فصلنامه زراعت و اصلاح نباتات
سال هفتم شماره 3 (پاییز 1390)

Environmental hazards of chemical fertilizers, energy and costs applied to produce them, and their negative impacts on biological and agronomic systems require moving toward sustainable low input agriculture. As a result, this experiment was conducted in 2009 on sweet corn (var. Shaker), at the research farm of Islamic Azad University, Karaj branch. Experimental design was randomized complete block in split factorial arrangement in three replications. Three factors of the experiment were chemical fertilizers (as factor a: nitrogen and phosphorus at 25%, 50%, 75% and 100% of recommended rate), animal manure (as factor b: 30,000 and 0 kg/ha) and finally, vermicompost (as factor c: 0, 10,000 kg/ha with animal base and 10,000 kg/ha with plant base). The highest fresh grain yield (24.12 ton/ha) was achieved in 75% fertilizer with manure and vermicompost(with animal base). The highest biomass was also achieved in chemical fertilizers at 100% with manure and vermicompost with plant base(17 ton/ha).

In order to investigation of destructive effectives of nitrogenous fertilizers on forage quality in maize, experiment was conducted at Iran in 2010. First physic & chemical characteristics of soil was determined. Field experiment was carried out by a randomized complete blocks design with 3 replications. The factor which studied was nitrogenous fertilizer (0, 100, 200, 300, 400 and 500 urea kg/ha). The results showed that planting density had significant effect on fresh forage yield, dry forage yield, protein percentage, plant height and oil percentage. Means compression showed that fresh forage yield, dry forage yield, protein percentage and oil percentage were achieved under application of 300 urea kg/ha and also highest plant height was achieved under application of 500 urea kg/ha. The results this experiment showed that forage quality decreased under increasing of urea and plant height increased under this condition.

In order to study, the effect of drought stress on vascular system in wheat rachis (var.Rowshan Back Cross) this experiment was conducted in the research farm of Islamic Azad University of Saveh in 2009-2010 years in 4 replications. This experiment was arranged in randomized complete blocks design with drought stress factor in two levels including: 1- Control (without drought stress, 2- drought stress (from stem elongation stage to complete anthesis). The number, size and distribution of vascular bundle in different parts of spike were checked. The results have shown that, in both samples (control and drought stress), number and size of central vascular bundle acropetally decreased along the rachis from proximal to distal part of spike as the most decreasing number and size dedicated in central part. Samples under drought stress condition revealed that the number and size of vascular bundles decreased as compare to control and it was the result of drought stress. The size of vascular bundles decreased along the rachis in both the treatments as the biggest size of vascular bundles revealed in the middle of spike and then in the proximal and distal of spike respectively. There was a positive relation between the number and weight of grains with the number and size of vascular bundles for each spikelet along rachis of spike. The spikelets of middle part of spike rachis had the most average of weight and number of grains in both treatments as compare to other parts. However there are less weight and number of grains in the spike under drought stress in compare with the same parts in control situation. As the results revealed, the weight and the number of grains in drought stress conditions decreased because of decreasing in number and size of vascular bundles along the rachis of spike.

In order to evaluate the effect of water stress and zeolite application on yield and components yield of winter safflower (Carthamus tinctorius L.), this study was carried out in field of Arak University in Markazi province in 2009. A split-plot arrangment of treatment in a randomized complete block design with three replications was used. Water stress (I0= Control irrigation, I1= Irriation about 85% plant requrment water, I2= Irriation about 70% of plant requrment water, I3= Irriation about 55% of plant requrment water, were assigned in the main plots and different levels of zeolite application (Z0= without zeolite application, Z1= 3 ton ha-1, Z1= 6 ton ha-1, Z1= 9 ton ha-1) in sub plots. Each sub plot consisted of 4 rows, 5 m long with 50 cm between rows space and 5 cm between plants on the rows. In this study characteristics such as: plant height, number of branches, number of boll per plant, number of grain per boll, 1000 grain weight, grain yield, leaf water percent, leaf eternity water and cell membrane instability were assessed. Results indicated that un-stress irrigation (control irrigation)with grain yield (2040 kg ha-1) and zeolite application (9 ton ha-1) variety with grain yield (1879 kg ha-1)were significantly superior to the other treatments.

In order to investigate the effect of irrigation by saline water in different growth stages on agronomical characteristics of rapeseed cultivars, this experiment was carried out by split plots design with 3 replications in 2010. The main factor was 3 levels of irrigation water (6, 10 and 12 ds/m) and the sub factor was sparing rapeseed cultivars including (Option 500, Hayola 401 and Heros). The results showed that salt stress had significant effect on biological yield, kernel yield, oil yield, oil percentage, branches number, silique number, silique number of branches, silique length of branches, seed number of main silique, seed number of silique and seed number of branches silique (P=0/01), harvest index, 1000 kernels weight and plant height (P=0/05) and highest upon characteristics were achieved under irrigation with 6 ds/m. Rapeseed varieties showed significant differences upon characteristics. Means comparison showed that highest kernel yield (2245 kg/ha) was achieved under Option 500 variety. Interaction of irrigation and variety wasn’t significant effect on all characteristics but means comparison showed that highest kernel yield (3108 kg/ha) was achieved under Option 500 variety under irrigation with 6 ds/m. The results of this experiment showed that irrigation by saline water decreased agronomical characteristics of rapeseed sorely and expedited flowering stage.

In order to study th effect of irrigation with saline water under different methods on yield quantitative and qualitative characteristics of Sorgum. An experiment conducted in experimental farm of Islamic Azad University Shahr-e-Qods Branch. Experimental design Included four treatments included T1: Saline and fresh water treatment, T2: Alternative saline and fresh water treatment, T3: Mixed saline and fresh water treatment, T4: Control treatment. Result had show that the better yields stabilized on N,P,K Macronutrient in related to T1 treatment that the soil Nitrogen before giving treatment was 0.95 mg/kg reported and after irrigation in, T1; 9% , T2 ; 20% and T3; 37% decrease observed . Same result acquired in P and K percentages that showed T1 treatment is best choice of this experiment.

In order to evaluate the effects of humic acid in drought and non-drought stress condition on yield and some quality characteristic of sugar beet, a study was conducted in 2010 in Islimic Azad Univ. of Karaj,Iran. The factor of humic acid was in three levels (non-using (control), using with irrigation water and foliar application of leaves). Another factor was limmited of irrigation, in two levels (irrigation after 40% depletion of available water and irrigation after 70% depletion of available water). In this experiment, quality and quantity characteristic of sugar beet assessed like, root yield, white sugar yield, sugar content, molasses sugar and total dry weight. Result of the experiment indicated that using of humic acid on root yield, white sugar yield, WSC and sugar content caused significant difference in 1% level. The best levels of root yield, white sugar yield and sugar yield was obtained using of humic acid with irrigation water. There was also signification difference between two levels of irrigation.