Effect of puddling intensity on physical properties of a silty clay soil under laboratory and field conditions |
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Authors: | S F Mousavi S Yousefi-Moghadam B Mostafazadeh-Fard A Hemmat M R Yazdani |
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Institution: | (1) College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran;(2) Rice Research Institute, Rasht, 41996-13475, Iran |
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Abstract: | Conventional tillage and planting method for rice (Oryza sativa L.) production in northern Iran is wet tillage (puddling). Effect of different puddling intensities on physical properties
of a silty clay soil (Typic Haplodalfs) was investigated under laboratory and field conditions. Changes in soil physical parameters
and water requirement for puddling were measured. For laboratory experiments, undisturbed cylindrical soil samples (diameter
and height of 50 cm), were used. A laboratory puddling apparatus was designed and constructed. The puddling intensity was
measured by duration of puddling. Four levels of puddling intensity were used as: P
0 (no puddling, control), P
1 (low), P
2 (medium) and P
3 (high). For field tests, 12 plots of 8 × 4 m were selected. The first tillage was performed with a moldboard plow and then
the plots were puddled with different intensity using a rotary tiller. The results showed that under laboratory conditions,
water content of the puddled layers decreased with an increase in settling time. During drying period, P
0 dried faster than P
1, P
2 and P
3. Puddling with low intensity in laboratory and field conditions caused bulk density of 0–15 cm soil layer to decrease by
24.07 and 25.45%, respectively. Increasing puddling intensity increased the bulk density. Bulk density increased with time
as particles settled after halting the puddling. Bulk density increased with depth as well. Under laboratory conditions, increasing
puddling intensity from P
1 to P
2 reduced percolation rate significantly. For all puddling intensities, soil moisture characteristic curves of both field and
laboratory samples showed that puddling increased the amount of water retained over the whole range of suctions. More water
was needed for P
3 as compared to P
1 and P
2. Under the laboratory and field conditions, the P
3 required 27.72 and 28.58% more water as compared to P
2, respectively. Although the mechanisms implemented for puddling were different under laboratory and field experiments, the
results were similar. Bulk density, soil moisture content and water percolation rate decreased faster in the puddled soil
under field and laboratory conditions. Therefore, to reduce the cost and time, the laboratory method could be used to study
the effects of puddling intensity on physical properties of paddy soils. Medium intensity puddling was shown to be the proper
tillage practice for paddy fields with silty clay soil. |
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Keywords: | Paddy fields Percolation rate Water retention Rice |
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