نشریه بوم شناسی گیاهان زراعی
سال دهم شماره 3 (پیاپی 37، پاییز 1393)

To assess some traits of 20 barley genotypes, the experiment was done in a randomized complete block design with four replications in Agriculture and Natural Resources Research Station, of Khorramabad in 2011-2012 growing season. Grain yield and some other agronomic traits were measured. Differences between genotypes were compared in terms of plant height, biological yield, grain yield and hectoliter weight was significant. Genotypes of 1 and 15 had the highest grain yield. Simple correlation coefficients indicated that grain yield, biological yield, straw yield and spike weight had positive and significant correlation. Highest correlation was observed in grain yield and biological yield (r = 0.90**). The results of stepwise regression analysis showed biological yield, spike weight, flag leaf length, flag leaf area, spike length, awn length were the traits influencing on grain yield. Therefore, these attributes can be considered as the most important plant characteristics and they could be a suitable choice to improve the yield of barley genotypes breeding programs. Spike weight, biological yield had the highest direct effect on grain yield. Also, Genotypes of 1 and 15 had the highest yield. The traits such as weight, spike, flag leaf length, flag leaf area, awn length and head length which had high correlation with grain yield were effective on yield increment.

Nowadays, implementation of simple and efficient methods for determining nitrogen needs has been considered in various plants. The simplest and most efficient methods for appreciate nitrogen requirement determination is leaf color chart (LCC). To determine of nitrogen fertilizer requirement in forage sorghum using leaf color chart, an experiment was conducted as factorial arrangement based on complete randomized block design with three replications at Agriculture and Natural Resources Research Station of Sabzevar in 2012 growing season. The factors were nitrogen rate in four levels including conventional (150), 25, 50, and 75 kg.ha-1 N and LCC scores was less than 4 and 5. The highest plant height, leaf dry weight, number of leaves per plant, biological yield and protein percentage were obtained in 75 and 50 kg.ha-1 nitrogen application. Using different amounts of nitrogen with reduction of LCC to 5 led to higher plants, more leaf dry weight, leaf numbers per plant, biological yield and protein content than using nitrogen with reduction of LCC to 4. On the whole, 50 kg.ha1 nitrogen with reduction of LCC to 5 was the best treatment for the highest quantity and quality yield achievement for forage sorghum. Also, LCC can be applied easily to determine sorghum nitrogen equipment.

The present study was conducted in a randomized complete block design with eight treatments and four replications. Eight types of potting media including perlite, perlite + vermiculite (1:1 v:v), perlite + peat moss (1:1 v:v), soil + perlite (1:1 v:v), perlite + soil + cow manure compost (4:3:3 v:v), perlite + soil + vermicompost (4:3:3 v:v:v), field soil and perlite + peat moss as conventional nutrient solution and planting media used in greenhouse (Control). During the growing season, the leaf area, plant height, stem basal diameter, tuber fresh and dry weight, tuber specific weight and tuber number per plant were measured. Analysis of variance showed significant differences between treatments in leaf area index, plant height, tuber number per plant and stem basal diameter. Growth and production of minituber were low in soil and soil containing medium. Therefore, the productivity of local soil was not corrected by any soil amendments. Soil containing medium had the highest bulk and particle density, EC and pH and the lowest porosity then produced the lowest number of tubers and fresh and dry weight of tubers. The highest number of tubers was produced in perlit + peat moss treatment. The maximum amounts of plant height were recorded in soil + perlite + compost treatments. The perlite + peat moss medium (1:1 v:v) is recommended for production of potato minitubers.

Considering of saline soils in middle part of Khuzestan province, Iran and also the leached soils having capacity to be saline, the irrigation agenda or the percent of irrigation water emission from the roots region must be adjusted and controlled so that a desirable balance of soil salinity in roots growth region is created to prevent salinization of soil after soil optimization. Therefore, current research is about the water and salt balance in roots growth region of sugarcane cultivated soils. Accordingly, the values of ΔZ (the variations of salinity supply), Z1, Z2 (the first and second concentration of salt level in the region of roots growth) and ECe (electrical conductivity level of saturated soil) in different months of cultivation year were calculated. The results indicated that calculated ECe had the intervals between 2.26 dS/m and 2.59 dS/m that by 10% crop decrement, it is less than determined allowable maximum,that is, ECe = 3/4 dS/m. On the other hand, the level of depth percolations resulting from irrigation showed the control sufficiency of salt accumulation in the depth of roots growth and the desirable agronomic conditions to plant growth are provided.

To study the effects of anti-transpiration spraying and irrigation cutting off in different growth stages on yield and yield components of sunflower hybrid of Farrokhas second crop at Miyaneh region, an experiment was conducted at the Research Station of Faculty of Agriculture Islamic Azad University (Miyaneh Branch) during 2013 cropping season. The experiment was in randomized complete block design with three replications. The experiment factors were anti-transpiration spraying with paraffin, atrazine, and phenyl mercuric acetate (PMA), along with irrigation cutting off in inflorescence full blooming and seed filling stages. The traits of seed yield,, biological yield, harvest index, number of seeds per head, seed weight, oil percent, leaf dry weight, head diameter was measured at the end of experiment. There were significant difference of interaction between irrigation cutting off and anti- transpiration application on seed weight, head diameter at 1% and oil percentage at 5% probability level. PMA application caused the highest seed yield and head dry weight. Irrigation cutting off in inflorescence emergence stage along with atrazine implementation led to the highest oil percentage, head diameter and seed number per head. Regarding the results, anti-transpiration application and longer water storage could be one of the suitable methods for high production of sunflower in arid and semi-arid areas.

The studies are needed to investigate the impact of these factors on crop yield and it requires a lot of time and cost. In recent years the agriculture production simulator models such as APSIM for irrigation management and fertilizer are used. These models taking into account several factors such as water management, physical and chemical properties of soil, water and nitrogen in the soil profile that can play an important role in modern agriculture. APSIM simulation model (Agricultural Production Systems Simulator) was first calibrated and validated using field data in 1392 and 1393. These data are including four irrigation levels 20 % more irrigation, equal to crop irrigation requirement, 20% and 40% less than irrigation requirement of maize and nitrogen fertilizer treatments are included 300, 150 and zero kg/ha. The cultivar of maize was hybrid SC704 of the late maturing type of corn varieties under furrows irrigation. APSIM simulation model was evaluated for predicting Maize yield, moisture and nitrogen of soil and by comparing simulated values with the measured data the validity of the model was confirmed. The maximum yield of maize was estimated 14593 kg/ha for irrigation and nitrogen amounts of 1400 mm and 450 kg/ha respectively. Comparing the results of simulation with measured data showed the relative average error (RAE) of soil moisture was in the range of 2-18% and RAE of soil nitrogen was 4-14%.

Effect of planting date and nitrogen fertilizer on yield and yield components of grain sorghum was investigated. The experiment was carried out in a split plot based on a randomized complete block design with three replications with four levels of nitrogen fertilizer including 0, 100, 150 and 200 kg.ha-1 as the main factor and planting dates including May 30, 15 and 30 June as sub plots. Nitrogen fertilizer significantly increased the yield (6.078 t.ha-1) and with consumption of 200 kg.ha-1 nitrogen, yield was increased dramatically. Taking 200 kg. ha-1 fertilizer increased biological yield (20.561 t.ha-1). Effect of nitrogen fertilizer on grain weight (2.414 g) and seed number was significant at 1%. The most effective planting time on the yield and yield components was May 30. The interaction between planting date and nitrogen fertilizer was not significant in any traits. According to the results of this experiment, 200 kg.ha­-1 N can be used to achieve maximum yield at first planting date.

Crop yield in rain-fed regions is always affected by environment so that the instability of crop yield is considerably high in this condition. The study was carried out to evaluate effects of seed priming with Cu I, Zn II, K I, ZnSo4 on germination traits and seedling establishment at two temperatures of (10 °C and 20 °C). Results showed that seed priming influenced germination rate significantly and the primed seeds revealed higher germination rate than the unprimed seeds. The higher value was obtained by ZnSo4 treatment. However, germination percentage was not affected by priming treatments even though the priming slightly improved the value in comparison to control. Results also showed that the response of primed seeds to the low temperature was higher than in the high temperature. Remobilization of seed reserves was enhanced under priming treatments and the percentage of reserves depletion, conversion efficiency and total mobilized reserves were increased by seed treatments. It was concluded that not only the used compounds (particularly ZnSo4) can improve lentil establishment at early stages but also the compounds could be useful at bio-fortification programs at later stages.