4R Nutrient Stewardship Research Articles

Effects of urea topdressing time on yield, nitrogen utilization, and quality of mechanical direct-seeding hybrid indica rice under slow-mixed fertilizer base application.

The use of controlled-release nitrogen (N) fertilizers has been shown to improve yield and N-use efficiency (NUE) in mechanical transplanted rice. However, the fertilizer requirements for mechanical direct-seeding rice differ from those for mechanical transplanted rice. The effects of controlled-release fertilizers on yield, NUE, and quality in mechanical direct-seeding rice are still unknown. Hybrid indica rice varieties Yixiangyou 2115 and Fyou 498 were used as test materials, and slow-mixed N fertilizer (120kg hm-2) as a base (N1), N1+urea-N (30kg hm-2) once as a base (N2), N1+urea-N (30kg hm-2) topdressing at the tillering stage (N3), N1+urea-N (30kg hm-2) topdressing at the booting stage (N4) four N fertilizer management to study their impact on the yield, NUE and quality of mechanical direct-seeding rice. Compared with Yixiangyou 2115, Fyou 498 significantly increased photosynthetic potential, population growth rate, root vigor, and N transport rate by 3.34-23.88%. This increase further resulted in a significant improvement in the yield and NUE of urea-N topdressing by 1.73-5.95 kg kg-1. However, Fyou 498 showed a significant decrease in the head rice rate and taste value by 3.34-7.67%. All varieties were treated with N4 that significantly increase photosynthetic potential and population growth rate by 15.41-62.72%, reduce the decay rate of root vigor by 5.01-21.39%, promote the N transport amount in stem-sheaths (leaves) by 13.54-59.96%, and then significantly increase the yields by 4.45-20.98% and NUE of urea-N topdressing by 5.20-45.56 kg kg-1. Moreover, the rice processing and taste values were optimized using this model. Correlation analysis revealed to achieve synergistic enhancement of high-yield, high-quality, and high-NUE in rice, it is crucial to focus on increasing photosynthetic potential, population growth rate, and promoting leaf N transport. Specifically, increasing the contribution rate of N transport in stem-sheaths is the most important. These findings offer an effective N management strategy for 4R nutrient stewardship (right source, right method, right rate and right timing) of mechanical direct-seeding hybrid indica rice.

The Role of Sulfur in Meeting 4R Nutrient Stewardship Goals

AbstractSulfur plays several roles in 4R plant nutrition. First, as an essential plant nutrient, it may need to be applied to optimize yields and quality of crops. Second, there may be a need to replenish the sulfur removed from the soil by crop harvests. Third, some forms of sulfur may have additional benefits through their effects on soil pH and on soil nitrogen processes. The three roles combine to support enhanced productivity with lower impacts on the environment. This article reviews basic sulfur nutrition, recent trends affecting the need for fertilizers, and the contribution of sulfur to improving productivity sustainably. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Integrating Enhanced‐Efficiency Fertilizers in 4R Nutrient Management

AbstractThe 4R nutrient stewardship framework has brought us closer to improving our nutrient use efficiency. However, given the inherent “leakiness” of the N cycle, it is challenging to increase N use efficiency to optimum levels. Newer fertilizer technologies, like enhanced‐efficiency fertilizers (EEFs), are tools that can help achieve this goal. To determine if EEFs should be incorporated into nutrient management programs, growers and crop advisers should consider the various types of EEFs available, their functions within the soil, and the timing of application relative to the crop’s nutrient uptake demand. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

What Is a 4R Plant Nutrient?

AbstractWhat is a plant nutrient? For many decades, plant nutrients have been defined by the concept of essentiality. More recently, however, 4R nutrient stewardship has been defined as management that produces sustainable outcomes. Some elements provide benefits even if they are not essential. A new definition of what a plant nutrient is has been proposed and is under consideration by authorities in fertilizer regulation. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Precise macronutrient application can improve cane yield and nutrient uptake in widely spaced plant-ratoon cycles in the Indo-Gangetic plains of India

IntroductionSugarcane is a long-duration and nutrient-exhaustive crop. To improve nutrient use efficiency, the 4R nutrient stewardship approach comprises applying nutrients at the right time and place with the right method and at the right proportion. Improper nutrient management in such a nutrient-exhaustive crop will result in various nutrient losses and environmental pollution.MethodsConcerning this, a field study was performed on calcareous soils of the lower Indo-Gangetic plains of India during two subsequent years at the Sugarcane Research Institute, RPCAU, India, to explore the effect of precise application of macronutrients (N and K) in different methods of applications. The application methods (broadcasting and band application) were maintained in the main plot, and split N and K applications were put in the subplots.Results and DiscussionA highly significant difference was observed in the numbers of millable cane, cane, and sugar yield under the split applications of fertilizer. The decline in millable cane numbers, cane, and sugar yield due to the broadcasting method was to the tune of 17.5 and 17.6%, 14.8 and 17.1%, and 14.7 and 15.8% in plant and ratoon crops, respectively as compared to band placement of the fertilizers. Yield increased by 16.0 and 15.1% under plant and ratoon crops, respectively, with seven split applications of N and K compared to the control (two split of N and no split application of K). Band placement of N and K fertilizers markedly improved the nitrogen uptake (284.1 and 287.3 kg ha−1, in plant and ratoon, respectively) and phosphorus uptake (34.9 and 28.3 kg ha−1 in plant and ratoon, respectively) when compared to broadcasting. Application of N and K in seven splits resulted in better availability of nutrients in the soil, thereby facilitating the higher NPK uptake by the plants and ratoon both comparing two split applications of N and no splitting of K. From this study, it was observed that the band placement coupled with seven splitting of N and K is the best fertilizer application protocol, ensuring higher growth, yield, quality, and nutrient uptake of sugarcane in the calcareous soils of the Indo-Gangetic plains.

Encouragement from the right source: Evaluating the impact of the 4R Nutrient Stewardship Certification Program in the Ohio Western Lake Erie Basin.

Harmful algal blooms are a considerable environmental issue predominantly caused by runoff of nutrients from agricultural lands. One high-profile set of practices promoted to combat this threat is the 4Rs of nutrient stewardship that concern using the right source of nutrients at the right rate and right time in the right place. While outreach for agricultural conservation is often undertaken by governmental or nonprofit entities, there is increasing interest in engaging agricultural retailers to leverage the trust that already exists between farmers and their agribusiness professionals. The 4R Nutrient Stewardship Certification Program, implemented in the Western Lake Erie Basin (WLEB) in 2014, certifies crop advising companies and agronomy retailers or Nutrient Service Providers (NSPs) to promote best practices in nutrient management. This program has since grown and now exists in six US states and the province of Ontario and Prince Edward Island in Canada. Using a survey of farmers in the WLEB, we investigate the impact of working with certified NSPs over time on farmers' reported 4R-related behaviors. We find evidence that working with a certified NSP has a positive impact on 4R behaviors that is independent of other potential explanations for this change (e.g., farmer concern about nutrient loss, local regulatory efforts, and exposure to general 4R-related outreach). Overall, these results suggest that the 4R Nutrient Stewardship Certification Program is having an independent, positive impact on farmer behavior, and engaging with agricultural retailers and agronomists can be effective at advancing adoption of environmentally impactful nutrient management practices.

Potassium and Zinc Management in Rice (Oryza sativa L.) based on 4R concept - A Review

Plant growth is highly influenced by the nutrient supply from soil and the external application of fertilizers. Plants must receive essential nutrients like N, P, K, S and micronutrients for optimum plant growth and development. In current agricultural practices, especially, in cereal-based cropping systems, the soil nutrient balance like potassium and zinc are disturbed to the negative side due to intensive exploitation of native soil nutrients and low external input application. Employing 4R nutrient stewardship (right time, right dose, right source and right method) in soil nutrient management will ensure higher yield, nutrient uptake, nutrient use efficiency, increase in farm income, and minimal damage to the environment through its demand-specific supplement and management. Equilibrium between different pools of nutrients is the major driving factor for nutrient supply and demand in the soil which can be compensated by the external supply of nutrients through the 4R approach. Adoption of 4R stewardship in rice-based systems will ensure the attainment of maximum yield and nutrient use efficiency provided all other growth factors are in optimal supply and will assist in attaining self-sufficiency in rice production.

Assessing Soil Potassium: Basic Principles and New Developments

Potassium (K) is an essential element for crop growth, playing a key role in photosynthesis, protein synthesis, and many other essential functions in the plant. In 2020, 44% of the soils sampled across North America tested below critical in K (meaning applying K fertilizer would result in a crop response). Assessing soils for nutrient availability is an important principle of 4R Nutrient Stewardship. The goal of this article is to provide information on the behavior of K in soils and how it influences the assessment of crop K needs. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

POTASSIUM APPLICATION USING THE 4R NUTRIENT STEWARDSHIP APPROACH FOR IMPROVING WHEAT GROWTH AND YIELD TRAITS

Potassium (K) plays a key role in numerous plant metabolic processes, and its adequate amount is necessary for proper plant growth and development. Imbalanced fertilizer application has rapidly depleted the soil available K and harmed crops. However, the science-based K application in crops must follow the 4R nutrient stewardship approach to enhance crop yields. Therefore, a planned pot study used the 4R nutrient management technique for wheat potassium management. The evaluation of two wheat cultivars (Punjab-2008 and Barani-2011) employed two commercial K sources (MOP and SOP) with different application methods (basal and foliar) and sowing times (15 October, 15 November, and 15 December). The wheat variety Punjab-2008 performed better in root and shoot length, fresh biomass, and grain yield between 15 October and 15 November. Meanwhile, the Barani-2011, sown on 15 November, produced higher total chlorophyll contents and water use efficiency (WUE). The use of SOP (high dose), MOP (medium to high dose), and foliar spray of SOP at 1.5% and 3% resulted in maximum shoot length and the root-to-shoot ratio for both tested cultivars. Punjab-2008 produced higher grain yield when applied with a high SOP level than a high level of MOP. Similarly, a maximum leaf area index and proline contents observed in Punjab-2008 occurred with a high level of SOP applied. In contrast, a higher net photosynthesis rate and WUE emerged in Barani-2011 under a medium SOP level and a higher level of MOP. Thus, the conclusion is that medium to high rates of SOP proved a better source of K nutrition for improving yield parameters of wheat cultivars.

Fertilization recommendation for Brassica oleracea using Bulletin 100 is still valid after more than two decades

The 4R Nutrient Stewardship is a concept that aims to optimize fertilization of agricultural crops, encompassing social, economic and environmental aspects. This concept involves 4 scientific principles (the right source of fertilizer, the right rate, the right timing and the right place) that should be defined based on local conditions and knowledge. This study aimed at determining best fertilization practices for broccoli in the region of Tatuí-SP in Brazil, using the 4R nutrient stewardship principles. Four experiments were installed, each one referring to a 4R principle, comparing the standard fertilization applied in the region with different management options. The recommended rate by the fertilization bulletin outperformed other rates we tested. An increase or decrease by 25% in the bulletin recommended rate led to a reduction in broccoli productivity. Mineral fertilizer source promoted highest growth, followed by a combination of mineral and organic. In regard to timing, the standard practice applied in the region, which is applying 100% of N and K at planting, did not differ from splitting the dose in 3 parcels. Lastly, applying the fertilizer in the planting row promoted better growth than broadcasting on the soil surface. The standard fertilization practiced in the region promoted the highest growth, although there are other possibilities in terms of timing and placement that also resulted in similar growth, and the decision should be made according to the reality of each farmer.

Significant reduction of ammonia emissions while increasing crop yields using the 4R nutrient stewardship in an intensive cropping system

Ammonia (NH3) emissions should be mitigated to improve environmental quality. Croplands are one of the largest NH3 sources, they must be managed properly to reduce their emissions while achieving the target yields. Herein, we report the NH3 emissions, crop yield and changes in soil fertility in a long-term trial with various fertilization regimes, to explore whether NH3 emissions can be significantly reduced using the 4R nutrient stewardship (4Rs), and its interaction with the organic amendments (i.e., manure and straw) in a wheat–maize rotation. Implementing the 4Rs significantly reduced NH3 emissions to 6 kg N ha–1 yr–1 and the emission factor to 1.72%, without compromising grain yield (12.37 Mg ha–1 yr–1) and soil fertility (soil organic carbon of 7.58 g kg–1) compared to the conventional chemical N management. When using the 4R plus manure, NH3 emissions (7 kg N ha–1 yr–1) and the emission factor (1.74%) were as low as 4Rs, and grain yield and soil organic carbon increased to 14.79 Mg ha–1 yr–1 and 10.09 g kg–1, respectively. Partial manure substitution not only significantly reduced NH3 emissions but also increased crop yields and improved soil fertility, compared to conventional chemical N management. Straw return exerted a minor effect on NH3 emissions. These results highlight that 4R plus manure, which couples nitrogen and carbon management can help achieve both high yields and low environmental costs.

Synergizing potato productivity and environmental performance with Nutrient Expert recommendation approach in northern China

Lack of evidence-based fertilizer recommendation has resulted in low productivity and nutrient use efficiency as well as nitrogen (N) pollution for potato in northern China. An innovative nutrient recommendation approach, Nutrient Expert (NE), has been developed for potato through adoption of 4R (applying the right nutrient source at the right rate, time, and place) nutrient stewardship technologies. However, large-scale evaluation of NE on improving potato productivity while minimizing environmental risks are not yet available. Here, we compared the performance of NE with farmers' practice (FP) and soil test (ST) based fertilizer recommendations in 38 potato farm fields in five provinces of China from 2017 to 2020. Compared to FP, NE significantly increased potato yield by 7% with 21% less N input, reduced N balance and N loss by 48% and 31%, and improved nutrient use efficiencies. Compared to ST, NE significantly reduced N input by 19 kg ha−1 without yield and profit losses, and decreased N balance and N losses by 27% and 13%, respectively. Based on a linear relationship between N balance and N application rate, the N application thresholds of 179–191 kg ha−1 were obtained to increase tuber yield and minimize N losses. The NE based N recommendation rate (182 kg ha−1) was within the range of N application thresholds, indicating the synergistic effect of NE on productivity and environmental performance. The NE tool could potentially be expanded to help achieve synergistic yield and environmental improvements in other potato production regions.

Climate‐Smart Fertilizers in 4R Nutrient Stewardship

Climate‐smart fertilizers will play an increasingly important role. They fit well into the 4R Nutrient Stewardship concept, which provides an excellent framework for recognizing and rewarding the farmers that adopt their use. Programs, protocols, and policies aimed at reducing the carbon footprint of agriculture need to recognize climate‐smart fertilizer use in a 4R framework. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Cereal production trends, nutrient use efficiency and its management practices in agriculture: A review

Boosting global food production to meet the escalating demand without distressing the environment is a major challenge of our time. In the present review study, a-59 years global cereal production and fertilizer use trends, nutrients use efficiency (NUE) and some of its management approaches in agriculture were evaluated. Accordingly, the world cereal production increased by 3.4-fold (876.9 to 2979 Mt) from 1961 to 2019, whereas the area of production increased moderately by 1.11 folds. The chemical N, P2O5, and K2O fertilizer consumption in cereal crop production were increased by 9.45 folds (from 6.9 to 65.2 Mt), 4-fold (from 6.6 to 26.3 Mt), and 4.34-fold (from 5.2 to 22.6 Mt), respectively. The estimated world cereal N, P, and K use efficiency is 33%, 16%, and 19%, respectively. The unaccounted 65% of N, 84% of P and 81% of K fertilizer was either remained in the soil or lost to the environment through volatilization, leaching, and run-offs leading to higher environmental and economic costs. Therefore, improving NUE is a crucial step to enhance crop yields, tackle environmental pollution, reduce production costs. Several NUE management approaches were identified such as soil management (use of organic inputs, 4R nutrient stewardship, adoption of modified fertilizer, root-zone nutrient management, etc.), plant management (growing nutrient use efficient cultivars, crop rotation, and so on), integrated soil-crop system management (ISSM), and application of precision agriculture. However, no single management approach solely resulted in higher NUE but rather the combination. Hence this could be applied in agricultural production to improve yield and NUE while minimizing environmental degradation.

Evaluating Impacts of 4R Nutrient Stewardship

Nutrients are essential for plant and animal agriculture and comprise a large portion of its outputs. The starting point for assuring beneficial impacts is the adaptive management built into 4R Nutrient Stewardship. To manage adaptively means to evaluate impacts in your decision cycle. The metrics you evaluate need to reflect impacts important to your local farming system. Farther‐reaching impacts of crop nutrition include water quality, air quality, carbon footprint, biodiversity, food security, human nutrition, farm livelihoods, and circularity. By better documenting the decision cycle, our current and past practices, and their relation to impacts, the industry has the opportunity to build public trust. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at https://bit.ly/3KYONvh. View all CEUs online at https://web.sciencesocieties.org/Learning‐Center/Courses.

The Food and Environment We Love; Examining the ‘On-the-Ground’ Application of the 4R Nutrient Stewardship in Ghana

The Food and Environment We Love; Examining the ‘On-the-Ground’ Application of the 4R Nutrient Stewardship in Ghana

Ensuring future agricultural sustainability in China utilizing an observationally validated nutrient recommendation approach

Fertilizer has revolutionized crop production, but a lack of evidence-based fertilizer usage has resulted in negative economic and environmental ramifications, particularly for smallholder farmers. This study aimed at developing an innovative nutrient recommendation approach, Nutrient Expert (NE), for improving yields of maize, wheat, and rice while optimizing fertilizer input through adoption of 4R (applying the right source of nutrients at the right rate, time and place) nutrient stewardship technologies, and evaluating the large-scale performance on crop productivity and the environmental impact of cropping systems. Thus, we compared NE to current farmers’ practice (FP) and soil test-based fertilizer application (ST) for 1,534 farm field experiments in order to validate the benefits of NE on both crop productivity and environmental protection in the main cereal production areas in China. Overall, the NE treatment achieved 4.4 % higher grain yield and 5.8 % more profit over FP, more yield for rice, but no differences for maize and wheat over ST. Nutrient Expert required 29.0 % and 14.7 % less fertilizer N than FP and ST, respectively. The NE recommendations improved the nitrogen (N) recovery efficiency by 10.8–13.4 percent points over FP across the 1,534 sites. Using the NE approach, on average, reactive N losses and greenhouse gas (GHG) emissions were reduced by 36.2 % and 21.5 % over FP, 16.0 % and 9.9 % over ST, respectively. The NE, as a user-friendly tool, is widely applicable across farm types and climatic regions. It could be beneficial for improving fertilizer use efficiency and maintaining strategic food security for smallholder production areas in China where N fertilizer is inappropriate and usually over applied. This approach could potentially be expanded to help reduce N losses and GHG emissions in other regions globally.

Optimizing Tomato Growth and Productivity Using Nitrogen and Irrigation Application Timing

Soil nutrients and water management practices according to the concept of 4R nutrient stewardship (right rate, right timing, right placement, and right source) can have significant benefits on crop productivity and reduce the negative effects of agricultural practices on the environment. Therefore, this present study evaluated the effects of nitrogen (N) application timing under different irrigation regimes on open-field, fresh-market tomato production in Florida. In this study, 2 N application timings applied at 25% pre-plant with 75% fertigation (BM), and 0 pre-plant with 100% fertigation (NB), were evaluated. The two N application methods were evaluates using three irrigation regimes: full irrigation (FI, 100% ETc), deficit irrigation (DI, 66% ETc), and regulated deficit irrigation (RDI, 66% ETc during the first 4 weeks after transplanting and 100% ETc afterward). The results showed that BM treatment significantly improved early-season tomato growth compared to NB treatment. The results also indicated that under RDI and DI irrigation conditions, tomato root length was lowest (average value of 13%) within the first 15 cm compared to 40% within 15–30 cm and 47% at 30–40 cm soil depths. Similar to plant growth, BM treatment significantly increased tomato yield (average valued 56.00 Mg ha−1) compared to the NB (average value 40.23 Mg ha−1). The application of DI throughout the growing season reduced tomato yield; however, there were no differences in yield under the RDI and FI irrigation regimes. Therefore, based on the results from this study, it can be concluded that, under Florida growing conditions, pre-plant N application is essential for tomato growth and productivity. Additionally, irrigation application using the RDI method could be successfully adopted in Florida tomato production for improved water savings without any negative effects on tomato growth and productivity.

Phosphorus Use Trends to Inform 4R Nutrient Stewardship and Reducing Losses from Cropland

AbstractPhosphorus (P) loss pathways should be considered in the context of how management strategies interact with soil and field characteristics. Investigations of P use, soil test P, and P use efficiency have provided some help in navigating through the plight of reducing P losses while maintaining profitable yield levels. The extent to which tillage practices and cover crops are utilized should inform P management strategies and how agronomic, economic, and environmental success are attained. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at https://www.certifiedcropadviser.org/education/classroom/classes/1007.

Is rice field a nitrogen source or sink for the environment?

Rice field has been traditionally considered as a nonpoint source of reactive nitrogen (N) for the environment, while it, with surrounding ditches and ponds, also contributes to receiving N inputs from atmosphere and waterbodies and intercepting N outputs from rice field. However, a comprehensive assessment of the N source or sink of rice field for the environment is lacking. Here, we conducted the 3-year systematic observations and process-based simulations of N budget at the Jingzhou site in Central China. We identified the roles of rice field and evaluated the opportunities for shifting its role from N source (i.e., outputs > inputs) to sink (i.e., outputs ≤ inputs). Rice field was found to be a N source of 24.2–28.7 kg N ha−1 for waterbodies (including surface and ground waters), but a N sink (2.2–8.8 kg N ha−1) for the atmosphere for the wet and normal year climatic scenarios. The “4R-nutrient stewardship” (i.e., using the right type of N fertilizers, at right rate, right time, and in right place) applied in rice field was sufficient for the source-to-sink shift for the atmosphere for dry year climatic scenario, but needed to implement together with improvements of irrigation and drainage for waterbodies. Furthermore, with the combination of these improved management technologies, rice field played a role as a N sink of up to 22.8 kg N ha−1 for the atmosphere and up to 2.0 kg N ha−1 for waterbodies, along with 24% decrease in irrigation water use and 21% decrease in N application rate without affecting rice yield and soil fertility. Together these findings highlight a possibility to achieve an environmental-friendly rice field by improving agricultural management technologies.