Granular Fertilizer Application Research Articles

Study the Physical Properties of Fertilizers and Plant Basin Parameters to Design the Tractor Operated Round Basin Maker cum Fertilizer Applicator for Orchard Crop

The physical form of fertilizer production is of extremely importance, both agronomically and in regard to satisfactory handling, transport, storage, and finally application to the field. The improvement of equipment for handling, storage, and application of granular fertilizer require a proper understanding of material properties and flow behavior. The most common problems encountered in fertilizers were caking, poor flow ability, segregation, dustiness and excessive hygroscopicity due to differences of physical properties. The physical properties such as moisture content, angle of repose and bulk density as important in designing the hopper and metering roller of fertilizer plays an important role in the storage, transport and application of fertilizer. The urea, Ammonium phosphate Sulphate, complex fertilizers and fertilizer ratio (10 26 26) per one orchard tree should be applied yearly trice based on crop requirement. The angle of repose value ranges 28° -37° the hopper angle was decided. For that, to flow the fertilizer freely from the hopper, the inclined angle of the hopper should be greater than 40° respectively. The lowest bulk density and tapped density observed 0.648 kg cm-3 and 0.708 kg cm-3 respectively. Coefficient friction for galvanized Iron (GI) material is very high So, based on the obtained results, a fertilizer applicator for orchard crops has been designed. The basin diameter of orchard palm varies from 1500 mm to 1750 mm the mean of 1650 mm. The root zone depth of orchard crop varies from 150 to 180 mm at radius of 1800 mm from the base of palm. The mean 171.66 mm hence depth of operation of machine was selected as 150 mm such that the machine does not interfere with root zone of orchard trees.

Influence of Soil and Nutrient Management Practices on Crop Productivity and Quality in High Tunnel Organic Leafy Green Production

Despite the growing interest in high tunnel organic vegetable production, limited information is available regarding optimizing nutrient management for organic leafy greens. This 3-year study examined the impacts of cowpea cover crop as well as different organic fertilizers and composts on yield, leaf mineral nutrient content, and phytochemical properties of organic leafy greens produced in high tunnels under Florida sandy soil conditions. The experiment was arranged in a split-split-plot design with three replications. The whole plots consisted of a cowpea (Vigna unguiculata ‘Iron & Clay’) cover crop and a weedy fallow control, with fertilization treatments in the subplots, including preplant application of granular fertilizer vs. weekly injection of liquid fish fertilizer at the same seasonal rates of nitrogen (112 kg/ha), phosphorus (9.8 kg/ha), and potassium (74.4 kg/ha). The sub-subplots included yard waste-based compost (22.4 Mt/ha), cow manure-based compost (22.4 Mt/ha), vermicompost (5.6 Mt/ha), and no compost control. Cowpea was broadcasted (112 kg/ha) in early July or mid-August and terminated 51 to 53 days after seeding. Pac choi (Brassica rapa var. chinensis ‘Mei Qing Choi’) was transplanted in mid-Sep. or mid-Oct. and harvested after 33 to 36 days. Baby spinach (Spinacia oleracea ‘Corvair’) or baby leaf lettuce (Lactuca sativa ‘Outredgeous’) was direct seeded subsequently as a catch crop. Each experimental unit remained in the same location across the 3 years of the study. Cover cropping had little influence on yields, leaf mineral nutrients, ascorbic acid content, total phenolics, and total antioxidant capacity of pac choi and baby spinach/lettuce. Compared with preplant application of the granular organic fertilizer, weekly liquid organic fertigation improved pac choi marketable yield and dry weight by 16.8% and 5.4% on average, respectively, and enhanced leaf nitrogen and phosphorus contents on a dry weight basis. Relative to the no compost control, yard waste compost consistently improved marketable yields of pac choi by 11.6% on average and led to higher yields of the baby spinach/lettuce catch crop in years 1 and 3, suggesting that compost applications may enhance seasonal nutrient availability to better meet crop demand. However, compost application exhibited inconsistent effects on crop mineral nutrient and phytochemical contents across the years, which could be attributed to the different nutrient compositions of the composts applied in each season, as well as the legacy effects from the previous season. Furthermore, the compost benefits may be influenced by the fertilization program as indicated by their interaction effects observed in this study.

Respons Pertumbuhan dan Produksi Benih Padi (Oryza sativa L.) varietas Inpari 32 sawah terhadap pemberian pupuk granul

Rice (Oryza sativa L.) is the main food and strategic commodity for Indonesia. This study aims to determine the response of growth and seed production of rice (Oryza sativa L.) Inpari 32 paddy rice varieties to the application of granular fertilizer. This research was conducted in the experimental field owned by PT. Sang Hyang Seri (Persero) Muncar Seed Production Unit on Jl. Raya Kedungrejo No. 4 -6 Village, Kec. Muncar Kab. Banyuwangi. This study used a non-factorial Randomized Block Design (RBD) with 1 factor and 6 replications. The dose factor (P) was P1 = 0 gram/plant, P2 = 1.70 gram/plant, P3= 2.70 gram/plant, P4 = 3.70 gram/plant. Data analysis uses the F test (ANOVA) and if there is a significant difference, then proceed with the calculation of BNJ (Honest Significant Difference) with an error rate of 5%. The results showed that the addition of granular organic fertilizer at a dose of 2.70 grams had a good effect on rice plants, because it was able to produce the highest number of productive tillers, namely 35.17 productive tillers, the highest wet weight was 64.88 grams, the highest dry weight was 59.75 grams, the potential per hectare the highest is 6.42 tons per hectare and the highest number of fruit seeds is 141.67 seeds, so the yield potential is higher.

РАБОЧИЙ ОРГАН ПЛОСКОРЕЗА-ГЛУБОКОРЫХЛИТЕЛЯ УДОБРИТЕЛЯ

The factor of preserving the fertile soil layer is most relevant on sloping lands, since streams formed by melt water and precipitation wash out nutrients and humus, and also destroy the soil surface. To prevent these processes, anti-erosion working units are used. The purpose of the research is to study the effect of soil tillage by the working unit of a flat-cutter-subsoiler of a fertilizer with the simultaneous application of granular fertilizers on its filtration properties. The work was carried out at the control site located in the Chuvash Republic. The soil is loamy. The depth of tillage and application of granular fertilizers was 30 cm. As granular fertilizers, they used - granulated manure, presented on the market and used by agricultural enterprises in crop production. The filtration coefficient, porosity, and bulk density of the soil were determined. Since the subsurface cutter tills the soil without turning the layer, samples were taken in different layers of the cut layer according to GOST R 58595–2019. The filtration coefficient, which determines the ability of the soil to absorb and pass moisture, averaged 96.2 cm per day, which can be considered a good result (for loams 20 ... 100 cm per day). The porosity was 54.3% (satisfactory condition - 50 ... 55%, excellent - 55 ... 65%), the bulk density of the soil - an average of 1.05 g/cm3 (loose or freshly plowed - 1.0 ... 1.2 g / cm3). In general, after soil cultivation by the working unit of the fertilizer subsoiler with the simultaneous application of granular fertilizers, the filtration properties of the soil correspond to generally accepted reference values.

Design and Experiment of Quantitative Seed Feeding Wheel of Air-Assisted High-Speed Precision Seed Metering Device

Aiming to solve the problems of the poor uniformity of seed flow discharge and serious damage of traditional straight grooved wheels to improve the performance of air-assisted maize high-speed precision seed metering devices, a staggering symmetrical spiral grooved feeding wheel with maize seeds was designed. To explore the influence of the spiral groove inclination angle and the length of the staggered symmetrical spiral groove feed wheel on the uniformity of seed flow discharge, the spiral groove length l and the spiral groove inclination angle ρ were used as the experimental factors, and the variation coefficient of the increase in seed, a full-factor simulation test was carried out for the test indicators, and it was found that both the inclination angle and the length of the spiral groove have an influence on the uniformity of seed flow discharge, and the influence of the inclination angle of the groove is more significant. Comparing the force of a single seed in the traditional straight grooved wheel and that of the spiral feeding wheel, it is found that the staggered symmetrical spiral grooved feeding wheel can reduce the damage of seed fertilizer. Through a bench test, the spiral groove length was found to be 50 mm, and the groove inclination angles are 30°, 45° and 90°. The test results show the variation trend and simulation results of the fluctuating coefficient of variation of the seed flow discharge in the bench test. The trend of change is basically the same. The inclination angle of the spiral groove is 45° and the uniformity of seed flow discharge is the best when the groove length is 50 mm, indicating that this structure can effectively improve the uniformity of material discharge, and the variation coefficient of seed flow discharge fluctuation is 3.12% and the seed breakage rate is 0.69%. Through the seeding performance test, it is verified that the staggered symmetrical spiral grooved feeding wheel can improve the seeding performance of the pneumatic high-speed precision metering device. When the metering device runs smoothly, the qualified rate reaches more than 90%, and the leakage rate is reduced to 0%. Therefore, the results of this study can provide a reference for research on uniform seeding, drill seeding and the uniform application of granular fertilizer.

An Improved Multi-Objective Optimization Decision Method Using NSGA-III for a Bivariate Precision Fertilizer Applicator

In order to boost the performance of a bivariable granular fertilizer applicator and simplify the control methodology of fertilization rate regulation, this paper proposed a fertilization decision method to obtain the optimal combination of rotational speed and opening length by selecting the accuracy, uniformity, adjustment time, and breakage rate as the optimization objectives. We processed the outlier data collected using the indoor bench test, segmented the data with the fertilization growth rate as the index, and proved the rationality of the data segmentation by an independent sample t-test. SVM, BPNN, ELM, and RVM were used to train the two data sections to create the fertilization rate prediction model, and the models with the highest accuracy in the two data sections were selected for the assembly of the final prediction model used to describe the fertilization process of the bivariate fertilizer applicator. Moreover, the fertilization performance problem model was established with the objectives of accuracy, uniformity, adjustment time, and breakage rate and was solved using the NSGA-III algorithm to gain an optimal fertilization decision. Compared with GA and MOEA-D-DE methods, the results show that, using the new method, the average relative error declines from 8.64% and 6.05% to 3.09%, and the average coefficient of variation reduces from 6.67% and 6.81% to 6.41%, respectively. In addition, the adjustment time lowers from 2.01 s and 1.33 s to 0.78 s, and the average breakage rate drops from 1.084% and 0.845% to 0.803%, respectively. It is indicated that the presented method offers the most notable improvements in accuracy and adjustment time, while the advancements in regard to uniformity and breakage rate is slight, but both are within a reasonable range.

Effect of Deep Placement of Large Granular Fertilizer on Ammonia Volatilization, Soil Nitrogen Distribution and Rice Growth

Excessive fertilization is often applied to produce rice. To reduce nitrogen loss and improve nitrogen use efficiency (NUE), we studied the effects of application depth (surface application, 5 and 10 cm) and shape of nitrogen fertilizers (row application and deep application of large granular fertilizer) on rice growth, soil N distribution and ammonia volatilization. The results showed that grain yield, shoot biomass and total dry biomass of the treatment with N in large granular fertilizer applied at 10 cm depth were significantly higher than those of all other treatments. Moreover, compared with the surface application, the N recovery efficiency and the N agronomic efficiency of deep application treatments were enhanced by 18.1–52.3% and 35.6–95.6%, respectively. Deep application significantly increased NH4+-N concentration at their fertilization points. During the growth season, N in large granular fertilizer treatments (mixed with clay to form an unusually large pellet of 1.0–1.5 cm in diameter) distributed closer to the roots, while N in other treatments, including row application treatments, was more widely distributed. Compared with the surface application, deep application significantly reduced NH3 volatilization and NH4+-N concentration in surface water by 58.7–64.8% and 26.0–72.5%, respectively. Furthermore, the NH3 volatilization from large granular treatment was 7.6–11.0% lower than that in the row application. In conclusion, applying N in large granular fertilizer at 10 cm depth reduces ammonia volatilization, and improves rice growth and grain yield, indicating improved NUE and lowered environmental risks.

DEVELOPMENT AND TESTING OF WALK-BEHIND GRANULAR FERTILIZER APPLICATOR FOR PRECISE FERTILIZER APPLICATION

The balanced use of fertilizer play vital role to maintain required nutrients level in the plants for their better growth. Currently, most of the fertilizer addition is carried out using manual broadcasting that reduces the fertilizer use efficiency due to non-uniform fertilizer distribution. Moreover, the excessive use of fertilizer not only results fertilizer wastage but also affect output quality of produce along with environmental pollution. Thus, in order to address these serious concerns and to increase fertilizer use efficiency, this research study was carried out for the development and testing of walk behind granular fertilizer applicator. The development of the applicator was carried out using locally available materials to reduce its capital cost. The performance evaluation of fertilizer applicator was carried out under laboratory and actual field conditions to determine various parameters like application rate, fertilizer missing index, fertilizer droppage rate, wheel slippage and field efficiency. The results showed that the average fertilizer rate for maize and cotton crop was found to be 69.17 and 157.05 kg/ha respectively. The fertilizer missing index was found to be zero. The average theoretical and effective field capacity was found to be 0.245 and 0.197 ha/h respectively with an average field efficiency of 81.52%. The average wheel slippage was calculated to be 8.78%.

Digestate Potential to Substitute Mineral Fertilizers: Engineering Approaches

The study aims to define the potential and technological aspects of the digestate treatment for its application as a biofertilizer. Life cycle assessment methodology was used in terms of digestate quality management. The potential of nutrients, organic carbon, and useful microelements in the digestate allows for its consideration as a mineral fertilizer substitute and soil improver. The valorization of digestate as fertilizer requires quality management and quality control. Based on the research focus, the successful soil application of digestate post-treatment technologies was analyzed. Among the different commercial options for digestate treatment and nutrient recovery, the most relevant are drying, struvite precipitation, stripping, evaporation, and membranes technology. Comparing the physical and chemical properties of the whole digestate, separated liquid, and solid liquor fractions showed that in the case of soil application of granular fertilizer, nutrients from the digestate are released more slowly than digestate application without granulation. However, realizing this potential in an economically feasible way requires improving the quality of digestate products through appropriate technologies and quality control of digestate products. To support the manufacture of quality digestate across Europe, the European Compost Network developed a concept for a pan-European quality assurance scheme.

Theoretical prerequisites for improving the body low loader granular fertilizer spreader

It is known that the use of granular forms of fertilizers is a universal solution for plant growing enterprises using organic, mineral, organomineral fertilizers in their activities. For crop farming enterprises, the application of granular fertilizers is the most convenient way to enrich the soil with nutrients. For the surface main application and top dressing, spreaders of different designs are used, distributing fertilizers in a continuous layer with different indicators of uniformity. At present, the development of machines of various designs is underway to operate applying solid fertilizers. The main tasks of research by various authors in the field of mechanization of the distribution of fertilizers over the surface of the field are to reduce the uneven distribution of fertilizers across the width, increase the sowing width, as well as reduce the changeover time for the fertilization operation. The article presents studies related to the improvement of the design of the working bodies of the machine for applying granular fertilizers, installed on the horizontal axis of rotation. To achieve the goal of increasing the working width of the unit without reducing the quality of the sifting, an option was proposed to supplement the design of a low-frame body spreader for solid fertilizers.

Development of test bench to determine the distribution of granular fertilizers in planting rows using spiral roller, two spiral rollers and fluted roller

The success of the application of granular fertilizers (GFs) in planting rows depends on the uniformity and performance of product dispensing systems, which are influenced by external factors. The objective of this study was to determine the outflow rates of two GF formulations (GF1 04-14-08 and GF2 04-30-10) using three types of fertilizer spreader-with one spiral roller (A), two spiral rollers (B), or a fluted roller (C)-and three operating speeds (1,11, 1.94, and 2.77 m s-1). The following parameters were determined in GFs: density, angle of repose, water content, and segregation (particle size). In the designed test bench, GFs were transferred from a reservoir to a spreader, and ultimately to a container, where they were weighed, and data were transmitted to the data acquisition system (DAS). A total of 7,560 outflow data points were collected (g s-1) and subjected to descriptive analysis of measures of central tendency, dispersion, asymmetry, and kurtosis, and Shewhart control charts were generated. Particle density and segregation were significantly different between the GFs, whereas the angle of repose and water content were not significantly different. The bench design and the DAS allowed measuring the outflow of GFs in different spreaders and demonstrated that this parameter was influenced by particle segregation. The segregation of GF1 was higher than that of GF2. The outflow variability at the speed of 1.11 m s-1 was lower, and the spreader with a fluted roller had the highest uniformity and was the most suitable for application with variable rates.

Effect of Vane Shape on Fertilizer Distribution for a Dual-Disc Spinner Spreader

Abstract.Spinner-disc spreaders are commonly used for application of granular fertilizers with components (divider, spinner-discs, and vanes) influencing material flow behavior and distribution. Fertilizer ricocheting off these components is an uncontrolled aspect of material flow that negatively impacts spread uniformity. Therefore, an investigation using potash (KCl) was conducted to understand the impact of vane shape on fertilizer flow, ricocheting and distribution for a dual-disc spinner spreader. Four different vane shapes were used in this study. The first two vanes (Vanes 1 and 2) were common to this type of spinner spreader with a tapered and open-faced design. However, Vane 1 had a forward tapered top edge at an angle of 32° while Vane 2 had a top edge that was tapered backwards at 15°. Vanes 3 and 4 both had C-channel cross sections with Vane 3 tapered from inside out but Vane 4 had a constant height. Treatments included application rates of 220 and 440 kg/ha using three spinner disc speeds (600, 700, and 800 rpm). Stationary tests were conducted using a collection device that mounted around the spinner discs and vanes in order to estimate fertilizer particle exit points off the vanes. Standard pan tests were conducted to characterize resulting spread patterns, effective spread width, and spread uniformity. Results indicated that the level of ricocheting was significantly impacted by top edge design of a vane and increased with disc speed. The forward, upward facing top edge of Vane 1 caused on average, 26% of the material flow to be ricocheted by the vanes thereby inducing an uncontrolled nature of spread. However, the rearward facing top edge of Vane 2 reduced ricocheting by 13% plus generated a backward particle rotation for those contacting it. The majority of ricocheting occurred when particles contacted the vanes compared to the spinner discs. Ricocheting generated an uncontrollable aspect of the spread pattern with these particles applied along the centerline of the spreader. The effective spread width increased with disc speed. All four vane shapes generated equal effective spread widths of 18.3 and 21.3 m at 600 and 700 rpm, respectively. However, at 800 rpm, Vane 4 generated the greatest effective spread width of 24.4 m compared to 22.9 m for the other three vanes. The wider spread width for Vane 4 was contributed to the rectangular U cross-section maximizing the horizontal velocity of potash particles when exiting the vanes compared to the other three, more open faced vanes. Finally, the spread uniformity varied by vane shape with Vane 2 consistently generating the lowest CVs. Keywords: Distribution, Ricocheting, Vane Design, Spread uniformity, pattern.

Development and performance evaluation of a control system for variable rate granular fertilizer application

A study was conducted to develop a control system for variable rate application (VRA) of granular fertilizers and evaluate its performance. By the use of a microprocessor, a pneumatic cylinder and a rotary shaft encoder, the manual mechanical fertilizer rate adjustment system of a seed drill (SOLA TRISEM 294/R ESP, Model: 37193 TIPO250) was modified and transformed to a real-time automatic control system. Laboratory based tests were conducted to evaluate the developed system performance in automatically applying the predetermined desired application rates at different ground speeds, which were within the range of 3–12 km h−1. Linear regression and ANOVA tests were among the measures used to assess the accuracy of the developed system. Results of this study revealed that the developed system enabled an efficient automatic setting of the desired fertilizer application rate. The investigated operating speeds showed no significant effects on the performance of the system (P > F = 0.7968). In addition, the system exhibited an overall application rate error (difference between desired and actual application rate) of ±2.6%. The response time of the developed system was found to range between 6 and 11 ms for a change of one kilogram in the application rate.

Citrus fruit yield response to nitrogen and potassium fertilization depends on nutrient-water management system

The objectives of the present study were to investigate the influence of water supply combined with different rates and methods of nitrogen (N) and potassium (K) application on fruit yield and nutrient use efficiency (NutUE) of citrus by monitoring plant nutritional status and soil solution dynamic. The experiment was carried out with 4-yr-old Natal sweet orange trees on Rangpur lime over 4 consecutive growing seasons. Treatments were composed of 2 rates of N and K (NK): 50% and 100% of the recommended rates for maximum yield in rain-fed environments and 3 nutrient-water management systems: non-irrigation + broadcast granular fertilizer, irrigation + broadcast granular fertilizer and fertilizer application via irrigation (fertigation). Fruit yield was maximum under fertigation with application of 50% of the NK rate, and fertigation improved NutUE by 22% compared to non-irrigated trees. However, no difference in productivity and NutUE occurred across nutrient-water management systems under 100% of the NK rate. Differences in plant nutritional were not consistent across treatments and did not contribute to explain variations in fruit yield and NutUE. Soil solution analysis of fertigated trees receiving 100% of the NK rate revealed the lowest pH value and the highest concentration of N-NH4. It is concluded that fruit yield responses of citrus trees treated with established NK rates for rain-fed environments might be limited by soil solution acidification and N-NH4 toxicity when fertilizers are applied via fertigation, being necessary further adjustments on fertilization management of fertigated citrus groves.

Development of a variable rate applicator for uniform fertilizer spreading

Environmental impact and economic concerns have driven a variable rate technology (VRT). Spinner spreaders were mainly used for granular fertilizer application since they are simple in design, inexpensive, and can cover large areas. However, the spreader was not adequate for VRT because uniformity changes drastically while varying application rates. Thus, the purpose of this study was to develop a variable rate applicator with uniform spreading patterns. A commercial spreader was modified with a controller and electric actuators for controlling fertilizer discharge directions and amounts. Database was established to determine the optimum discharge direction according to the fertilizer application amount. The uniformity of spreading patterns in accordance with the spread amount per set unit area was evaluated by the statistical coefficient of variation (CV) lower than 15% is assumed to prevent damage to the crop. Test results showed that CVs were 8%, 9%, and 8%, respectively, for a tractor in race track mode (adjacent passes in same direction of travel) at 200 kg/hm2, 300 kg/hm2, and 400 kg/hm2. This indicates that the fertilizer was spread uniformly, while the coefficient of variation was 12% at 200 kg/hm2 in back and forth mode (adjacent passes in the opposite direction of travel). Overall, the results suggest that the race track mode is suitable for operation of a tractor to ensure uniform spreading of fertilizer when applying at variable rates. The future goal is to establish a system for automatic variable rate application according to location in connection with soil analysis and geographic information systems. Keywords: variable rate technology, fertilizer application, uniform spreading, spinner, granular applicator, fertilizer amount control DOI: 10.25165/j.ijabe.20191202.3242 Citation: Han C-W, Lee S-Y, Hong Y-K, Kweon G-Y. Development of a variable rate applicator for uniform fertilizer spreading. Int J Agric & Biol Eng, 2019; 12(2): 82–89.

Nitrogen Recovery and Loss from Kentucky Bluegrass Fertilized by Conventional or Enhanced-Efficiency Urea Granules

Easy handling and low unit N cost make prilled urea (46-0-0) a popular fertilizer. While incomplete recovery of granular urea applications by turfgrass is documented, field evaluations of NH3 volatilization mitigation by coatings or bioinhibitor efficiency enhancements are limited. Meanwhile, NH3 emissions reduce air quality and contribute to nutrient loading of water resources. Our objectives were to quantify 3- and 6-d ammonia emission and 9-week turfgrass recovery of unincorporated granular fertilizer application to turfgrass. In 2014 and 2015, commercial urea-N fertilizers were broadcast over a mature Kentucky bluegrass (Poa pratensis L. ‘Midnight’) lawn at 43 kg ha−1. Treatments included conventional urea and three enhanced-efficiency fertilizers; a blended fertilizer with 25% of its urea-N supplanted by polymer- and polymer-/sulfur-coated prills, or two stabilized urea fertilizers both amended by N-(n-butyl) thiophosphoric triamide (NBPT) and dicyandiamide (DCD) inhibitors. Using a 51% ‘trapping-efficiency’ flux chamber system under the field conditions described, 23.1 or 33.5% of the conventional urea-N was lost as NH3 over the respective 3- or 6-d period following application. Alternatively, dual amendment by NBPT and DCD resulted in approximately 10.3 or 19.6% NH3-N loss over the respective 3- or 6-d periods, and greater fertilizer-N recovery by the turfgrass over the 9-week experiments.

Application of Granular Organic Fertilizer to Improve Yield of Red Onion

Application of Granular Organic Fertilizer to Improve Yield of Red Onion

Design and development of a two wheel tractor driven coconut fertilizer applicator

Coconut (Cocos nucifera L.) is a perennial tree crop with about 60 years of economic life span. Decreasing soil fertility over several decades due to inadequate replenishment of the exhausted nutrients is a major problem affecting coconut production. The annual yield from a single tree can be increased from 50-70 nuts up to 100-125 nuts by proper application of fertilizer. There is no efficient method to apply fertilizer to coconut estates at present except manual application, which is laborious. The general objective of this research was to investigate an efficient method for applying fertilizer to coconut estates. After investigating physical properties of raw materials and their influences on the performance of fertilizer application, a two-wheel tractor driven granular fertilizer applicator was developed. Main components of the applicator are hopper, opposite-direction screw, two sets of furrow openers, fertilizer tubes, and a furrow closer. Power transmission from the engine to the applicator was done by chain and sprockets. The applicator was designed to apply 5 kg of fertilizer mixture per palm at an optimum speed of 1.1 km/h. The fertilizer applicator was evaluated in a coconut estate and received satisfactory results. It performed at a fertilizer feeding capacity of 0.45 ha/hr with 72.7 % efficiency. Compared to the traditional method, this fertilizer applicator could save 96.5 % of time and 94 % of the cost of fertilizer application per hectare. COCOS Vol. 20: 27-37 (2013)

Phosphorus migration analysis using synchrotron radiation in soil treated with Brazilian granular fertilizers

The aim of this study was to evaluate the phosphorus (P) mobility in a tropical Brazilian soil type red Oxisol treated with three different forms of granular fertilizer. Total Reflection X-Ray Fluorescence (TXRF) was applied to determine the concentration of P at different distances from granular fertilizer application point. The results showed that most of the P from fertilizers tends to concentrate in a region of up to 10mm around the place of the fertilizer deposition.

Growth and Nitrogen Status of Young Pecan Trees Using Fertigation

The prolonged period from tree planting to first commercial harvest of pecan [Carya illinoinensis (Wangenh.) K. Koch] provides incentive for many growers to intensively manage young trees to induce commercial production as soon as possible. This management includes high nitrogen (N) application rates with or without fertigation. However, there remains little data regarding the effect of N fertilization or fertigation on young pecan trees grown under southeastern U.S. orchard conditions. The objectives of this study were to compare the effects of fertigation with more commonly recommended forms of fertilization on growth and leaf N, phosphorous (P), potassium (K), and zinc (Zn) concentrations of first- through third-leaf pecan trees irrigated with microsprinklers. An optimal growth rate of young pecan trees was obtained as easily with a balanced granular fertilizer application using significantly less N compared with fertigation applications. The minimal treatment differences observed along with the fact that leaf N concentration never fell below the minimum recommended level in any treatment throughout the study supports the supposition that first-year pecan trees require no N fertilizer during the year of establishment. Only modest N application rates are required during the second and third growing seasons. This practice helps to promote optimal tree growth while minimizing excessive losses of N to the environment.