Understanding Nutrient Use Efficiency

Nutrient Use Efficiency (NUE) is a key concept in modern agriculture, denoting the plant’s capacity to effectively use fertilizer nutrients for growth. Discussions on NUE often focus on nitrogen, while phosphorus and potassium efficiencies are known as PUE and KUE. Improving NUE is critical for sustainable crop production, as it increases agricultural productivity and reduces ecological impact. Fertilizers are substantial agricultural inputs. Enhancing NUE allows for optimized fertilizer use, higher yields, and maintained soil fertility, contributing to more resilient farming systems. Sustainable practices like precision farming, cover cropping, and crop rotation boost NUE through enhanced natural nutrient cycling and reduced losses, leading to better economic, social, and environmental outcomes in agriculture. Ultimately, NUE measures the proportion of applied nutrients effectively used by plants for growth processes, against the total applied.

Calculating Nutrient Use Efficiency

Calculating nutrient use efficiency (NUE) is essential for improvement. Cristian Terrones, a Sustainability Specialist with eight years at ICL’s Agronomy Team, specializes in NUE. His role involves aiding farmers to meet sustainability objectives with the right tools. Terrones notes that NUE is pivotal for enhancing biodiversity, as it measures crop nutrient utilization. It’s assessed by plant nutrient uptake or the yield per nutrient unit added. NUE can be expressed as agronomic efficiency (AE), physiological efficiency (PE), or apparent recovery efficiency (ARE), which consider yields against fertilizer application, nutrient uptake, and fertilizer recovery, respectively. These metrics are adjusted for soil and irrigation nutrients, making them ideal for research rather than practical farming. A more user-friendly metric is Partial Factor Productivity (PFP), akin to AE but without the need for such corrections.

Nutrient Efficiency Ratio

The Nutrient Efficiency Ratio (NER) is a metric for gauging crop nutrient use by considering how various nutrients interact and their balance affects growth. It’s calculated by dividing the plant’s dry matter yield by the total uptake of nutrients like nitrogen, phosphorus, and potassium. A higher NER indicates more efficient nutrient use for biomass, while a lower NER points to possible nutrient deficiencies. NER helps evaluate and improve nutrient management in crops.

Factors Influencing Nutrient Use Efficiency

Nutrient use efficiency is affected by factors including soil properties, climate, plant genetics, and farming techniques. Soil characteristics like pH and texture influence nutrient accessibility, with acidic conditions reducing phosphorus and alkaline conditions limiting micronutrients. Soil compaction can also hinder nutrient absorption. Weather elements such as temperature and moisture play roles in plant growth and nutrient loss, while genetic differences among crops dictate their nutrient needs and uptake efficiencies.

Strategies for Enhancing Nutrient Use Efficiency in Plants

Given the significance of nutrient use efficiency, agronomists and farmers seek ways to enhance it on their lands. There are several methods for improving nitrogen use efficiency:

• Optimizing fertilizer application rates involves applying the appropriate amount of fertilizer in accordance with crop requirements, considering factors such as soil type, crop type, and expected yield. Soil tests, plant tissue tests, or predictive models can help estimate crop needs and adjust fertilizer rates accordingly.
• Precision fertilization techniques entail applying fertilizers to match crop demand and minimize losses, such as through banding or side-dressing near the crop’s roots. This reduces nutrient losses through volatilization or leaching and enhances fertilizer efficiency. Enhanced Efficiency Fertilizers (EEF), like Controlled Release Fertilizers (CRF), offer high efficiency by simultaneously reducing all losses.
• Conservation tillage practices, such as reduced tillage or no-till farming, can improve nitrogen use efficiency by reducing soil disturbance, promoting organic matter accumulation, and enhancing soil structure. These benefits boost soil water-holding capacity, nutrient cycling, and crop growth.
• Incorporating cover crops into rotations helps enhance nitrogen use efficiency by increasing nitrogen fixation, reducing soil erosion, and improving soil health. Cover crops capture residual nitrogen, preventing its loss through leaching or runoff while also enhancing soil structure and nutrient availability for subsequent crops.

In conclusion, nutrient use efficiency depends on multiple factors, necessitating a holistic approach that considers soil, plant, weather, and management practices.

ICL Innovation for Nutrient Use Efficiency

Continual research in optimizing nutrient utilization is essential for assisting farmers in enhancing their agricultural practices. Through research, novel technologies and practices can be discovered to maximize nitrogen use efficiency while mitigating environmental consequences. ICL takes pride in leading efforts to uncover innovative products that enhance NUE and contribute to sustaining a healthy global environment for everyone. Through innovative and sustainable products such as biostimulants,controlled-release fertilizers, and water-soluble fertilizers, ICL empowers farmers to enhance the nutrient use efficiency in crops.

Biostimulants

Biostimulants stimulate soil activity, increasing the availability of nutrients for crops. This proves especially valuable in conditions where heat, drought, or disease stress restrict nutrient uptake by plant roots. By stimulating soil microbial activity and promoting root growth and development, biostimulants increase root surface area, enabling plants to access more nutrients. ICL biostimulants have demonstrated the capacity to increase crop yields, improve crop quality, and cope with environmental stresses. They can be used in conjunction with conventional fertilizers or other crop protection products, offering farmers a versatile tool to optimize crop growth sustainably.

Controlled Release Fertilizers

Controlled-release fertilizers (CRFs) proficiently supply nutrients to plants, gradually releasing them over an extended period. In contrast to traditional fertilizers, which dissolve rapidly post-application and necessitate several applications, CRFs mitigate nutrient loss to the environment and enhance nutrient use efficacy. Matching the nutrient delivery of CRFs with the requirements of crops facilitates optimal growth while minimizing nutrient leaching, volatilization, denitrification, and run-off. Moreover, CRFs can sustain or increase crop yields with less total nutrient inputs, presenting a vital alternative in areas where nitrogen inputs are regulated. In a trial on seed potatoes, the application of Agromaster Coated N treatment resulted in a 12% additional yield per unit of nutrient applied and a 14% superior return on investment. A pot experiment with red beetroot, executed by NMI b.v. (Nitrogen Management Institute, The Netherlands) in 2021, monitored the NH₃ and N₂O emissions, and total N leached from application of conventional urea and CRF. Overall, when using conventional urea, 40-50% of N applied was lost to the environment. By using CRFs, N losses were limited to only 15% of the total N applied. CRF reduced N leaching by up to 60%, NH₃ volatilization by up to 60% and N₂O emissions by more than 10%. Less N losses lead to higher NUE and, therefore, higher yields. In this trial, CRFs improved NUE by more than 80% and increased yield by more than 30% as compared with urea. These studies, among numerous others, underscore the tangible advantages of controlled-release fertilizers in optimizing nutrient use efficiency across various crops.

Water Soluble Fertilizers (WSF)

ICL has developed a wide range of WSF for fertigation systems. WSF improves nutrient availability and reduces losses. Fertigation increases enormously nutrient use efficiency. Irrigation systems deliver nutrients directly to plant roots to ensure crops benefit from targeted, precise nutrient doses that meet crops’ needs while minimizing nutrient losses through leaching or runoff, reducing fertilizer waste, and maximizing uptake.