Double Disc Opener Research Articles

Determining of the parameters of a double disk opener

The article presents the calculation of the seed slots formed in the soil under the influence of double-disk opener and the determination of the geometric parameters of the double-disc opener of the device for direct sowing of seeds into the soil.

Innovative seed planter implements for resource-saving sowing technologies

Ensuring a smooth flow of seed with a decrease in the number of injured seeds, a given instability of the total seeding, regardless of the forward speed of the sowing implement with the necessary distribution of seeds along the length and depth of the furrow, all these are the main tasks for modern sowing systems of sowing machines. Thus, we could come to the conclusion that the work devoted to improving the quality indicators of sowing agricultural crops with a seeder by developing a reel-to-reel sowing device with a four-section reel, the grooves of which are formed by the surface of rotation of the torus and are rotated relative to each other along a helical line, at an angle of 45 degrees, as well as a double-disc opener with a seed flow shaper for placing them on the bottom of the furrow is of great importance for the agro-industrial complex of Russia. The article deals with the improving the quality indicators of sowing crops by a planter equipped with reel seeding devices and four-section. the current research also presents and analyses the results of field experiments.

Soil Rut Effects on Planter Performance for Cotton in a Conservation Tillage System

Highlights Soil rutting commonly occurs during harvest and these ruts can adversely affect row crop planter performance. Four rut types were used, two formed by a tire and two formed by cutting the soil and removing soil from the ruts. Cotton seedling emergence at 15 days after planting typically was greater in unrutted soil than in rutted soil. Regression equations show a trend of decreased emergence as rut depth increased for both a sandy loam and a clay soil. Abstract. Soil rutting commonly occurs during harvest and ruts formed during harvesting can adversely affect row crop planter performance at the start of the subsequent cropping season. We conducted a three-year experiment on a sandy loam and a clay soil to investigate effects of soil ruts on the performance of a row crop planter while planting cotton into a rolled rye cover crop, and effects of planter depth setting on planter performance when planting through soil ruts. The four rut types used, prior to planting the rye cover crop in the fall, were a single tire rut, the rut from a dual pair of tires, and two rut types formed by cutting the soil 25 and 50 mm (1 and 2 in.) deep and removing soil from the ruts. The results show that although not all differences were statistically significant, for five of the six combinations of year and soil, cotton seedling emergence at 15 days after planting was greater when the soil had no rut, i.e., flat unrutted soil, than when the planter traveled across soil ruts while planting. In four of the six combinations of year and soil, emergence was significantly greater for the no rut soil condition than for a rut which was formed the previous fall by cutting 50 mm (2 in.) deep and removing soil from the rut. The three seeding depth settings used in the experiment positioned the bottom peripheries of the two disks of the double-disk opener 28, 35, and 40 mm (1.1, 1.4, and 1.6 in.) beneath the bottom peripheries of the depth-gauge wheels, providing those nominal seeding depths before the closing wheels firmed the soil. The planter depth setting did not significantly affect emergence at 15 days after planting for any of the six combinations of year and soil. Mean values of emergence at 15 days after planting in the sandy loam, averaged over the three years, were 13.9, 11.5, 12.2, 11.4, and 7.6 plants/m of row length (4.2, 3.5, 3.7, 3.5, and 2.3 plants/ft of row length) for the No rut, Single tire, Dual tire, Shallow cut, and Deep cut conditions, respectively. The means in the clay were 13.6, 5.7, 5.8, 12.6, and 7.4 plants/m of row length (4.2, 1.7, 1.8, 3.8, and 2.3 plants/ft of row length), respectively. Regression equations show a trend of decreased emergence as rut depth increased for both soils, with the clay regression line having a greater magnitude slope than the sandy loam line. Keywords: Cotton, Emergence, Planters, Planting, Seeders, Seeding, Soil ruts, Sowing.

Seeding System Configuration Effects on Sunflower Seedling Emergence and Yield under No-Tillage

No-tillage farming can improve crop productivity and the reliability of cropping compared with conventional tillage. The effects of three different seeding system configurations on surface residue handling, sunflower emergence and stand establishment, yield, and gross income were investigated over three cropping seasons. The seeding system configurations comprised of (1) turbo coulter blade, (2) notched disc row cleaner before turbo coulter blade, and (3) no residue handling unit installed in front of a double-disc opener. For all three seeding system configurations, crop residue cover on sown rows (after seeding) was greater than the minimum recommended value of 30% for no-tillage. Residue cover was best with the notched disc row cleaner in front of the turbo coulter blade compared to the other two seeding systems. Furthermore, the notched disc row cleaner in front of the turbo coulter blade produced the highest plant emergence counts and the most uniform stand establishment. Sunflower yield and gross income were highest with the notched disc row cleaner in front of the turbo coulter blade (3.16 Mg·ha−1 and 902 USD·ha−1) compared to when only the turbo coulter blade (2.38 Mg·ha−1 and 680 USD·ha−1) or no residue handling unit (1.69 Mg·ha−1 and 482 USD·ha−1) was used.

Substantiation of the presence and parameters of seed guides in the openers, which increase the quality of sowing and yield

One of the promising methods for improving the uniformity of seed distribution in the soil is the control of the grain flow by guiding elements in the openers. This creates favorable conditions for the flight of seeds in the openers and when leaving them backwards, which equalizes the speed, in modulus, of seeds and the unit, improves the uniformity of their distribution in the soil. The presence and parameters of the guiding elements of the openers was theoretically substantiated, which gave the development of the process of controlling the grain flow in the openers and at the exit from them by using the guiding elements. Analytical expressions have been obtained to determine the characteristics of the movement of particles on various surfaces, which are recommended to be used for guides in the openers. Experimental studies have shown that openers with guides reduce the coefficient of variation along the row by 20 ... 45% and have it 88 ... 98%, and in depth - 24 ... 27%. On the basis of experiments, it is recommended that 3 ... 4 guides are recommended for front openers (arithmetic mean interval along the row 18.5 ... 23.5 mm, coefficient of variation 88 ... 98%). The advantage of the experimental opener in the distribution of seeds by depth is due to the use of guide elements in combination with an improved soil shedding process. This eliminated the technological drawback - the formation of a sub-opener inclined surface (arithmetic mean interval 42 ... 37 mm, coefficient of variation 24 ... 27%). For a double disc opener, an improved guide is recommended, the bottom edge of which protrudes 2 cm in front of the vertical diameter of the discs and is located at a distance of 9 cm from the reference plane. The arithmetic mean spacing along the row of this opener is 15 mm, the coefficient of variation is 106%.

Design and experiment evaluation of furrow compaction device with opener for maize

The double-disc opener of maize precision seeder is an important component which affects sowing quality. After the double-disc opening operation, there will be many unfavorable phenomena such as a W-shaped bottom with pointed ridge, returning soil to furrow, loose and rough furrow sidewall, and large soil blocks in the furrow bottom. These phenomena often cause the problems of poor sowing depth consistency and seed spacing uniformity. In order to solve the above problems, the furrow compaction device with opener was designed to compact and reshape the original seed furrow, eventually forming a smooth and flat V-shaped seed furrow. Through theoretical calculations and kinematic analysis, the main structural parameters of the device were limited to a small range: the spring stiffness coefficient k=0.96-4.19 N/mm and the angle of the furrow compaction wheel φ=30°-60°. In the soil-bin experiment, the rotary combination design was adopted to study the effects of the parameters of the furrow compaction device with opener on the seeds location variation. The regression model of two factors with respect to each indicator was established in the Design-Expert software, revealing the effects of two factors on the indicators. Finally, the optimal structural parameters obtained were: the spring stiffness coefficient k=4.0 N/mm, and the angle of furrow compaction wheel φ=42.4°. The field test was carried out to verify the effect of the furrow compaction device with opener on the performance of precision seeder. The results showed that the average values of the sowing depth variable coefficient, the lateral deviation and the seed spacing variable coefficient respectively were 5.77%, 5.1 mm and 9.54% in the treatment of the furrow compaction device with opener. All indicators were superior to the traditional double-disc opener. This research can provide references for the design of furrow opening device and maize precision seeder. Keywords: furrow opener, seed furrow, compaction, sowing depth variable coefficient, lateral deviation, seed spacing variable coefficient DOI: 10.25165/j.ijabe.20201302.4941 Citation: Wang W J, Diao P S, Jia H L, Chen Y L. Design and experiment evaluation of furrow compaction device with opener for maize. Int J Agric & Biol Eng, 2020; 13(2): 123–131.

Design of depth-control planting unit with single-side gauge wheel for no-till maize precision planter

Abstract: No-till planters are very popular for maize seeding in fields covered with residue in annual wheat-maize double cropping system in North China Plain. However, there is no suitable depth control mechanism for existing no-till maize planters, and as a result, it is hard to obtain consistent planting depth, uniform emergence, and good passing ability at the same time. For the above reasons, a proper planting unit with a new type of depth-control mechanism was developed in this study. The mechanism consists of a single-side gauge wheel, a parallel four-bar linkage, a pair of double-disc opener, a V-shape press wheel and a depth regulator, which can adjust the planting depth from 30 mm to 90 mm to satisfy the agronomic requirement under different field conditions. Based on analysis and calculation, the width of gauge wheel was set to 50 mm while the length of parallel four-bar linkage was set to 350 mm. Field experiment was conducted and the results indicated that the newly designed planting unit with single-side gauge wheel performed well with regard to planting depth uniformity and anti-blocking ability. The planting depth uniformity and seed spacing quality were 95.45% and 91.90%, respectively, when the average height of stubble was 22.5 cm and residue amount was 0.64 kg/m2 in the field. It can satisfy the requirement of no-till maize planting on the cropland with residue and stubble in North China Plain. Keywords: no-till planter, maize precision planter, planting unit, depth control, single-side gauge wheel, residue, stubble DOI: 10.3965/j.ijabe.20160906.2394 Citation: Zhang R, Cui T, Yin X W, Zhang D X, Li K H, Han D D, et al. Design of depth-control planting unit with single-side gauge wheel for no-till maize precision planter. Int J Agric & Biol Eng, 2016; 9(6): 56－64.

Specific demands to the traction of cutting discs and furrow openers for the no-tillage system

The objective of this study was to identify the specific demands to the traction considering the work depth and the soil area mobilized by different associations between crop residue coulter discs and fertilizer furrow openers of crop planters, for the no-tillage system, subject to the ground speed. This experiment was conducted in a farm in the city of Santa Maria (Brazil – Rio Grande do Sul), in a soil classified as Red Ultisol with sandy loam texture. The experiment consisted of 24 combinations of treatments, in a factorial design of 2x3x4. The treatments were obtained by the interaction of furrowers (hoe furrow opener and double-disc opener) with three arrangements in relation to the cutting discs (without disc, smooth and offset fluted coulter) and speeds (1.11, 1.67, 2.22 and 2.78 m s -1 ). The combination of mechanisms was possible through the coupling in a mobile tool holder structure and by using an instrumented tractor as a power source. There was a significant influence of all factors on the variables. The double-disc presented the highest specific demand due to the depth, with 24.08 kN m -1 , while the hoe opener required 19.09 kN m -1 . For the need of traction per mobilized soil area, the double-disc opener also had superior requirement, 9.94% higher. Therefore, the hoe opener is more efficient in the use of traction. The use of cutting discs integrated with this furrow opener reduced the extension of the demands and provided lower speed influence, while the opposite happens for the double-disc furrow opener. Regardless of the combination, an increment of variables was observed with the increase of speed.

CORN ROOTWORM MANAGEMENT USING COMBINATIONS OF ROOTWORM AND NON-ROOTWORM TRAITED CORN WITH AND WITHOUT FORCE 3G INSECTICIDAL MATERIALS, 2013

Corn rootworm (NCR/WCR) management efficacy trials were conducted to evaluate transgenic insect-resistant hybrids and granular insecticide combination treatments near Bryant, Cavour and Colman in South Dakota. Granular applications were made by using four rows (approximately 50 ft long; spaced 30 inches apart) treatment plots at planting-time. Experimental plots were arranged in an RCB design with four replications. Granular insecticides were applied with Noble metering units or SmartBox delivery system. All metering units were calibrated on the planter before treatment applications and mounted on a 4-row Kinze corn planter. In-furrow treatments were placed directly between double-disk openers and into the open seed furrow. Hybrids evaluated included: ‘Pioneer Optimum AcreMax1’ (‘OAM1’) ‘Pioneer 38H03AM1’, ‘Agrisure 3122’ ‘Syngenta Agrisure3122’, ‘VT Triple’ (‘VT3’) ‘Monsanto/DeKalb DKC43-27’, ‘Genuity VT Triple Pro’ (‘GEN SS 95:5RIB’) ‘Monsanto/DeKalb DKC49-29RIB’, ‘Genuity VT Triple Pro’ (‘GEN SS 90:10RIB’) ‘Monsanto/DeKalb DKC52-04RIB’, and Roundup Ready2 (RR Hybrid) ‘Monsanto/DeKalb DKC52-62’. Corn seed was planted at a rate of approximately 30,000 kernels per acre. Six roots per replication were dug randomly from the two outer rows, washed and rated using the Oleson 0 to 3 root injury rating scale. The center two rows were used for yield assessments. Yield and root rating data were analyzed by using SAS version 9.2 PROC MIXED/PDIFF option with Saxton’s lettering macro.

Effect of Planting Methods on Spring Canola (Brassica napus L.) Establishment and Yield in the Low-Rainfall Region of the Pacific Northwest

Growers are becoming interested in producing canola (Brassica napus or B. rapa) in the dryland, wheat-fallow region of the Pacific Northwest. Currently, agronomic research for spring canola in this region has not been initiated. This study evaluated the effect of no-till planting methods on stand establishment, crop yield, and seed oil quantity of spring canola in Washington and Oregon in 2009 and 2010. The treatments included: double disk opener; broadcast; broadcast plus rolled; Kile opener; Cross-Slot opener; and hoe opener (at Washington only). In this study, canola establishment was generally greatest with the double disk opener and least in the broadcast or broadcast plus rolled treatments at all four site-years. Yield was least in the broadcast treatment and rolling broadcast seed increased yield only 50% of the time. In three out of four site-years, canola planted with the various no-till openers yielded higher than broadcast seed. The adoption of spring canola in the wheat-fallow region of the Pacific Northwest would improve pest management strategies, diversify markets, and increase sustainability.

Integration of minimum tillage, crop rotation and organic amendments into a ginger farming system: Impacts on yield and soilborne diseases

Ginger ( Zingiber officinale) production is facing increasing disease and pest pressure and declining yield with continuing intensive cultivation practices. A four year experiment was established in south-eastern Queensland on a red ferrosol that had a long (>60 years) history of ginger farming. Minimal tillage and organic amendments were compared with conventional practice that involved frequent tillage and soil fumigation using 1,3-dichloropropene (Telone ®). Ginger crops were grown in the second and fourth year of the experiment, following an annual rotation with different cover crops including oats ( Avena sativa), Brassica spp., soybean ( Glycine max) and forage sorghum ( Sorghum bicolour X S. sudanese). A pasture ley of Pangola grass ( Digitaria eriantha subsp. pentzii) provided a treatment continuum from major to minor disruption in the soil's physical fertility and biological communities, and was therefore only planted to ginger in the fourth year of the experiment. Ginger seed-pieces (sections of the rhizome used for planting) were planted into both tilled and untilled beds using a double disc opener on a specially designed ginger planter. Rhizome yield in the final year was greatest (74.2 t/ha) and losses to pathogens ( Pythium myriotylum and Fusarium oxysporum f. sp. zingiberi) minimal (7.0%) in the pasture ley that had been cultivated prior to planting ginger. Furthermore, the minimum-tilled cover cropped treatment, which likewise had been cultivated prior to planting ginger, yielded well (62.0 t/ha), with few losses (5.0%) from rhizome rots. Conversely the fumigated treatment had the highest losses (35.9%) due to Pythium Soft Rot and lowest yields (20.2 t/ha). Minimum-tilled plantings of ginger, however, resulted in poor yields (30.9–43.1 t/ha) but had acceptable levels of disease.

Development of a Desiccated Cadaver Delivery System to Apply Entomopathogenic Nematodes for Control of Soil Pests

Entomopathogenic nematodes may be more capable of controlling soil pests when they are harbored by desiccated cadavers. A small-scale system was developed from a modified crop seed planter to effectively deliver desiccated nematode-infected cadavers into the soil. The system mainly consists of a metering unit, an air pressure source, a cadaver scraper, a custom-designed cadaver container, tension adjustment devices, double disk soil opener, a discharge tube, a packer wheel, and a press-drive wheel. The metering unit intermittently discharges a cadaver to the discharge tube at a constant rate. The double disk opener creates a narrow 7.5-cm deep slot for the placement of the discharged cadavers. The packer wheel then covers the cadavers with loose and somewhat moist soil. The spring tension device and the press-drive wheel control the slot depth. The number of cells on the metering plate controls the cadaver delivery rate regardless of the travel speed. The metering unit with modified double bean plates has delivery accuracy between 79% and 94% at 500-Pa air pressure. A slower travel speed and fewer cells on the metering plate improved the accuracy of delivery. When the travel speed was 4.8 km/h or slower, the desiccated cadaver delivery system performed satisfactorily in both laboratory and field tests, and delivered the cadavers at a rate of 1.6, 3.3, or 6.6 cadavers/m length in the soil.

Effects of Novel Disk-type Furrow Opener Used in No-Tillage System on Micro Environment of Seed

Problem statement: Offset Double-Disk Opener (DDO) is a popular furrow opener in conservation tillage. It has some limitations such as negative suction to penetrate in the soil, hair pinning and mixing seed and fertilizer in the slot. Because of importance of separation of seed and fertilizer in the slot, by adding two horizontal mi ni disks to DDO a modified opener was made (MDO) which placed the fertilizer between and under two r ows of seed. Approach: To consider performance of novel opener an indoor comparison test between DDO and MDO was performed at soil bin. The experiment was conducted with three working speeds (3, 6 and 8 km h -1 ), two bulk densities of soil (1.1 and 1.4 Mg m -3 ) and two levels of residues (1 and 2 ton ha -1 ). The experimental design consisted in a (3◊2◊2) complete randomized factorial with three re plicates for each test. Moisture of seed furrow, separation of seed and fertilizer, hair pinning and resultant forces acting on the openers were used a s assessing indexes. Results: There was no significant difference between soil m oisture content in slots created by DDO and MDO at 0-4 cm depth, but at 4-8 cm the in the slot created by MDO moisture content was higher about 9%. Horizontal force for b oth openers increased with increasing speed and soil bulk density. Vertical force for DDO was negat ive so it needed additional weight for penetrating in the soil, but vertical force for MDO was positive a nd, which can solve the challenge of penetration in the soil in DDO. In soft soil with heavy residues s ome trash was pushed by DDO into seed furrow (hair pinning) but at MDO seed were placed at clean groove. Lateral and vertical separation of seed and fertilizer was performed effectively by MDO (4. 5 and 5 cm, respectively) while DDO put seed and fertilizer close to each other. Conclusion: Overall, the Modified Offset Double-disks (MDO) had better performance. So by adapting this opener with no-tillage drillers it would possible to have higher yield in conservation tillage where the most appropriate opener is disk type.

Atributos químicos de um latossolo bruno sob sistema plantio direto em função da estratégia de adubação e do método de amostragem de solo

Adubo em sulco de semeadura nem sempre aumenta a produtividade de culturas anuais, contudo aumenta a variabilidade química das áreas agrícolas, especialmente dos nutrientes P e K. Essa variabilidade é maior no sistema plantio direto por não haver homogeneização da camada superficial pelo preparo mecânico. Neste trabalho, avaliou-se, em um Latossolo Bruno, por longo período sob plantio direto, o efeito de estratégias de aplicação de adubo sobre a distribuição de alguns atributos químicos do solo em profundidade após três e seis anos do início do experimento e sobre a variação desses atributos em função de dois métodos de coleta de amostras de solo, com e sem inclusão da linha de semeadura. Foram feitos dez tratamentos, nove contemplando fontes de P (fosfato natural e superfosfato triplo - STP), mecanismos sulcadores (disco duplo e haste), formas (sulco e superfície) e épocas (inverno e verão) de aplicação de adubo de semeadura e um tratamento controle, sem adubação. Os atributos químicos do solo foram maiores nas camadas superficiais e sua distribuição em profundidade, com exceção do P, não foi alterada pelas estratégias de adubação. O teor de P foi menor na profundidade de 0-5 cm com o uso contínuo, por mais de três anos, do sulcador tipo haste e com a ausência de adubação. Com a inclusão da linha de semeadura na amostragem, foram observados maiores teores de K e Ca e maiores valores de CTC. Os métodos de coleta de amostras de solo, com e sem inclusão da linha de semeadura, e as profundidades de coleta 0-10 e 0-20 cm foram semelhantes quanto à interpretação dos resultados das análises para recomendação de adubação e calagem para áreas sob sistema plantio direto, por longo período.

Effects of a new wide-sweep opener for no-till planter on seed zone properties and root establishment in maize ( Zea mays, L.): A comparison with double-disk opener

According to the kind of opener applied, no-tillage seeders can variously modify soil physical properties in relation to soil and climate conditions, thus potentially affecting crop emergence and early growth. The technological evolution of seeders for direct drilling of arable crops, progressively achieved in recent years, has been considerable, but new improvements now available need to be individually tested. In a field trial at Udine (NE Italy), the effects of a new kind of wide-sweep opener (i.e., side coulters curved upwards in their final part and slightly angled towards the direction of work) on soil physical properties in the seed zone and on crop emergence and early root growth of maize were evaluated in four different soils over a 2-year period (2002–2003), in comparison with the widely used double-disk opener. With respect to the double-disk opener, in general the wide-sweep type led to higher soil–residue mixing—without excessive reduction of the soil-covering index being observed, −27 and −6%, respectively. The wide-sweep opener also showed lower bulk density and soil penetration resistance in the top 5-cm soil layer of the seed furrow, although no greater root length density was found in maize at the three-leaf stage, probably due to the smoothing effect caused by the side coulters at the seeding depth. A certain delay in plant emergence in some cases was also revealed for the wide-sweep opener, which may be related to the lower soil/seed contact. Deviations from this general behaviour in the various soils (texture and initial conditions) are discussed.

Drill and crop performances as affected by different drill configurations for no-till seeding

No-till farming can reduce soil erosion, conserve soil moisture and minimize labor and fuel consumption. A 2-year field trial of seeding wheat ( Triticum aestivum L.), and corn ( Zea mays L.) and soybeans ( Glycine max [L.] Merr) with a low disturbance no-till drill was conducted on clay loam soils with three different stubble conditions and in a laboratory condition. The sites were located at the Manitoba Zero Tillage Research Farm in Brandon, Man., Canada. The drill’s seeding-unit consisted of a large offset double disc opener, gauge wheel and press wheel. A fertilizer attachment was an option for mid-row fertilizer banding. Seeding trials were conducted with four different drill configurations as treatments. When the press wheel was removed from the original seeding unit, the speed of emergence and the plant population were reduced in the normal and dry seeding condition. In the wet soil condition, advantages on the speed of emergence were observed without using press wheel. In the soft soil condition (laboratory condition), the removal of the gauge wheel resulted in two-fold greater seeding depth, which resulted in reduced speed of emergence and plant population. Those drill configurations without using press or/and gauge wheels had lower crop yields in the dry and normal seeding conditions. Effects of press and gauge wheels on drill and crop performances differed between dry and wet soil condition, and between field and laboratory. In general, banding fertilizer at the same time as seeding had little negative effects in this regard.

Direct corn seedling. Effects of residue clearance on implant efficiency

This article describes the effects of three seeding unit designs on plant residue clearance along the central line ofdirect corn (Zea Mays L.) seeding and the subsequent influence on crop emergence. The equipment assemblies testedwere three different combinations of the implements turbo coulter blade (TCB), double disc opener with a seed presswheel and covering/packing wheels (DDO), notched disc row cleaner with a track wheel or floating star cleaner (RC)as follows: (1) TCB+DDO, (2) RC+TCB+DDO and (3) TCB+RC+DDO. Under the field conditions tested, residueclearance before the cutting action of the turbo coulter blade (combination 2) gave rise to the best crop stand and cropuniformity. The seeding assembly that moves soil and clears away plant debris along the seeding furrow shows a directeffect on seed emergence.

Regulated deficit irrigation in "Clementina de Nules" citrus tree, 2. Effects on vegetative growth

This article describes the effects of three seeding unit designs on plant residue clearance along the central line ofdirect corn (Zea Mays L.) seeding and the subsequent influence on crop emergence. The equipment assemblies testedwere three different combinations of the implements turbo coulter blade (TCB), double disc opener with a seed presswheel and covering/packing wheels (DDO), notched disc row cleaner with a track wheel or floating star cleaner (RC)as follows: (1) TCB+DDO, (2) RC+TCB+DDO and (3) TCB+RC+DDO. Under the field conditions tested, residueclearance before the cutting action of the turbo coulter blade (combination 2) gave rise to the best crop stand and cropuniformity. The seeding assembly that moves soil and clears away plant debris along the seeding furrow shows a directeffect on seed emergence.

Emergence of irrigated cotton in flatland planting in relation to furrow opener type and crust-breaking treatments for Cambisols in central Iran

Emergence of cotton ( Gossypium hirsutum L.) under flatland mechanized planting system with crust-forming soil and saline soil and irrigation water can be suboptimal in central Iran. A field experiment was conducted to determine furrow opener type and crust-breaking method effects on cotton emergence on a silty clay soil (Calcic Cambisols). The effects of five planters (equipped with runner, single- and double-disk type openers) and five crust-breaking methods (using rolling cultivator, rolling-type crust breaker, spike-tooth, chain-type harrows and no crust-breaking) on the seedling emergence were studied. The results showed that planter type significantly affected cotton seedling emergence. In non-crust-breaking method, the best emergence was produced with the double-disk opener planter that created crack lines along the seed rows. This phenomenon was not observed with the runner-type opener planter. However, some crack lines were observed on the outside edges of its smooth-crown zero-pressure press wheels tires, which resulted in large clod formation after crust-breaking and had therefore negative effect on seedling emergence. Crust-breaking had negative effect on final emergence for double-disk planter due to filling the crack lines with loosened soil. Crust-breaking improved emergence percentages for runner opener planters, when the depth of penetration of the crust breaker teeth was shallow. The conclusion is that irrigated cotton emergence on crust-forming soils in a flatland planting system might significantly be improved by selecting a double-disk planter with zero-pressure press wheel tires without any crust-breaking operation under the soil and climate of central Iran.

Draught Requirement of Trailing-foot and Shallow Injection Equipment for Applying Slurry to Grassland

Surface spreading of slurry leads to the inevitable emission of ammonia into the environment. Injection of slurry on grassland reduces these emissions. However, injection of slurry by deep working injector tines with goose foot chisels (wings) requires high draught forces. This type of injection has the risk of the crop dying back under dry soil conditions and is not possible on all soil types. In recent years, new slurry application techniques for grassland have been developed that achieve a large reduction in emissions of ammonia, but require less draught force. These techniques include cutting a shallow slit in the sward, into which slurry is applied, and application of the slurry in bands on the soil surface using a trailing foot implement. In a series of experiments on sandy loam, clay and peat soils, the draught force requirement of single elements of five new slurry application techniques was investigated. The application techniques were a trailed sliding foot element and four shallow injection elements: angled-disc coulters (double-disc opener), thick-disc coulter, flat disc coulter followed by a vertical injection coulter and knife coulter followed by a vertical injection coulter. The application technique, working depth and soil conditions had a significant influence on the draught force. For a working depth of 5 cm, the required draught forces per shallow injector element, measured in this experiment, were in the range of 202–706 N for a double-disc opener, 284–991 N for a thick-disc coulter, 361–1260 N for a flat-disc coulter plus injector and 389–1358 N for a knife coulter plus injector. The lowest draught forces occurred on peat soil and the highest forces on dry clay. The trailing foot required an average draught force of 39 N. The draught force of the trailing foot did not relate to the soil conditions but an effect of the grass sward condition was suggested.