On the second day there was a focus on SCRSF products and technology, formulation and application insight, which then continues into the third day.The following section takes some of the subject material from the presentations, and in two cases New AG International has gone back to the presenters for additional comment. It begins with New AG International asking some of the presenters from these sessions to give a quick-fire overview of their presentations. Then, we look at some of the presentations in more detail – namely the difficulties in quantifying the SCRSF market, using SRF on coffee in Brazil and then trialling controlled-release urea and stabilised urea in Brazil.
Adubos Real Renato Fonseca de Paiva Gerente de Marketing e P&D What is the subject of your presentation at NAI Brazil (SCRSFs track) and what are the key take-away messages? The subject of presentation is the benefits of using enhanced efficiency fertilizers in tropical agriculture, especially in Brazil. The cultivation conditions are quite favourable to losses such as volatilization, nitrogen denitrification and phosphorus fixation. Among alternatives to mitigate losses, the use of enhanced efficiency fertilizers has stood out. Real TURBO, a special fertilizers line, from Adubos Real contribute a lot in this regard. They are fertilizers with ingredients that reduce nitrogen and phosphorus losses. In this way, nutrients are available longer in the soil solution contributing to nutrition. As the losses of nutrients in the environment are less, it is possible to work with adjusted fertilizer doses. This contributes to reducing environmental impacts and helps the rational use of inputs.
When it comes to SCRSFs where do you expect to see the significant developments in the next few years? (will the main drivers be technology, pricing or increased adoption rates, for example) The greater the adoption of these technologies, the better for all agribusiness. Some challenges must be overcome, such as the prejudice that they are very expensive products. Indeed, they have a higher value than conventional fertilizers. However, the return on investment is greater than that of conventional fertilizers. In addition, there is greater certainty that the investment in fertilization will be returned with less influence from environmental factors in the success of fertilization. The technologies shipped in these fertilizers have been improving every year. It is important that the product has its manufacturing and positioning appropriate to each particular crop where it will be used. That is why local validations are extremely important. The greater the use of SCRSFs, the smaller the difference between their prices and those of conventional fertilizers. And more benefits for the entire agribusiness chain, especially for the farmer.
If there was a particular crop or sector that you think would benefit most from SCRSFs and isn't currently using in any great volume - what would it be? Talking about the Brazilian market, phosphate fertilizers with enhanced efficiency can contribute a lot in the rational use of inputs in soy and corn crops. In terms of nitrogen fertilization, crops such as corn, coffee and the forest sector stand out. All of these crops can benefit from reduced greenhouse gas emissions and reduced environmental impact, as well as increased productivity.
BASF Dr Maarten Staal Team Leader Technical Sales N-Management What is the subject of your presentation at NAI Brazil (SCRSFs track) and what are the key take-away messages? One of the most investigated urease inhibitors is N-(n-butyl) thiophosphoric triamide (NBPT)*. So far, mainly applications on straight urea have been described in literature and little information is available on storage stability of NBPT containing urease inhibitors in urea based NPK and ammonium sulfate (AS) fertilizer mixtures. In this research the influence of AS and phosphate fertilizers on urease inhibitor stability have been investigated. Both phosphate and AS containing fertilizers significantly increased the degradation speed of NBPT. In my presentation I will discuss different ways to mitigate this degradation.
When it comes to SCRSFs where do you expect to see the significant developments in the next few years? (will the main drivers be technology, pricing or increased adoption rates, for example) Initiatives to reduce emissions from fertilizers (e.g. NEC directive, European Green Deal, China’s zero-growth policy) are more and more being translated into regulations that also involve fertilizer use. Such regulations will lead to an increasing demand of technologies that increase the nitrogen use efficiency, such as SCRSFs. Among controlled release, slow release and stabilized fertilizers, the latter is the most affordable tool to reduce ammonia and nitrous oxide emissions from nitrogen fertilizers and improve nitrogen use efficiency (NUE). BASF´s nitrogen stabilizer portfolio includes both urease inhibitor (Limus®, containing a patented synergetic mixture of NBPT and NPPT) and nitrification inhibitor (Vibelsol®, containing DMPP) products. In addition, we are developing innovative and sustainable active ingredients to address the market need for nitrogen stabilizers that can be used on a broad range of fertilizers and crops.
If there was a particular crop or sector that you think would benefit most from SCRSFs and isn't currently using in any great volume - what would it be? The use of SCRSF in mineral fertilizer for row crops is currently very limited. Farmers would benefit from using urease inhibitors (UI) and nitrification inhibitors (NI) by improving the NUE of their fertilizer resulting in higher yields and improved crop quality. Especially in Latin America, where farmers are using relatively low rates of nitrogen fertilizer, the use of UI and NI products often lead to a significant yield increase and improved profitability of farms. In addition, these stabilizers improve the ecological footprint of their business by reducing nitrate leaching and lowering greenhouse gas emissions.
* Kiss, S. and Simihaian, M. (2002): Improving Efficiency of Urea Fertilizers by Inhibition of Soil Urease Activity. Kluwer Academic Publishers, Dordrecht, The Netherlands.
Café Brasil Fertilizantes Company Maria Tais Buzzo Gomes R&D Director
What is the subject of your presentation at NAI Brazil (SCRSFs track) and what are the key take-away messages? Our main subject is to present the slow release technology included at "Ciclus NK" product, from Café Brasil Fertilizantes Company, with its advantages and benefits to coffee areas, based on years of research. The most important message is to introduce a tool that can help the farmer to manage the fertilizing with great cost benefit, environmental sustainability and climate independence.
When it comes to SCRSFs where do you expect to see the significant developments in the next few years? (will the main drivers be technology, pricing or increased adoption rates, for example) We expect a significant increase with the growing adoption of technology, due to better cost benefit and the agronomic results of the products, especially at citrus, forestry banana and other perennial crops.
If there was a particular crop or sector that you think would benefit most from SCRSFs and isn't currently using in any great volume - what would it be? All the perennial crops at no mechanized areas have great potential to adopt SCRSFs, due to economy of labour and machine operations, reducing the production cost and all the other crops can take advantages of the technology to manage climate changes and instability.
Koch Industries Matias Ruffo Agronomy Manager Latin America & South Africa
What is the subject of your presentation at NAI Brazil (SCRSFs track) and what are the key take-away messages? The presentation will cover Koch Agronomic Services´ portfolio of SCRSFs, including AGROTAIN® nitrogen stabilizer with special emphasis on recently launched products such as ANVOL® (urease inhibitor) and CENTURO® (nitrification inhibitor) nitrogen stabilizers. ANVOL launched in Brazil in 2020, and is the technology behind SuperN®PRO treated urea. ANVOL with the patented active ingredient Duromide delivers the longest-lasting protection against ammonia volatilization. CENTURO is a next-generation nitrification inhibitor for anhydrous ammonia and UAN. Featuring the patented active ingredient Pronitridine, CENTURO offers highly effective below-ground nitrogen protection. When it comes to SCRSFs where do you expect to see the significant developments in the next few years? (will the main drivers be technology, pricing or increased adoption rates, for example) The most significant developments will most likely be the widespread adoption of more effective nitrogen stabilizers, particularly urease and nitrification inhibitors. The growth will mainly be due to an increasing grower focus on improving fertilizer efficiency especially with the challenging economics for commodity crops. The main challenge for controlled release fertilizers still is the relatively high cost compared to stabilizers in markets that are more sensitive to input cost. If there was a particular crop or sector that you think would benefit most from SCRSFs and isn't currently using in any great volume - what would it be? There is still considerable growth potential for stabilized nitrogen sources in key crops like corn and sugarcane, as more urea is used in cropping systems that maintain a significant amount of residue on the soil surface (mechanical harvest, no-till cropping systems). Coffee is a key crop for slow and controlled-release fertilizers due to the large planted area, high nutrient application rate, large number of manually operated farms and high value of the crop.
Hunter Swisher Chief Executive Officer Phospholutions, Inc.
What is the subject of your presentation at NAI Brazil (SCRSFs track) and what are the key take-away messages? The focus of my talk is on RhizoSorb, a patented nutrient delivery technology that releases nutrients like phosphorus more efficiently than current SCRSFs. It works by storing and releasing nutrients within the soil based on a chemical gradient, providing a more plant-dependent release profile. RhizoSorb is a soil amendment/fertilizer additive used to improve phosphorus use efficiency by increasing uptake and decreasing unwanted tie-up and leaching.
When it comes to SCRSFs where do you expect to see the significant developments in the next few years? (will the main drivers be technology, pricing or increased adoption rates, for example) The main drivers will be cost, consumer demands for sustainably grown food, and environmental regulations. I believe nutrient use efficiency requires a combination of emerging technologies to maximize farmer profitability. I also believe the ag/food value chain monetizing the environmental benefit is an important driver for rapid adoption.
If there was a particular crop or sector that you think would benefit most from SCRSFs and isn't currently using in any great volume - what would it be? I believe the biggest impact (environmentally speaking) is in broad-acre row crops (corn, soybean, wheat, etc.). Adoption of new technology is historically slow and requires a clear and compelling ROI to overcome a perceived risk. If farmer profitability is not significantly increased, the incentive to adopt new technologies is minimal until environmental regulation increases pressure or incentivizes farmer adoption.
Pedro Lopes Garcia Researcher at CENA/USP What is the subject of your presentation at NAI Brazil (SCRSFs track) and what are the key take-away messages? Quantifying the nutrient recovered by agricultural crops using SCRSFs can help to recommend the best fertilization management practices, and to avoid economic losses and pollution. The subject of my presentation is to provide information about the quantity of nitrogen-fertilizer recovery in maize and common bean in a specific site in Brazil using blends of controlled-release and NBPT-treated urea.
When it comes to SCRSFs where do you expect to see the significant developments in the next few years? (will the main drivers be technology, pricing or increased adoption rates, for example) There are different types of SCRSFs around the world. It is interesting to research the nutrient recovery by crops and other analyses applying SCRSFs in different soil, weather conditions, and crop systems. It can provide knowledge to improve the SCRSFs technologies for different situations and crops, reduce acquisition costs, or even fertilizer rate.
If there was a particular crop or sector that you think would benefit most from SCRSFs and isn't currently using in any great volume - what would it be? SCRSFs normally have higher costs than conventional fertilizers and depending on the soil, weather conditions, and crop systems it would be an alternative to reduce the number of mechanized operation and nutrient losses, improving the synchronism of nutrient release and recovery by crops. Economic researches involving agronomic analyses in annual and perennial crops (maize, common bean, sugarcane, coffee, eucalyptus, and other crops) would help to increase the use of SCRSFs.●
Steve Buissinne/Pixabay
At New AG International’s NAI Brazil event in November 2020, editor-in-chief Luke Hutson gave an overview of the difficulties in quantifying the SCRSF market at a global level.
The first and most obvious problem is the range of products. Just look at the acronym SCRSF. Let’s start to break it down: S – this stands for slow-release and refers to urea-reaction products, which includes sulphur-coated urea. CR – this stands for Controlled release, which refers to the coated products, usually solid, granular. S - and the second ‘S’ is for stabilised fertilizers, which refers to the nitrogen fertilizers that receive inhibitors and these can be liquid or solid. As will be apparent in another feature in this e-book (See: Commodity fertilizer companies continue to push into the enhanced efficiency sector), there are multiple products here, some are solid, some are liquid, while the inhibitors themselves are added to products. There is also another major difficulty in that many SRF and CRF products are used in non-agricultural markets – namely, the recreational, so-called turf markets, and ornamental markets.
Limited published data The first point to make is that published data by country for the consumption of scrsf is limited. A notable example is Australia. There would appear to be two reasons for this – the first is that consumption levels would be low compared to conventional fertilizers and so it might not always be practicable to do so. Much also depends on how a country – and more specifically its fertilizer association – tracks the consumption of fertilizer. Sometimes this will be done on a nutrient basis, split out for only a few products for each nutrient. And secondly, the production of SCRSFs is highly concentrated in a few countries and so it will only be through trade data that you might be able to learn something about a country’s SCRSF consumption. Such an exercise becomes even harder when considering the use of inhibitors. Here, the volumes are derived largely by an assessment of how much tonnage of a product receives an inhibitor? (eg a percentage of applied ammonia in USA). However, there is a further complication because some inhibitor products can be added on farm – so how can you be sure of the tonnage receiving the inhibitor? Often the stabilised fertilizers are separated from the coated fertilizers. But really the bigger question is whether it even makes sense to assess the market on global level? There data becomes more limited as you move away from the main consuming countries. And if there is a lack of transparency in data for agricultural end-users for SCRSF, it is even more the case for the non-agricultural markets.
Breaking the code When products are traded around the world, they are given an HS code, usually six digits, but for more detail they go up to 10. One of the problems in quantifying the slow- and controlled release market is that there is not a code for every single product. Let’s take the code 3102100090 as an example. The code for standard urea is usually in 6 digits – 310210. Further digits are added for greater detail. But here’s the problem: the ten-digit code can be used for technical urea and sulphur-coated urea. Sulphur-coated urea is one of our slow release products but the code ending in nine-zero can refer to technical urea, of which it’s end-uses can be diesel exhaust fluid. This will make tracking trade flows for sulphur-coated urea more difficult. Another example is the 31052000 code. This is a general code for classification for a fertilizer containing three fertilising elements – so standard NPKs. Rather usefully, an import record for India shows the code and provides a description next to it – the description said this was a shipment ‘Osmocote slow release 13-13-13’ the ICL product. This again highlights the problem – how do you know if it is an NPK or a controlled release NPK? So let’s look at some data. There are two major studies in the last 10 years that have tried to quantify the Slow/controlled release market.
Published research There are two pieces of published work detailing global SCRSF consumption that are most often quoted: The work of Sarah P Landels of AgIndustries Research and Consulting. She presented her work at the New Ag/IFA slow/controlled release conference in 2013. RAMS & Co 2018, who presented their results at New Ag International/IFA conference slow/controlled release conference in 2019.
Chart 1 Source: AgIndustries Research and Consulting
Firstly, let’s look at Landels work. This chart shows the ‘world’ market consumption for 2009/10. Notice how the regional split was done – USA, Western Europe, and Japan and even then it is a mix of one region and two countries. This basically took the most important markets at the time. China would now need to be on this list. But for this research, USA was by far the largest market. Product type then becomes important. The coated sector was bigger for USA, while the slow release sector was biggest for Western Europe. The Japanese market was dominated by coated products. AgIndustries ‘global’ total consumption was nearly 900,000 product tonnes/year.
Extrapolation exercise The next chart tries to extrapolate from that early Landel’s data to see where we would be today, and later tries to add an estimated component for China.
Source: AgIndustries Research and Consulting / RAMS & Co / Author
Chart 2 takes the total figure from Landel’s at 2010 at approx. 900,000 t/y and extrapolates using the growth rate given in Landel’s presentation (to 2015 it was 2-3.75%). Some data published by RAMS & Co for 2016 and 2018 (2.1 M t CRF, 1.8 M t SRF) has then been added for 2016 and 2018. The major point to note here is that RAMS & Co were including China while the Landel/AgIndustries information from 2010 did not have a component for China. This explains the difference. It should also be noted that RAMS & Co, like Landels, were considering CRF and SF, not stabilised products.
The next thing to do is to try to estimate the capacity for China. This was based upon the author’s own research from 2016 and is 3.4 million t. In data presented by Kingenta in January 2021 for the growth of specialty market in China to 2024, the current figure for CRF production was given as approximately 4 million t for 2019, which would seem to support the 3.4 million t figure from 2016. Kingenta has a 5.5% growth figure for production of CRF out to 2024.
Chart number 3 is quite busy, so let’s take the green dots first. These are the author’s estimates for China’s CRF and SRF capacity, from research from 2015-2016. It might well be a little higher now. The main point here is that we want capacity to be higher than consumption.
The black line is merely taking the estimate for Chinese capacity 3.4 million t and then adding to the to 1 million (from the Landels extrapolation) for 2016. For 2018, we draw a triangle to the RAMS & Co consumption figure and to 4.9 million t, which is assuming an 90% operating rate on capacity estimate of 5.3 million t (from chart). The result is a triangle offering a landing zone for the consumption figure in 2018 – with RAMS & Co 3.9 million t offering low end, and 4.9 (0.9*5.3) million t at the high end. The range of 1 million might seem large, but even if you take average of 4.4 million t this is still only small percentage of bulk fertilizer consumption – Urea (130 M mt), DAP (34 M mt), MAP (24 M mt), MOP (70 M mt) UAN (20 M mt) AN (22 M mt) CAN 15 M mt). AS (25 M mt) = total approx. 340 M mt. 4.4/340 = 1.3% (2018). The aim here is to find the boundaries to the market size.
And finally, we arrive at the point of the exercise, and one of the aims of analysis - to arrive at the point of prediction. This refers to Chart 4. If we extrapolate RAMS & Co from 2018 using a reasonable 3% CAGR, which is a modest growth rate, we see the blue broken projection line getting closer to capacity (assuming this is reasonably accurate) and therefore we would make the prediction: a new investment cycle in 2022-2024 begins in SCRF capacity.
Summary So, let’s review where we have been:
Coffee consumption was 168 million bags (60kg-bags) in 2019/2020, according to the International Coffee Organisation. By far the biggest producer is Brazil, and this crop is the focus of research in Brazil for the application of CRFs/SRFs is coffee. A slow release product known as Ciclus NK, producted by CaféBrasil Fertilizantes Company, has featured in many trials in the coffee areas of Minas Gerais.
Ciclus NK is a granular product that contains urea formaldehyde to provide the slow release element, according to Maria Tais Buzzo Gomes, R&D Director for CaféBrasil. From September to April is the key growing period and the time to apply nitrogen and potassium to the coffee – normally in 3-4 split applications, said Gomes, when delivering a presentation at NAI Brazil’s conference in November 2020. Gomes presented results from 2009-2015. The objective was to evaluate the effect of Ciclus NK compared to conventional fertilizer practices on vegetative growth, mineral nutrition and coffee production. Ciclus NK was applied at 50% and 70% N of official recommendation, and run in trials against a farmer using conventional doses, and a control. In the presentation, Gomes presented a table of foliar analysis from the four treatments in the trial. She pointed out that there was no statistical difference in N and K in the 70% N Ciclus NK, 50% Ciclus NK and Farmer treatments, but that the control was statistically lower. She said that indicated that the plant was not using its reserves of nitrogen in the Ciclus NK treated crops to compensate for the lower application of N. Following the conference, Gomes explained to New AG International how foliar analysis could be used to show that plants were not using N reserves when the amount of N fertilizer was reduced. Gomes said that if you measure the foliar content of nitrogen, it is possible to determine that soil nitrogen reserves are not being used if the control is statistically lower, and the foliar N content of the farmer crops (those using a conventional dose) are similar to those of the Ciclus NK applications where nitrogen was reduced. “Statistically different” means that the control is lower, not by chance, but implies an absence of additional nutrients. Therefore, it is necessary to have analysis for a control, a farmer or conventional dose, and the reduced nutrient dose, which in this case was Ciclus NK, in order to make the comparison. This is shown in the table.
Among the metrics used was the number of vegetative nodes (NVN) and the growth of plagiotropic branches (GPB), both of which were on average higher.
“What is the explanation to the higher vegetative growth,” asked Gomes in her presentation. She said it was likely the continuous nutrient availability. The research has enabled a reduction in recommended N by official institutes, using 60% of the recommended amount for productive coffee areas. It means 5-6 kg of nitrogen per bag based on yield forecast. Ciclus can be applied once at the beginning of rainy season. NAI Brazil, R&D Director told New AG International. ●
The use of blends of controlled-release urea and conventional urea have been trialled on common bean in Brazil.
Pedro Lopes Garcia of Stable Isotopes Laboratory, Center for Nuclear Energy in Agriculture (CENA), University of São Paulo (USP), Piracicaba 13416-000, São Paulo, Brazil, was a presenter at NAI Brazil in November 2020. His presentation touched on the results of a paper published in 9 December 2020 in Agronomy journal, an open source journal published by MDPI. The nitrogen requirements of the common bean (Phaseolus vulgaris L.) during its vegetative and reproductive stages can be satisfied with a single application of a blend of polymer-sulphur coated urea (PSCU) and conventional urea treated with NBPT, according to the paper’s abstract. The research evaluated two blends (70% PSCU+ 30% U and a 30% PSCU + 70% U) across three N fertilization management programmes – namely: incorporated, broadcast, and split application. The metrics for each programme was soil ammonia volatilization (AV), N mineral content (NM), plant N uptake (NU) and N recovery from Urea (NUR), and yield (GR). The soil type was Rhodic Eustrustox and irrigated field experiments were conducted in 2018 and 2019, and N application was 90 kg/ha.
Key results The blend with more PSCU tended to result in lower ammonia volatilization because of the controlled N release provided by the insoluble polymers. “The split N application in our research provided better conditions for the early growth of common bean than other N management practices, based on the slightly higher daily rate of N uptake observed from V2 to V4,” the authors wrote in the paper. The paper went on to consider the effects of broadcast application on the yield and N recovery. Broadcast application using blends of PSCU and U (70%PSCU + 30%U and 30%PSCU + 70%U) did not improve grain yield compared to N incorporated application at sowing and split N application in irrigated experiments in Rhodic Eutrustox soil during the mild winter in Brazil, the paper concluded. When making the conclusion, the authors said that broadcast application resulted in lower grain yield than the control treatment (without N-fertilizer application) and the split N application treatment. Broadcast application resulted in lower NUR in the grain at harvest than split N application, which indicated that broadcast application was less efficient at supplying N from the U source in the blends.
Effect of blends of polymer-sulfur coated urea (PSCU) and conventional urea (U) (70%PSCU + 30%U and 30%PSCU + 70%U) applied incorporated, broadcast and split on 15N-fertilizer recovery (aerial part) of U treated with NBPT during mild winter growing season of common bean (2018 and 2019). Vertical bars indicate the standard error of the mean. Means followed by different letters indicate difference (p ≤ 0.05) among treatments. The rate of N was 90 kg ha−1 and the results are in % of total N applied.” Lopes Garcia et al. See text for discussion.
The previous table highlighted the impact on N recovery from urea (NUR). The authors found that the U source provided 18% of the NUR in common bean plants with the 70%PSCU + 30%U blend and 48% with the 30%PSCU + 70%U blend. “These NURs are higher than 50% considering the proportion of U in each blend. The non-recovery of N from U by plants can be attributed to ammonia volatilization, which reached 12% of the total N applied, on average, under split N application and broadcast application, and the likely percolation of N below the common bean root zone,” the authors noted. What is the significance of these NUR figures? Following the presentation, Lopes Garcia explained to New AG International: “In our research with common bean it was just possible to use 15N in the Urea source in the blend to evaluate the N recovery by plants. It is interesting to note that Urea was treated with NBPT, and the NUR in the figures especially at the R9 common bean growth stage (whole plant) was higher than 50%, considering the proportion of Urea in each blend. The N recovery by common bean using just conventional urea is normally lower than 50%. In future studies, is also interesting to evaluate the N recovery from polymer-sulphur coated urea (PSCU) using 15N as we evaluated in maize, providing the total N recovery using these blends in common bean. We also observed that the NUR in the common bean grain was lower in broadcast N application than split and incorporated N application and it directly correlated with common bean yield indicating that broadcast N application was less efficient at supplying N from the U source and providing lower yield than split N application.”
There was an interesting observation regarding broadcast application. The paper indicated that further investigations could be done on N uptake - from V4 until R8 - since the broadcast application resulted in a higher daily rate of N uptake than the other N fertilization management practices. Broadcast application resulted in higher N uptake and NUR at V4 than the other N management practices, and higher total N uptake at R9 than split N application, especially in the grain. The authors suggested these results suggest that broadcast application probably provided a greater priming effect than the other N management practices between V4 and R8, as the plants had lower NUR in the grain at R9 in the broadcast application than in the split N application. “In addition, the plants tended to reach their maximum NUR at the R6 growth stage with both blends. This tendency probably occurred because U is a soluble N source; after R6, the N from this source was probably located below the roots, and the plants probably absorbed more N from the soil and from PSCU which provided N higher on the soil surface. It would be of interest to confirm this hypothesis in another study with 15N in the PSCU source, the authors said.
Study for N-recovery in maize In a second paper, the same authors looked further into the nitrogen management with blends of controlled-release and conventional urea treated with NBPT and the N-recovery in maize. Similar to the trial detailed above, there were two blends 30% PSCU+70% U and 70% PSCU+30% U. Field experiments were conducted for two growing seasons (2017–2018 and 2019–2020) in Rhodic Eutrustox soil. Again, measurements were taken of volatilization of ammonia (AV) and soil N mineral content (NM); plant N uptake (NU) and N-fertilizer recovery (NR); and yield (GY). The 70%PSCU + 30%U application resulted in the highest yield in 2017–2018, and the N treatments did not affect yield in 2019–2020. NR was 3% on average at vegetative leaf stage 4 (V4), and PSCU, the main N-fertilizer supplier applying 70%PSCU + 30%U. After V4, the main N-fertilizer supplier is PSCU for 70%PSCU + 30%U and U for 30%PSCU + 70%U application. The concluding discussion said: In Rhodic Eutrustox soil, blends of PSCU and U treated with NBPT (70%PSCU + 30%U and 30%PSCU + 70%U), at a rate of 180 kg N ha−1, applied incorporated at sowing, broadcast on the soil surface at sowing, and split (30% incorporated at sowing and 70% side-dressing at V4) can ensure N throughout the maize cycle in Brazilian condition. In season 2, the PSCU was the main N-fertilizer supplier at the V4 growth stage, applying 70%PSCU + 30%U, and both blends can ensure 73.8% of N-fertilizer recovery (maize aerial part + root) of which 47.9% in the grain. What did the results tell us about the potential for yields using these blends – is it a case that they could maintain yields using less N inputs? Again, following the presentation, Lopez Garcia explained to New AG International: “In Rhodic Eutrustox soil, especially in the second season of our research, we observed that is possible to provide high maize yield after the recent application of limestone, plowing, and harrowing with good fertility of soil until 60 cm depth without N fertilizer application. In this situation, is possible to apply these blends aiming to replace the N extracted by harvest and reduce the N fertilizer rate using the most cost-effective N fertilization management option reducing economic losses and environmental pollution. In future studies, it would be of interest to make similar research using these blends labelled with 15N in a sandy loam soil that is more responsive for N fertilizer application in maize in Brazil.” ●
Journal reference:
Agronomy MDPI Nitrogen Fertilization Management with Blends of Controlled-Release and Conventional Urea Affects Common Bean Growth and Yield during Mild Winters in Brazil Pedro Lopes Garcia, Renata Alcarde Sermarini, Paulo Cesar Ocheuze Trivelin Published: 9 December 2020 15N-Fertilizer Recovery in Maize as an Additional Strategy for Understanding Nitrogen Fertilization Management with Blends of Controlled-Release and Conventional Urea Pedro Lopes Garcia, Renata Alcarde Sermarini, Carlos Roberto de Sant Ana Filho, José Albertino Bendassolli, Beatriz Nastaro Boschiero and Paulo Cesar Ocheuze Trivelin Published: 9 December 2020 (same as above paper)
Agronomy (ISSN 2073-4395; CODEN: ABSGGL) is an international, scientific, peer-reviewed, open access journal published monthly online by MDPI.
NBPT = (N-(n-butyl) thiophosphoric triamide)
