Minimum Soil Disturbance Planting For Rice-based Rotations In Northwest .
Minimum Soil Disturbance Planting for Rice-based Rotations in Northwest Bangladesh: Effects on Plough Pan and Water Balance By Mir Nurul Hasan Mahmud MS (Irrigation and Water Management) This thesis is presented for the degree of Doctor of Philosophy of Murdoch University 2021
Declaration I declare that the thesis is my own account of my research work that has not been previously submitted for any degree at any other institution at any level. Mir Nurul Hasan Mahmud ii
Abstract Soil degradation in the rice-based cropping system of Bangladesh has prompted research to switch from conventional tillage (CT) to minimum soil disturbance crop establishment, featuring strip planting (SP) and increased crop residue retention. However, the new residue retention levels and crop establishment methods need to be tested for their water use efficiency. Therefore, two field trials were initiated to evaluate the effects of SP and bed planting (BP) with increased crop residue retention on soil physical properties, components of the water balance and water productivity in two rice-based crop rotations. Field trials were conducted during 2015-2017 in two long-term conservation agriculture (CA) experimental fields established since 2010 in two regions of northwest Bangladesh, namely 1) Alipur, the alluvial soil region, and 2) Digram, the High Barind Tract (HBT) region. The trials consisted of three tillage treatments in the main plots - SP, BP and CT. The subplots comprised of two levels of residue retention - high residue (HR) and low residue (LR). High residue and LR treatment involved the retention of respectively 50 % and 20 % by the height of the previous crop, either anchored or loose. Strip planting and BP were done with a Versatile Multi-crop Planter mounted on a two-wheel tractor (2-WT). Seven years of continuous CA practices have provided evidence that minimum soil disturbance and increased residue retention have altered the soil physical properties in both silty loam soil at Alipur and silty clay loam soil at Digram. The physical changes were reflected in the reduction of soil BD, enhancement of total porosity (TP) and reduction of penetration resistance (PR) in the 0-20 cm soil depth. High residue treatment reduced BD from 1.37 to 1.33 g cm-3 at Alipur and 1.27 to 1.24 g cm-3 at Digram soil in the 0-10 cm soil depth compared to the LR treatment. High residue retention increased macroporosity by an average of 55 % over LR treatment. Irrespective of residue retention, the average (two soils) decrease in BD was 4.5 % and 2.6 % in 0-10 cm depth for SP and BP treatment, respectively, compared to CT. The highest BD of 1.65 g cm-3 was achieved at 10-20 cm soil depth in the iii
CT plot, which clearly indicates a massive plough pan at this depth. However, BD of the plough pan was reduced by 3.8 % in the SP and 4.6 % in the BP treatment indicating the amelioration of subsoil compaction due to the absence of puddling over seven years. Penetration resistance in the plough pan was also decreased from 2.15 MPa (CT) to 1.93 MPa (SP) at Alipur and 2.55 MPa (CT) to 2.32 MPa (SP) at Digram. In the silty loam soil, saturated hydraulic conductivity (Ksat) at 0-10 cm under CT was 1.00 cm hr-1 which was increased to 1.39 cm hr-1 by SP and to 1.52 cm hr-1 by BP. In the silty clay loam soil, Ksat at 0-10 cm was increased from 0.32 cm hr-1 under CT to 0.66 cm hr-1 by SP and to 0.81 cm hr-1 by BP. In 1020 cm soil depth, Ksat increased from 0.22 cm hr-1 under CT to 0.48 cm hr-1 by SP and to 0.43 cm hr-1 by BP. Soil compaction by a 2-WT with a single wheel-pass, two wheel-passes, and four wheelpasses with and without extra loading was also tested in non-CA fields adjacent to the two long-term trials. At 0-5 cm depth, soil BD with a single wheel pass was 1.37 g cm-3, which increased to 1.40 g cm-3 after two passes, and further increased to 1.47 g cm-3 with four passes. The BD of 0-5 cm depth with no extra loading was 1.37 g cm-3 which was increased to 1.39 g cm-3 with 100 kg extra loading and further increased to 1.43 g cm-3 with 200 kg extra loading. At 5-10 cm depth, compaction by CT involving four passes indicated that a 2-WT, when frequently trafficked at this depth for many years, creates a dense soil layer that is reasonably related to the formation of the plough pan. The least limiting water range (LLWR) range could be a good indicator of soil quality in soil compaction studies since the LLWR concept includes the effects of several growth-limiting factors such as matric potential, aeration and penetration resistance that are integrated into a single parameter. Conventional tillage had a larger LLWR which is also comparable to the LLWR of strip tillage single wheel pass treatment. Conservation agriculture practice facilitates tillage, fertilizer and seeding operation in a single pass. Thus, single wheel pass traffic by a low weight 2-WT may not create measurable compaction in the surface soil and the subsurface soil. iv
High rice residue retention treatment increased wheat yield by 7-18 % in the whole study period (2015-2017) compared to low residue retention. Strip planting increased wheat yield by 18-25 % compared to CT in the three years. By contrast, BP increased wheat yield by 16 % compared to CT in 2015 but not in 2016 or 2017. Strip planting saved 15-36 % irrigation water for wheat growth compared to CT in three years. In contrast to SP, BP saved only 8-25 % irrigation water than CT. Irrigation water productivity of wheat was higher under SP (2.2 kg m-3) than that under BP (1.7 kg m-3) and CT (1.3 kg m-3). The results suggest that SP performed better than BP in terms of crop productivity and irrigation water productivity. Total water losses under SP continuous flooding irrigation were 80.0-125.0 cm, while the values were 82.0-123.0 cm for BP and 66.0-86.0 cm for CT. Deep drainage during the rice crop for SP, BP and CT accounted for about 41 %, 44 %, and 39 % of the total loss, respectively. Alternate wetting and drying irrigation reduced the drainage losses by 35 %, 26 % and 48 % for SP, BP and CT, respectively. The yield of rice ranged from 6.1-6.9 t ha-1, 6.16.6 t ha-1 and 6.5-6.7 t ha-1 for SP, BP and CT, respectively. Irrigation water productivity for rice was higher under CT (0.88 kg m-3) compared to SP (0.66 kg m-3) and BP (0.60 kg m-3). Improved crop yield under SP with residue retention should encourage smallholder farmers to adopt minimum soil disturbance planting in the rice-based rotation. However, altered water balance in the non-puddled minimum soil disturbance plot may require more irrigation for rice while allowing greater infiltration to groundwater. In contrast, for wheat, SP and HR had positive effects on water use and water productivity. Since water lost by deep percolation returns to the groundwater and is potentially available for reuse, non-puddled rice can beneficially increase groundwater recharge when practised in a large command area. Hence, CA practices appear to decrease the requirement for groundwater for irrigation of dry season wheat while increasing the potential for groundwater recharge, but this needs further investigation. v
Keywords: Barind area (Bangladesh); bed planting; conservation agriculture; conventional tillage; deep drainage; least limiting water range; minimum soil disturbance; number of wheel passes; soil compaction; strip planting; water balance. vi
Table of contents Declaration . .ii Abstract . . iii Keywords .vi Table of contents . . .vii List of Tables . . xiii List of Figures . .xvi List of Abbreviations . . xxiii List of botanical names xxvii Acknowledgements .xxviii 1 General Introduction . 1 1.1 Overview . 1 1.2 Research gaps . 5 1.3 Hypothesis . 8 1.4 Objectives . 8 1.5 Structure of this Dissertation . 9 2 Review of Literature . 11 2.1 Concept of tillage . 11 2.2 Conventional Tillage . 11 2.3 Puddling . 12 2.4 Plough pan . 13 2.5 Conservation Agriculture . 14 2.6 Advantages and disadvantages of Conservation Agriculture . 15 2.7 Minimum soil disturbance . 16 2.1.1 No-tillage or Zero Tillage . 16 2.1.2 Strip Planting . 16 2.1.3 Bed Planting . 17 2.8 Non-puddled transplanting of Rice . 18 2.9 Effect of minimum soil disturbance on soil physical and hydrologic properties . 19 2.1.4 Soil bulk density . 20 2.1.5 Soil water storage . 25 2.1.6 Hydraulic conductivity and infiltration rate . 27 2.10 Effect of minimum soil disturbance on water saving and water productivity . 29 vii
2.11 Review of water balance studies for rice . 35 2.12 Review of water balance studies for wheat . 37 2.13 Water balance models for irrigated rice . 39 2.14 Effect of compaction on soil physical properties . 41 2.15 Effect of repeated wheel passes on soil compaction . 42 2.16 Subsoil compaction by vehicle weight . 44 1.17 Conclusions . 45 3 Effects of medium to long-term minimum soil disturbance and residue retention on soil physical properties in two rice-based rotations in northwest Bangladesh. . 48 3.1 Introduction . 48 3.2 Materials and methods . 49 3.2.1 Experimental sites . 49 3.2.2 Climate and weather . 53 3.2.3 Experimental design, and tillage and residue management treatments . 54 3.2.4 Soil sample collection and bulk density. 57 3.2.5 Soil porosity and pore size distribution . 60 3.2.6 Soil water content and soil penetration resistance . 60 3.2.7 Soil penetration resistance measurements in the trenches . 61 3.2.8 Measurements of saturated hydraulic conductivity (Ksat) . 62 3.2.9 Soil water retention curve . 63 3.2.10 Infiltration measurements in the field . 64 3.2.11 Soil physical parameters of natural soils . 65 3.2.12 Statistical methods . 66 3.3 Results . 67 3.3.1 Alipur . 67 3.3.2 Digram . 81 3.3.3 Soil physical properties in natural soils of five different locations . 94 3.4 Discussion . 99 3.4.1 Effects of residue retention on soil physical properties . 99 3.4.2 Effects of Strip Planting on soil physical properties . 102 3.4.3 Effects of Bed Planting on soil physical properties . 109 3.5 Conclusions . 115 viii
4 Compaction by 2-wheel tractor wheeling under controlled-traffic strip planting: characterisation of changes in soil physical properties by least limiting water range, and chickpea emergence . 117 4.1 Introduction . 117 4.2 Materials and methods . 120 4.2.1 Experimental site and soil texture . 120 4.2.2 Experimental treatments and layout. 121 4.2.3 Soil sampling . 124 4.2.4 Penetration resistance measurements in the trench . 126 4.2.5 Penetration resistance measurements in the laboratory . 127 4.2.6 Penetration resistance for θFC, θPWP and water content at sowing . 128 4.2.7 Soil water retention curve . 129 4.2.8 Infiltration measurements in the field . 130 4.2.9 Measurements of saturated hydraulic conductivity . 130 4.2.10 Chickpea emergence . 131 4.2.11 Statistical analysis . 132 4.3 Results . 133 4.3.1 Aipur 2015 . 133 4.3.2 Alipur 2016 . 135 4.3.3 Digram 2016 . 156 4.3.4 Thakurgaon 2017 . 176 4.4 Discussion . 181 4.4.1 Effect of tillage, loading weight, and number of wheel passes on soil physical properties . 181 Penetration resistance . 184 4.4.2 The implication of soil water content, number of wheel passes and formation of a plough pan. 185 4.4.3 Least Limiting Water Range and Plant Available Water. 186 4.4.4 Effect of loading weight and number of wheel passes treatments on Infiltration and hydraulic conductivity . 188 4.4.5 Effect of loading weight and number of wheel passes treatments on chickpea emergence . 190 4.5 Conclusion. 193 5 Effect of minimum soil disturbance planting on the water balance of wheat in northwest Bangladesh . 195 ix
5.1 Introduction . 195 5.2 Materials and Methods . 197 5.2.1 Experimental site . 197 5.2.2 Experimental design and treatments . 197 5.2.3 Irrigation Scheduling . 197 5.2.4 Components of water balance . 198 5.2.5 Irrigation water productivity and Crop water use efficiency . 201 5.2.6 Wheat crop management. 201 5.2.7 Statistical Method . 202 5.3 Results . 202 5.3.1 Water balance components . 202 5.3.2 Soil Water storage . 210 5.3.3 Effect of tillage on the yield of Wheat . 216 5.3.4 Yield components of wheat . 218 5.3.5 Irrigation water productivity . 223 5.3.6 Crop water use efficiency . 225 5.3.7 Measured crop evapotranspiration vs simulated crop evapotranspiration at different growing stages of wheat . 227 5.3.8 Simulated cumulative crop evapotranspiration, transpiration, and soil evaporation. . 232 5.4 Discussion . 236 5.4.1 Yield advantages by minimum soil disturbance and residue retention. 236 5.4.2 Effect of SP on Irrigation water savings . 237 5.4.3 Effect of BP on Irrigation water savings. 238 5.4.4 Effect of BP and SP on crop evapotranspiration and soil water storage . 239 5.4.5 Effect of SP on Irrigation water productivity and crop water use efficiency 242 5.4.6 Effect of BP on Irrigation water productivity and crop water use efficiency 243 5.4.7 Effect of residue retention on irrigation water productivity . 243 5.5 Conclusion. 244 6 Effect of minimum soil disturbance planting on the water balance of rice in northwest Bangladesh . 245 6.1 Introduction . 245 6.2 Material and Method . 245 6.2.1 Experimental site . 245 x
6.2.2 Experimental design and treatments . 246 6.2.3 Water balance model. 246 6.2.4 Water balance components measurements in the field . 251 6.2.5 Crop management practices . 252 6.2.6 Statistical analysis . 252 6.3 Results . 253 6.3.1 Effect of tillage on irrigation water requirement . 253 6.3.2 Effect of tillage on percolation losses . 253 6.3.3 Effect of tillage on seepage losses . 255 6.3.4 Effect of tillage on crop evapotranspiration (ETc) . 255 6.3.5 Effect of tillage on irrigation water requirement according to growing stages 260 6.3.6 Effect of tillage on percolation losses according to growing stages . 260 6.3.7 Effect of tillage on seepage losses according to growing stages . 262 6.3.8 Effect of tillage on ETc according to growing stages . 263 6.3.9 Effect of tillage on total water use, rice grain yield and water productivity . 279 6.4 Discussion . 282 6.4.1 Effect of SP on irrigation water requirement for land preparation . 283 6.4.2 Effect of SP on irrigation water requirement from transplanting to harvest. 284 6.4.3 Effect of SP on seepage and percolation losses . 288 6.4.4 Effect of SP on Evapotranspiration. 291 6.4.5 Effect of SP on grain yield . 291 6.4.6 Effect of SP on water productivity. 293 6.4.7 Effect of BP on irrigation water requirement for land preparation . 293 6.4.8 Effect of BP on irrigation water requirement from transplanting to harvest . 294 6.4.9 Effect of BP on seepage and percolation losses. 295 6.4.10 Effect of BP on Evapotranspiration . 296 6.4.11 Effect of BP on rice grain yield . 297 6.4.12 Effect of BP on water productivity . 298 6.5 Conclusion. 299 7 General discussion . 301 7.1 Tillage and residue management effects on soil physical properties . 302 7.2 Effect of infiltration variability on the irrigation requirement . 308 xi
7.3 Effect of wheel compaction by a 2-WT . 310 7.4 Controlled traffic farming system . 314 7.5 Real water saving vs groundwater recharge . 314 7.6 Effect of tillage and residue management on the crop performance . 316 7.7 Recommendations for Further Research . 317 8 References . 319 9 Appendix . 379 10 Publications from this study . 381 xii
List of Tables Table Table 2.1 Table 2.2 Table 2.3 Table 2.4 Table 3.1 Table 3.2 Table 3.3 Table 3.4 Table 3.5 Table 3.6 Table 3.7 Table 3.8 Table 3.9 Table 3.10 Table 3.11 Table 3.12 Table 3.13 Table 3.14 Table 3.15 Table 3.16 Title Page No. Regional area of annual cropland under Conservation Agriculture 15 (CA) in 2015-16 Effect of zero tillage (ZT) or no-tillage (NT) and residue retention on 22 soil bulk density as compared to conventional tillage (CT) Effect of minimum soil disturbance on water productivity 31 The effect of different wheel loads applied to different soils in different 42 parts of the world on bulk density and penetration resistance. Experimental site characteristics of two different locations in North- 50 west Bangladesh Initial soil properties of two long-term experimental sites in Rajshahi 50 since the beginning of the present study that started in 2015 Cropping sequence of two long-term experimental sites in Rajshahi 51 since establishment in 2010 Tillage treatments details at Alipur and Digram 54 Dry weight of residues retained of different crops under different 55 tillage treatments in the Boro rice dominant cropping sequence at Alipur in 2014 to 2017. Dry weight of residues retained of different crops under different 56 tillage treatments in the wheat dominant cropping sequence at Digram in 2014 to 2017. Depths of soil samples collected from different positions of different 58 tillage treatments Description of undisturbed natural sites at five locations in three 65 districts with short to medium long-term CA practice. Soil BD (g cm-3) in the 0-30 cm depth as affected by three tillage and 67 two residue retention treatments after 7 years of minimum soil practices treatments in the Alipur long term experiment. Saturated hydraulic conductivity taken after lentil harvest in February 71 2017 for three soil depths under three tillage treatments and two residue retention treatments for Alipur long-term experiment. Soil physical properties according to the sampling position for SP and 77 BP treatments at three depths of Alipur soil. Effect of tillage on soil infiltration characteristics taken after lentil 78 harvest in February 2017 at Alipur, Rajshahi. Soil dry bulk density (g cm-3) in the 0-30 cm depth as affected by three 80 tillage and two residue management treatments after 7 continuous years of disturbance treatments in the Digram long term experiment. Saturated hydraulic conductivity taken after wheat harvest in March 85 2017 for three soil depths under three tillage treatments and two residue levels for Digram long term experiment. Soil physical properties according to the sampling position for Strip 91 planting and bed planting treatments at three depths in Digram soil. Effect of tillage on soil infiltration characteristics taken after wheat 92 harvest in March 2017 at Digram, Rajshahi. xiii
Table Table 4.1 Table 4.2 Table 4.3 Table 4.4 Table 4.5 Table 4.6 Table 4.7 Table 4.8 Table 4.9 Table 4.10 Table 4.11 Table 4.12 Table 4.13 Table 4.14 Table 4.15 Table 5.1 Title Page No. Soil physical parameters measured before wheel trafficking 119 experiments at three locations and different depths. SWC was the residual water content after monsoon rice harvest at Alipur measured in February. At Digram SWC was the residual water content after wheat harvest in March. At Thakurgaon SWC was the residual water content after monsoon rice harvest measured in January. Treatment identification and tyre/axle configuration 121 Mean soil bulk density (g cm-3) values under different tillage, loading 131 weight, and number of wheel passes treatments taken in 2015 Alipur, Rajshahi. Penetration resist
to adopt minimum soil disturbance planting in the rice-based rotation. However, altered water balance in the non-puddled minimum soil disturbance plot may require more irrigation for rice while allowing greater infiltration to groundwater. In contrast, for wheat, SP and HR had positive effects on water use and water productivity.
Chapter 1 describes the role of a visual guide within the context of soil risk ratings and soil-quality monitoring, and evaluates the effects of soil disturbance. Chapter 2 defines and describes the visual attributes that determine a soil-disturbance class. Chapters 3 through 6 describe each disturbance class, its criteria, and where it may occur.
Bruksanvisning för bilstereo . Bruksanvisning for bilstereo . Instrukcja obsługi samochodowego odtwarzacza stereo . Operating Instructions for Car Stereo . 610-104 . SV . Bruksanvisning i original
10 tips och tricks för att lyckas med ert sap-projekt 20 SAPSANYTT 2/2015 De flesta projektledare känner säkert till Cobb’s paradox. Martin Cobb verkade som CIO för sekretariatet för Treasury Board of Canada 1995 då han ställde frågan
service i Norge och Finland drivs inom ramen för ett enskilt företag (NRK. 1 och Yleisradio), fin ns det i Sverige tre: Ett för tv (Sveriges Television , SVT ), ett för radio (Sveriges Radio , SR ) och ett för utbildnings program (Sveriges Utbildningsradio, UR, vilket till följd av sin begränsade storlek inte återfinns bland de 25 största
Hotell För hotell anges de tre klasserna A/B, C och D. Det betyder att den "normala" standarden C är acceptabel men att motiven för en högre standard är starka. Ljudklass C motsvarar de tidigare normkraven för hotell, ljudklass A/B motsvarar kraven för moderna hotell med hög standard och ljudklass D kan användas vid
LÄS NOGGRANT FÖLJANDE VILLKOR FÖR APPLE DEVELOPER PROGRAM LICENCE . Apple Developer Program License Agreement Syfte Du vill använda Apple-mjukvara (enligt definitionen nedan) för att utveckla en eller flera Applikationer (enligt definitionen nedan) för Apple-märkta produkter. . Applikationer som utvecklas för iOS-produkter, Apple .
3 Objectives of Soil Mechanics To perform the Engineering soil surveys. To develop rational soil sampling devices and soil sampling methods. To develop suitable soil testing devices and soil testing methods. To collect and classify soils and their physical properties on the basis of fundamental knowledge of soil mechanics. To investigate the physical properties of soil and
Astrophysics Research Institute The Astrophysics Research Institute (ARI) is one of the world’s leading authorities in astronomy and astrophysics. Its work encompasses a comprehensive programme of observational and theoretical research, telescope operation, instrument development, academic learning and outreach activities. The ARI has been honoured with various awards and prizes including: n .
