Article

Penetration Forces at Different Soil Conditions for Punches Used on Punch Planters

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Abstract

Penetration forces of punches designed for use in a no-till punch planter were evaluated for two soils at three different moisture levels and three bulk density levels. The standard cone penetrometer was used as a reference. A procedure using PVC molds for preparing standardized soil samples, measured penetration resistance at 40, 60, and 80 mm. The penetration forces for two punch widths approximately doubled at each depth interval. Soil moisture content at typical field conditions required the highest penetration forces. Changes in bulk density resulted in the biggest changes in penetration force. At median moisture level, increments of 0.15 Mg/m3 in bulk density for a silt loam soil and of 0.20 Mg/m3 for a sandy loam soil resulted in approximately a threefold increase in penetration forces. A good correlation wax observed between the cone penetrometer data and the penetration forces for the two punches.

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... Cone penetrometers are simple, easy to use and relatively inexpensive devices for assessing the penetration resistance or mechanical impedance of soils [26]. Standard cone penetrometer (ASAE S313.2, 1994) has cone base of 323 mm 2 (20.27 mm diameter) for soft soil, or 130 mm 2 (12.83 mm diameter) for hardened soil, both types being introduced into the soil with a uniform rate of 0.0305 m/s [19]. ...
... Best results are obtained if such tests are carried out in winter. Studies conducted by Collins (1971) and Voorhees and Walker (1977) showed that soils with high moisture content have low penetration resistance [19]. If a 15 mm high layer of precipitation as rain is settled on the soil, one should wait two days for the redistribution of the water in the soil, before assessing soil resistance by penetrometer tests [15]. ...
... If a 15 mm high layer of precipitation as rain is settled on the soil, one should wait two days for the redistribution of the water in the soil, before assessing soil resistance by penetrometer tests [15]. Experiments carried out by Ayers (1980) showed that clay soils require 24 hours to complete distribution of the water content, while coarse soils require less time [19]. A generally accepted method is to measure penetration resistance at or near field moisture capacity [9]. ...
... In a previous investigation into the shape of the punches and the force required for penetration, it was observed that force is linearly proportional to the width of the tip (Molin and Bashford, 1996). In the first trial, the punches were 32 mm wide ( fig. ...
... The site of the field tests was managed as no-till for several years. The results of the cone index profiles are presented in figure 3. The cone index values were similar to those obtained in a laboratory study of punch penetration forces with soil from the same site as these field tests (Molin and Bashford, 1996). Estimation of the penetration forces for this field test were made with the assumption that no speed effect was involved and that the increase in penetration force, as stated before, was linearly proportional to the projected area of the punch. ...
Article
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A punch planter was designed for no-till conditions. Initially, the penetration forces acting on two different punches were evaluated in laboratory tests with two different soils and varying soil moisture contents and bulk densities. A standard cone penetrometer was used as a reference. Soil samples were prepared using PVC molds with a procedure based on the Proctor test. Bulk density was the factor that resulted in the biggest changes in penetration force. Good correlations were observed between the cone penetrometer data and punch penetration forces. A prototype punch planter for corn was designed and built using a commercial vacuum seed meter. The seed meter was evaluated in the laboratory, vertically and inclined. The prototype planter with the seed meter attached was also evaluated in the laboratory. The results were not significantly affected by the working position of the seed meter nor by speeds between 1.0 and 3.0 m/s for the seed meter and planter prototype. Field tests were conducted at several residue covers at 2.0 m/s and no significant differences in plant spacings were observed. The prototype was modified to be able to plant different population rates. Seed spacings of 136, 165 and 210 mm were obtained by constructing three punch wheels with different punch lengths. Laboratory and field tests were run at speeds of 1.5, 2.0 and 2.5 m/s. The field tests were run in three different residue covers (corn, grain sorghum and soybean). Despite problems with synchronization between the seed meter and punch wheels in some combinations, the length of the punches seemed to cause no significant problems at the speeds tested. A soil cleaning device was designed to reduce the soil disturbance. The volume of soil displaced by the smallest punch wheel was less than half of that displaced by a commercial no-till planter. Planting depth regularity was evaluated, showing good uniformity. Though the results are promising, recommendations for further improvement are proposed, especially related to the synchronization between the seed meter and punch wheel.
... In a previous investigation into the shape of the punches and the force required for penetration, it was observed that force is linearly proportional to the width of the tip (Molin and Bashford, 1996). In the first trial, the punches were 32 mm wide ( fig. ...
... The site of the field tests was managed as no-till for several years. The results of the cone index profiles are presented in figure 3. The cone index values were similar to those obtained in a laboratory study of punch penetration forces with soil from the same site as these field tests (Molin and Bashford, 1996). Estimation of the penetration forces for this field test were made with the assumption that no speed effect was involved and that the increase in penetration force, as stated before, was linearly proportional to the projected area of the punch. ...
Article
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A punch planter for corn was designed, prototyped, and evaluated for no-till conditions using a commercial seed metering unit. The seed meter was evaluated for seed spacing performance at the vertical position with 2.5 kPa of vacuum, as specified by the manufacturer, and at a 22°incline with 4.0 kPa of vacuum. The prototype punch planter was evaluated at a 22°incline with 4.0 kPa of vacuum. Only small changes occurred in the seed meter performance when speed varied from 1 to 3 m/s. The precision of seed spacing decreased approximately 6.0% when compared with the seed meter results. Field tests were conducted with several residue covers for testing the residue effect at a speed of 2.0 m/s. No significant difference was observed in the planter performance. The multiples index (more than one seed in one space) increased up to 5.0% when compared to laboratory results. Emergence may have been affected by environmental conditions, but the precision during field tests was better than in the laboratory tests.
... Experimental testing of penetration resistance is properly done if the soil is not dry or very wet, and best results are obtained if the tests are carried out in winter [14]. The critical value of penetration resistance, or the value from where the problems for crop development begin, varies between 1000-3500 kPa [3]. ...
Conference Paper
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Heavy agricultural machinery is major cause of one of the processes of soil degradation, compaction, which became a problem of significant proportions, especially on soils with high moisture. Excessive traffic affects soil quality and crop production, and also causes environmental problems. The paper presents the results of research conducted to determine soil compaction on three experimental fields: plot of energy willow, plot of clover and cherry orchard, while different moisture contents represent subfactor. Maximum penetration resistances were recorded at 45 cm depth, where the soil is severely compacted: 3194.5 kPa on the soil cultivated with energy willow, 2984 kPa in the orchard, respectively 3069 kPa on the plot of clover.
... Denemelerde bugüne kadar farkl ı ara şt ı rmac ı lar tarafı ndan geli ştirilen yuvaya ekim makineler ı üzerinde kullan ı lan dört farkl ı yuva aç ı cı uç kullan ı lm ışt ı r ( Molin ve Bashford, 1996; Debicki ve Shaw, 1996 ). Bu uçlar ı n şematik görünü şleri ve projeksiyon alan ı değ erleri şekil 1, 2, 3 ve 4' de verilmi ştir. ...
... As the cells are in the top of the ring, the seed meter does not have larger limitations on being turned clockwise or counterclockwise. That is another great limitation of commercial units for allowing rows with left and right yawing for compensating the lateral force effect of the wheel (Molin et al., 1996). A toolbar was set up for attaching the prototype to the three points hitch of the tractor (Figure 3). ...
Conference Paper
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Some attempts have been made trying to implement different approaches for seed placement into the soil for no-till systems, avoiding coulters and their accessories that still present problems working on crop residue. Punch planting is one of the possibilities, but is limited on seed spacing adjustment. A prototype was developed based on previous works and consists on a punch wheel that has the ability to adjust its diameter so the tips will change the distance, producing seed spacing that may vary from 0.16 to 0.21m. The idea is based on a set of two plates with opposite spiral slots and a third plate with radial slots in between those two. With an external effort the punches attached to the sliding plates will expand or contract. The prototype was built and required also a personalized vacuum seed meter. Test shown it feasible as the accessories and seed meter are implemented.
... bore cylinder could generate 790 N (180 lb) of force. This cylinder bore diameter was based on the work of Molin and Bashford (1996). Their research simulated field working conditions in a laboratory to evaluate penetration forces required to pierce soil at different moisture levels and bulk densities. ...
Article
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A machine capable of placing planting holes for a wide variety of spacings in plastic mulch beds with very little physical reconfiguration was designed and tested. The three-point hitch mounted machine was demonstrated with two horticultural crops which have widely varying within-row and between-row spacing requirements: onions and potatoes. The piercing mechanisms were powered by pneumatic cylinders, and the on-board controls allowed users to adjust the number and spacing of holes. Switches enabled between-row spacing to vary by placing from one to four planting holes across a standard 76-cm (30-in.) bed. For the algorithm used, a dial was set to create the within-row spacing between 15 and 61 cm (6 and 24 in.). These control settings and a fixed tractor speed acted as inputs to a microprocessor which calculated hole placement frequency and initiated cylinder activation. The machine has been in use for two planting seasons with promising results. Hole placement accuracy data were collected for both onions and potatoes. The potato tests were performed for a within-row spacing of 30 cm (12 in.) and produced 96% of the planting holes within 10% of the target spacing distance. The onion tests were performed for a within-row plant spacing of 15 cm (6 in.) and produced 98% of the planting holes within 10% of the target spacing distance. The technology used for this research is readily available and is a viable option to accomplish numerous planting configurations with very little reconfiguration of machine components.
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Measured cone index values were adjusted for soil water content and bulk density by normalizing their effects using a covariance analysis as described by Chris tens en et al. (1989). Cone indices adjusted by covariance analysis allowed the testing of tillage differences at a given depth and across depths. The procedure showed that double disking a Sharpsburg silty clay loam soil reduced the cone penetration resistance to 152 mm depth. The penetration resistance was similar in the deeper undisturbed zones. Unadjusted field measured cone indices showed differences in the deeper zones though no tillage was performed. Keywords. Soil strength^ Core penetrometer^ Cone index. I nformation about soil strength is useful to assess its effect on crop root penetration and plant growth. Soil strength can be quickly assessed by using a core penetrometer to measure penetration resistance. Penetration resistance values can be used to characterize soils in terms of crop growing abihty and resistance to root penetration and seedling emergence (Bowen, 1976; Taylor and Gardner, 1963). Cone penetration results represent a composite soil behavior since soil fails by some combination of cutting, shearing, compaction, and flowing (Gill and Vanden Berg, 1968). However, the interpretation of a cone index is difficult even in homogeneous soils, because the proportion of shear, compression and tensile components that the cone index reflects, varies with soil conditions (Mulqueen et al., 1977). Major factors affecting the cone penetration resistance are soil water content, bulk density, soil type, soil strength, base diameter of cone, apex angle, penetration speed, and surface roughness of the cone. Cone penetrometers have been used in soil dynamics (Gill and Vanden Berg, 1968), tillage (Cassel, 1982; Threadgill, 1982), research related to root growth (Taylor et al., 1966), soil compaction (Raghavan and McKyes, 1977), trafficability (WES, 1948; Flores et al., 1990), and soil strength (Kondner, 1960) studies. Various cone penetrometer types such as static, quasi static, dynamic, and their applications were comprehensively reviewed by Perumpral (1987).
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Thesis (M.S.)--University of Wyoming, 1969. Includes bibliographical references (leaves [37]-38).