providing nutrients where they are needed, farmers prevent potential plant stress caused by malnutrition. As a result, farmers can expect a greater yield.
- Profit margins: Farmers can expect to get higher returns on investment (ROI) for two reasons:
- By decreasing inputs, they are cutting costs.
- By improving yields, they invest less time and earn more from the same area of the farm.
In addition to the personal benefits a farmer gets from nitrogen analysis, there are some environmental advantages which result from optimized nitrogen fertilizer use.
- Minimized nutrient wastage: Excessive amounts of fertilizers are among the main causes of nutrient waste. The plants can’t use them quickly, nor can the soil microflora break them down. A major portion of the nitrogen is washed away by runoff and often ends up in ponds and seas where it causes eutrophication or leaches into the soil. By reducing fertilizers, water and soil pollution is reduced.
- Fewer carbon emissions: There are fewer emissions of nitrous oxide, a greenhouse gas that is 300 times stronger than carbon dioxide in producing climate change effects. It is emitted during the manufacture of nitrogenous chemicals, and breakdown of unused nitrogen fertilizers.
Getting more out of less
Many Agremo users come back regularly for additional nitrogen analysis. Scientists recommend an annual check of soils, as nutrient use differs based on the crops. The soil fertility zoning should be done at least once in three years. After all, reducing the use of fertilizers is one of the main interests behind the use of sustainable precision farming methods, intended to help feed ever-growing populations with our limited resources.
Read here how you can make the prescription maps for spraying with the Plant Vigor analysis.
