Blended Fertilizer Research Articles

Characteristics of Nitisol profiles as affected by land use type and slope class in some Ethiopian highlands

BackgroundThe success of soil management depends on understanding of how soils respond to agricultural land use practices over time. Nitisols are among the most extensive agricultural soils in the Ethiopian highlands but soil degradation threatens their productive capacity. In this study, the effects of two land use systems, intensive cereal and agroforestry systems, and slope class on physical and chemical characteristics of some Nitisol profiles were investigated. In total 12 sample profiles were described and soil samples were collected from each of the identified master horizon. Soil physical characteristics evaluated were particle size distribution, structural aggregate stability, water holding capacity and bulk density. Chemical characteristics determined were exchangeable bases and cation exchange capacity, soil pH and the contents of organic carbon (OC), total nitrogen (TN), available phosphorus (AP) and some micronutrients.ResultsAmong the physical characteristics, land use and slope significantly (p < 0.05) affected particle size distribution and plant available water content. The mean sand (28%) and silt (26%) particles in the intensive cereal system were significantly (p < 0.05) higher compared to 15% sand and 18% silt in the agroforestry system. Conversely, the mean values of fine grained texture materials including 39% fine sand, 42% fine silt and 67% clay in the agroforestry system were significantly higher than 30% fine sand, 21% fine silt and 46% clay in the cereal system. Similarly, the lower slope had significantly (p < 0.05) higher fin texture materials (39% fine sand, 30% fine silt, and 63%) clay) compared to 17% fine sand, 14% fine silt and 51% clay fractions in the upper slope. The proportion of water stable aggregate (WSA) were highlight (63–94%) and there was no significant difference between land types and slope classes. Following from high structural aggregate stability, the soils have high water holding capacity that ranged from 22 to 32% at PWP to 34–49% at FC while plant available water content (AWC) was in the 120–230 mm m−1 range. Considering the chemical characteristics, land use significantly affected soil pH, total nitrogen (TN), exchangeable magnesium (Mg2+), potassium (K+), percent base saturation (PBS), and available micro nutrients—iron (Fe2+), manganese (Mn2+) and zinc (Zn2+). The mean pH value (5.29) in the intensive cereal system strongly acidic while the pH value for the agroforestry system (6.12) was taken moderately acidic. The mean OC content was 2.0 and 2.1% for the intensive cereal and agroforestry systems that were rated very low. The mean TN values were 0.15 and 0.22% for intensive cereal and agroforestry systems that were taken as low to very low. Similarly the mean values for AP were 8 and 10 mg kg−1 for cereal and agroforestry systems that were rated low. On the other hand, the CEC, exchangeable bases (Ca2+, Mg2+, K+) and PBS of the soil were rated high while Na+ appeared only in trace amount, and there was no significant difference between land use type and slope classes except for Mg2+, K+ and PBS. Mean values of Mg2+ and K+ (15 and 3 cmol(+) kg−1) and PBS (75%) in the agroforestry system were significantly higher than those in the cereal system (6 and 1.6 cmol(+) kg−1 of Mg2+ and K+ and 51% PBS). Among micronutrients, land use significantly (p < 0.05) affected available Fe2+, Mn2+ and Zn+. The mean values of Fe2+ (97 mg kg−1) and Mn2+ (68 mg kg−1) in the agroforestry system were taken as excessively high while they were moderately sufficient (37, 39 mg kg−1, respectively) in the cereal system. Slope effects were significant for OC, TN and AP having higher mean values (2.5% OC, 0.22% TN and 17 mg kg−1 AP) in the lower slope than in the upper slope (1.5% OC, 0.13% TN and 8 mg kg−1 AP).ConclusionLand use and slope had significant effect on some soil physical and chemical characteristics. The land use practices in the intensive cereal system are adversely affecting important soil characteristics as compared to the soil under the agroforestry system. These include alteration of particle size distribution, strongly acidic soil reaction, organic matter and nutrient depletion (N, P, K and Zn) and low plant available water content. Among the inappropriate land use practices include repeated cultivation to create fine seedbed that predisposes the soil to erosion, unbalanced fertilizer application, rotation of maize with potato that are depleting soil nutrient stocks (e., K and Zn), and removal of crop residues from fields. Therefore, a more balanced fertilizer blend application that contain N, P, K and Zn combined with liming to raise soil pH, organic matter management and integrated soil water conservation are recommended.

Nutrient and mercury transport in a sub-arctic ladder fen peatland subjected to simulated wastewater discharges

Safely treating wastewater in remote communities and mining operations in sub-arctic Canada is critical to protecting the surrounding aquatic ecosystems. Undisturbed fen peatlands have been used to minimize the release of contaminants to the aquatic ecosystems; however, there is a limited understanding of wastewater transport or polishing in undisturbed fen peatlands. To elucidate these processes, a small (9800m2, ~250m long) ladder fen was continuously injected with a wastewater surrogate derived from a custom fertilizer blend and 38m3day−1 of water for 51days. The simulated wastewater included sulphate (27.2mgL−1), nitrate (7.6mgL−1), ammonium (9.1mgL−1), phosphate (7.4mgL−1), and chloride (47.2mgL−1). Major ion, total mercury (THg) and methylmercury (MeHg) pore water concentrations were measured throughout the study period. No wastewater contaminants were detected in the site outlet (~250m down-gradient) and most wastewater contaminants, except for SO42− and Cl−, remained relatively immobile. Within the SO42− plume, MeHg and THg concentrations became highly elevated relative to background (up to 10ngL−1, ~ three to five-fold increase) and MeHg comprised 60–100% of dissolved THg in the pore water. No MeHg or THg was exported at the outflow. The large increase in THg cannot be solely accounted for by the increase in MeHg and was likely due to enhanced decomposition of the peat substrate by increased microbial activity due to electron acceptor loading. Since the added nutrients were effectively transformed, sequestered or otherwise removed from pore waters in this experimental system, it appears that fen peatlands have a large capacity to safely treat residential wastewater nutrients; however, the inadvertent increases in THg and MeHg require further investigation and potential management.

Potassium Fertilization and its Level on Wheat (Triticum aestivum) Yield in Shallow Depth Soils of Northern Ethiopia

Many un-updated reports indicated that potassium was not deficient in Ethiopian soils. However, it was later proved that many Ethiopian soils are potassium deficient. Hence, the Ethiopian Soil Information System (EthioSIS) has initiated potassium fertilizer demonstrations in 2014 using K containing blended fertilizers in different parts of the country. But, there were no evidences about the K in the blended fertilizer is enough for wheat demand or not. Thus, a field experiment was conducted to evaluate the response of wheat to additional K rates on top of the K containing blended fertilizers. The experiments were laid out in Randomized Complete Block Design with 4 levels of potassium (0, 30, 60, 90, of K2O kg/ha) replicated 3 times. Data on yield and yield components of wheat crop were collected and analysis of variance was done. Results depicted that plant height and harvest index were not significant. However, spike length, grain yield and straw yields of wheat were significantly affected by K application rates. Hence, the highest spike length was obtained at a rate of 90 kg/ha K2O but the highest grain and straw yield of wheat were obtained at 30 kg/ha K2O . Besides, the highest apparent K recovery and agronomic use efficiency were found at 30 kg K2O /ha. Therefore, potassium fertilization is important and its level in the blended formula did not meet the wheat requirement in the study area.

Optimum potassium fertilization level for growth, yield and nutrient uptake of wheat (Triticum aestivum) in Vertisols of Northern Ethiopia

Potassium fertilization was started in 2014 using K containing blended fertilizers in Ethiopia. However, there was no evidence whether the recommended rates of K in the blended formula (which is be...

Effect of Organic and Inorganic Fertilizer Application on Soil Phosphorous Balance and Phosphorous Uptake and Use Efficiency of Potato in Arbegona District, Southern Ethiopia

Phosphorus is often an important limiting factor for crop yields, and in addition, low soil fertility and crop nutrient imbalances are major obstacles preventing Ethiopian farmers from realizing high agricultural productivity. Effect of the sole and combined application of farmyard manure (FYM) and inorganic fertilizers on tuber yield, nitrogen (N) uptake and use efficiency of Irish potato (Solanum tuberosum L.) was assessed in a field experiment carried out in Arbegona district of Sidama zone in Southern Ethiopia. The studied nutrient management practices were control (without fertilizer) and farmyard manure (FYM), recommended N and phosphorus (P), blended (17.3 N3, 4.7 P2O5, 7.41 S2, 23 Zn0, 3 B within 100 kg) plus potassium (K) fertilizers and combined half FYM and recommended NP and combined half FYM and blended plus K fertilizer. Treatments arranged in randomized complete block design with three replications. The experimental soil was loamy and very strongly acidic, low in organic carbon and available P and medium in total N and available K. Results showed that the applied FYM and inorganic fertilizer individual and in combination were resulted positive N balances. Potato plants amended with sole blended fertilizer, combined half recommended NP and FYM, and combined half FYM and blended fertilizers improved total dry tuber yield and total N uptake more than twofold (100%) as compared to the control. In the amendments, average agronomic and physiological efficiency of N supply and uptake were 48 and 46 kg dry tuber, respectively. Furthermore, 112% of apparent recovery efficiency of N was obtained across the treatments. Soil amendments resulted the highest net benefits with acceptable marginal rate of return (above 100%). Generally, soil amendments either in sole or combined inorganic and organic fertilizers could be considered to improve soil fertility status and potato yield in the study area.

Enhancing inorganic fertilizer use in Imo State, Nigeria

For the period covering 1990 to 2011, more than USD 9 million was spent per day to import food in Nigeria. In the face of dwindling foreign reserve, and the population of Nigeria projected to be 400 million by 2050 this expenditure is not sustainable. The challenge of feeding this number of people is enormous but is achievable if the full agricultural potential of each state in the country is attained. The desired increase in crop yield is possible through sustained efforts towards increasing crop output per hectare rather than bringing more arable land into cultivation. Increased and more efficient fertilizer use hold the key to increase in crop yield per hectare, but there are limitations. This work, therefore, attempts a review of constraints to fertilizer use in Imo state including: high cost and unavailability of fertilizers; profitability of fertilizer use; lack of soil test; dependence on unpredictable rainfall due to climate change; traditional cropping system; tillage practices; and available fertilizer blends among others. A more efficient fertilizer use requires site-specific fertilizer recommendation. This will be facilitated by establishment of standard soil testing laboratories across the agricultural zones for easy access to farmers in addition to the use of appropriate soil test kits. It may also be necessary to have fertilizers packaged in quantities less than 50 kg bags which may be more affordable to farmers considering their small farm holdings. While irrigation should be used to augment rainfall, efficiency of fertilizer use can be improved by the use slowand controlled-release fertilizers in order to counteract fertilizer nutrient losses through leaching, volatilization and the consequent debilitating effect in the environment.Keywords: fertilizer use, Imo State, soil test, cropping system, irrigation, rain fed

Site‐Specific Nutrient Management for Cassava in Southern India

Cassava (Manihot esculenta Crantz.) yield in the major growing environments of India has been stagnating despite the development of high yielding varieties and increasing use of chemical fertilizers. On farm experiments were conducted to evaluate the performance of site‐specific nutrient management (SSNM). Field and crop specific NPK rates were calculated using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The average 2‐yr yield advantage of SSNM over farmer fertilizer practice (FFP) was 7 Mg ha−1. The N agronomic efficiency increase of SSNM over FFP was 32 kg kg−1, the N recovery efficiency of SSNM was 0.14 kg kg−1 greater than that of FFP and the N physiological efficiency of SSNM was 54 kg kg−1 greater than that of FFP, whereas the partial factor productivity of SSNM was 148 kg less than that of FFP. Use of SSNM led to a reduction of fertilizer costs by an average of US$10 ha−1 crop−1 and an increase in gross return above fertilizer costs by $254 ha−1 crop−1 compared with FFP. Zone NPK recommendation maps and customized fertilizer blends were also developed. The results showed the potential of SSNM in significantly increasing yield and nutrient use efficiency of cassava. Future research is needed to validate the customized fertilizer blends and fine tune zone NPK recommendation maps which will help reduce the need for field specific modeling and intensive crop monitoring.

Blended Fertilizers Effects on Maize Yield and Yield Components of Western Oromia, Ethiopia

Appropriate fertilization practices based on actual limiting nutrients and crop requirement for a given crop is economic and judicious use of fertilizers for sustainable crop production. In view of this, a study was conducted at Kejo and Ongobo farmers’ fields, located at GobuSeyo District of East Wollega Zone of Oromia region in 2011 to evaluate the effects of blended fertilizers for maize production. The five treatments used for the field experiment were control (without fertilizer), recommended NP, recommended NP + Cu + Zn, blended fertilizer and blended fertilizer + Cu+ Zn. The treatments were laid out in RCBD design with four replications. The results of the study revealed that the analysis of variance among fertilizers types showed significant differences (P ≤ 0.05) on almost all the maize characters tested. However, applied Cu and Zn to either of the recommended NP fertilizers or blended fertilizer showed no significant difference on maize agronomic characters and yield except leaf area. The shortest mean days to 50% tasseling (85.25), silking (87.25) and maturity (154.25) of maize were obtained from blended fertilizers with Cu and Zn, whereas the longest days were recorded for the control plot. The maximum mean grain yield (8399.7 kg ha-1), stover yield (8553.1 kg ha-1) and total biomass yield (16867.7 kg ha-1) were recorded for blended fertilizers with Cu and Zn, whereas the lowest mean grain yield (2824.8 kg ha-1) were recorded for control. Blended fertilizers had improved grain nutrient uptakes and agronomic efficiency of maize. It was also apparent that much of the nutrients applied were assimilated by the grain than that achieved by the stover. The result of the study showed that blended fertilizers increased maize productivity compared to the previously existing NP fertilizers in the country and appropriate fertilization practices can improve the current situation.

Yield and Nitrogen Uptake of Bowl‐Seedling Machine‐Transplanted Rice with Slow‐Release Nitrogen Fertilizer

Slow‐release N fertilizer is considered an effective method of improving the N use efficiency (NUE). To investigate yield and N uptake of bowl‐seedling machine‐transplanted rice (Oryza sativa L.) with slow‐release N fertilizer, three fertilizers treatments including slow‐release fertilizer blend (SFB), polymer‐coated urea (PCU), and sulfur‐coated urea (SCU), and two fertilizer methods including single basal application (B), and combined with tillering urea (BT) were performed from 2013 to 2014 in Jiangsu Yellow Sea Farm of China. Conventional split fertilization (CK) and zero N treatment (N0) are controls. Yield and NUE improvement was found in PCU under both fertilization methods in both years when compared with the CK. The SCU only showed a slight yield increase in 2014, while SFB increased the yields and NUEs under both fertilization methods in both years. The BT‐SFB got the highest yields as 13.6 and 13.3 Mg ha−1, as well as increased 7.9 and 10.8% compared with CK in both years, respectively. The recovery efficiency of N was also the highest for BT‐SFB with 52.7 and 38.5% for 2013 and 2014, respectively. The results indicated that SFB can meet the rice N demand and improve the yield and NUE, and the combined application of tillering urea and SFB was better than that of single basal application with SFB.

Life cycle assessment (LCA) of different fertilizer product types

Appropriate use of fertilizer in crop production to limit the environmental impact is essential for sustainable agriculture. While much is known about the environmental impact of fertilizer production only a limited amount of data is available covering the whole fertilizer supply chain. Up to now no comparison was done on the environmental impact of different fertilizer types (i.e., complex fertilizer, bulk blend fertilizer and single nutrient fertilizer). A cradle-to-field life cycle assessment (LCA) for the fertilizer supply chain in Germany, from extraction of raw materials, via fertilizer production, transportation and storage until final application in the field was carried out. Two different complex fertilizers were compared with single nutrient fertilizers (containing only one nutrient) and bulk blend fertilizers (containing more than one nutrient as a dry mixture). The five most relevant impact categories (i.e., climate change, acidification, eutrophication, fossil fuel depletion and resource depletion) were selected to cover different environmental impacts. Additionally, a scenario analysis was carried out focusing on nitrous oxide (N2O) emissions, as new catalytic reduction techniques for the manufacturing of nitrogen (N) containing fertilizers are available that can lead to drastic reductions of N2O emissions.Production of fertilizers causes high values in the impact categories climate change, fossil fuel depletion and acidification, whereas resource depletion is dominant for production and transportation. For the impact category eutrophication, the application of fertilizer is the most important factor.For a fertilizer strategy with low phosphorus application rate, a bulk blend or single nutrient fertilizer with calcium ammonium nitrate is the most sustainable choice, while for a fertilizer strategy with a balanced nutrient formula, a bulk blend or single nutrient fertilizer with calcium ammonium nitrate or a standard complex fertilizer are sustainable options. Scenario calculations with reduced N2O emission during the production process reveals that this reduction technique is not relevant for urea based fertilizers leading to the conclusion that products containing urea need different emission reduction techniques to keep up with the environmental improvements of other nitrogen fertilizers.With an optimized fertilization strategy the environmental burden can be reduced up to 15%. As nitrogen application rates strongly affect the LCA results it is essential that the right amounts of N are used and that for N fertilizer production the best available technique should be installed. Furthermore, a careful consideration concerning the fertilizer product type should be part of every LCA of food and agricultural products, as this has a great impact on LCA results.

Ballistic Modeling and Pattern Testing to Prevent Separation of New Zealand Fertilizer Products

Abstract. In recent years twin disc centrifugal spreaders have become larger with some manufacturers claiming to be able to spread fertilizer products as far as 60 m. To achieve wider spread widths, the fertilizer particle exit velocity off the disc has increased, as a result the ballistic qualities of the product becomes more critical. This case study uses data-mined information from Ravensdown Fertiliser Co-op Ltd, a major fertilizer supplier. This article examines and researches products used by arable and grassland farmers and studies the effect of changes in product characteristics on spread bout width from these newer spreaders. Ballistic modeling, based on particle density, size, and shape was used to test the distance fertilizer particles travel at various velocities. Fertilizer particle velocities were measured by high speed photometry using both common fertilizers and common spreaders found in New Zealand. Spreading equipment was pattern tested using the New Zealand Spreadmark method. Ballistic modeling of particles proved appropriate in ideal conditions. Fertilizer manufacturers believe that spreader operators often fail to take account of physical characteristics of products being spread and target the widest bout width possible. This can lead to an in-field Coefficient of Variation (CV) which is much greater than 15% and leads to sub-optimal utilization of fertilizer, where variations in particle size distribution occur. Similar situations have been experienced when spreading fertilizer blends; where blends previously spread successfully, at narrower bout widths now separate. Ballistic models could provide bout width recommendations for products and blends, for a range of applicators and reduce crop striping.

English

Increasing fertilizer rates at sowing can provide significant increases in grain yield in vegetable crops. However, very high rates can impair root development because of increased soil salinization in the rows mainly because of KCl fertilizer. Broadcast fertilization without incorporation into soil may be a viable strategy to avoid this salinization. Therefore, we conducted a study to determine the effect of different fertilizer rates applied to the soil surface without incorporation on common bean grain yield and yield components in a no-tillage system. An irrigated field experiment with a randomized block experimental design with four replications was conducted in Brazil during the 2012 and 2013 growing seasons. The treatments consisted of four fertilizer rates of an N-P-K blend that were 0, 50, 100 (15 kg ha-1 of N, 90 kg ha-1 of P2O5 and 45 kg ha-1 of K2O) and 150% of the recommended fertilizer rate for in-furrow applications. Increasing broadcast fertilizer application provided a significant increase in common bean grain yield. The application of 300 kg ha-1 of fertilizer (100% of the recommended fertilizer rate) on the soil surface without incorporation provided a similar result as the application of the same amount in the seed row. The results document that broadcast application of a fertilizer blend on the soil surface without incorporation is a viable management tool to increase common bean grain yield in no-tillage systems in soil with high fertility, which is based mainly on its content of organic matter, phosphorus, and base saturation. Key words: Phaseolus vulgaris L., surface fertilization, Cerrado, no-tillage system.

Lentil (Lens Culinaris Medikus) Current Status and Future Prospect of Production in Ethiopia

Lentil is among the oldest domesticated crop in the world. It is a cool season food legume playing a significant role in human and animal nutrition as well as soil fertility maintenance. It can be grown in rotation to cereal crops which promote sustainable cereal-based production systems with a potential of fixing free nitrogen reached up to 107 kg ha-1. It is the most important crop because of its high protein content and fast cooking characteristic. The major lentilgrowing countries are Canada, India, Turkey, Australia, USA, Nepal, China, and Ethiopia. Lentils have an indeterminate growth habit and flowering begins from the lowest branches, gradually moving up the plant and continuing until harvest. It is well adapted to various soil types and also considered as drought-resistant crop. But it is susceptible to excessive water stress. World lentil production has been increasing in recent years with most of the production coming from North American and Asian countries. Productivity of lentil in Ethiopia varies from region to region due to variation in environment and biotic factors. Currently, lentil is considered as a cash crop that fetches higher price compared to most of the cereals and pulses grown in Ethiopia. It is often claimed that, the internal (local) market seriously competes with the external market. Lentil has huge potential of reducing poverty and contributes to sustainable economic development in Ethiopia. Despite the country’s potential and sustained development efforts to get the pulse sub-sector moving, the competitiveness of lentil and hence its contribution to economic development is threatened by low productivity and inconsistent supply of products that does not met both export quality and quantity. On the other hand, the ever increasing population and ever changing client demand of lentil is the good opportunity for boosting production at farm level. In Ethiopia, lentil has received little attention in research, development and external fund attraction. Thus, it is essential to work with federal and regional seed enterprises, farmers’ cooperatives, unions, and seed producing farmers with involvement of private sectors in a coordinated manner to ensure adequate supply of locally certified seeds. It is also necessary to develop recommendations for organic and inorganic fertilizers that are most suitable for lentil production. These recommendations will depend on soil maps and controlled trials of blended fertilizers to determine the optimal balance of macro- and micronutrients. Providing of effective extension service is inevitable to break the existing resistance by awareness creation through demonstration at farmers training centers. Complementary lentil technologies including tillage frequency, seed treatment, planting techniques, genetically improve seed, pests and weed management practices have to be provide to boost production. Indeterminate growth habits of lentil makes not to mature at the same time and brought sever shattering problems before harvest. Harvesting while it is still green is recommended as one option to reduce shattering. Research on the development and promotion of tools (harvester) that would enable farmers to harvest lentil on time is important. Increasing farmers’ access to price information, increase the transparency of the market and would enable farmers make better selling decisions and provide increased bargaining power. The establishment of strong linkage among producers, suppliers, consumers, processors, whole sellers, and retailers is inevitable to begin value chain. A review has been made for boosting production and creating the demand for the use of improved technology keeping in view the enormous contribution of lentil for food and nutritional security.

Three-year growth response of young Douglas-fir to nitrogen, calcium, phosphorus, and blended fertilizers in Oregon and Washington

Studies of nutrient limitation in Douglas-fir forests of the Pacific Northwest focus predominantly on nitrogen, yet many stands demonstrate negligible or even negative growth response to nitrogen fertilization. To understand what nutrients other than nitrogen may limit forest productivity in this region, we tested six fertilizer treatments for their ability to increase stem volume growth response of dominant and co-dominant trees in young Douglas-fir plantations across a range of foliar and soil chemistry in western Oregon and Washington. We evaluated responses to single applications of urea, lime, calcium chloride, or monosodium phosphate at 16 sites, and to two site-specific nutrients blends at 12 of these sites. Across sites, the average stem volume growth increased marginally with urea, lime, and phosphorus fertilization. Fertilization responses generally aligned with plant and soil indicators of nutrient limitation. Response to nitrogen addition was greatest on soils with low total nitrogen and high exchangeable calcium concentrations. Responses to lime and calcium chloride additions were greatest at sites with low foliar calcium and low soil pH. Response to phosphorus addition was greatest on sites with low foliar phosphorus and high soil pH. Blended fertilizers yielded only marginal growth increases at one site, with no consistent effect across sites. Overall, our results highlight that calcium and phosphorus can be important growth limiting nutrients on specific sites in nitrogen-rich Douglas-fir forests of the Pacific Northwest.

Testing of commonly used mixing and sampling procedures to evaluate fertilizer blends prepared with matched and mismatched particle sizes.

Bulk blending of dry fertilizers is a common practice in the United States and around the world. This practice involves the mixing (either physically or volumetrically) of concentrated, high analysis raw materials. Blending is followed by bagging (for small volume application such as lawn and garden products), loading into truck transports, and spreading. The great majority of bulk blended products are not bagged but handled in bulk and transferred from the blender to a holding hopper. The product is then transferred to a transport vehicle, which may, or may not, also be a spreader. If the primary transport vehicle is not a spreader, then there is another transfer at the user site to a spreader for application. Segregation of materials that are mismatched due to size, density, or shape is an issue when attempting to effectively sample or evenly spread bulk blended products. This study, prepared in coordination with and supported by the Florida Department of Agriculture and Consumer Services and the Florida Fertilizer and Agrochemical Association, looks at the impact of varying particle size as it relates to blending, sampling, and application of bulk blends. The study addresses blends containing high ratios of N-P-K materials and varying (often small) quantities of the micronutrient Zn.

Nutrient uptake and growth of fireweed (Chamerion angustifolium) on reclamation soils

Forest land reclamation after oil sands mining requires the re-establishment of self-sustaining boreal forest ecosystems consisting of native forest plant species. This greenhouse study examined germination, growth, and nutrient uptake of fireweed (Chamerion angustifolium (L.) Holub), a circumpolar species common to the boreal forest. Fireweed was grown on a variety of reclamation soil types that varied widely in nitrogen and phosphorus contents and which were subsequently amended with different fertilizer formulations. Germination, initial root growth, and aboveground growth without fertilizer were greatest on the forest floor – mineral mix soil. With fertilization, the best fireweed growth occurred with nitrogen–phosphorus–potassium (NPK) fertilization, but with N-only or PK-only fertilization, the growth response was dependent on the soil type, indicating that site-specific fertilizer blends may be necessary for maximizing plant growth. Nutrient uptake with no fertilizer amendment was greatest in the forest floor – mineral mix soil, whereas the peat – mineral mix soil showed almost no N uptake even though it had the highest soil N supply rate. Fireweed shows great potential for use in forest reclamation as it is capable of germinating and growing on reclaimed soils and is effective in taking up nutrients from the soil, thereby promoting nutrient capture, accumulation, and likely nutrient cycling on newly reclaimed sites.

Case Study: Distribution Uniformity of a Blended Fertilizer Applied Using a Variable-Rate Spinner-Disc Spreader

Abstract. Blended fertilizers are commonly applied to crop and pasture land using spinner-disc spreaders. However, the nature of blended fertilizers can make it difficult to spread uniformly due to varying physical properties of the N, P, and K raw constituents, which can lead to segregation during application. Further, variable-rate application of blended fertilizer could pose challenges in terms of accuracy and uniformity to meet target prescription rates. Therefore, the objective of this study was to evaluate the potential of fertilizer segregation during application with a spinner-disc spreader. A series of standard pan and field tests were performed to evaluate mass and nutrient distribution for a blended fertilizer (17-17-17) using a spinner-disc spreader. Field tests were performed by generating prescription maps, randomly placing pans across the field, then applying the blended fertilizer and analyzing the collected material for N, P 2 O 5 and K 2 O mass fractions. Both mass and nutrient distribution patterns were generated and then compared. Field data in combination with prescription and as-applied maps were used to evaluate spreader performance and product segregation. A rating of 17-18-17 was determined for the blended fertilizer. P 2 O 5 and K 2 O mass fraction varied significantly (coefficient of variation, CV, 25.0% and 26.0%, respectively) based on the single-pass pattern measurements. Field application also produced high variability of P 2 O 5 and K 2 O mass fractions with CV’s ranging between 16.8% and 37.2%, respectively. These results indicated the occurrence of fertilizer segregation. Nitrogen mass fraction, spread variability was low (CV = 4%) based on the pan tests but was contributed to N being provided by both ammonium nitrate and diammonium phosphate (DAP) constituents of the blend. Particle size analysis supported the notion that segregation occurred mainly due to size variability between the constituents. During field tests, actual rates were consistently higher than the prescribed rates. While the prescription and as-applied maps showed high correlation (R = 0.75 to 0.94), the as-applied maps did not reflect the actual field application (R = 0.25 to 0.67). Finally, the existence of fertilizer segregation indicated further research is required to understand segregation of blended fertilizers when applied using spinner spreaders.

Ammonium in Nutrient Solutions Decreases Free Chlorine Concentration from Sodium Hypochlorite

The objective was to quantify the effect of water-soluble fertilizers on concentration of free chlorine level in a sodium hypochlorite solution. Research on the disinfestation strength and phytotoxicity risk of chlorine compounds is needed, because control of waterborne pathogens has been based on response to free chlorine, whereas dual injection of fertilizer and chlorine is a common horticultural practice. Free chlorine from sodium hypochlorite was applied at 2.6 mg·L−1 chlorine (Cl) to deionized water only (control) or deionized water with 11 nutrient solutions at 200 mg·L−1 nitrogen (N). Nutrient solutions included reagent-grade ammonium sulfate (NH4)2SO4, ammonium nitrate (NH4NO3), potassium nitrate (KNO3), and urea salts and seven commercial blended N–P–K water-soluble fertilizers that contained both macro- and micronutrients. Commercial fertilizers contained ammonium-N at 0% to 50% of total-N, urea-N at 0% to 14% of total-N, and nitrate-N at 50% to 93% of total-N. Free Cl (mg·L−1), total Cl (mg·L−1), and oxidation-reduction potential (ORP, in mV) were measured 2 min and 60 min after Cl was applied. Combined Cl was calculated as the difference between the total and free Cl measurements. All solutions were maintained at pH 6 and 25 °C. In the control solution, free Cl was 2.6 mg·L−1 after 2 minutes and decreased to 2.2 mg·L−1 after 60 minutes. The ammonium-containing solutions (NH4)2SO4 and NH4NO3 resulted in free Cl below 0.1 mg·L−1 after 2 minutes. Urea reacted more slowly than ammonium salts, whereby free Cl decreased to 2.3 mg·L−1 after 2 minutes and 0.4 mg·L−1 after 60 minutes. In contrast, KNO3 had less impact on free Cl with 2.4 mg·L−1 free Cl available at both 2 minutes and 60 minutes. With all commercial fertilizers tested, free Cl decreased after 2 minutes to below 0.1 mg·L−1. Total Cl remained above 2 mg·L−1 after 60 minutes in all treatments, indicating that the majority of Cl was in a combined form for ammonium and urea salts and commercial fertilizers. The ORP of commercial fertilizer blends and ammonium-containing salts was lower than 600 mV, whereas deionized water, KNO3, and urea treatments had ORP levels above 650 mV. Nutrient solutions containing ammonium or urea required 20 mg·L−1 or more of applied Cl to provide residual free Cl above 2 mg·L−1 at 2 minutes.

Effect of fertilizer potential acidity and nitrogen form on the pH response in a peat-based substrate with three floricultural species

The potential of a water soluble fertilizer (WSF) to raise or lower substrate-pH is estimated in calcium carbonate equivalents (CCE) of acidity or basicity per unit mass of fertilizer. The CCE is currently estimated using Pierre's Method, PM, which is based on assumptions as to the effects of nitrogen and other ions in field soils that may not apply in container substrates. In a greenhouse experiment, the substrate-pH change was measured with 18 WSFs that varied in the concentration of NH4-N, NO3-N, urea-N and other nutrients. ‘Ringo Deep Red’ Pelargonium×hortorum (Bailey. L.H.), ‘Super Elfin Bright Orange’ Impatiens wallerana (Hook. F.), and ‘Ultra Red’ Petunia×hybrida seedling plugs were grown in 70%:30% (v:v) peat:perlite substrate amended with dolomitic hydrated limestone. Plants in 900mL, 6-celled containers were top-irrigated with a total of 3.07L over 4 weeks at 100mgL−1 N without leaching. Plant species varied in their pH effect, in the order from acidic to basic of Pelargonium, Impatiens, and Petunia. Fertilizer CCE was positively correlated with substrate-pH, with r2 between 0.54 and 0.80 depending on the species. Multivariate regression also quantified NH4-N, NO3-N, and urea-N concentration effects on substrate-pH and CCE of applied fertilizer. Estimated mequiv. of acid (negative values) or base (positive values) per mmol of each nitrogen form applied were NH4-N −0.6678, −0.6143, −0.8123; NO3-N 0.0713, 0.2746, −0.1296; and urea-N −0.2038, −0.1445, −0.2711 for Impatiens, Petunia, and Pelargonium, respectively. Ammonium-N therefore had a strong acid effect, nitrate-N was a weak base or acid, and urea-N was a weak acid. Calculation of CCE based on PM or nitrogen alone provided a similar R2 with observed pH, despite a wide range in concentrations of macronutrients other than N in the fertilizer blends. Pierre's Method and nitrogen estimates of CCE for fertilizer blends were similar to each other (R2=0.97). However, PM estimates were biased compared with experimental results, over-predicting acidity of high-ammonium fertilizers, and over-predicting basicity of high-nitrate fertilizers. Results indicate that nitrogen form and concentration may provide a simple estimation of the acidity or basicity of blended fertilizers, although research under other growing conditions would be required. Accurate estimation of CCE is important to help growers formulate appropriate fertilizers to balance other factors such as water alkalinity and plant species.

Use of Scanning Near-Infrared Spectroscopy as a Quality Control Indicator for Bulk Blended Inorganic Fertilizers

The use of bulk blended fertilizers worldwide has become preferred to compounded chemical fertilizers. This poses new problems in obtaining a representative sample for laboratory analysis. There are huge variations in particle-size distribution, shape of particles, and bulk density. These factors results in separation when attempting to obtain smaller subsamples. Turnaround time of wet chemical analysis by the laboratories (usually 1–2 weeks) further compounds the problem. A procedure was developed to obtain reliable composition results for quality control of bulk blend fertilizers using near-infrared spectroscopy (NIRS) technology. Results are available immediately. Another challenge is obtaining reliable chemical analyses for preparing the NIRS calibrations. To overcome this, an exact formulation is prepared in the laboratory using the raw materials. The size of each such mixture (approximately 500 g) is sufficient to allow the complete sample to be scanned on a scanning NIRS instrument with rotating sample container. All raw materials are also scanned individually. Robust calibrations were obtained in this manner, and special control systems were implemented to ensure and verify the reliability of the results. The results of the NIRS were shown to be acceptable and on par with the chemical composition for the following elements: nitrogen (N), phosphorus (P), potassium (K), and sulfur (S). Better results were obtained for N if separate calibrations were prepared for N sources (urea, ammonium, and nitrate). The best results for all components were obtained using Partial Least Squares (PLS) chemometrics with Standard Normal Variant (SNV) Detrend Pathlength correction and wavelengths between 950 and 1650 nm. Calibrations for other parameters are in process.