Polyolefin-coated Urea Research Articles

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English

Fate and efficiency of 15N-labelled slow- and controlled-release fertilizers

Slow- and controlled-release N fertilizers are designed to increase efficiency and reduce N losses by better synchronizing N availability with plant demand. This paper reviews the use of 15N with these fertilizers to collect quantitative data on the efficiency, residual value and N losses for which relatively few data are available compared with conventional labelled urea and ammonium-based fertilizers. In general, studies of slow-release forms (isobutylidene diurea, oxamide, ureaform) with rice and upland crops show one or more benefits, including improved N uptake efficiency, and reduced N losses via leaching or NH3 volatilization under conditions which favor such losses (coarse textured soils, alkaline pH, respectively). Benefits from residual 15N may accrue in the year following application. Studies with controlled-release 15N-labelled sulfur coated urea (SCU) show benefits in situations such as paddy soils where losses from broadcast urea are a substantial problem. In experiments with 15N polyolefin-coated urea (POCU), rice plant recovery of broadcast conventional urea or ammonium salts ranged from 24 % with losses of 50–45 % with losses of 33 %. Where 15N labelled SCU or POCU was used, the rice recovery ranged from 26 % with losses of 14–72 % with losses of 10 %. Experiments using POCU with corn, barley and potato show similar results. The paucity of published data obtained using 15N points to the need for further studies that will provide concrete evidence for the development of innovative fertilizers with enhanced efficiency and an evidence-based set of recommendations for their selection and use.

Effects of phosphorus-based application of animal manure compost on the yield of silage corn and on soil phosphorus accumulation in an upland Andosol in Japan

Animal manure contains significant amounts of nitrogen (N) and phosphorus (P) that can be utilized as fertilizer. However, manure application rates are generally set to meet crop N demand, which results in excess P application which increases the risk of P loss into bodies of water. We examined the application method of manure compost based on crop P demand on the dry matter yield of silage corn (Zea mays L. var. indentata), on nutrient uptake and on soil P accumulation in an upland Andosol with a high P-fixing capacity. Cattle and poultry manure composts (CMC and PMC) with different P solubility were applied to meet the crop’s N requirements (N-based application) or P requirements (P-based application) in 3 consecutive years. Supplemental N was applied using polyolefin-coated urea in the P-based treatments. The dry matter yields and nutrient uptakes of silage corn in the P-based CMC and PMC application systems were similar to those in the corresponding N-based systems. The average relative efficiency of N in CMC (33%) was close to the predicted value (30%) during the study. On the other hand, the relative efficiency of N in PMC (42%) was higher than the predicted value (28%). The average relative efficiency of P from CMC and PMC was 109% and 50%, respectively. These were higher than the predicted values based on the available P proportion (the sum of water- and sodium bicarbonate-soluble P) for CMC (78%) and PMC (34%), indicating that the available P fraction in the manure composts was more effective than that in P fertilizer for corn growth or that the other P fractions were also effective for corn. P-based manure compost application lowered the soil P accumulation to between 41 and 43% of the value in the N-based accumulation (versus a value of between 31 and 40% of that value for soil Truog-P). Compared to N-based manure compost application, P-based manure compost application with supplemental N fertilizer produced similar dry matter yields of corn and suppressed soil P accumulation in the upland Andosol field.

Polyolefin‐Coated Urea Decreases Ammonia Volatilization in a Double Rice System of Southern China

Field evaluations of slow‐release N fertilizers are needed to improve N use efficiency while reducing NH3 volatilization. Ammonia volatilization losses, floodwater NH4+, and aboveground rice (Oryza sativa L.) tissue N accumulation were compared between non‐coated urea (NCU) and polyolefin‐coated urea (POCU) applications in a double‐rice production system of subtropical China. A factorial treatment design included two urea sources such as POCU and NCU applied at 75 and 150 kg N ha−1, and a no‐N control. For early and late rice seasons, floodwater NH4+ and pH increased significantly within 7 to 10 d after NCU applications and then decreased rapidly. Nitrogen losses through NH3 volatilization accounted for 16 to 30% and 4 to 8% of the total N applied for NCU and POCU, respectively. Applications of POCU significantly increased N accumulation in aboveground rice biomass due to a slower N release and better synchrony between in‐season rice N demand and N supply from this fertilizer. Applications of POCU at a rate of 75 kg N ha−1 provided the optimal amounts of N for early and late rice crops and reduced NH3 volatilization losses. The use of slow release urea fertilizers should increase N use efficiency and maintain the high grain yield in the double rice production systems of subtropical China.

Recovery and Leaching of 15N-Labeled Coated Urea in a Lysimeter System in the North China Plain

The effectiveness of polyolefin-coated urea (Meister-5 and Meister-10; CU) in a wheat (Triticum aestivum L.)-maize (Zea mays L.) rotation system was studied in lysimeter plots located in the North China Plain for three consecutive maize-wheat-maize cropping seasons. An isotopic method was used to compare the fate of CU to that of non-coated urea (NCU), and N application rates of 0, 100, 150 and 225 kg N ha −1 were evaluated. The results showed that the nitrogen use efficiency ( 15NUE) of CU was 13.3%–21.4% greater than that of NCU for the first crop. Alternatively, when the difference method was applied (apparent NUE), no significant variations were observed among treatments in all three seasons. Although inorganic N leached from the 1.3 m layer was less than 1% of the total applied N, unidentified losses of 15N (losses of 15N = 15N applied as fertilizer – 15N absorbed by crops – 15N remaining in the 0–0.2 m layer – 15N leached from the 1.3 m layer) in CU-treated plots were 24.2%–26.5% lower than those of NCU-treated plots. The nitrate concentration in the 0–1.3 m layer of CU plots at the end of the experiment was 53% lower than that of NCU-treated plots. Thus, CU increased crop N uptake from fertilizer and reduced unidentified losses of applied N, which can reduce the risk of groundwater pollution.

Use of Polyolefin-coated Urea to Improve Indica Rice Cultivation in Sandy Soils of the West African Lowlands

Use of Polyolefin-coated Urea to Improve Indica Rice Cultivation in Sandy Soils of the West African Lowlands

Inhibition of seedling establishment by nitrogen application in direct sowing culture of paddy rice in old region

The effects of the nitrogen application rate and type of nitrogen fertilizer on rice seedling establishment for seeds without or with calcium peroxide coating under drained paddy field conditions were investigated. The seedling establishment rate for the seeds without coating decreased with the application of ammonium sulfate (AS) at the rates of 4 and 8 g m−2. The pH in the soil solution was in the appropriate range for rice growth, and the ferrous ion concentration and EC in the soil solution were lower than the threshold for rice growth in all the plots. The ammonium nitrogen concentrations in the soil solution in the AS application plots were exceeded 2 mg kg−1, which is the threshold for seed emergence. Seedling establishment for the seeds with calcium peroxide coating was not inhibited by the AS application even at the rate of 8 g m−2. The application of ammonium phosphate (AP), urea (U), and polyolefin-coated urea (PCU) at the rate of 4 g m−2 did not inhibit the seedling establishment in the case of both calcium peroxide-coated seeds and non-coated seeds. The ammonium nitrogen concentration in the soil solution at the time of sowing was less than 2 mg kg−1 in all the treatments except for the AS treatment. These results showed that nitrogen application, which increases the ammonium nitrogen concentration in the soil solution at sowing, inhibits seedling establishment for non-coated seeds and does not inhibit seedling establishment for coated seeds.

Nitrate leaching and nitrogen recovery following application of polyolefin-coated urea to potato.

High N fertilizer and irrigation amounts applied to potato (Solanum tuberosum L.) on coarse-textured soils often result in nitrate (NO3) leaching and low recovery of applied fertilizer N. This 3-yr study compared the effects of two rates (140 and 280 kg N ha(-1)) of a single polyolefin-coated urea (PCU) application versus split applications of urea on 'Russet Burbank' potato yield and on NO3 leaching and N recovery efficiency (RE) on a loamy sand. Standard irrigation was applied in all years and excessive irrigation was used in another experiment in the third year. At the recommended rate of 280 kg N ha(-1), NO3 leaching during the growing season was 34 to 49% lower with PCU than three applications of urea. Under standard irrigation in the third year, leaching from five applications of urea (280 kg N ha(-1)) was 38% higher than PCU. Under leaching conditions in the first year (> or = 25 mm drainage water in at least one 24-h period) and excessive irrigation in the third year, PCU at 280 kg N ha(-1) improved total and marketable tuber yields by 12 to 19% compared with three applications of urea. Fertilizer N RE estimated by the difference and 15N isotope methods at the 280 kg N ha(-1) rate was, on average, higher with PCU (mean 50%) than urea (mean 43%). Fertilizer N RE values estimated by the isotope method (mean 51%) were greater than those estimated by the difference method (mean 47%). Results from this study indicate that PCU can reduce leaching and improve N recovery and tuber yield during seasons with high leaching.

Nitrate Leaching and Nitrogen Recovery Following Application of Polyolefin-Coated Urea to Potato

Nitrate Leaching and Nitrogen Recovery Following Application of Polyolefin-Coated Urea to Potato

EFFECT OF WATER MANAGEMENT AND POLYOLEFIN-COATED UREA ON GROWTH AND NITROGEN UPTAKE OF INDICA RICE

ABSTRACT Poor water management and high nitrogen (N) losses are the key problems faced by rice farmers under rainfed inland valley systems. There is a need to evaluate different N fertilizers so as to identify one that could withstand these problems. The performance of polyolefin-coated urea (POCU) was therefore compared with conventional urea in a pot experiment with indica rice (Oryza sativa L. cv. IR36), using two water management systems: 1) Submerged condition referred to as good water management (GWM), and 2) excessive irrigation (over 4000 mm in 120 days) referred to as poor water management (PWM). The study was carried out during 1997 and 1998 cropping seasons under glasshouse conditions. For PWM in 1997, the pots were subjected to leaching only whereas in 1998, they were subjected to both surface runoff and leaching. For both cropping seasons, POCU-treated plants under PWM had a significantly higher grain yield (377.5 and 343.0 g m−2) than urea-treated plants (316.5 and 260.5 g m−2). In addition, POCU-treated plants had a significantly higher number of grains per panicle than urea-treated plants. In 1998, both the partial factor productivity of applied N and the agronomic nitrogen-use efficiency of POCU-treated plants under GWM and PWM were significantly higher than those of urea-treated plants. It can be inferred that (using sandy soils and under PWM), POCU could perform significantly better than conventional urea. This finding is important, considering the usually high nitrogen losses in rice-growing inland valley swamps.

Nitrous oxide and nitric oxide emissions from maize field plots as affected by N fertilizer type and application method

N2O and NO emissions from an Andisol maize field were studied. The experimental treatments were incorporation of urea into the plough layer at 250 kg N ha–1 by two applications (UI250), band application of urea at a depth of 8 cm at 75 kg N ha–1 plus incorporation of urea into the plough layer at 75 kg N ha–1 (UB150), band application of polyolefin-coated urea at a depth of 5 cm at 150 kg N ha–1 (CB150), and a control (without N application). N2O fluxes from UI250 and UB150 peaked following the incorporation of supplementary fertilizer, and declined to the background level after that, while the N2O flux from CB150 was relatively low but remained at a constant level until shortly after harvest. Accordingly, the total N2O emissions during the whole cultivation period from the three treatments were not significantly different. The fertilizer-derived N2O-N losses from UI250, UB150 and CB150 were 0.15%, 0.27% and 0.28% of the applied N, respectively. However, it was suggested that, due to the low plant N recovery, UI250 had a significantly larger potential for indirect N2O emission than the other treatments. On the other hand, NO emissions from UI250 and UB150 were 12 times higher than that from CB150, and the fertilizer-derived NO-N losses from the three treatments were 0.16%, 0.27% and 0.026% of the applied N, respectively. Significant NO fluxes were detected only when urea-N fertilizer was surface-applied and incorporated into plough-layer soil.

Evaluation of Polyolefin-coated Urea for Potato Production on a Sandy Soil

Field studies were conducted on a Hubbard loamy sand (sandy, mixed, frigid Entic Hapludoll) during 1996 and 1997 at Becker, Minn., to evaluate the effect of a polyolefin-coated urea (POCU) fertilizer (Meister, Chisso Co., Japan) on yield and quality of irrigated `Russet Burbank' potatoes (Solanum tuberosum L.). The POCU was a 3:1 mixture of 70-day and 50-day release formulations, respectively, based on historical soil temperatures at the site. The study compared five banded nitrogen (N) rates (110, 155, 200, 245, and 290 kg·ha-1 N) as a split application of urea applied at emergence and hilling, vs. POCU applied at planting. All plants received an additional 30 kg·ha-1 N as monoammonium phosphate band-applied at planting. Yields were higher in 1996 because of cooler temperatures and poor tuber set in 1997. Total and marketable yields averaged, respectively, 3.9 and 3.3 Mg·ha-1 higher with POCU than with urea. Total yield was not affected by rate of N application regardless of source, but marketable yield increased linearly with N rate. The yield of marketable tubers larger than 170 g increased linearly with N rate in both years. Gross return was 10% higher with POCU than with urea, but estimated net return showed a significant sourc × N rate interaction. The net return increased by $3.13 per kg of urea-N applied, but there was no significant change across POCU application rates.

Polyolefin-coated urea as a fertilizer for rice on soil with high nitrogen leaching loss

Polyolefin-coated urea as a fertilizer for rice on soil with high nitrogen leaching loss

Reducing nitrate content in lettuce using polyolefin-coated fertilizers

Pot experiments were conducted in order to investigate the effects of the controlled-release characteristic, nitrogen form and application method of polyolefin-coated fertilizers on the nitrate content and yield of lettuce (Lactuca sativa L.). Comparing broadcast application of polyolefin-coated urea (POCU) and urea at four fertilization levels, it was found that application of POCU decreased the nitrate content and increased the yield, due solely to its controlled-release characteristic. Comparing band applications of POCU or polyolefin-coated diammonium-phosphate (POC-DAP) to broadcast application of ammonium nitrate, it was found that a band application of both urea and ammonium containing polyolefin-coated fertilizers can decrease nitrate content in lettuce, without causing any significant yield decrease. This was a combined effect of the controlled-release characteristic and realized ammonium nutrition. Comparing effects of broadcast, band and spot applications of POC-DAP, it was found that nitrate content, was the lowest in the spot application treatment. However, considering both nitrate content and yield, band application was found to be the most effective application method.

455 Response of Irrigated Potatoes to Polyolefin-coated Urea

Polyolefin-coated fertilizers are slow-release fertilizers coated with thermoplastic resins that have a temperature-dependent nutrient release pattern. A field study was conducted on a Hubbard loamy sand during 1997 and 1998 at Becker, Minn., to evaluate the effect of polyolefin-coated urea (POCU) fertilizers (Meister, Chisso Co., Japan) on yield and quality of irrigated `Russet Burbank' potatoes (Solanum tuberosum L.). The coated fertilizers were POCU-50 and POCU-70, which release 80% of their N in 50 and 70 days, respectively, at 25 °C, and a 1 POCU-50: 1POCU-70 mixture. The study compared three soluble urea treatments (N at 0, 140, and 280 kg·ha-1) split-applied at planting, emergence, and hilling vs. the same N rates of coated urea fertilizers applied in a band at planting. In 1997, a season characterized by high leaching, total and large tuber (>168 g) yields were higher with coated urea sources than soluble urea at equivalent N rate, but the N sources gave similar yields in 1998 when leaching was minimal. In both years, doubling the rate of N as soluble or coated urea from 140 to 280 kg·ha-1 had no effect on total yield, but increased the marketable yield (tuber size). Yields were higher in 1998 compared to 1997 due to poorer tuber set in 1997. However, the percentage of large tubers was higher in 1997. Specific gravity increased slightly with N rate but did not differ with N source at equivalent N rate. Hollow heart incidence was similar among all treatments in 1997, but it increased with N rate and was similar among N sources in 1998.

Mitigation Alternatives to Decrease Nitrous Oxides Emissions and Urea‐Nitrogen Loss and Their Effect on Methane Flux

AbstractNitrous oxide (N2O) and methane (CH4) are greenhouse gases that are contributing to global warming potential. Nitrogen (N) fertilizer is one of the most important sources of anthropogenic N2O emissions. A field study was conducted to compare N‐use efficiency and effect on N2O and CH4 flux, of urea, urea plus the nitrification inhibitor dicyandiamide (U + DCD), and a control release fertilizer, polyolefin coated urea (POCU) in irrigated spring barley (Hordeum vulgare L.) in northeastern Colorado. Each treatment received 90 kg urea‐N ha−1 and microplots labeled with 15N‐fertilizer were established. Average N2O emissions were 4.5, 5.2, 6.9, and 8.2 g N ha−1 d−1 for control, U + DCD, POCU, and urea, respectively. During the initial 21 d after fertilization, N2O emissions were reduced by 82 and 71% in the U + DCD and POCU treatments, respectively, but continued release of N fertilizer from POCU maintained higher N2O emissions through the remainder of the growing season. No treatment effect on CH4 oxidation in soils was observed. Fertilizer 15N found 50 to 110 cm below the soil surface was lower in the POCU and U + DCD treatments. At harvest, recovery of 15N‐fertilizer in the plant‐soil system was 98, 90, and 85% from POCU, urea, and U + DCD, respectively. Grain yield was 2.2, 2.5, and 2.7 Mg ha−1 for POCU, urea, and U + DCD, respectively. Dicyandiamide and POCU showed the potential to be used as mitigation alternatives to decrease N2O emissions from N fertilizer and movement of N out of the root zone, but N release from POCU does need to be formulated to better match crop growth demands.

Properties and Use of MEISTER (Polyolefin-coated Urea) with Accurately Controlled Availability in Japan

Polyolefin-coated urea commercially called “MEISTER” was invented by T. Fujita and his co-workers. It shows primarily temperature-dependent dissolution and is divided into two groups of dissolution: ordinary (linear) and delayed (sigmoid). The dissolution of MEISTER in the soil is predicted easily with reasonable accuracy by a portable computer using temperature data. Thus, we can select kinds of MEISTER that can release N meeting the plant demand. It has been common knowledge that polymer-coated materials are used mainly on lawns, professional turf, and container-grown ornamental and horticultural plants and to a limited extent, in vegetable production. However, MEISTER is applied not only to high-value crops but also to low-value crops in Japan because this fertilizer can contribute to innovative fertilizer placement and farming systems (described later in this abstract), thereby the total farming cost can be notably reduced. Innovative fertilizer applications; co-situs placement and single basal application Innovative farming systems; paddy rice 1) no-till rice culture by direct-seeding and a single basal co-situs application and 2) no-till transplanting rice culture by single basal fertilization; and upland and horticultural crops 1) multi-cropping by a single basal fertilization and 2) no-till cropping by a single basal co-situs application.

Single Basal Fertilization of MEISTER (Polyolefin-coated Urea) to Cyclamen

A capillary watering system can easily control water supply to cyclamen and can save nutrient losses by leaching. Introduction of single basal placement using MEISTER will be useful to innovate the traditional cyclamen culture. The conventional cyclamen culture using Nutricote needs double transplanting and double fertilization. In the new cyclamen culture, cyclamen seedlings (sowed on the plug tray in early January) were transplanted to 15-cm pots fertilized with MEISTER in early June. The selected MEISTER was one belonging to the sigmoid dissolution group, which showed delayed release during summer and the maximum release in early September. The new fertilization supplied N to the plants until the end of growing season. The growth of cyclamen plants on two experimental plots were compared at the flowering stage. Numbers and weight of flowers per pot and bulb weight were greater in the new culture than in the conventional culture though the total volume of leaves was less in the former. Regarding the nutrient absorption, the plants of the new culture showed lower concentrations of N and P in the leaves but higher concentrations of Ca and Mg compared to those in the conventional culture. Such nutrient uptake could contribute to preventing the occurrence of tipburn in the new culture.

A Single Basal Application of MEISTER (Polyolefin-coated Urea) to the Strawberry Greenhouse Soil in Kumamoto, South Japan

It is not uncommon that tipburns, deformation, and poor coloring of strawberries, delaying of differentiation of flowering buds and flowering, etc., occur reflecting rapid changes in soil solution concentrations by repeated applications of conventional fertilizers. These physiological disorders contribute to lowering the yield and quality of strawberries to a significant extent. Polyolefin coated urea called “MEISTER” is one of the excellent controlled availability fertilizers whose dissolution is primarily controlled by temperature. Therefore, blended materials of a few MEISTER products can supply N matching the plant demand for the long growing season (8 months). This results in contributing to the prevention of occurrences of the physiological disorders described above. Treatment plots using blended materials of MEISTER products were early dissolution, even dissolution, and late dissolution and were fertilized with a single basal application. Compared with the conventional plot, the late dissolution plot was most suitable for strawberry growth, producing the largest yield of high quality. The new fertilization using MEISTER will contribute to decreasing the amount of fertilizer to apply, eliminating topdressing, saving labor cost, etc.

An Innovative Application of MEISTER (Polyolefin-coated Urea) to Strawberry Pots to Supply N for the Whole Growing Season in Kumamoto, South Japan

A hundred days and 240 days are required for growing strawberry plants in the nursery and in the greenhouse, respectively. Therefore, fertilization using conventional fertilizers is often repeated. To eliminate repeated topdressing, to decrease the amount of N to apply, and to save farming labor, a new fertilization method using MEISTER was studied. Since MEISTER is an excellent controlled fertilizer, the new method can apply all N necessary to grow strawberry plants almost for a year only by a single application (no N fertilizer is applied to the greenhouse soil). The experimental plots basically consist of two kinds of treatment: changing ratios of soil volume per pot or per plant (50 to 800 ml/pot) and kinds and levels of fertilizers (conventional fertilizer and two kinds of MEISTER). The experimental results showed 1) soil of ≥200 ml/pot is necessary to grow strawberry seedlings in summer when the soil is subjected to drying, 2) a blended material of two MEISTER products with sigmoid dissolution can supply N for the whole growing season, and 3) MEISTER application can reduce 40% of the total N conventionally applied.