M. Alizadeh; F. Mirzaei; T. Sohrabi; M. Kavoosi; M.R. Yazdani
Abstract
Water management in cracked paddy soils is an important issue in rice cultivation. In order to investigate the effect of rice straw and zeolite and their interaction effect on the physical condition of soils of paddy fields and prevention of crack, rice straw factor at four levels (0, 0.5, 1 and 1.5 ...
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Water management in cracked paddy soils is an important issue in rice cultivation. In order to investigate the effect of rice straw and zeolite and their interaction effect on the physical condition of soils of paddy fields and prevention of crack, rice straw factor at four levels (0, 0.5, 1 and 1.5 percent) zeolite factor at four levels (0, 8, 16 and 24 tons per hectare) and also moisture stages of soil which are wet and dry stages at 5 levels which have been studied in three replication as factorial based on the complete randomized block design in Rice Research Institute of Iran. Soil distance from the wall of the container, the width of cracks, a few days to reach the crack with a certain width, bulk density and surface cracks were measured. Results showed that adding high levels of residue to delay the occurrence of cracks. However, the addition of zeolite has no significant effect in delaying the cracks. The relationship between bulk density and surface cracks that follow the linear equation, With increasing cracks surface, bulk density is increased. Finally, Can be concluded that the addition of plant residues, causing disappearance of existing cracks and returned to the soil to be the initial state.
B. Hassanpour; F. Mirzaei; S. Arshad; H. Kossari
Abstract
In the present study, two methods of predicting evapotranspiration by the use of satellite images were compared. Field data in a corn site was measured at agricultural engineering research institute private farm in 6 days. Consequently MODIS images were used for predicting evapotranspiration by SEBAL ...
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In the present study, two methods of predicting evapotranspiration by the use of satellite images were compared. Field data in a corn site was measured at agricultural engineering research institute private farm in 6 days. Consequently MODIS images were used for predicting evapotranspiration by SEBAL and S-SEBI algorithms. These algorithms are different in predicting sensible heat flux. The results show that RSME value for the net radiation and soil heat flux was respectively 46 and 43 (w/m2). SEBAL algorithm is capable to estimate sensible heat flux more accurate than S-SEBI so it is able to estimate latent heat flux more accurate. The RSME amount in sensible heat flux and latent heat flux for SEBAL algorithm are 58 and 31 (w/m2) respectively. These amounts in S-SEBI algorithm are 111 and 74 (w/m2). The differences between two algorithms could be because of the use of meteorological data in predicting sensible heat flux and aerodynamic resistance in SEBAL algorithm. Also the results show that SEBAL algorithm estimates hourly evapotranspiration by the difference of 0.05 mm/hour which is about 1% of hourly evapotranspiration Whereas S-SEBI predicted it by the difference of 0.11 and 11%. The difference between measured daily evapotranspiration and SEBAL -based daily evapotranspiration was 0.4 mm that is about 1% less than measured. Whereas these differences by S_SEBI are 1mm and 12%.
M. Alizadeh; F. Mirzaei; T. Sohrabi
Abstract
Abstract
Rice can be cultivated in various soils but soil with heavy texture and low permeability is more appropriate for its growth than other types of soil texture. It’s assumed that existence of zeolite in soil can be effective for moisture retention and avoiding of occurrence of crack in soil. ...
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Abstract
Rice can be cultivated in various soils but soil with heavy texture and low permeability is more appropriate for its growth than other types of soil texture. It’s assumed that existence of zeolite in soil can be effective for moisture retention and avoiding of occurrence of crack in soil. In order to investigation of the effect of zeolite on moisture status and hydraulic properties of Guilan province’s paddy’s soils, zeolite factor was conducted in four levels (0, 8, 16, 24 tons per ha) in five stages of soil moisture (saturation, appearance of capillary crack, final crack, returning from final crack to capillary crack, destruction of crack) in three replications as factorial based on complete randomized block design in a soil texture (Silty clay) as the dominant texture in Guilan area in Iran’s Rice Research Institute. Results showed that moisture in saturation stage did not change much by adding zeolite, while in capillary crack stage, moisture storage has increased to 7% and in final crack stage, it has increased to 17 %. So you see, after a cycle of dry and wet, the amount of moisture and bulk density has not turned back to its primitive amount, also the volume of inflammation in soil’s moistening trend is far lower than the volume of subsidence in soil’s drying trend and the soil has not turned back to its primitive volume. Finally, the effect of zeolite on the volume of consumable water has been significant at five percent statistical level.
Keywords: Zeolite, Clinoptilolite, Cracked soil, Water condition, Rice
