Trend analysis of yield, production and cultivated area of cereal in Iran during the last 50 years and prediction of future situation

Trends in cultivated area, yield and production of wheat, barley and rice as the main cereal crops of Iran were studied during 1350-1382 using time series analysis and the situation of future were predicted for 1382-1400 period. The results showed that country-level cultivated area of cereals is leveled off after and initial increase and the current area under cultivation will be maintained until year 1400. However, cultivated area of irrigated wheat and rice will be increased slightly. During the last 32 years cereals yield is increased considerably. Mean annual rate of yield increase was much higher for irrigated cereals (62.5 kg year-1) and rice (69.7 kg year-1) compared to rainfed cereals (12.6 kg year-1), this incremental trend will be continued towards year 1400. The increase of cereal yield in spite of constant cultivated area is led to increase in total production and it was predicted that total cereal production of country will be exceed 26 million tons in target year of 1400. However, per capita cereal production which was at its highest in the mid years of the study period, was decreased later and at present is about 310 kg which is not much different from the baseline year (1350). Per capita production of cereals will remain unchanged until year 1400 because of high predicted population growth rate

Weed seed bank dynamics under various rotations and field production resources

Weed seed bank dynamics in corn, sugar beet and wheat plots in rotation with wheat were studied under conventional and ecological management systems during 2 years. The experiment was laid out in a split- plot design in a randomized complete block, where 3 crop rotations were assigned to main plots and 5 cropping systems including high–input, medium–input, low–input, integrated and organic systems were allocated to subplots. The results showed that crop species and weed management practices in different cropping systems significantly affected weed seed bank composition. However, weed seed bank dynamics were indirectly affected by crop rotation. The highest mean weed seed density and weed species diversity in soil surface layer was observed in organic system while high–input system had the lowest seed density. Weed seed density of soil surface layer in organic and low–input systems were twice of that in deeper soil layer. However, in high–input system weed seed bank was uniformly distributed over soil layers. The highest weed seed density was observed in continuous wheat plots where seeds were mainly accumulated at soil surface layer. Corn-wheat and sugar beet-wheat rotations led to a lower seed bank density and more uniform distribution of weed seeds in soil

Evaluation of droght tolerance of new wheat genotypes under water stress conditions

To evaluate the drought tolerance of new wheat genotypes to terminal water stress in field conditions, an experiment using a split plot design based on compelet randomaised block design with three replications was conducted in Torogh Agricultural Research Station (Mashad) in 1382-83. Irrigation treatments with two levels were allocated in main plots: I1- full irrigation (100% water use in different development stages) and I2- water stress (withdrawal of irrigation from anthesis stage to maturity with prevention of precipitation using mobile rain shelter). Number of 16 elite wheat genotypes suited for cold regions of Iran and Khorasan province (C-82) were allocated in sub plots. Results showed that, irrigation treatment had a significant effect on grain yield (GY), harvest index (HI), No. of spike per m2 (S.m-2), No. of grain per spike (G.S-1) and thousands kernel weight (1000 KW). There was significant differences between genotypes. C-82-5 was a high yielding genotype in both conditions (control and water stress) and had optimum level of HI, G.S-1 and 1000 KW. The tolerance of genotypes to water stress was evalovated with different drought tolerance indices, such as stress tolerance index (STI). Results showed that, C-82-5 was a high yielding genotype with more tolerance to terminal water stress

The effect of sowing date and plant density on yield and yield components of safflower (Carthamus tinctorious L.) in Rokh plateau .

To investigate the effect of sowing date and plant density on yield and yield components of safflower ( Carthamus tinctorious) as well as evaluating the possibility of the second sowing of the plant in Torbat Heidariyeh , a field experiment was conducted in Rokh, Cold Season Cereal Research Station 2005 . The experiment was conducted in split plot arrangement in complete randomized block design with four replications . Main plots were sowing date in five levels including 9 April, 10 May, 31 May, 20 June, 11 July and sub plots were plant density in three levels including 300000, 400000, 500000 plants per hectar. Some charactristics such as the number of capitulum per square meter, seed number in capitulum, seed weight, harvest index and seed yeild was evaluated.The highest seed yield was obtained in first sowing date in 3347 kg/ha and a delay in sowing date resulted a decrease in yield. The cold weather in (05/11/2005) caused flower fertility not accured, consequently, sowing was not successful . Results showed that the effect of sowing date on yield depends on the number of capitulum per unit area and the number of grains per capitulum. These two characteristics in th first sowing date in respect of the other dates were higher. The effect of density on yield was significant resulted on yield increase due to capitulum increase in unit area. As a result, the first sowing date with the highest density is recommended. However, The third and fourth sowing date can be considered as the second planting in a sequeational cropping system