Showing 6 results for Paddy Field
M. Rabiee, M. Kavoosi, P. Tousi Kehal,
Volume 15, Issue 58 (3-2012)
Abstract
To determine the proper nitrogen fertilizer rates and its application times for achieving high grain and oil yields of rapeseed cultivar, Hyola 401, a research was carried out in paddy fields of Rice Research Institute of Iran in Rasht during two cropping seasons. A factorial experiment was conducted in a completely randomized block design with three replications. The experimental factors were pure nitrogen fertilizer rate at five levels of 0, 60, 120, 180 and 240 Kg ha-1 and fertilizer application times at five levels of all fertilizer at planting 1/3 at planting + 2/3 in stem elongation 1/3 at planting + 1/3 in stem elongation + 1/3 before flowering 1/3 in 3-4 leaf stages + 1/3 in stem elongation +1/3 before flowering 1/4 at planting + 1/4 in 3-4 leaf stages + 1/4 in stem elongation + 1/4 before flowering. The results of statistical analyses showed that from amony nitrogen rates, application of 240 Kg N ha-1 and 180 Kg N ha-1 with average production of 2505 Kg ha-1 and 2596 Kg ha-1 respectively showed the highest grain yield and were in the same group. of Nitrogen application times, application of 1/3 at planting + 1/3 in stem elongation + 1/3 before flowering had the highest grain and oil yields with average of 2155.3 Kg ha-1 and 9865 Kg ha-1, respectively. Maximum oil percentage was observed in control treatment (without N-fertilizer application) and the highest oil yield was obtained for nitrogen rates of 180 and 240 Kg ha-1. Also, the highest growth period was observed for the treatment of 240 Kg nitrogen with 206.3 days. The results showed that nonsignificant difference exists between the nitrogen rates of 180 and 240 Kg ha-1 in grain and oil yields. Therefore, the rate of 180 Kg ha-1 is recomended due to less fertilizer consumption and prevention of destructive effect on the environment
S. Yousefi-Moghadam, S. F. Mousavi, B. Mostafazadeh-Fard, M. R. Yazdani, A. Hemmat,
Volume 16, Issue 60 (7-2012)
Abstract
Puddling is the most common method of land preparation for lowland rice cultivation. The purpose of this study was to assess the influence of various intensities of puddling on percolation rate, water retention by soil and the amount of water used for different puddling intensities in three dominant soil textures of paddy fields in Guilan province. Undisturbed soil samples were taken from 3 different soils including silty clay, clay loam and loam, with 3 replications. The soil samples were puddled by a laboratory apparatus with different intensities. The results showed that the low puddling intensity treatment caused a 29.3, 32.4 and 36% reduction of percolation rate in silty clay, silty loam and loam textures, respectively. Increasing puddling intensity from low to medium reduced percolation rate significantly, but high intensity was not effective. Soil moisture characteristic curves of all three soils showed that water retention was increased by puddling treatments. Water retention in silty clay was higher than the other two soils. The high intensity treatment needed more water than low intensity for puddling. Increasing puddling intensity from medium intensity to high intensity caused 15.4, 14.1 and 16.3% increase in the amount of water required for puddling in silty clay, silty loam and loam textures, respectively. Generally, in all the three studied soil textures, the amount of water used for high-intensity puddling was more than medium-intensity puddling, while it had no significant effect on water percolation rate and soil water retention.
M. R. Yazdani, M. Parsinejad, A. R. Sepaskhah, N. Davatgar, S. Araghinejad,
Volume 18, Issue 69 (12-2014)
Abstract
Intermittent irrigation of paddy fields with long intervals can cause cracks in heavy soils, facilitate loss of water and finally damage the crop. This study was carried out in order to investigate the cracking trend and some other factors affecting soil cracking in four different physiographical areas of paddy field. The study areas were Rasht, Shanderman, Astaneh and Khomam in Guilan province. The experiment was carried out in paddy fields with transplanted rice by determining the physical properties relevant to cracking behavior after irrigation withdrawal in the reproductive stage. Soil analysis showed that despite similarity in type of dominant minerals, the linear expansion coefficients of Rasht and Khomam soils were higher than those of two other areas. In addition, there was a significant relationship between crack dimensions and volumetric soil water content and clay content. Furthermore, the temporal variation in study of crack development (depth, width and density) showed that they varied in different areas and were affected by volumetric soil water content and the groundwater depth. In addition, the depth of cracks in all soils did not reach the hard pan. All the investigated soils showed a definite threshold for width and depth of cracks for 20-25 days after irrigation withdrawal. After this period, specific values for width (about 3.0, 2.0, 2.5, and 5.0 cm) and depth of cracks (20, 25, 17, and 27 cm) were registered for Astaneh, Khomam, Shanderman and Rasht, respectively
M. Marzi Nohadani, B. Mostafazadeh-Fard, S. F. Mousavi, M. R. Yazdani, M. R. Alizadeh,
Volume 19, Issue 72 (8-2015)
Abstract
The common method of puddling is using a conventional tiller which requires long time of soil operations.In this study, the effects of tillage equipment on moisture characteristic curve of a paddy soil were investigated. The treatments included tillage equipment (T1: conventional tiller, T2: rotary puddler, T3: cone puddler, T4: tractor mounted rotivator) and number of puddlings (P1: puddling once, P2: puddling twice, P3: three times'puddling and P4: four times'puddling). The results showed that at saturation point, tractor mounted rotivator presented the highest moisture content. At field capacity and permanent wilting point, the cone puddler showed the highest moisture value. The two newly made units held more moisture and saved water. In different tillage equipment, increasing the number of puddling reduced soil moisture. Available moisture in the soil without tillage (control) was less than in soils under rotary puddler and cone puddler.
M. Masoomi, M. Pourgholam-Amiji, M. Parsinejad,
Volume 26, Issue 1 (5-2022)
Abstract
In this study, the Drainmod-S model was used to vary soil salt concentration and the effect of underground drainage on the amount of leaching in a physical model (large lysimeter). A soil extractor was installed at depths of 40, 50, and 70 cm at a distance of 35 cm from the drainage to measure the salinity of the soil solution. In this study, three scenarios were applied including salinity profiles under conventional conditions (mid-season and end-season drainage), soil salinity profiles under different drainage conditions, and prior scenarios with saline irrigation. The second and third scenarios were applied in four drainage stages, respectively. These stages include transplanting and mid-season drainage (days 15 to 20), mid-season drainage (days 35 to 40), mid-season and end-season drainage (days 55 to 60), and end-season drainage (days 75 to 80). The results showed that after simulating the total solute concentration overtime at a depth of 40 cm and comparing it with the measured values, the coefficient of determination (R2) was 0.77 indicating an acceptable Drainmod-S model simulation. This parameter for simulating solute concentration at 50 and 70 cm depth was 0.76 and 0.75, respectively. The mean absolute error parameter (MAE) value was also negligible.
Mohammad Mohammadian, Saheb Soodaie Mashaee, Mortaza Nasiri,
Volume 30, Issue 3 (10-2026)
Abstract
A field experiment was conducted using a factorial in a randomized complete block design to evaluate the growth and yield of rice (Oryza sativa L.) cv. Hashemi in response to nitrogen (N) and phosphorus (P) fertilization. The first factor comprised four N levels (0, 46, 69, and 92 kg N ha⁻¹), and the second factor comprised three P₂O₅ levels (0, 23, and 46 kg P₂O₅ ha⁻¹), with three replications conducted over two cropping years. At the end of the growing season, growth indices, yield, and yield components of rice were measured. The results indicated that the main effects of N and P fertilization on several traits (aboveground dry matter, grain yield, and straw yield) were significant at the 1% probability level. The N × P interaction for grain yield and the main effect of year were significant for most traits at the 5% level. The highest grain yield (935.2 kg ha⁻¹) and straw yield (1455 kg ha⁻¹) occurred with 92 kg N ha⁻¹ and 46 kg P₂O₅ ha⁻¹, representing increases of 115% and 120%, respectively, relative to the control (no N or P applied). This treatment is recommended for rice production under ratoon cultivation in areas with similar climatic and soil conditions
