Can a Change in Agriculture Management Practice Improve Soil Physical Properties
, Holger Lilienthal 2, Ewald Schnug 2, Rosa Lasaponara 3 and Elsayed Said Mohamed 4,5,*Round 1
Reviewer 1 Report
This paper identified if and how conservation tillage practices in organic management do improve soil physical properties compared to the conventional management by assessing the infiltration capacity and degree of compactness, and Hydrus-1D model was applied to simulate the saturated hydraulic conductivity with different soil depth, the results reveal organic farming practices reduces the bulk density, and increases infiltration. Hydrus-1D is useful in assessing the hydraulic parameters and simulates the water transfer in soil matrix. Some of the questions are below:
(1) Are the hydraulic parameters in table 3 evaluated using parametric inversion tool in Hydrus-1D model, what are the differences of measured value?
(2) Figure 5 presents hydraulic conductivity with the increasing of soil depth; can you prove the simulation results are accurate? And as well as Fig.6.
Author Response
This paper identified if and how conservation tillage practices in organic management do improve soil physical properties compared to conventional management by assessing the infiltration capacity and degree of compactness, and Hydrus-1D model was applied to simulate the saturated hydraulic conductivity with different soil depths, the results reveal organic farming practices reduces the bulk density and increases infiltration. Hydrus-1D is useful in assessing the hydraulic parameters and simulates the water transfer in the soil matrix. Some of the questions are below:
- Are the hydraulic parameters in table 3 evaluated using parametric inversion tool in Hydrus-1D model, what are the differences of measured value?
The study was conducted on matched field pairs in Baden-Württemberg, Germany. The conservation tillage treatments effect of OM (superficial tillage using chisel at 10 cm depth) was compared with conventional tillage practices CM (mouldboard ploughing at 30 cm depth). The field pairs were homogenous in most respects which would reflect tillage impacts. The field measurement differences under each tillage including soil texture, soil dry bulk density, soil field capacity, and the soil wilting point were used for the hydraulic parameters in table 3 and evaluated using parametric inversion tool in Hydrus-1D model. That the Hydrus-1D model according to van Genuchten (1980) to compute the water retention parameters depend on the Rosetta model (Chaap et al., 2001). These field measurements under the tillage impacts were implemented in Rosetta model to compute the hydraulic parameters.
Schaap, M.G., F.J. Leij, and M. Th. van Genuchten. 2001. Rosetta: a computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions. Journal of Hydrology. 251:163-176.
(2) Figure 5 presents hydraulic conductivity with the increase of soil depth; can you prove the simulation results are accurate? And as well as Fig.6.
- For the obtained simulation results of the hydraulic conductivity with the soil depth. The hydraulic parameters a, n, Alpha, and Ks in table 3 were evaluated using the parametric inversion tool in the Hydrus-1D model. That the Hydrus-1D model according to van Genuchten (1980) computes the water retention parameters depending on the Rosetta model (Chaap et al., 2001) was applied. These field measurements under the tillage impacts were implemented in Rosetta model to compute the hydraulic parameters. Then the obtained results using the Van Genuchten equation were validated using the Root Mean Square Error (RMSE) in Excel Microsoft 10, with the measured field soil water at field capacity and at the wilting point at the lab using the pressure membrane and the pressure cooker, respectively. The validation results were implemented in the Hydrus-1D model to calculate the hydraulic parameters a, n, Alpha, and Ks depending on the measured parameters under the tillage impact. Then we obtained the results of the hydraulic conductivity with the soil depth with time under each soil tillage.
Reviewer 2 Report
Conservation tillage in organic management (OM) had a pronounced effect on soil quality with a better soil penetration resistance compared to the conventional management (CM). Furthermore, soil hydraulic properties under different tillage practices have got little attentions due to the difficulties in preparing different soil physical measurements. The study was conducted on matched field pairs in Baden-Würt-temberg, Germany. The conservation tillage treatments effect of OM was compared with conventional tillage practices CM. This is a useful paper and is well-written containing some interesting results. It is acceptable for publication following consideration and response to the following points.
(1) The drawing of the Fig. 1 is not standard, such as no scale and no legends, and more relevant information should be given. In addition, the picture is blurred.
(2) Line 152: The permeability coefficient of unsaturated soil changes with the water head, while the permeability coefficient of saturated soil has only one value. Whether the equation is correct, or give more explanation.
(3) Line 202: “The upper boundary conditions for the investigated sites were in pressure head -1 cm” Please provide relevant evidence and why it is negative. If the h is the water potential at upper soil surface, the soil surface is very dry and the actual water potential is very large, not -1cm.
(4) Line 260: “The OM showed higher penetration resistance especially in the upper layer 0-10cm (Fig.4)” This description does not match the rule in Fig. 4. Please confirm and modify it.
(5) The parameters of a and n in Table 3 should be obtained more reliably by the soil-water characteristic curve of the soil rather than the particle size distribution curve of the soil. The results of numerical simulation in Fig. 6 (c) and the measured soil-water characteristic curve are mutually verified, which will be more convincing. The following references are available for the measurement of soil-water characteristic curves.
Junran Zhang, Geng Niu, Xuchang Li, et al. Hydro-mechanical behavior of expansive soils with different dry densities over a wide suction range[J]. Acta Geotechnica, 2020, 15(01): 265-278.
Junran Zhang, Zhihao Meng, Tong Jiang, et al . Experimental Study on the Shear Strength of Silt Treated by Xanthan Gum during the Wetting Process [J]. Applied Sciences, 2022, 12(12): 6053.
Siwei Wang, Xinxin Zhao, Junran Zhang, et al. Water retention characteristics and vegetation growth of biopolymer-treated silt soils [J]. Soil &Tillage Research, 2023, 225: 105544.
Author Response
Conservation tillage in organic management (OM) had a pronounced effect on soil quality with a better soil penetration resistance compared to the conventional management (CM). Furthermore, soil hydraulic properties under different tillage practices have got little attentions due to the difficulties in preparing different soil physical measurements. The study was conducted on matched field pairs in Baden-Würtntemberg, Germany. The conservation tillage treatments effect of OM was compared with conventional tillage practices CM. This is a useful paper and is well-written containing some interesting results. It is acceptable for publication following consideration and response to the following points.
-The authors would like to thank the reviewer for his valuable comments
(1) The drawing of the Fig. 1 is not standard, such as no scale and no legends, and more relevant information should be given. In addition, the picture is blurred.
- It is modified
- Line 152: The permeability coefficient of unsaturated soil changes with the water head, while the permeability coefficient of saturated soil has only one value. Whether the equation is correct, or give more explanation.
The permeability coefficient of unsaturated soil changes was calculated using the Wooding equation that depends on the measured steady state infiltration rate (qs). While the saturated hydraulic conductivity (Ks) was calculated in this experiment depend on the calculated unsaturated hydraulic conductivity using the Wooding’s equation according to Gardner’s equation (Gardner, 1958). As follow:
That the infiltration rate of water through the soil surface was investigated in this experiment using the hood-infiltrometer device. This instrument allows measuring the steady state infiltration rate (qs). Into the soil surface, the amount of water infiltrating each 30 seconds was monitored versus time until reaching the infiltration steady state (Fig. 2).
During the process, the last five readings at the steady state were averaged and the steady flow rate was recorded. For all the investigated sites, the steady state infiltration rate was measured at a pressure head of -1 cm, and samples taken for measurements were in 3 replicates. Data collected in the field were as flow rates (Qs) and converted into steady infiltration rate (qs) according to (Reynolds and Elrick, 1991) as follows:
(1)
Where: Qs is steady flow rate [L3 L-1]; r is radius of the hood (L); and qs is steady state of the infiltration rate [L.T-1]. Infiltration data using hood-infiltrometer based mainly on the Wooding's analytical method [25]. Thus, with determination of Qs, unsaturated hydraulic conductivity of the investigated soil was computed according to (Wooding, 1968):
(2)
Where Ku is unsaturated soil hydraulic conductivity [L.T-1], and α is sorptivity number of the soil [L-1]. The soil sorptivity number (α) is a constant set equal to the reference value of 0.12 cm-1 for agriculture soils. With computing of unsaturated hydraulic conductivity using the Wooding’s equation, saturated hydraulic conductivity (Ks) was calculated according to Gardner’s equation (Gardner, 1958):
(3)
Where Ks is saturated soil hydraulic conductivity [L.T-1], h is pressure head [L].
-Reynolds, W. and D. Elrick, Determination of hydraulic conductivity using a tension infiltrometer. Soil Science Society America Journal, 1991. 55(3): p. 633-639.
-Wooding, R., Steady infiltration from a shallow circular pond. Water resources research, 1968. 4(6): p. 1259-1273.
-Gardner, W., Some steady-state solutions of the unsaturated moisture flow equation with application to evaporation from a water table. Soil science, 1958. 85(4): p. 228-232.
- Line 202: “The upper boundary conditions for the investigated sites were in pressure head -1 cm” Please provide relevant evidence and why it is negative. If the his the water potential at upper soil surface, the soil surface is very dry and the actual water potential is very large, not -1cm.
- To investigate the soil hydraulic parameters, (especially for estimating the preferential water flow pathways under various managements), in situ field techniques, as those based on the Hood infiltrometer/tension infiltrometer, have received increasing attention. This is also based on the fact that the tension infiltrometer required a low amount of water to investigate and process the infiltration trials, and is suitable for the assessment soil hydraulic properties in spatial variation, compared to the pressure/ring infiltrometer [27].
- Using the tension infiltrometer or the hood infiltrometer according to the principle of (Schwärzel and Punzel, 2007), the pressure head is negative value that the soil water retention into the vertical flow into the soil is in a negative value depend on the soil wter inverse retention. Thus, the principle of the Schwärzel and Punzel, 2007 in manufacturing the device was prepared to adjust the pressure head according to this soil physical concpt.
- During the process, the last five readings at the steady state were averaged and the steady flow rate was recorded. For all the investigated sites, the steady state infiltration rate was measured at the identified pressure head at this region with a pressure head of -1 cm, and samples taken for measurements were in 3 replicates. This instrument allows measuring the steady state infiltration rate (qs). Into the soil surface, the amount of water infiltrating each 30 seconds was monitored versus time until reaching the infiltration steady state (Fig. 2).
Figure . Principle of infiltration measurement using a Hood Infiltrometer (Schwärzel and Punzel, 2007).
- Line 260: “The OM showed higher penetration resistance especially in the upper layer 0-10cm (Fig.4)” This description does not match the rule in Fig. 4. Please confirm and modify it.
- Yes, you are right. Sorry for this mistake
It is corrected as follow:
The OM showed lower penetration resistance especially in the upper layer 0-10cm (Fig.4), while the CM soils at 10 -70 cm depth showed higher penetration. These results show that when the soil is converted to OM, more compactness could appear in the deep soil. That could lead to a decrease in macro-pores and bio-pores.
- The parameters of a and n in Table 3 should be obtained more reliably by the soil-water characteristic curve of the soil rather than the particle size distribution curve of the soil. The results of numerical simulation in Fig. 6 (c) and the measured soil-water characteristic curve are mutually verified, which will be more convincing. The following references are available for the measurement of soil-water characteristic curves.
- The hydraulic parameters a, n, Alpha, and Ks in table 3 were evaluated using parametric inversion tool in Hydrus-1D model. That the Hydrus-1D model according to van Genuchten (1980) to compute the water retention parameters depends on the Rosetta model (Chaap et al., 2001) were applied. These field measurements under the tillage impacts were implemented in Rosetta model to compute the hydraulic parameters. Then the obtained results using Van Genuchten equation were validated using the Root Mean Square Error (RMSE) in Excel Microsoft 10, with the measured field soil water at field capacity and at wilting point at the lab using the pressure membrane and the pressure cooker, respectively. The validation results were implemented in the Hydrus-1D model to calculate the hydraulic parameters a, n, Alpha, and Ks depend on the measured parameters under the tillage impact
Schaap, M.G., F.J. Leij, and M. Th. van Genuchten. 2001. Rosetta: a computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions. Journal of Hydrology. 251:163-176.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
Dear Authors,
After my caraful evalution, the paper have some revision comments to improve it. You should consider them. You can find my detailed revision comments and my concerns about the some methods in the original paper,
Best wishes,
Comments for author File: Comments.pdf
Author Response
After my careful evaluation, the paper has some revision comments to improve it. You should consider them. You can find my detailed revision comments and my concerns about some methods in the original paper,
-The authors would like to thank the reviewer for his valuable comments into the manuscript
Reviewer 4 Report
I have carefully read the manuscript and found it interesting. The subject of the manuscript is consistent with the scope of the Journal. The paper includes results from a comprehensive and thoroughly conducted experimental work. It is generally well written and well organized. I recommend accepting the manuscript.
Author Response
thank you very much
Round 2
Reviewer 3 Report
The paper can be accepted,
