Granular Superphosphate Research Articles

The effectiveness of forms of mineral fertilisers and productivity of winter wheat on grey-meadow soils of Kyrgyzstan

Fertilisation of winter wheat is necessary to provide the crop with nutrients for optimal growth, development, and formation of the crop. However, the effectiveness of fertilisers may depend on their shape, soil conditions, and climate. The purpose of the study is to examine the effectiveness of using various forms of mineral fertilisers on the formation of productivity of winter wheat on grey-meadow soils of Kyrgyzstan. In 2019-2021, field experiment was conducted in the Educational-experimental Farm of the Kyrgyz National Agrarian University, named after K.I. Skryabin to achieve this goal. As a result of the study, it was identified that the formation of high yields of winter wheat is closely related to the use of nitrogen-containing fertilisers in crop rotation, which contributes to the accumulation of nitrate nitrogen in the soil. The substantial effect of ammonium nitrate and granulated superphosphate on the nitrogen regime of the soil was also noted. The concentration of carbon-ammonium-soluble phosphates is determined by the actions of ammonium sulphate, ammonium nitrate, and all forms of phosphorus fertilisers, but no special changes in the phosphate regime of the soil under the influence of forms of phosphorus fertilisers were identified. However, when using complex fertilisers, a slight accumulation of mobile phosphorus in the soil was noted. The introduction of ammonium nitrate ensures the yield of winter wheat grain at the level of 56 centner/ha, ammonium sulphate – 53.1 centner/ha. granulated superphosphate provided the highest level of winter wheat yield – 55.5 centner/ha and the highest increase in yield against the background of nitrogen-potassium nutrition – 8.7 centner/ha. Therefore, for winter wheat, after rowed precursors, it is preferable to apply ammonium nitrate from nitrogen forms of fertilisers. As an alternative to it – ammonium sulphate or urea, from phosphorus forms of fertilisers – granular superphosphate. The practical importance of the results of the study allows for developing more effective methods of using fertilisers and increasing the productivity of grain crops on grey-meadow soils of Kyrgyzstan and in other regions with similar soil and climatic conditions

Design of a shelf pneumatic classifier for separating a polydisperse mixture of granulated superphosphate

The object of this study is a polydisperse mixture of granular superphosphate. It is emphasized that existing technologies of granulation and processing of granules lead to the formation of dusty fractions of small particles. The content of small fractions in the finished product should be minimal and, in connection with this problem, the task is to remove small particles from the mixture. The purpose of the current experimental study is to classify a polydisperse mixture of granular superphosphate in a pneumatic classifier. The device includes an inclined perforated shelf with an unloading space between its end and the wall of the apparatus. It has been experimentally revealed that the maximum efficiency of extraction into the entrainment of small particles is achieved with a width of the discharge space equal to 0.5 of the length of the cross-sectional side of the apparatus; the degree of perforation of the shelf is 5 %; the angle of inclination of the shelf is 25–30°; the speed of the gas flow in the free section of the apparatus is 3.7 m/s. It is shown that the degree of extraction into the entrainment of a small fraction less than 1 mm in size reaches 70–75 %, the content of the small fraction in the carry-over is 96–98 %, and the large fraction is less than 5 %. By processing experimental data, an empirical equation was built that makes it possible to determine the concentration of particles in the gas stream for individual fractions of the material. It is shown that due to the implementation of an active aerodynamic weighing mode, the shelf pneumatic classifier works at specific loads for air flow rate less than the typical designs of fluidized bed separators. It is noted that the effective operation of the shelf pneumatic classifier in the production of granular mineral fertilizers is ensured at a productivity of no more than 10–12 t/h. With greater productivity, there is a need to install several devices in the technological line

ВПЛИВ ВАПНУВАННЯ ТА МІНЕРАЛЬНИХ ДОБРИВ НА ВРОЖАЙНІСТЬ ПШЕНИЦІ ОЗИМОЇ НА ЧОРНОЗЕМІ ОПІДЗОЛЕНОМУ

One of the factors of soil degradation is acidification, which is manifested even in chernozems that have a close to neutral or neutral in nature reaction of the soil solution. In terms of acidity, wheat belongs to the group of crops that prefer slightly acidic and close to neutral reaction of the soil environment and responds well to liming not only strong and medium acid, but also weakly acidic soils. Therefore, obtaining objective data on its response to different doses of lime and fertilizer systems in a long stationary experiment is relevant. The aim of the research was to establish the effect of liming in combination with the application of different types and doses of mineral fertilizers on the dynamics of winter wheat yield on chernozem podzolic in field crop rotation. The study was conducted in a stationary experiment (certificate NAAS №86), laid on the research field of Uman NUS, with geographical coordinates of 48 ° 46 '56,47' 'N. w. and 30 ° 14 '48.51' 'east. e. The experiment was based on a 4-field field crop rotation (winter wheat, sugar beet, corn, peas) in three fields. Growing a variety of winter wheat Mission Odesa and Lazurna. The total dose of lime was calculated by the level of metabolic acidity. A single dose of defect containing 60% CaCO3 was 9.0 t/ha. Defect, in doses of 4.5 t/ha 9.0 and 13.5 t/ha was introduced under the first three crops of crop rotation - winter wheat, sugar beet and corn. Against the background of liming mineral fertilizers were applied in the form of ammonium nitrate, granular superphosphate and potassium chloride. The issue of complex influence of different doses of defects and mineral fertilizers on the productivity of winter wheat on chernozem podzolic heavy loam of the Right-Bank Forest-Steppe of Ukraine is considered. Carrying out liming with a defect dose of 9.0 t/ha in the first rotation - increased the yield of winter wheat with the application of mineral fertilizers at a dose of N90P60K60 by 0.83 t/ha, or 12%, and in the second rotation - by 0.41 t/ha, or 7%. With the introduction of 0.5 and 1.5 doses of lime, the increase in yield for two rotations of crop rotation, respectively, was 4% and 10%. Applying 1.5 doses of lime, calculated on the basis of metabolic acidity, has a lower starting effect compared to a single dose, but has a longer aftereffect. The application of defect at a dose of 4.5–13.5 t/ha contributed to an increase in yield on average for two rotations of crop rotation by 0.17–0.35 t/ha. Improving the potassium nutrition of plants increases the efficiency of liming - the increase in grain yield is 0.28-0.63 t/ha.

Yield and quality of soybean seeds depending on inoculation and fertilizing in the conditions of the Right Bank Forest Steppe

The defining condition for increasing soybean crops productivity is the development and implementation of technologies for its cultivation, which most fully meet the genetic characteristics of the variety and take into account the interaction of plant organisms with the combined effects of hydrothermal conditions and anthropogenic factors. Among the criteria for assessing the effectiveness of technological methods of growing crops, one of the most important is their impact on the yield and quality of marketable products. The aim of the research is to establish the effect of seed inoculation by a multifunctional microbial preparation based on nitrogen-fixing and phosphorus-mobilizing bacteria and different doses and terms of mineral fertilizers application on yield and quality indicators of soybean seeds of different maturity groups in the Right-Bank Forest-Steppe conditions. Field research was conducted during 2013-2015 in the research field of SE "RF" Salivonkivske " Institute of Bioenergy Crops and Sugar Beets NAAS, of Ukraine. The soil of the experimental site is typical low-humus medium loam chernozem. The humus content in the layer 0-20 cm - 4.56%, in the layer 20-50 cm - 4.27%, the pH of the salt extract - 6.7-7.2. Content of easily hydrolyzed nitrogen (according to Cornfield) - 155-161 mg/kg of soil, mobile phosphorus (according to Chyrikov) - 44-54 mg/kg of soil, exchangeable potassium - 95-107 mg/kg of soil. The establishment of the field experiment involved the study of the action and interaction of three factors: A – variety: Vilshanka (early-ripening), Suzirya (medium-ripening); B – pre-sowing seed treatment: without inoculation, Phosphonitragin; C - fertilizers: without fertilizers (control); P60K60; N15P60K60; N30P60K60; N45P60K60; P60K60 + N15; N15P60K60 + N15; N30Р60К60 + N15. Predecessor - winter wheat. Soybean cultivation technology is generally accepted for the Right-Bank Forest-Steppe of Ukraine, except for the factors studied in the experiment. The fertilizing system provided for the application of phosphorus and potassium fertilizers (granular superphosphate and potassium salt) at the rate of P60K60 for basic tillage, as well as nitrogen (ammonium nitrate) - according to the experimental scheme: for pre-sowing cultivation and fertilizing in the budding phase. Inoculation was performed by a complex bacterial preparation for soybeans based on strains of nodule bacteria (Br.japonicum) and phosphorus-mobilizing microorganisms (B. mucilaginosus). Weather conditions in the years of research differed significantly from each other and relative to long-term averages. In 2013, the growth and development of plants took place at an average daily temperature in the range of 19.1-19.8 ℃, the amount of precipitation - 251.4-334.0 mm and the amount of active temperatures (> 10, ℃) - 2036.3-2258, 7 ℃. In 2014, the values of these indicators were, respectively, 18.6-19.5 ℃, 308.7-337.2 mm and 2020.4-2216.7 ℃; in 2015 - 21.1-21.6 ℃, 135.3-166.5 mm and 2040.5-2324.4 ℃. The aim of the research to establish the effect of seed inoculation by multifunctional microbial preparation based on nitrogen-fixing and phosphorus-mobilizing bacteria and different doses and terms of mineral fertilizers on yield and quality of soybean seeds different ripeness groups. Methods - field (to study the interaction of the research object with biotic and abiotic factors), combine harvesting (to determine the seed yield), biochemical - to determine the quality of the crop; statistical (to determine the probability of research results). It was found that the most favourable conditions for the maximum productivity of crops formation of early-maturing soybean variety Vilshanka and medium-ripening variety Suzirya both in terms of yield and yield of crude protein and oil were created by seeds bacterization by Phosphonitragin and mineral fertilizers + N30P60 . According to these indicators, the reaction of varieties to the action and interaction of technological techniques studied in the experiment was similar. Retail application of nitrogen fertilizers (for pre-sowing cultivation and fertilizing in the budding phase) contributed to the formation of higher plant productivity than a single application of the same rate of nitrogen fertilizers. Model of growing technology of intensive soybean varieties Vilshanka and Suzirya, which involved seeds inoculation by bacterial preparation based on strains of nodule bacteria (Br. Japonicum) and phosphate-mobilizing microorganisms (B. mucilaginosus) and application of N30P60K60 as base fertilizer and fertilizing provided the highest yields - 2.91 and 3.17 t/ha, respectively, which is more than in the control by 54.0 and 44.7%. In the same variant, the highest yield of crude protein and oil was obtained - in the precocious variety, respectively, 1.18 and 0.62 t/ha, in the medium-ripe variety - 1.32 and 0.63 t/ha.

Flow of simple superphosphate using two-stage decomposition of phosphorite

The methods for producing simple superphosphate by two-stage sulfuric acid decomposition of natural phosphates are analyzed. For the first stage, the process of decomposition of high-carbonate powdered phosphorite is studied depending on the rate of sulfuric acid from stoichiometry to the formation of H3PO4, its concentration and the reaction time of the starting components. For the second stage, the process of neutralization of phosphoric acid is studied, depending on the norm of phosphate rock for the formation of Ca(H2PO4)2. The drying process of superphosphate is carried out, in which granular superphosphate is obtained, and P2O5total. - 12%, P2O5free. - 4.6%, P2O5dig : P2O5total = 90%, P2O5 water : P2O5total = 79%.

Laboratory germinability and germination energy of spelt grain depending on fertilization and storage

Spelt is a promising crop for processing, as valuable micronutrients are evenly distributed in its grain, while in modern wheat bread varieties they are concentrated in the hull, aleurone layer and germ. Its proteins contain more gliadins and fewer glutenins, making gluten weak, but better digestible in the human body.
 Purpose and objectives: to assess the germinability and germination energy of spelt depending on the types, doses and timing of nitrogen fertilization and storage period.
 Materials and methods. The study was conducted in the Laboratory of Evaluation of Grain and Grain Product Quality of the Chair of Grain Storage and Processing Technologies of Uman National University of Horticulture. We studied winter spelt variety Yevropa created by hybridization of Triticum aestivum L. with Triticum spelta L. Fertilizers were ammonium nitrate, ammonium sulfate, granular superphosphate, and potassium chloride.
 Results and discussion. The study found that before storage the germination energy of grain was 87–90% depending on fertilization. Nitrogen fertilizers significantly increased this indicator. When grain was stored for 30 and 90 days, the germination energy was the highest and amounted to 98–99%. Longer storage significantly decreased this parameter. It was the lowest after P60K60 application: 95%, 92% and 87% when grain was stored for 180, 270 and 360 days, respectively.
 Before and after 30- and 90-days storage of spelt grain, this parameter amounted to 99% and regardless of fertilizers. The lowest laboratory germinability was observed after 1-year storage of grain (81–84% depending on fertilizers). This indicator was the highest with P60 + N120, amounting to 84%, and the lowest without fertilizers or with N60S70 + N60.
 Conclusions. The germination energy of spelt grain was found to be the highest after 30- to 180-day storage (96-99%). This indicator was most affected by nitrogen fertilizers. After 360-day storage, the germination energy reduced to 87–91% depending on the type and timing of nitrogen fertilization. The laboratory germinability of spelt grain of 97–99% maintained from harvesting to storage day 180. When spelt grain was stored in sealed containers without temperature control, this indicator gradually decreased to 81–84% for 360 days of storage, depending on fertilizers

УРАЖЕННЯ БУРЯКУ ЦУКРОВОГО ЦЕРКОСПОРОЗОМ І КАГАТНОЮ ГНИЛЛЮ ЗАЛЕЖНО ВІД ОСОБЛИВОСТЕЙ УДОБРЕННЯ

The results of field and laboratory research on podzolized heavy loam chernozem of the Right-Bank Forest-Steppe of Ukraine to study the effect of various fertilization systems on the infestation of sugar beet by cercosporosis and gray rot are presented. It has been found that changes in nitrogen, phosphorus and potassium nutrition have a different effect on the development of diseases. The semi-rotted cattle manure on straw bedding and mineral fertilizers in the form of aqueous ammonia, ammonium nitrate, granular superphosphate, mixed potassium salt, potassium chloride, ammonium nitrate phosphate fertilizer grade A and liquid complex fertilizers of grade 10–34–0 were used in the experiment. The rate of manure is 40 t/ha, the rate of mineral fertilizers – N120Р120К120. Fertilizers were applied in August during fall plowing, as well as in late autumn at the end of October, together with the soil subsurface loosening to a depth of 14–16 cm, and in spring – for presowing cultivation. The degree of the leaf apparatus damage by cercosporosis and the intensity of the disease development were determined. The resistance of root crops to gray rot was determined by a microbiological method. For this, cuttings from root crops were placed in Petri dishes with a provocative background of a pure culture of the fungus Botritis cinerea Pers. The conducted studies have established that, depending on the types, forms and timing of mineral fertilizers against the background of manure, the degree of the leaf apparatus infestation of beets with sugar cercosporosis varies from 24 to 48 % and increases both for insufficient and unbalanced phosphorus nutrition. At the same time, the improvement of nitrogen nutrition, especially with the late autumn application of aqueous ammonia, compared with its introduction for the August plowing, contributes to an increase in the degree of stability of the leaf apparatus of sugar beet to cercosporosis from 46.6 to 60.0 %. Improving the mineral nutrition of plants through the use of fertilizers helps to increase the resistance of root crops to decay. At the same time, depending on the fertilizer application system, the degree of stability compared to the control without fertilizers increases by 8.5–38.9 %. This was especially effectively promoted by the improvement of phosphorus nutrition of plants. A high correlation dependence was established between the damage of leaf apparatus of sugar beet by cercosporosis and the formation of a rotten mass of root crops (r = 0.85).

Bakery properties of spelt wheat grain depending on fertilization and storage period

The article presents the study results of spelt wheat grain baking properties depending on fertilization and storage period. Europe (huskless) winter spelt wheat variety obtained by hybridization of Triticum aestivum L./Triticum spelta L. was studied. For fertilization, ammonium nitrate, ammonium sulfate, granular superphosphate, potassium chloride were used. Spelt wheat grain was stored for a year without air access at an unregulated temperature regime dry (moisture content during storage – 13.0–13.5 %) in airtight polyethylene sleeves in the conditions of usual storage. It was found that spelt wheat has a high response to the application of nitrogen fertilizers. The protein content increased from 18.6 to 22.8 % in P60K60 + N120 variant. The spelt wheat grain quality varied depending on the storage period. Thus, before storage, the gluten content was 41.1–50.4 % depending on the fertilizer variant. The lowest indicator was in the control variant and for P60K60 introduction – 41.1–41.2 %. In other fertilizer variants, the gluten content was at the level of 49.1–49.9 %. The largest was in P60K60 + N60S70 + N60 –50.4 % variant or 9 % compared to the control. Storage had a positive effect on the gluten content in spelt wheat grain as its content increased signifcantly. It can be explained by the post-harvest grain ripening, in the process of which the protein-proteinase complex changes due to the oxidizing action, oxygen, in particular. Thus, after storage for 30 days, this indicator was 41.8–52.1 % depending on the experiment variant. It was the largest when N60S70 + N60 was applied – 52.1 %, and the smallest in the variant with no fertilizers and with phosphorus-potassium (P60K60) fertilizer – 41.8–42.3 %. These indicators exceeded the gluten content before storage by an average of 1.2 abs. %. The content of protein and gluten-forming fractions is the highest after storage for 90 days. These indicators almost did not change after 180–270 days of storage. After 360 days they decreased to the grain quality indicators before storage. The gluten deformation index increased to 105–108 units of GSI instrument or by 4–8 % depending on the fertilization compared to fresh grain. Gluten moisture content decreased after 30 days of grain storage, and then increased to 68.0–69.8 % after 360 days, depending on the experiment variant. The grain acidity also increased from 3.0 to 4.0–4.1 degrees. Key words: spelt wheat, fertilization, storage, protein, gluten, dynamics, moisture content, acidity.

Estimation of dimensional and qualitative parameters of disk spreader with electric drive

Purpose. Experimental methods to estimate the flight range of mineral fertilizer granules, to determine the shape of the fertilizer scattering torch, to compare the results of practical research with theoretical calculations of the flight range. Methods. Full-scale experimental studies of a mock-up sample of a fertilizer spreader. Results. To improve the quality of sieving, a multi-disc device for sifting mineral fertilizers over the field surface is proposed. It is proposed to make the device in the form of independent, functionally independent modules. Each module consists of three independent units: a fertilizer tank with an agitator; horizontal disc dispenser with calibration holes; a horizontal spreader plate. Each of the modules is equipped with its own electric drive, allowing them to be individually adjusted to a specific operating mode. As a result of studies of a prototype dispenser with active forced-batch dosing of bulk mineral fertilizers, its satisfactory performance was obtained. This makes it possible to regulate the dosage of fertilizers on the spreading disc within the specified limits, and the range of spreading the fertilizers through the individual setting of a certain number of rotational speed of the spreading disc. This arrangement does not limit their number and attachment points on the frame, and the working width of the unit will be regulated only by their number and the range of fertilizer spreading by each individual block. Conclusions. The flight range of mineral fertilizer granules depends on the frequency of rotation of the spreading disc, its height above the surface of the field, and the coefficient of windage of the fertilizers. With a change in the location of the spreading disc height from 0.2 to 1 m, at a spreading disc speed of 46.6; 33.3; 50 s-1, the spreading range for granular superphosphate (double) varies from 1.56 to 7.65 m, granular superphosphate from 1.54 to 7.24 m, granular ammonium nitrate from 1.46 to 6 m. The flight ranges of pellets obtained by practical and theoretical methods coincide within the limits of the requirements. The shape of the resulting spreading spot of fertilizer granules allows, in the case of installing several spreading modules in a line, to obtain fertilizer spreading in the form of an elongated ellipse. Keywords: mineral fertilizers, scatter torch, granules, spreading disc, rotation frequency, flight range.

ВОДОУТРИМУВАЛЬНА ЗДАНІСТЬ БУРЯКУ ЦУКРОВОГО ЗАЛЕЖНО ВІД УДОБРЕННЯ

The results of a field experiment held on podzolic black heavy loam soil of the Right-Bank Forest-Steppe of Ukraine, studying the effect of various fertilization systems on the water-holding capacity of sugar beet, are presented. It was found that the change in nitrogen, phosphorus and potassium nutrition has a different effect on this indicator when closing the leaves of sugar beet plants between rows and during the harvest time. Half-dead cattle manure KRS on straw bedding aw well as mineral fertilizers, namely aqueous ammonia, ammonium nitrate, granular superphosphate, mixed potassium salt, potassium chloride, ANP fertilizer grade A and liquid complex fertilizer grade 10–34–0 were used during the experiment. Manure was applied at a dose of 40 t / ha and mineral fertilizers – N120Р120К120. Fertilizers were applied in August during fall plowing, as well as in late autumn (at the end of October) together with moldboard-free loosening of the soil to a depth of 14–16 cm and in spring –under pre-sowing cultivation. The dynamics of the intensity of water return was monitored by cut sugar beet leaves under conditions of rapid natural evaporation by weighing them every 0.5, 1 and 2 hours (according to Arland's method). It was found that the leaves of sugar beet, both with insufficient and unbalanced nitrogen nutrition, have a weak water-holding capacity during the growing season. Improving phosphorus nutrition, especially when applying liquid complex fertilizer grade 10–34–0, helps increase the water-holding capacity of sugar beet plants throughout the growing season. Replacing potassium chloride with potassium salt mixed as part of a complete mineral fertilizer significantly increases the water-holding capacity of sugar beets due to the better provision with sodium. This is particularly evident in the second half of the growing season. With the age of sugar beet plants, a distinct decrease in the intensity of water loss is observed regardless of fertilization, which can be explained by an increase in the content of bound water due to a rise of the amount of dry matter.

УРОЖАЙНІСТЬ ПШЕНИЦІ ОЗИМОЇ ЗАЛЕЖНО ВІД СИСТЕМ ОСНОВНОГО ОБРОБІТКУ ҐРУНТУ ТА УДОБРЕННЯ

УРОЖАЙНІСТЬ ПШЕНИЦІ ОЗИМОЇ ЗАЛЕЖНО ВІД СИСТЕМ ОСНОВНОГО ОБРОБІТКУ ҐРУНТУ ТА УДОБРЕННЯ

Identification of vivianite formed on the roots of paddy rice grown in pots

An understanding of the phosphate (P) dynamics in paddy rice fields is the basis for improving P fertilizer efficiency and reducing P loss from paddy fields. During the ripening stage of rice plants cultivated in pots, we identified vivianite on the roots. We placed 3 kg of air-dried soil in a pot with coated urea (1 g N), coated potassium sulfate (1 g K2O) and granular superphosphate (1 g P2O5) as basal fertilizers. Three rice seedlings were transplanted into each pot and grown until the ripening stage under submergence outdoor conditions. The bulk soil showed a black color indicating the formation of amorphous FeS. According to the soil analysis data, the oxalate-extractable Fe content was much greater than the labile S and P contents, indicating that enough Fe(II) can be supplied to the S and P for the reaction. Bluish vivianite particles were observed on the roots using an optical microscope. Scanning electron microscopy revealed that the vivianite was an aggregate of platy crystals, and an energy dispersive X-ray analysis showed that Fe and P were the major elements in the crystal aggregates. The diffraction peak positions by the X-ray microdiffractometer were very close to the reported pattern for vivianite. Future research on the dynamics of P is expected based on vivianite formation in paddy field soils.

Nutrient fluxes in runoff on reseeded blanket bog, limed and fertilized with urea, phosphorus and potassium

Abstract. Studies have been made of the effects of 15 g N/m2 as urea in two dressings during April and June on annual nutrient fluxes in runoff from reseeded blanket bog also receiving annually 6 g P/m2 as granular superphosphate and 6 kg K/m2 as potassium chloride. Urea applications increased significantly (P < 0.05) the mean annual ammonium‐N flux from 17 mg/m2 for the P + K plots to 245 mg/m2 for the N + P + K plots. Annual fluxes of total P, K and Ca were also increased (P < 0.05) by the addition of urea. This was attributed to the effects of increased acidity around grass roots following N uptake as ammonium‐N. In contrast, nitrate‐N was removed from rainwater throughout the year and concentrations in runoff were at the limit of detection (< 0.01 mg/1) on many occasions. Concentrations of organic‐N in runoff exceeded those of ammonium‐N, but were not significantly changed by fertilization.

Effect of Single Superphosphate and Granular Superphosphate Fertilizer on Rice Yield

Effect of Single Superphosphate and Granular Superphosphate Fertilizer on Rice Yield

Wide-Swath Vertical Type Centrifugal Spreader

ABSTRACT Aprototype of a vertical spreader was constructed and tested under both laboratory and field conditions. The experimental results were used to calculate the effective swath width and uniformity of distribution of the new spreader. Optimal swath widths of 54 m and 27 m were calculated for granular superphosphate and urea, respectively, with a coefficient of variation better than 15%. A moderate side wind did not affect the swath width but reduced the uniformity of distribution. The results of the research can be applied for a wide-swath and highly effective distribution method for granular materials.

Methods of measuring residual value of fertilizers

Subterranean clover was grown on five different soils in the glasshouse with superphosphate treatments, which provided factorial combinations of previously and of currently applied phosphorus. For most treatments, powdered superphosphate was used but on two of the soils there was an additional set of treatments using granular superphosphate. In a further set of treatments on these two soils, Wimmera ryegrass was grown. Values for yield and for uptake of phosphate were used to test measures of residual value. The measure of residual value was the slope of the yield-fertilizer curve for the previous application divided by slope for the current application. Where only the rapidly ascending part of the response surface was available, linear equations satisfactorily described the response. Where the region in which yields approached the maximum was also available, a modified form of the exponential or Mitscherlich equation was found to be preferable. For linear equations, methods for calculating the confidence limits of the ratio were available. For the non-linear equations it was found that the joint confidence regions were generally symmetric and confidence regions derived by assumin g the functions were approximately linear were adequate. It was shown that the confidence limits were wide and that effects of treatments which may be small are difficult to prove. No significant effects of granulation or of level of application were detected, nor were there significant differences between the two species. With repeated clipping of the ryegrass, the previous application of phosphate became relatively less effective on a soil of low buffering capacity for phosphate and relatively more effective on a soil of high buffering capacity. Hence, residual value does not necessarily have a unique value through a season. It was suggested that these contrasting effects were due to progressive depletion of the phosphate in the soil of low buffering capacity, and to increasing root density in the, soil of high buffering capacity.

Evaluation of phosphate fertilizers: I. Immediate value of dicalcium phosphate, nitrophosphates, Gafsa rock phosphate basic slag and potassium metaphosphate for barley and ryegrass

SUMMARYThree granular nitrophosphates containing 5, 26 and 50 % of their total phosphorus in a water-soluble form, granular potassium metaphosphate, Gafsa rock phosphate and basic slag (both as powders) were compared with granular superphosphate and powdered dicalcium phosphate as standards in two annual experiments with ryegrass and in three experiments with barley.In 1960 total yields of ryegrass during a whole season were similar with all fertilizers. Nitrophosphate-5, Gafsa rock phosphate and basic slag acted more slowly than granular superphosphate and grass grew less well and took up less phosphorus during the first 12 weeks. Over the whole growing season more phosphorus was taken up by grass from powdered dicalcium phosphate and from granular potassium metaphosphate (0.5–2.0 mm) than from granular superphosphate (1.0–4.0 mm).Powdered dicalcium phosphate was equivalent to about 60% as much phosphorus applied as superphosphate to barley. Rock phosphate was almost inert and percentage granular superphosphate equivalents of basic slag and potassium metaphosphate were 22 and 23% respectively. Percentage superphosphate equivalents of the granular nitrophosphates were 1, 25 and 53% and almost equal to the water-soluble phosphate they contained.

The Dissolution and Migration of Phosphorus from Granular Superphosphate in Some Michigan Soils

AbstractThe purpose of this study was to determine the rate of dissolution and migration of phosphorus from granular superphosphate under different soil conditions. The effect of variation in soil type, soil moisture, compaction, and soluble phosphorus level in soils was considered.Laboratory studies were conducted in which fertilizer granules and tablets were placed in soils for varying time periods, after which the remaining phosphorus in the recovered granule and in the soil was measured by chemical or radioactive isotope techniques.Rapid dissolution of phosphorus from fertilizer granules in contact with moist soil was experimentally verified. At field capacity moisture contents, 50 to 80% of water soluble phosphorus moved out of the granules in 24 hours. Even in soils as low as 2 to 4% moisture, approximately 20 to 50% of the phosphorus moved from the granule into the soil in a one day period. It was found that both commercial and experimental superphosphate 4–8 mesh granules had a strong tendency to absorb moisture when placed in a saturated atmosphere. In relatively dry soils, moisture is drawn from the soil mass toward the granule, thereby forming a moist shell.The degree of soil compaction around the granule affects the rate of fertilizer dissolution. However, differences in compaction were found to have less effect than variations in soil moisture.Placing radioactive fertilizer granules in soils with extremely high available phosphorus contents or in contact with non‐radioactive superphosphate did not markedly reduce the rate of dissolution of granular phosphorus.Migration studies showed that phosphorus moved very little under the conditions studied. Maximum movement of about one inch occurred at soil moistures approximating field capacity on three soils. Most of this movement took place in the first week of a 4‐week period. Compacting soil tended to increase both dissolution and migration of fertilizer phosphorus. The larger the superphosphate granule, the more extensive was phosphorus migration.