Evaluation of alternative containers to determining the working width of fertilizer spreaders

Farmers have difficult of determining the evenness of transverse distribution and the working width, due the tests with this aim require equipments and complex methodologies. So, this study evaluates some alternative containers with the aim to allow a more accessible adjustment of the full width of the solid fertilizer spreaders. Four different containers were tested: i) standard container constructed in accordance with ISO 5690/1; ii) container of polyethylene (plastic trays) with screen shading to prevent the ricochet of material; iii) containers composed by boxes of long-life milk, and iv) containers composed by flowerpots (number 3.5). Also, three different spreaders were used for the tests. Alternative containers showed greater retention of particles than the standardized containers. The full width of work obtained for the coefficients of variation of 12.5; 15; 17.5 and 20%, ranged due the containers in the different pathways. The flowerpots of polyethylene showed similar results to the standardized containers. The heights of the containers were more important for its efficiency than its area of collection.

Soil chiseling and fertilizer location in sugarcane ratoon cultivation

While the pre-harvest sugarcane burning is a disused practice, green harvest requires changes concerning ratoon cultivation due to the presence of a thick layer of straw. The experiment, conducted in a mechanical green harvesting area cultivated with sugarcane, consisted of two stages: in the first stage, the mechanical straw cutting performance of flat disks with different geometry edges was evaluated, considering two types of disks and 10 replications in a completely randomized design; in the second stage, the effect of soil chiseling on both sides of planting lines, using shanks with straw cutting flat disks, was assessed, as well as fertilizer deposition form. The experimental design in the second stage was completely randomized, with seven treatments and five replications. Treatments consisted of a combination of two straw cutting disks (smooth or toothed edge), chiseling presence or absence, and fertilizer deposition forms (broadcast, on the planting line, and incorporated into chiseling furrows). The toothed disk differed from the smooth one, presenting lower values of horizontal and vertical forces, and torque. The agroindustrial variables pol (%), brix (%), fiber (%), and ATR (kg Mg-1) were not influenced by the fertilizer deposition form and soil chiseling. However, the localized fertilizer deposition increased crop yield when compared with broadcast fertilization.

Electrically driven fertilizer applicator controlled by fuzzy logic

The present study shows the development, simulation and actual implementation of a closed-loop controller based on fuzzy logic that is able to regulate and standardize the mass flow of a helical fertilizer applicator. The control algorithm was developed using MATLAB's Fuzzy Logic Toolbox. Both open and closed-loop simulations of the controller were performed in MATLAB's Simulink environment. The instantaneous deviation of the mass flow from the set point (SP), its derivative, the equipment´s translation velocity and acceleration were all used as input signals for the controller, whereas the voltage of the applicator's DC electric motor (DCEM) was driven by the controller as output signal. Calibration and validation of the rules and membership functions of the fuzzy logic were accomplished in the computer simulation phase, taking into account the system's response to SP changes. The mass flow variation coefficient, measured in experimental tests, ranged from 6.32 to 13.18%. The steady state error fell between -0.72 and 0.13g s-1 and the recorded average rise time of the system was 0.38 s. The implemented controller was able to both damp the oscillations in mass flow that are characteristic of helical fertilizer applicators, and to effectively respond to SP variations.

Technology for sugarcane agroindustry waste reuse as granulated organomineral fertilizer

Aiming to evaluate the use of sugarcane industry waste such as byproducts from vinasse concentration process, it was assessed the organomineral fertilizer BIOFOM (concentrated vinasse, filter cake, boiler ash, soot from chimneys and supplemented with mineral fertilizers). The study included characterization and agronomic potential analysis of a test plant (corn), by noting the differences between mineral fertilizers and BIOFOM fertilization until 45 days after sowing. The technology traditionally used to produce BIOFOM was based on vinasse evaporation with high heat transfer coefficients. It was observed that the technology, which can be formulated according to the needs of any crop, could be used in many cases as mineral fertilizer. Therefore, the use of this organomineral fertilizer reduces waste generation of sugarcane industry.

LONG-TERM EFFECTS OF SWINE wastewater AND MINERAL FERTILIZER ASSOCIATION ON SOIL MICROBIOTA

ABSTRACT Swine wastewater (SW) application in agricultural soils may affect its microbial community in a long term. The objective of this study was to evaluate prospective changes in soil bacterial community after eight years continuous application of swine wastewater. The wastewater doses tested were 0; 100; 200 and 300 m3 ha-1, being applied from the beginning of the experiment and with or without recommended fertilization. Three soil samples were taken from each plot for determinations of basal respiration, microbial biomass and metabolic quotient. We also performed DGGE analysis and made a correlation between soil chemical conditions and microbial activity. Microbial community underwent significant structural changes from swine wastewater applications. Higher SW doses (200 and 300 m3 ha-1) influenced significantly (p <0.05) and benefitted certain bacteria groups.

Response of weed populations to tillage, reduced herbicide and fertilizer rates in wheat (Triticum aestivum) production

Field experiments were carried out in 1999 and 2000 to investigate the effects of conventional (CT) and no-tillage (NT) systems, interacting with three herbicide dose levels and three nitrogen (N) levels on weed growth and wheat production of two varieties. There was a higher grain yield for NT system compared with CT in one year. CT weed biomass was lower than from NT weed biomass, in both varieties. No differences on wheat biomass and grain yield were observed between full and reduced herbicide rates. N fertilizer increased wheat biomass and grain yield significantly. Only N medium level had an effect upon weed biomass with respect to non-fertilized plots, while the highest fertilization rate lowered weed biomass. Conventional tillage, reduced herbicide rates and nitrogen fertilization were effective ways of limiting weed production in wheat.

GROWTH AND YIELD RESPONSE OF MAIZE (Zea mays) TO INTER AND INTRA-ROW WEED COMPETITION UNDER DIFFERENT FERTILIZER APPLICATION METHODS

A field experiment was conducted for two consecutive years to study the effect of fertilizer application methods and inter and intra-row weed-crop competition durations on density and biomass of different weeds and growth, grain yield and yield components of maize. The experimental treatments comprised of two fertilizer application methods (side placement and below seed placement) and inter and intra-row weed-crop competition durations each for 15, 30, 45, and 60 days after emergence, as well as through the crop growing period. Fertilizer application method didn't affect weed density, biomass, and grain yield of maize. Below seed fertilizer placement generally resulted in less mean weed dry weight and more crop leaf area index, growth rate, grain weight per cob and 1000 grain weight. Minimum number of weeds and dry weight were recorded in inter-row or intra-row weed-crop competition for 15 DAE. Number of cobs per plant, grain weight per cob, 1000 grain weight and grain yield decreased with an increase in both inter-row and intra-row weed-crop competition durations. Maximum mean grain yield of 6.35 and 6.33 tha-1 were recorded in inter-row and intra-row weed competition for 15 DAE, respectively.

Intensification of Operation of Inclined Plate Settler at Fertilizer Plant

Fertilizer plant’s process waters contain high concentrations of nitrogen compounds, such as ammonium and nitrate. Phosphorus and fluorine, which originate from phosphoric acid and rock phosphate (apatite) used in fertilizer production, are also present. Phosphorus and nitrogen are the primary nutrients causing eutrophication of surface waters. At fertilizer plant process waters are held in closed internal circulation. In a scrubber system process waters are used for washing exhaust gases from fertilizer reactors and dry gases from granulation drums as well as for cooling down the fertilizer slurry in neutralization reactor. Solids in process waters are separated in an inclined plate settler by gravitational sedimentation. However, the operation of inclined plate settler has been inadequate. The aim of this thesis was to intensify the operation of inclined plate settler and thus the solids separation e.g. through coagulation and/or flocculation process. Chemical precipitation was studied to reduce the amount of dissolved species in process waters. Specific interest was in precipitation of nitrogen, phosphorus, and fluorine containing specimens. Amounts of phosphorus and fluorine were reduced significantly by chemical precipitation. When compared to earlier studies, annual chemical costs were almost eight times lower. Instead, nitrogen compounds are readily dissolved in water, thus being difficult to remove by precipitation. Possible alternative techniques for nitrogen removal are adsorption, ion exchange, and reverse osmosis. Settling velocities of pH adjusted and flocculated process waters were sufficient for the operation of inclined plate settler. Design principles of inclined plate settler are also presented. In continuation studies, flow conditions in inclined plate settler should be modelled with computational fluid dynamics and suitability of adsorbents, ion exchange resins, and membranes should be studied in laboratory scale tests.

Effects of fertilizer type and rate on partitioning of soil organic matter into pools of different stability

Type and rate of fertilizers influence the level of soil organic carbon (Corg) and total nitrogen (Nt) markedly, but the effect on C and N partitioning into different pools is open to question. The objectives of the present work were to: (i) quantify the impact of fertilizer type and rate on labile, intermediate and passive C and N pools by using a combination of biological, chemical and mathematical methods; (ii) explain previously reported differences in the soil organic matter (SOM) levels between soils receiving farmyard manure with or without biodynamic preparations by using Corg time series and information on SOM partitioning; and (iii) quantify the long-term and short-term dynamics of SOM in density fractions and microbial biomass as affected by fertilizer type and rate and determine the incorporation of crop residues into labile SOM fractions. Samples were taken from a sandy Cambisol from the long-term fertilization trial in Darmstadt, Germany, founded in 1980. The nine treatments (four field replicates) were: straw incorporation plus application of mineral fertilizer (MSI) and application of rotted farmyard manure with (DYN) or without (FYM) addition of biodynamic preparations, each at high (140 – 150 kg N ha-1 year-1; MSIH, DYNH, FYMH), medium (100 kg N ha-1 year-1; MSIM, DYNM, FYMM) and low (50 – 60 kg N ha-1 year-1; MSIL, DYNL, FYML) rates. The main findings were: (i) The stocks of Corg (t ha-1) were affected by fertilizer type and rate and increased in the order MSIL (23.6), MSIM (23.7), MSIH (24.2) < FYML (25.3) < FYMM (28.1), FYMH (28.1). Stocks of Nt were affected in the same way (C/N ratio: 11). Storage of C and N in the modelled labile pools (turnover times: 462 and 153 days for C and N, respectively) were not influenced by the type of fertilizer (FYM and MSI) but depended significantly (p ≤ 0.05) on the application rate and ranged from 1.8 to 3.2 t C ha 1 (7 – 13% of Corg) and from 90 to 140 kg N ha-1 (4-5% of Nt). In the calculated intermediate pool (C/N ratio 7), stocks of C were markedly higher in FYM treatments (15-18 t ha-1) compared to MSI treatments (12-14 t ha-1). This showed that differences in SOM stocks in the sandy Cambisol induced by fertilizer rate may be short-lived in case of changing management, but differences induced by fertilizer type may persist for decades. (ii) Crop yields, estimated C inputs (1.5 t ha-1 year-1) with crop residue, microbial bio¬mass C (Cmic, 118 – 150 mg kg-1), microbial biomass N (17 – 20 mg kg-1) and labile C and N pools did not differ significantly between FYM and DYN treatments. However, labile C increased linearly with application rate (R2 = 0.53) from 7 to 11% of Corg. This also applied for labile N (3.5 to 4.9% of Nt). The higher contents of Corg in DYN treatments existed since 1982, when the first sampling was conducted for all individual treatments. Contents of Corg between DYN and FYM treatments con-verged slightly since then. Furthermore, at least 30% of the difference in Corg was located in the passive pool where a treatment effect could be excluded. Therefore, the reported differences in Corg contents existed most likely since the beginning of the experiment and, as a single factor of biodynamic agriculture, application of bio-dynamic preparations had no effect on SOM stocks. (iii) Stocks of SOM, light fraction organic C (LFOC, ρ ≤ 2.0 g cm-3), light fraction organic N and Cmic decreased in the order FYMH > FYML > MSIH, MSIL for all sampling dates in 2008 (March, May, September, December). However, statistical significance of treatment effects differed between the dates, probably due to dif-ferences in the spatial variation throughout the year. The high proportion of LFOC on total Corg stocks (45 – 55%) highlighted the importance of selective preservation of OM as a stabilization mechanism in this sandy Cambisol. The apparent turnover time of LFOC was between 21 and 32 years, which agreed very well with studies with substantially longer vegetation change compared to our study. Overall, both approaches; (I) the combination of incubation, chemical fractionation and simple modelling and (II) the density fractionation; provided complementary information on the partitioning of SOM into pools of different stability. The density fractionation showed that differences in Corg stocks between FYM and MSI treatments were mainly located in the light fraction, i.e. induced by higher recalcitrance of the organic input in the FYM treatments. Moreover, the use of the combination of biological, chemical and mathematical methods indicated that effects of fertilizer rate on total Corg and Nt stocks may be short-lived, but that the effect of fertilizer type may persist for longer time spans in the sandy Cambisol.