- Email: [email protected]
Soil layer displacing plough ― Part 1: Cernozem soil
Engineering in Agriculture, Environment and Food 8 (2015) 83e87
Contents lists available at ScienceDirect
Engineering in Agriculture, Environment and Food journal homepage: http://www.sciencedirect.com/eaef
Research paper
Soil layer displacing plough d Part 1: Cernozem soil* Ken Araya a, *, Azuma Araya b, Feng Liu c, Zhongchao Gao c, Huibin Jia d, Chunfeng Zhang d, Qiuji Wang c, Enjin Kuang c, Baoguo Zhu d, Nannan Wang d, Qingying Meng d a
Environmental Science Laboratory, Senshu University, 3 Avenue, Suishamachi, Toyohira, Sapporo 062-0912, Japan Faculty of Agriculture, University of Hokkaido, Sapporo 060-0808, Japan c Academy of Agricultural Sciences of Heilongjiang, Harbin, Heilongjiang 150086, PR China d Jamusi Branch, Academy of Agricultural Sciences of Heilongjiang, Jamusi, Heilongjiang 154007, PR China b
a r t i c l e i n f o
a b s t r a c t
Article history: Available online 11 April 2015
Chernozem is a soil group with calcium carbonate which is found extensively throughout the Heilongjiang province of the People's Republic of China. As one of the main corn belts in the world, the area has continuous planting of corn every year, but that lead to continuous cropping injury. Many corn stalks remain on the soil surface in autumn, so these corn stalks should be buried into the subsoil to retain rainwater underground. This can be accomplished with a special plough which we newly designed and built in this paper. The results show that when the corn stalk length was less than 1000 mm, a smooth burial took place. A total draught of this plough was measured at about 35 kN. © 2015 Asian Agricultural and Biological Engineering Association. Published by Elsevier B.V. All rights reserved.
Keywords: Chernozem Continuous cropping injury Soil improvement Soil layer displacement Plough configuration
1. Introduction Chernozem, which is a special soil group characterized by calcium carbonate, CaCO3, is widely distributed in the Heilongjiang province of the People's Republic of China near the border with Russia (Gongzitong, 1999; Tseng et al., 1963). The annual precipitation there is only about 700 mm. Fig. 1 shows a typical chernozem of a cultivated field in Anda, Heilongjiang (latitude: 46 240 2800 N, longitude: 125190 2800 E). The first horizon (Ap) is a black and gray soil with humus (8%e10%) that is suitable for plant growth and has a thickness of about 100 mm. The second horizon (A) is a calcareous and impermeable soil (clay) with less organic matter and a thickness of about 150 mm. The third horizon (Bca) is calcareous and impermeable parent material (clay, thickness about 150 mm). The fourth horizon (Cca) below about 400 mm depth is calcareous and impermeable gleyed soil (clay) with rust spots (Zhao, 1992). With the impermeable A, Bca and Cca horizons, plants suffer from both drought and excess moisture. The soil hardness (penetration resistance) of the A, Bca and Cca horizons is more than 5.0 MPa (cone penetrometer, 30 cone angle, 16 mm base
*
Presented in part at the Conference of JSAM-Hokkaido in August 2013. * Corresponding author. E-mail address: [email protected] (K. Araya).
diameter). Roots of plants cannot penetrate into the A, Bca and Cca horizons. This area is one of the main corn (maize) belts in the world, and the corn here is continuously planted every year, which triggers continuous cropping injury. Hence, the corn yield is declining, and its quality is also becoming poor (Gao et al., 2012). It is firstly recommended that the top soil (the 0e200 mm depth layer with margin) and the subsoil (the 200e400 mm depth layer) should be displaced to eliminate the continuous cropping injury, and the top soil should be left for about five years (resolution period) underground (Gao et al., 2012). After corn is harvested, the stalks are left on the soil surface (Fig. 2). Corn is generally harvested by hand here; the corn stalks are cut by using a sickle. They are gathered and used as a fuel in winter. However, a lot of the corn stalks remain on the soil surface unused (Fig. 2). They are then burnt away in autumn, causing terrible air pollution. It is also recommended that these corn stalks should be buried into the subsoil to retain rainwater underground. In order to improve a heavy clay soil (meadow soil), we have already tried this; trash such as corn stalks remaining on the soil surface in autumn were gathered and buried into subsoil (Zhang & Araya, 2001a, 2001b; Zhang et al., 2001) with a three-stage soil layer mixing plough developed by us. With this method, we achieved proper results on the meadow soil conditions, and we felt this method can be adapted to the chernozem soil conditions, too. However, this plough cannot be directly adapted for improvement
http://dx.doi.org/10.1016/j.eaef.2015.04.004 1881-8366/© 2015 Asian Agricultural and Biological Engineering Association. Published by Elsevier B.V. All rights reserved.
84
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
Fig. 3. Soil layer displacing plough with a corn stalk collector.
Fig. 1. Typical chernozem at a crop field in Anda, Heilongjiang, P. R. of China. Ap horizon, calcareous blocking structure with abundant organic matter; A horizon, calcareous and impermeable soil with less organic matter and few roots; Bca horizon, calcareous and impermeable parent material with a significant concentration of FeeMn; Cca horizon, calcareous and impermeable gleyed soil with rust spots.
of the fields with continuous cropping injury because this plough does not interchange the top soil and subsoil. We newly designed and built a special plough (soil layer displacing plough with a corn stalk collector) which consists of three plough bodies (Fig. 3). This plough (length: about 2000 mm; weight: about 150 kg) is much simpler than the previous threestage soil layer mixing plough (Zhang et al., 2001; length: about 3000 mm; weight: about 500 kg) and can be effectively used for the fields with the continuous cropping injury. This paper deals with that plough configuration (Fig. 3). 2. Principle of soil layer displacing plough with a corn stalk collector
bodies each till the 200 mm depth layer (Gao et al., 2012; Araya et al., 2013a, 2013b, 2013c). The shape and configuration of the second plough body is due to the previous reports (Jia et al., 1998b; Zhang & Araya, 2001b). The trash collector of the previous threestage soil layer mixing plough is just used here as the second plough body (corn stalk collector) of the present soil layer displacing plough with a corn stalk collector (Fig. 3). Fig. 5 shows schematic diagram of the displacing process of the Ap and Bca horizons (mainly) and the burying process of corn stalks into subsoil with four stages. With the first plough body, the Bca horizon (200e400 mm layer) is raised up to 200 mm and is inverted on the right side of the plough body. As the same time, a ditch is constructed (Stage 1). The right wheels run in the furrow. The second plough body runs on the soil surface in the next and adjacent furrow. It gathers the corn stalks distributed on the soil surface and drops them into the ditch made by the first plough body (Stage 2).
In order to displace the top soil (0e200 mm layer, Ap and a part of A horizons) and the subsoil (200e400 mm layer, a part of A and Bca horizons), 400 mm deep layer can be tilled by a single huge mould plough (Bowser & Cairns, 1967), but a huge traction force is required (Jia et al., 1998a). Hence, we designed and built a special plough (Figs. 3 and 4) which consisted of three plough bodies. The first and third plough
Fig. 2. Corn field after harvesting (right), after sickling by hand (left) and after cut corn stalks are carried out (center).
Fig. 4. Schematic diagram of soil layer displacing plough with a corn stalk collector (2nd plough body). All dimensions are in mm; GL ¼ ground level.
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
85
ploughing (Jia et al., 1998b). Three soil sections from the 2000 mm plot length were prepared with the same experimental conditions and their photos were taken. Fig. 6 illustrates the distinct horizons before ploughing were displaced, and a new horizon was obtained (corresponding to Stage 4 in Fig. 5). The new solum after ploughing was divided into four layers (I, II, III and IV). Grids as shown in Fig. 6 were drawn on each photograph, and the number of stalks (f1, f2, f3 and f4) in each layer was determined on the photograph (Jia et al., 1998b). The total mass of the corn stalks buried M in g is
M ¼ rs
2 ds plðf1 þ f2 þ f3 þ f4 Þ 2
(1)
where rs is mean density of the corn stalks in g mm3, ds is mean diameter of the corn stalks in mm, l is the length of the corn stalks tested in mm, f1, f2, f3 and f4 are each number of the corn stalks in I, II, III and IV layers.
Fig. 5. Schematic diagram of displacing Ap and Bca horizons (mainly) and burying corn stalks into subsoil.
3.2.1. Mean buried depth of corn stalks The mean buried depth of the corn stalks t in mm is defined as
t¼ The third plough body is also running in the adjacent furrow soon after the 2nd plough body and tills the Ap horizon (0e200 mm layer) and drops it into the ditch made by the first plough body (Stage 3). Hence, the Ap horizon is placed on the corn stalks. Subsequently, the whole plough runs in the next and adjacent furrow. The first plough body raises the Bca horizon (200e400 mm layer) exposed by the third plough body up to 200 mm, inverting it, thus covering onto the Ap soil on the right (Stage 4). With subsequent running of the whole plough in the adjacent furrow, the top soil (0e200 mm Ap horizon) and the subsoil (200e400 mm Bca horizon) are displaced, and the trash such as sickled corn stalks are buried to 400 mm depth. The disk harrow mounted on the end of the machine (Fig. 3) makes even the final soil surface. 3. Materials and methods 3.1. Corn stalk burying test 3.1.1. Field preparation Five plots of 500 mm width 2000 mm length (1 m2) were marked on the soil surface by slaked lime, and corn stalks (200 g each) with five different average lengths (l ¼ 300, 500, 1000, 1500 and 2000 mm) were distributed on each plot. This layout corresponds to 2.0 Mg/ha, which is an average amount of corn stalks remaining on the soil surface after harvesting by hand and carried out the corn stalks from the fields and was actually measured (the center in Fig. 2). The average height of the uncut standing corn stalks (the right in Fig. 2) was about 2000 mm and there were not actually so long stalks such as 1500 and 2000 mm after carried out the cut corn stalks by hand. The 500 mm width of the plot was needed because the operating width of the three plough bodies was 400 mm (Fig. 4). The whole experiment was carried out in one pass.
100f1 þ 200f2 þ 300f3 þ 400f4 f1 þ f2 þ f3 þ f4
(2)
If a stalk was seen within two layers, the layer where a longer part of the stalk occupied was taken.
3.2.2. Traction test The plough in Fig. 3 was mounted on a tractor which was used to support the plough but did not provide power (Fig. 7). This was drawn by another tractor through a traction dynamometer which installed strain gauges (capacity 100 kN, Araya et al., 1996). Hence, only the horizontal force (draught) of the plough was measured once a reduction for the running resistance of the supported tractor was made. To determine the draught of each of the three plough bodies, the third plough body was operated alone, following removal of the first and second plough bodies. The second plough body was then attached, and the draught of the second and third plough bodies was then determined together. The first plough body was then added, and the total draught of all three plough bodies was determined together. Three to five measurements were carried out for each configuration. The working depth of the third plough bodies was set at 0e200 mm (Fig. 4) from the soil surface, and that of the second plough body at 0 mm, adjusting the gauge wheel of the plough to run at a narrow distance from the soil surface (Fig. 4). The working depth of the first plough body was then set at 200e400 mm (Fig. 4).
3.2. Stalk mass buried The extent to which stalks were buried into the subsoil was determined by photographic analysis of the soil section after
Fig. 6. Depiction of corn stalk mass buried and mean buried depth (view of solum cross-section).
86
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
Fig. 9. Soil section after ploughing when average length of corn stalks was 300 mm.
Fig. 7. Traction test of plough using a traction dynamometer. Second tractor providing pulling power not shown.
4. Results and discussion 4.1. Soil penetration resistance The mean soil penetration resistance (soil hardness) before ploughing is shown in Fig. 8. At depths below 100 mm depth, there was a plough pan where the soil penetration resistance was more than 5.0 MPa (a cone penetrometer having 30 cone angle and 16mm base diameter). The mean soil penetration resistance (soil hardness) after ploughing is also shown in Fig. 8. It was 0.2 MPa down to 200 mm depth and 2 MPa below 200 mm depth. 4.2. Corn stalks buried Fig. 9 shows the soil section after ploughing. The average length of the buried corn stalks was 300 mm. The corn stalks were buried
at a depth of 300e350 mm. The Bca soil was on the Ap soil and the corn stalks were below the Ap soil. The corn stalks were not mixed into the Ap soil. However, they were mixed into the A horizon of the meadow soil when operated by the previous three-stage soil layer mixing plough (Zhang et al., 2001). Fig. 10 shows the calculated mass of the corn stalks buried M in g. The mean density of the corn stalks rs was 1.59 104 g mm3 which was actually measured (water content 12.5% w.b.). The mean diameter of the corn stalks ds was 20.0 mm which was also actually measured. From Fig. 10, we can see that when the length of the corn stalks was less than or equal to 1000 mm, the calculated mass of corn stalks buried M was about 100 g. However, when it was more than 1000 mm, the mass of corn stalks buried decreased, and a smooth burying of the corn stalks did not take place. Fig. 11 shows the calculated mean depth buried of corn stalks t in mm. In this case also, when the length of the corn stalks was less than or equal to 1000 mm, the calculated mean depth of the buried corn stalks t was 300e400 mm, and when it was more than 1000 mm, the depth decreased. Therefore, under that condition, a smooth burying of the corn stalks did not occur. The reason why the smooth burial of the corn stalks did not take place when the length of the corn stalks was more than 1000 mm, is the distance between the plough frame and the second plough body. That is, when the length of corn stalks was more than 1000 mm, they interfered in the plough frame (Fig. 3). Consequently, the flow of the corn stalks on the second plough body became unsteady, and they piled up there. The corn stalks were trapped in front of the second plough body instead of being buried evenly. However, as there were not so long corn stalks such as 1500 and 2000 mm in the actual field after harvesting by hand and carried out the cut corn stalks from the fields (the center in Fig. 2), the clogging of the corn stalks did not occur in the actual field. 4.3. Traction (draught) The results of the draught test of the ploughs are shown in Fig. 12. The running resistance of the wheel tractor (Fig. 7) on which
Fig. 8. Soil penetration resistance, MPa.
Fig. 10. Mass of corn stalks buried as a function of stalk length.
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
87
injury. A lot of the corn stalks remain on the soil surface unused in autumn. They are then now burnt away, causing terrible air pollution. It is secondary recommended that these corn stalks should be buried into the subsoil to retain rainwater underground. For this purpose, we designed and built a special plough which consists of three plough bodies. This paper deals with this plough configuration.
Fig. 11. Mean depth of buried corn stalks as a function of stalk length.
1. The soil hardness (penetration resistance) of the A, and Cca horizons is more than 5.0 MPa. Roots of plant Bca s cannot penetrate into these horizons. 2. When the length of the buried corn stalks was less than 1000 mm, a smooth dispersal of the corn stalks took place. 3. A total draught of this plough was measured at about 35 kN excluding the running resistance which is much smaller than that of the previous three-stage soil layer mixing plough. Acknowledgements The authors are grateful to the National Science Council of P. R. of China for financially supporting this research under Special Fund for Agro-scientific Research in the Public Interest (No. 201303126). References
Fig. 12. Results of traction test of plough. ( ), standard deviation.
the plough was mounted was about 7 kN (see arrow). The third plough body, which tilled the 0e200 mm layer, showed resistance at about 9 kN (arrow). The draught of the second plough body, which gathered the corn stalks on the soil surface and dropped them down into the ditch made by the first plough body, was about 1.0 kN (arrow). The draught of the first plough body, which tilled the 200e400 mm layer, was about 25 kN (arrow), giving a total draught of about 35 kN excluding the running resistance. This total draught of 35 kN is much smaller than that of the previous threestage soil layer mixing plough (about 50 kN, Zhang et al., 2001). 5. Summary and conclusions Chernozem, which is a special soil group characterized by calcium carbonate, is widely distributed in the Heilongjiang province of the People's Republic of China near the border with Russia. With the impermeable A, Bca and Cca horizons, plants suffer from both drought and excess moisture. This area is one of main corn belts in the world and the corn here is continuously planted every year which triggers continuous cropping injury. Hence, it is firstly recommended that the top soil and the subsoil should be displaced to eliminate the continuous cropping
Araya K, Zhao D, Liu F, Jia H. Improvement of planosol solum: Part 6: field experiments with a three-stage subsoil mixing plough. J Agric Eng Res 1996;65: 151e8. Araya K, Zhang C, Jia H, Liu F, Gao Z, Zhu B, et al. Soil investigation in Maoxinzhen, Heilongjiang, P. R. of China. J JSAM-Hokkaido 2013a;53:21e5. Araya K, Zhang C, Jia H, Liu F, Nie S, Zhu B, et al. Soil investigation in Farm 291, Heilongjiang, P. R. of China. J JSAM-Hokkaido 2013b;53:27e30. Araya K, Zhang C, Jia H, Liu F, Gao Z, Sun S, et al. Soil layer displacing plough for elimination of herbicide residue and continuous cropping injury, investigation in Baoqing, Heilongjiang, P. R. of China. J JSAM-Hokkaido 2013c;53: 31e6. Bowser WE, Cairns RR. Some effects of deep plowing a solonetz soil. Can J Soil Sci 1967;47:239e44. Gao Z, Liu F, Zhang C, Hu F, Kuang E, Cui X, et al. Elimination of herbicide residue by soil displacing plough in soybean fields. Trans Chin Soc Agric Eng 2012;28(20): 202e9. Gongzitong. Chinese soil taxonomy. Beijing: Science press; 1999. p. 544e52. Jia H, Liu F, Zhang H, Zhang C, Araya K, Kawabe H. Improvement of planosol solum: part 8, analysis of draught of a three-stage subsoil mixing plough. J Agric Eng Res 1998a;70:185e93. Jia H, Liu F, Zhang H, Zhang C, Araya K, Kawabe H. Improvement of planosol solum: part 10, mixing of wheat straw and corn stalk into subsoil. J Agric Eng Res 1998b;71:221e6. Tseng CS, Chuang CP, Li NP. On the genesis and classification of paichiang soils. Acta Pedol Sin 1963;11(2):111e29. Zhang C, Araya K. A three-stage soil layer mixing plough for improvement of meadow soil, Part 1: mechanical properties of soils. J Agric Eng Res 2001a;78(3):253e60. Zhang C, Araya K. A three-stage soil layer mixing plough for improvement of meadow soil, Part 2: soil bin experiments. J Agric Eng Res 2001b;78(4):359e67. Zhang C, Araya K, Liu F, Jia H, Zhang H, Yang S. A three-stage soil layer mixing plough for improvement of meadow soil, Part 3: field evaluation. J Agric Eng Res 2001;79(1):47e53. Zhao D. Improvement of low yield soils in three-river plain. Heilongjiang Science and Technology Press; 1992. p.8.
Contents lists available at ScienceDirect
Engineering in Agriculture, Environment and Food journal homepage: http://www.sciencedirect.com/eaef
Research paper
Soil layer displacing plough d Part 1: Cernozem soil* Ken Araya a, *, Azuma Araya b, Feng Liu c, Zhongchao Gao c, Huibin Jia d, Chunfeng Zhang d, Qiuji Wang c, Enjin Kuang c, Baoguo Zhu d, Nannan Wang d, Qingying Meng d a
Environmental Science Laboratory, Senshu University, 3 Avenue, Suishamachi, Toyohira, Sapporo 062-0912, Japan Faculty of Agriculture, University of Hokkaido, Sapporo 060-0808, Japan c Academy of Agricultural Sciences of Heilongjiang, Harbin, Heilongjiang 150086, PR China d Jamusi Branch, Academy of Agricultural Sciences of Heilongjiang, Jamusi, Heilongjiang 154007, PR China b
a r t i c l e i n f o
a b s t r a c t
Article history: Available online 11 April 2015
Chernozem is a soil group with calcium carbonate which is found extensively throughout the Heilongjiang province of the People's Republic of China. As one of the main corn belts in the world, the area has continuous planting of corn every year, but that lead to continuous cropping injury. Many corn stalks remain on the soil surface in autumn, so these corn stalks should be buried into the subsoil to retain rainwater underground. This can be accomplished with a special plough which we newly designed and built in this paper. The results show that when the corn stalk length was less than 1000 mm, a smooth burial took place. A total draught of this plough was measured at about 35 kN. © 2015 Asian Agricultural and Biological Engineering Association. Published by Elsevier B.V. All rights reserved.
Keywords: Chernozem Continuous cropping injury Soil improvement Soil layer displacement Plough configuration
1. Introduction Chernozem, which is a special soil group characterized by calcium carbonate, CaCO3, is widely distributed in the Heilongjiang province of the People's Republic of China near the border with Russia (Gongzitong, 1999; Tseng et al., 1963). The annual precipitation there is only about 700 mm. Fig. 1 shows a typical chernozem of a cultivated field in Anda, Heilongjiang (latitude: 46 240 2800 N, longitude: 125190 2800 E). The first horizon (Ap) is a black and gray soil with humus (8%e10%) that is suitable for plant growth and has a thickness of about 100 mm. The second horizon (A) is a calcareous and impermeable soil (clay) with less organic matter and a thickness of about 150 mm. The third horizon (Bca) is calcareous and impermeable parent material (clay, thickness about 150 mm). The fourth horizon (Cca) below about 400 mm depth is calcareous and impermeable gleyed soil (clay) with rust spots (Zhao, 1992). With the impermeable A, Bca and Cca horizons, plants suffer from both drought and excess moisture. The soil hardness (penetration resistance) of the A, Bca and Cca horizons is more than 5.0 MPa (cone penetrometer, 30 cone angle, 16 mm base
*
Presented in part at the Conference of JSAM-Hokkaido in August 2013. * Corresponding author. E-mail address: [email protected] (K. Araya).
diameter). Roots of plants cannot penetrate into the A, Bca and Cca horizons. This area is one of the main corn (maize) belts in the world, and the corn here is continuously planted every year, which triggers continuous cropping injury. Hence, the corn yield is declining, and its quality is also becoming poor (Gao et al., 2012). It is firstly recommended that the top soil (the 0e200 mm depth layer with margin) and the subsoil (the 200e400 mm depth layer) should be displaced to eliminate the continuous cropping injury, and the top soil should be left for about five years (resolution period) underground (Gao et al., 2012). After corn is harvested, the stalks are left on the soil surface (Fig. 2). Corn is generally harvested by hand here; the corn stalks are cut by using a sickle. They are gathered and used as a fuel in winter. However, a lot of the corn stalks remain on the soil surface unused (Fig. 2). They are then burnt away in autumn, causing terrible air pollution. It is also recommended that these corn stalks should be buried into the subsoil to retain rainwater underground. In order to improve a heavy clay soil (meadow soil), we have already tried this; trash such as corn stalks remaining on the soil surface in autumn were gathered and buried into subsoil (Zhang & Araya, 2001a, 2001b; Zhang et al., 2001) with a three-stage soil layer mixing plough developed by us. With this method, we achieved proper results on the meadow soil conditions, and we felt this method can be adapted to the chernozem soil conditions, too. However, this plough cannot be directly adapted for improvement
http://dx.doi.org/10.1016/j.eaef.2015.04.004 1881-8366/© 2015 Asian Agricultural and Biological Engineering Association. Published by Elsevier B.V. All rights reserved.
84
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
Fig. 3. Soil layer displacing plough with a corn stalk collector.
Fig. 1. Typical chernozem at a crop field in Anda, Heilongjiang, P. R. of China. Ap horizon, calcareous blocking structure with abundant organic matter; A horizon, calcareous and impermeable soil with less organic matter and few roots; Bca horizon, calcareous and impermeable parent material with a significant concentration of FeeMn; Cca horizon, calcareous and impermeable gleyed soil with rust spots.
of the fields with continuous cropping injury because this plough does not interchange the top soil and subsoil. We newly designed and built a special plough (soil layer displacing plough with a corn stalk collector) which consists of three plough bodies (Fig. 3). This plough (length: about 2000 mm; weight: about 150 kg) is much simpler than the previous threestage soil layer mixing plough (Zhang et al., 2001; length: about 3000 mm; weight: about 500 kg) and can be effectively used for the fields with the continuous cropping injury. This paper deals with that plough configuration (Fig. 3). 2. Principle of soil layer displacing plough with a corn stalk collector
bodies each till the 200 mm depth layer (Gao et al., 2012; Araya et al., 2013a, 2013b, 2013c). The shape and configuration of the second plough body is due to the previous reports (Jia et al., 1998b; Zhang & Araya, 2001b). The trash collector of the previous threestage soil layer mixing plough is just used here as the second plough body (corn stalk collector) of the present soil layer displacing plough with a corn stalk collector (Fig. 3). Fig. 5 shows schematic diagram of the displacing process of the Ap and Bca horizons (mainly) and the burying process of corn stalks into subsoil with four stages. With the first plough body, the Bca horizon (200e400 mm layer) is raised up to 200 mm and is inverted on the right side of the plough body. As the same time, a ditch is constructed (Stage 1). The right wheels run in the furrow. The second plough body runs on the soil surface in the next and adjacent furrow. It gathers the corn stalks distributed on the soil surface and drops them into the ditch made by the first plough body (Stage 2).
In order to displace the top soil (0e200 mm layer, Ap and a part of A horizons) and the subsoil (200e400 mm layer, a part of A and Bca horizons), 400 mm deep layer can be tilled by a single huge mould plough (Bowser & Cairns, 1967), but a huge traction force is required (Jia et al., 1998a). Hence, we designed and built a special plough (Figs. 3 and 4) which consisted of three plough bodies. The first and third plough
Fig. 2. Corn field after harvesting (right), after sickling by hand (left) and after cut corn stalks are carried out (center).
Fig. 4. Schematic diagram of soil layer displacing plough with a corn stalk collector (2nd plough body). All dimensions are in mm; GL ¼ ground level.
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
85
ploughing (Jia et al., 1998b). Three soil sections from the 2000 mm plot length were prepared with the same experimental conditions and their photos were taken. Fig. 6 illustrates the distinct horizons before ploughing were displaced, and a new horizon was obtained (corresponding to Stage 4 in Fig. 5). The new solum after ploughing was divided into four layers (I, II, III and IV). Grids as shown in Fig. 6 were drawn on each photograph, and the number of stalks (f1, f2, f3 and f4) in each layer was determined on the photograph (Jia et al., 1998b). The total mass of the corn stalks buried M in g is
M ¼ rs
2 ds plðf1 þ f2 þ f3 þ f4 Þ 2
(1)
where rs is mean density of the corn stalks in g mm3, ds is mean diameter of the corn stalks in mm, l is the length of the corn stalks tested in mm, f1, f2, f3 and f4 are each number of the corn stalks in I, II, III and IV layers.
Fig. 5. Schematic diagram of displacing Ap and Bca horizons (mainly) and burying corn stalks into subsoil.
3.2.1. Mean buried depth of corn stalks The mean buried depth of the corn stalks t in mm is defined as
t¼ The third plough body is also running in the adjacent furrow soon after the 2nd plough body and tills the Ap horizon (0e200 mm layer) and drops it into the ditch made by the first plough body (Stage 3). Hence, the Ap horizon is placed on the corn stalks. Subsequently, the whole plough runs in the next and adjacent furrow. The first plough body raises the Bca horizon (200e400 mm layer) exposed by the third plough body up to 200 mm, inverting it, thus covering onto the Ap soil on the right (Stage 4). With subsequent running of the whole plough in the adjacent furrow, the top soil (0e200 mm Ap horizon) and the subsoil (200e400 mm Bca horizon) are displaced, and the trash such as sickled corn stalks are buried to 400 mm depth. The disk harrow mounted on the end of the machine (Fig. 3) makes even the final soil surface. 3. Materials and methods 3.1. Corn stalk burying test 3.1.1. Field preparation Five plots of 500 mm width 2000 mm length (1 m2) were marked on the soil surface by slaked lime, and corn stalks (200 g each) with five different average lengths (l ¼ 300, 500, 1000, 1500 and 2000 mm) were distributed on each plot. This layout corresponds to 2.0 Mg/ha, which is an average amount of corn stalks remaining on the soil surface after harvesting by hand and carried out the corn stalks from the fields and was actually measured (the center in Fig. 2). The average height of the uncut standing corn stalks (the right in Fig. 2) was about 2000 mm and there were not actually so long stalks such as 1500 and 2000 mm after carried out the cut corn stalks by hand. The 500 mm width of the plot was needed because the operating width of the three plough bodies was 400 mm (Fig. 4). The whole experiment was carried out in one pass.
100f1 þ 200f2 þ 300f3 þ 400f4 f1 þ f2 þ f3 þ f4
(2)
If a stalk was seen within two layers, the layer where a longer part of the stalk occupied was taken.
3.2.2. Traction test The plough in Fig. 3 was mounted on a tractor which was used to support the plough but did not provide power (Fig. 7). This was drawn by another tractor through a traction dynamometer which installed strain gauges (capacity 100 kN, Araya et al., 1996). Hence, only the horizontal force (draught) of the plough was measured once a reduction for the running resistance of the supported tractor was made. To determine the draught of each of the three plough bodies, the third plough body was operated alone, following removal of the first and second plough bodies. The second plough body was then attached, and the draught of the second and third plough bodies was then determined together. The first plough body was then added, and the total draught of all three plough bodies was determined together. Three to five measurements were carried out for each configuration. The working depth of the third plough bodies was set at 0e200 mm (Fig. 4) from the soil surface, and that of the second plough body at 0 mm, adjusting the gauge wheel of the plough to run at a narrow distance from the soil surface (Fig. 4). The working depth of the first plough body was then set at 200e400 mm (Fig. 4).
3.2. Stalk mass buried The extent to which stalks were buried into the subsoil was determined by photographic analysis of the soil section after
Fig. 6. Depiction of corn stalk mass buried and mean buried depth (view of solum cross-section).
86
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
Fig. 9. Soil section after ploughing when average length of corn stalks was 300 mm.
Fig. 7. Traction test of plough using a traction dynamometer. Second tractor providing pulling power not shown.
4. Results and discussion 4.1. Soil penetration resistance The mean soil penetration resistance (soil hardness) before ploughing is shown in Fig. 8. At depths below 100 mm depth, there was a plough pan where the soil penetration resistance was more than 5.0 MPa (a cone penetrometer having 30 cone angle and 16mm base diameter). The mean soil penetration resistance (soil hardness) after ploughing is also shown in Fig. 8. It was 0.2 MPa down to 200 mm depth and 2 MPa below 200 mm depth. 4.2. Corn stalks buried Fig. 9 shows the soil section after ploughing. The average length of the buried corn stalks was 300 mm. The corn stalks were buried
at a depth of 300e350 mm. The Bca soil was on the Ap soil and the corn stalks were below the Ap soil. The corn stalks were not mixed into the Ap soil. However, they were mixed into the A horizon of the meadow soil when operated by the previous three-stage soil layer mixing plough (Zhang et al., 2001). Fig. 10 shows the calculated mass of the corn stalks buried M in g. The mean density of the corn stalks rs was 1.59 104 g mm3 which was actually measured (water content 12.5% w.b.). The mean diameter of the corn stalks ds was 20.0 mm which was also actually measured. From Fig. 10, we can see that when the length of the corn stalks was less than or equal to 1000 mm, the calculated mass of corn stalks buried M was about 100 g. However, when it was more than 1000 mm, the mass of corn stalks buried decreased, and a smooth burying of the corn stalks did not take place. Fig. 11 shows the calculated mean depth buried of corn stalks t in mm. In this case also, when the length of the corn stalks was less than or equal to 1000 mm, the calculated mean depth of the buried corn stalks t was 300e400 mm, and when it was more than 1000 mm, the depth decreased. Therefore, under that condition, a smooth burying of the corn stalks did not occur. The reason why the smooth burial of the corn stalks did not take place when the length of the corn stalks was more than 1000 mm, is the distance between the plough frame and the second plough body. That is, when the length of corn stalks was more than 1000 mm, they interfered in the plough frame (Fig. 3). Consequently, the flow of the corn stalks on the second plough body became unsteady, and they piled up there. The corn stalks were trapped in front of the second plough body instead of being buried evenly. However, as there were not so long corn stalks such as 1500 and 2000 mm in the actual field after harvesting by hand and carried out the cut corn stalks from the fields (the center in Fig. 2), the clogging of the corn stalks did not occur in the actual field. 4.3. Traction (draught) The results of the draught test of the ploughs are shown in Fig. 12. The running resistance of the wheel tractor (Fig. 7) on which
Fig. 8. Soil penetration resistance, MPa.
Fig. 10. Mass of corn stalks buried as a function of stalk length.
K. Araya et al. / Engineering in Agriculture, Environment and Food 8 (2015) 83e87
87
injury. A lot of the corn stalks remain on the soil surface unused in autumn. They are then now burnt away, causing terrible air pollution. It is secondary recommended that these corn stalks should be buried into the subsoil to retain rainwater underground. For this purpose, we designed and built a special plough which consists of three plough bodies. This paper deals with this plough configuration.
Fig. 11. Mean depth of buried corn stalks as a function of stalk length.
1. The soil hardness (penetration resistance) of the A, and Cca horizons is more than 5.0 MPa. Roots of plant Bca s cannot penetrate into these horizons. 2. When the length of the buried corn stalks was less than 1000 mm, a smooth dispersal of the corn stalks took place. 3. A total draught of this plough was measured at about 35 kN excluding the running resistance which is much smaller than that of the previous three-stage soil layer mixing plough. Acknowledgements The authors are grateful to the National Science Council of P. R. of China for financially supporting this research under Special Fund for Agro-scientific Research in the Public Interest (No. 201303126). References
Fig. 12. Results of traction test of plough. ( ), standard deviation.
the plough was mounted was about 7 kN (see arrow). The third plough body, which tilled the 0e200 mm layer, showed resistance at about 9 kN (arrow). The draught of the second plough body, which gathered the corn stalks on the soil surface and dropped them down into the ditch made by the first plough body, was about 1.0 kN (arrow). The draught of the first plough body, which tilled the 200e400 mm layer, was about 25 kN (arrow), giving a total draught of about 35 kN excluding the running resistance. This total draught of 35 kN is much smaller than that of the previous threestage soil layer mixing plough (about 50 kN, Zhang et al., 2001). 5. Summary and conclusions Chernozem, which is a special soil group characterized by calcium carbonate, is widely distributed in the Heilongjiang province of the People's Republic of China near the border with Russia. With the impermeable A, Bca and Cca horizons, plants suffer from both drought and excess moisture. This area is one of main corn belts in the world and the corn here is continuously planted every year which triggers continuous cropping injury. Hence, it is firstly recommended that the top soil and the subsoil should be displaced to eliminate the continuous cropping
Araya K, Zhao D, Liu F, Jia H. Improvement of planosol solum: Part 6: field experiments with a three-stage subsoil mixing plough. J Agric Eng Res 1996;65: 151e8. Araya K, Zhang C, Jia H, Liu F, Gao Z, Zhu B, et al. Soil investigation in Maoxinzhen, Heilongjiang, P. R. of China. J JSAM-Hokkaido 2013a;53:21e5. Araya K, Zhang C, Jia H, Liu F, Nie S, Zhu B, et al. Soil investigation in Farm 291, Heilongjiang, P. R. of China. J JSAM-Hokkaido 2013b;53:27e30. Araya K, Zhang C, Jia H, Liu F, Gao Z, Sun S, et al. Soil layer displacing plough for elimination of herbicide residue and continuous cropping injury, investigation in Baoqing, Heilongjiang, P. R. of China. J JSAM-Hokkaido 2013c;53: 31e6. Bowser WE, Cairns RR. Some effects of deep plowing a solonetz soil. Can J Soil Sci 1967;47:239e44. Gao Z, Liu F, Zhang C, Hu F, Kuang E, Cui X, et al. Elimination of herbicide residue by soil displacing plough in soybean fields. Trans Chin Soc Agric Eng 2012;28(20): 202e9. Gongzitong. Chinese soil taxonomy. Beijing: Science press; 1999. p. 544e52. Jia H, Liu F, Zhang H, Zhang C, Araya K, Kawabe H. Improvement of planosol solum: part 8, analysis of draught of a three-stage subsoil mixing plough. J Agric Eng Res 1998a;70:185e93. Jia H, Liu F, Zhang H, Zhang C, Araya K, Kawabe H. Improvement of planosol solum: part 10, mixing of wheat straw and corn stalk into subsoil. J Agric Eng Res 1998b;71:221e6. Tseng CS, Chuang CP, Li NP. On the genesis and classification of paichiang soils. Acta Pedol Sin 1963;11(2):111e29. Zhang C, Araya K. A three-stage soil layer mixing plough for improvement of meadow soil, Part 1: mechanical properties of soils. J Agric Eng Res 2001a;78(3):253e60. Zhang C, Araya K. A three-stage soil layer mixing plough for improvement of meadow soil, Part 2: soil bin experiments. J Agric Eng Res 2001b;78(4):359e67. Zhang C, Araya K, Liu F, Jia H, Zhang H, Yang S. A three-stage soil layer mixing plough for improvement of meadow soil, Part 3: field evaluation. J Agric Eng Res 2001;79(1):47e53. Zhao D. Improvement of low yield soils in three-river plain. Heilongjiang Science and Technology Press; 1992. p.8.