Nitrogen use efficiency has been a widely used concept in agricultural research for decades. NUE is often described as the ratio of crop yield to the amount of nitrogen fertilizer applied or taken up by the crop.
What is Nitrogen Use Efficiency?
Nitrogen use efficiency (NUE) is a term that is used to describe the efficiency of a plant in using applied or fixed nitrogen for biomass production. It is further defined as the ratio between crop yield and the amount of nitrogen absorbed from the soil through roots or from the atmosphere through fixation by bacteria.
NUE is an important trait in crop breeding programs, which aims to improve crop yield while reducing input costs, such as fertilizers, and at the same time keeping nitrogen out of the environment. Reducing fertilizer inputs would lead to fewer greenhouse gas emissions and less nitrate leaching into the groundwater and surface water.
Increasing NUE can help reduce farmers’ input costs, and increase profits. A high nitrogen use efficiency means that more of the applied nitrogen is taken up by the crop and has a positive impact on both the environment and farmersβ profits.
Furthermore, it is a measure of the amount of nitrogen (N) taken up by a crop compared to the amount applied. It is an important indicator of environmental sustainability and economic efficiency in crop production because it shows the relationship between N inputs and crop yield.
A nitrogen use efficiency of 50% means that half of the applied nitrogen remained in the crop after growth was completed.
For example, if you have 100 pounds of N fertilizer available for corn production and you apply it all at once before planting, but only 70 pounds are taken up by the crop during the growing season, your agronomic NUE is 70%. This means that 30 pounds were lost to the environment due to denitrification and leaching.
It can be expressed as either a percent (e.g., 50%) or a ratio (e.g., 1:1). In both cases, the units are equal to mass units such as pounds per acre (lb/acre), kilograms per hectare (kg/ha), or grams per square meter (g/m2).
A high agronomic NUE means that more of the N supplied to a crop is used by it β a desirable situation for profit margins, environmental concerns, and sustainability. It can be confusing to try and understand the difference between nutrient use efficiency and agronomic nitrogen use efficiency (NUE). Fundamentally, nutrient use efficiency can be defined as any measure of how well a plant utilizes nutrients.
It is a subset of this that relates to the likely increase in crop yield when additional N fertilizer is applied by farmers. The focus on crop yield is what differentiates agronomic NUE from other measures of plant nutrient uptake.
It uses the ratio of grain produced (or increase in grain production) by the amount of fertilizer applied. For example, if you apply 200 lb/acre of N and get a 50-bushel increase in corn yield, then your agronomic NUE would be: 200 lb/acre / 50 bu/acre = 4 lb grain per pound of N fertilizer applied.
It is a key parameter for describing an agroecosystemβs nitrogen (N) balance. Thus, it can be used to evaluate the sustainability of a cropping system and to guide Nitrogen management practices.
Agronomic NUE is the ratio between crop N uptake (CropNUptake) and the amount of N applied to the crop (FertilizerN + ManureN + BiologicalNfixation). It can be expressed as: AgronomicNUE = CropNUptake / FertilizerN + ManureN + BiologicalNfixation
For example, if a farmer applies 100 kg/ha of fertilizer N to a wheat crop and at harvest, 30 kg/ha of N are recovered in the grain, then AgronomicNUE = 0.30.
It provides a measure of the effectiveness of all available N inputs in producing crop yield, as well as providing a means by which to compare and contrast different N management strategies.
Agronomic NUE has been defined as the ratio of crop biomass per unit amount of applied or recovered fertilizer N or the total amount of N fixed by legumes.
Agronomic NUE = Crop biomass / Total plant-available N inputs
It is the proportion of applied fertilizer N that is recovered in the target crop. The ideal efficiency, which is rarely achieved, would be 100%, meaning that all the N applied is recovered in the crop.
The term agronomic does not refer to the farming practice but to the actual amount of N that is used by a crop. This may be less than what was actually applied or supplied and can be due to various factors such as losses through leaching or denitrification or immobilization of fertilizer N by microorganisms in the soil.
The importance of NUE
There are several reasons why nitrogen use efficiency is important in the soil. Here are some of them:
- It reduces economic losses from low yields and poor quality.
- It improves the sustainable use of natural resources.
- It reduces pollution from nitrogen fertilizer.
- Lower costs are associated with applying a lower amount of nitrogen fertilizer that is still sufficient to achieve crop-yield targets.
- Lower environmental impacts, particularly on water quality, due to reduced leaching and volatilization losses of nitrogen.
- Higher protein content in grain crops. This can increase the economic value of grain and improve the animalβs ability to convert feed into meat or milk.
How to calculate nitrogen use efficiency
NUE is calculated using the following formula:
The equation for NUE can be found by dividing grain yield by the total amount of N available to the crop.
g/ha grain yield (crop dry matter) Γ· g/ha applied N.
For example, consider a crop yielding 3.5 t/ha of wheat with a total N content of 0.24%. The measured amount of N in the grain is, therefore:
3.5 Γ 0.24% = 8.4 kg/ha.
If the crop has been supplied with 100 kg/ha of N (including soil mineralization), then the cropβs NUE is 8.4%.
How to increase the nitrogen use efficiency
Here are some ways farmers can improve it:
1. You can improve it by choosing the right type of fertilizer. Organic fertilizers are great. When these organic fertilizers are applied to the soil, they release nutrients slowly with the help of microbes present in the soil and thus enhance the NUE.
2. Using appropriate cultivation methods.
3. Planting suitable varieties.
4. Applying the right amount of fertilizer at the right time. Fertilizer should be applied before sowing or during sowing whenever possible in order not to waste crops as much as possible.
5. It can also be improved by crop rotation and cover crops. When used together, these practices can help reduce the negative environmental effects of conventional farming practices where farmers apply excess nitrogen to ensure all plants get enough nitrogen.
The traditional approach of applying adequate amounts of nitrogen is costly and inefficient. Cover crops and crop rotation can help reduce this cost by improving the NUE in your fields, which means that you will be able to produce more with less nitrogen fertilizer application.
When it comes to crop rotation, remember that not all rotations are created equal. Some rotations can decrease NUE compared to a straight corn-soybean rotation. For example, planting corn after soybeans will generally improve NUE compared to planting soybeans after corn.
Cover crops have been shown to increase NUE because they take up nitrogen from the soil; a process known as immobilization. Nitrogen immobilization is when microorganisms use organic sources of nitrogen in the soil and convert them into new living tissue (microorganisms).
The microorganisms then die and release this organic nitrogen back into the soil for plants to use. However, cover crops do require management, including proper termination methods and dates.
How can GeoPard help to increase nitrogen use efficiency?
GeoPard is a precision farming solution that provides farmers with the necessary data and information to produce crops more efficiently. GeoPard provides plant-specific insights into the yield potential of each field, and the status of nitrogen, potassium, and phosphorus in the soil. Below are ways GeoPard help to increase it:
1. They provide a full cycle of calculation (how much nitrogen is already in the soil, how much should be added, how much is left at the end of the season) and do planning for the next season.
GeoPard helps to increase NUE by providing precise recommendations on how much fertilizer to apply and when to apply it. It helps farmers reduce the amount of fertilizer that is applied without affecting crop yield. This means that farmers will spend less money on fertilizer and reduce their environmental impact at the same time.
GeoPard recommends precise amounts of fertilizer that should be applied based on soil characteristics, historical weather data (to estimate how much water will be lost to evapotranspiration), and current weather data (which can be used to predict when a good window of opportunity will appear to apply the recommended amount).
2. They make analyses based on Infographics (Data from machinery (As-applied fertilization, as-planted, Yield, Protein)
The most important aspect of GeoPard is its ability to analyze information in a user-friendly way. This system provides the data in an easily understandable fashion, allowing for better decisions in the future. The information that is gathered by GeoPard includes the following: As-applied fertilization, as-planted, yield, and protein.
This information is gathered using machinery and using a simple process, providing the farmer with all of the most important data in one place. The data can then be used to help make important decisions about what needs to be done to improve nitrogen use efficiency on their farm.
3. They provide analytics (Equations to calculate N uptake on each sq m)
One of the main benefits of the GeoPard Crop Management System is that it provides growers with an effective tool for understanding and analyzing crop growth. The GeoPard Crop Management System uses advanced analytics to help growers with their NUE.
The system provides analytics for each square meter, which enables growers to understand the required amount of nitrogen needed for each area. By using this information, growers can avoid over-fertilization and save money by minimizing their fertilizer costs.
Analytics are provided in a simple form: equations that tell you how much nitrogen you need on each square meter.
4. They create Agronomic Planning for the next season based on accurate data and GeoPard modeling
GeoPard provides you with vital information about each part of the field and maps out areas where nitrogen is needed most. Based on this information, growers can plan the number of fertilizers to be applied in particular parts of the field, which saves time, money, and resources.
It is the ratio of crop nitrogen uptake to the amount of nitrogen applied. It is a major determinant of crop productivity and profitability, and an important indicator of sustainable agricultural practices.
The less amount of nitrogen that is used by a crop the more efficient it can be considered to be. Furthermore, the NUE is affected by many factors including soil properties, management practices, and environmental conditions.
Frequently Asked Questions
1. What are the benefits of increasing nitrogen use efficiency?
Increasing it brings several benefits. It enhances crop productivity, reduces environmental impact, saves costs, and promotes sustainable agriculture.
Efficient nitrogen use ensures optimal plant growth, minimizes nitrogen runoff and greenhouse gas emissions, lowers input expenses, and supports long-term soil fertility. By prioritizing it, farmers can achieve better yields, protect the environment, save money, and contribute to sustainable farming practices.
2. How much fertilizer per square meter?
The amount of fertilizer per square meter varies depending on the crop, soil conditions, and nutrient requirements. It is best to conduct a soil test to determine the specific fertilizer recommendations for optimal plant growth. Soil testing provides accurate information to determine the correct amount of fertilizer to apply per square meter, ensuring efficient nutrient supply for the plants.
3. What are two strategies for increasing nitrogen use efficiency?
There are two effective strategies for increasing NUE:
- Split Application: Splitting the nitrogen fertilizer application into multiple doses throughout the growing season allows for better synchronization between plant demand and nutrient availability. This approach minimizes nitrogen losses and ensures that plants receive nitrogen when they need it most.
- Enhanced Nutrient Management: Implementing precision nutrient management practices, such as using site-specific application techniques and adjusting fertilizer rates based on soil and plant needs, can significantly improve it. By tailoring nutrient inputs to specific areas or zones within a field, farmers can optimize fertilizer usage and minimize nutrient wastage.
These strategies contribute to maximizing the effectiveness of nitrogen fertilizers, reducing environmental impacts, and improving crop performance while maintaining sustainable agricultural practices.
4. Which crop is the most efficient user of nitrogen?
Among various crops, legumes are considered the most efficient users of nitrogen. Leguminous crops, such as soybeans, peas, and lentils, have the unique ability to form a symbiotic relationship with nitrogen-fixing bacteria in their root nodules.
This enables them to acquire nitrogen directly from the atmosphere, reducing their dependence on external nitrogen sources like fertilizers. As a result, legumes have a higher nitrogen use efficiency and can contribute nitrogen to the soil, benefitting subsequent crops in a rotation system.
5. How much nitrogen does wheat need per acre?
The nitrogen requirements of wheat per acre vary depending on several factors, including soil fertility, environmental conditions, and the specific growth stage of the wheat crop. On average, wheat typically requires approximately 100 to 150 pounds of nitrogen per acre.
6. How much water does wheat need per acre?
The water requirements of wheat per acre depend on various factors, including climate, soil type, and growth stage of the crop. On average, wheat requires approximately 20 to 30 inches of water throughout its growing season. However, it is essential to consider the specific water needs of the wheat variety being grown and to monitor soil moisture levels regularly.
7. How much fertilizer per acre for wheat?
As a general guideline, wheat crops typically require around 100 to 150 pounds of nitrogen per acre. Phosphorus and potassium requirements vary depending on soil test results, but a common recommendation is to apply approximately 50 to 80 pounds of phosphorus and 40 to 60 pounds of potassium per acre.
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