Energy consumption and rice milling quality upon drying paddy with an industrial horizontal rotary dryer (IHRD) developed in northern Iran were investigated and compared with those of the conventional industrial batch-type bed dryer (IBBD) at five paddy final moisture levels (8.0, 9.0, 10.0, 11.0, and 12.0%, w.b).
Dry paddy soils and wet paddy fields exhibited relatively lower Hg fluxes than other agricultural soils.
Dry paddy soils had low soil porosity which might minimize the interface of soil to the atmosphere.
The average fluxes of Hg from agricultural bare soils, dry paddy soils, and wet paddy fields were in the ranges of 18.2 135, 2.7 14.2, and 1.4 22.8 ng m−2 h−1, respectively.
Besides, low penetrations of solar radiation and relevant biotic activities in dry paddy soils might also result in low air Hg concentrations in soil pool which in turn result in minimal diffusions of Hg to the atmosphere.
In the second wintering test, the seeds were placed under flooded and dry paddy conditions.
The seed viability of cultivated rice was 5% in dry paddy and 0.5% in flooded paddy, but weedy rice maintained a high viability during winter of 90% in the dry paddy and 61% in the flooded paddy.
Therefore, the second field experiment for seed wintering was carried out in a flooded paddy as well as in a dry paddy field.
The results were almost identical to the first year experiment except that the seed viabilities significantly decreased in the flooded paddy as compared with the dry paddy field for both weedy rice (WD-3, PBR) and cultivated rice (Hopum, Ilpum).
In this study, the wintering rate of weedy rice seeds was about 90% on the dry paddy and 60 80% on the flooded paddy, which was much higher than that of cultivated rice (below 5%).
