CROP PHYSIOLOGY
Year:2013 | Volume:5 | Issue:19|Papers Count:15

In order to investigate the effect of green gram sowing date as a green manure and different levels of nitrogen and phosphorous fertilizers on wheat grain yield of Chamran cultivar this experiment was conducted as split-plot factorial experiment based on completely randomized blocks design with three replications in 2008-2009 cropping year. Two green gram sowing dates 3 July and 10 August plus fallow plot were considered as main plot. Three levels of nitrogen fertilizer (without fertilizer, 60 and 120 kg net nitrogen per hectare) as the first factor and three levels of phosphorous fertilizer(without fertilizer, 45 and 90 kg net phosphorous per hectare) as the second factor were in sub-plots. Results indicated that the effect of green manure and the interaction of experimental treatments on grain yield at five percentage probability level and the effect of nitrogen and phosphorous treatments on this trait at one percentage probability level was significant. Sowing green gram manure in dates 3 July and 10 Aug increased grain yield by the amount of 15.3 and 3.1 percentage as compared with fallow treatment. Delaying in green gram sowing date reduced the useful effects of the green manure in grain yield. The highest grain yield was belonged to the treatment combination 120 kg nitrogen +90 kg phosphorous at green gram sowing date on 3 July. Generally, the results of this research showed that sowing green gram as a green manure on date 3 July increased wheat grain yield as compared with fallow conditions. Also, it is clear that when using green gram as green manure, grain yield in fertilizer treatments 60 kg nitrogen and 45 kg phosphorous per hectare was higher than treatment 120 kg nitrogen +90 kg phosphorous per hectare in fallow conditions. Increasing the grain yield in green manure treatments as compared with fallow treatment was due to increasing grain number per unit area and biological yield.

Salinity tension is considered as a restricting factor for plant productions. In this research the effect of paclobutrazol as a triazole regulator on morphological and biochemical indices of Brassica (napus L.) seedlings under salinity tension in vitro culture conditions has been investigated. After rinsing and sterilizing the seeds of B. napus L. ten seeds were cultured in morashig and oscog base cultures environment consisted the concentrations of 0, 50 and 100 mM sodium chloride )various levels of salinity) and concentrations 0, 5, 10 and 20 mg per liter paclobutrazol. After 4 weeks, the obtained results showed that stem and root length, stem and root dry weight, chlorophyll a content, total chlorophyll and seedling carotenoids in salinity tension significantly decreased. Whereas, the amonth of lipid peroxidation and restore sugars and proline increased in salinity tension. Paclobutrazol increased the amonth of morphological and biochemical parameters of seedlings in all levels either in salinity tension situation or normal situation a lot. Therefore paclobutrazol treatment in B. napus L. seedlings under salinity tension improved tension symptoms and damages due to salinity in these seedlings.

This research was conducted in order to investigate the effective factors on germination, growth and seedling establishment of maize seedling hybrid SC704 cultivar under salinity and drought tension conditions and determine the best priming treatment in tension conditions at Safi-Abad Agriculture Research Center of Dezful in summer 2010. This research was performed as a factorial experiment basis on completely randomized design with three replications in two parts lab and pot. The first factor including three levels of priming (control, potassium nitrite and distilled water), the second factor including two levels of osmotic solutions (NACL and PEG) and the third factor including five levels of osmotic potentials (0,-0.3, -0.6,-0.9 and -1.2 MPa). In this research some related indices to seed germination such as germination percentage, length, fresh and dry weight of root and shoot and mean required time for germination were measured. Results indicated germination delay in both solutions of NACL and PEG. Priming treatment and tension conditions affected germination percentage and other germination indices as well, and had significant difference. In lab conditions, seeds were germinated at all concentrations of NACL solution, but no germination was observed at -1.2 MGa caused by PEG treatment. Seed priming increased germination and seedlings growth under salinity and drought tensions. According to the observed results, in lab conditions, halopriming treatment and in greenhouse hydropriming treatment, were the best and the most effective treatments.

Considering the important physiological role of potassium and high demand of sugarcane to this element, lack of using potassium fertilizers during past years and severe depletion of soil under cultivation, this research was carried out with the aim of investigating the effect of potassium fertilizers on sugarcane yield changes in Khouzestan province. According to this, an experiment as complete randomized blocks with 6 treatments and 4 replications was conducted at two regions of Karoun and Haft-Tappeh Agro-Industries on CP48-103 cultivar. The treatments included the first treatment control without potassium consumption; the second, third and fourth treatments including 200 kg K2O consumption as base from resourses potassium sulfate, potassium nitrate and potassium chloride resourse, respectively, the fifth treatment 200 kg K2O consumption as one fourth split during early planting and the rest of potassium fertilizer along with nitrogen fertilizer consumption three times from potassium nitrate resourse and the sixth treatment 200 kg K2O consumption as one fourth split during early planting and the rest of potassium fertilizer along with nitrogen fertilizer consumption three times from potassium chloride. The results showed there was no significant difference between the fertilizer treatments at Haft-Tappeh region, but, in Karoun region because of more favorable soil conditions as regard to potassium (less depletion), significant difference at p<5 percentage level was observed among the fertilizer treatments in regard to yield, sugar percent and syrup percentage. The highest yields were obtained from the split treatments (the fifth and sixth). The highest yield with the amonth of 147.5 tons/ha was obtained from the sixth treatment and the highest sugar percent and syrup percent was obtained at the amonth of 12.9 percentage and 32.1 percentage from the fifth treatment. Also, the highest degree of purity with the amonth of 89.7 percentage was obtained from the fifth treatment (sugar harvest time). The results of this research showed, the amonth of potassium was insufficient in soil and the effect of under studied treatments caused significant difference on sugarcane yield.

In order to investigate the effect of different levels of irrigation, nitrogen and plant density on physiological traits of grains corn hybrid SC.704 this research was conducted at the research field of Natural Resources and Agricultural Sciences University of Khouzestan located in Ramin town. This research was consisted of three experiments each as split plots using randomized complete blocks design with three replications every year. In each experiment, one of the levels of irrigation treatment was implemented. The irrigation treatment including three levels of optimum irrigation, moderate tension and sever drought tension (irrigation after depletion of 30, 40 and 50 percentage of field capacity, respectively). Irrigations in all of the treatments was implemented after 30 percentage deplition of agronomy capacity till 4-5 leaf stage (seedling establishment) and after this stage until 10 days before physiological maturity, irrigation treatments were exactly implemented. In each experiment nitrogen as the main treatment were three application levels equal to 140, 180, and 220 Kg net nitrogen ha-1 and plant density as sub treatment were three density levels 6, 7.5, and 9 plants per m-2. The results showed by increasing the intensity of drought tension leaf rolling percentage increased, but relative water content and nitrogen percentage of ear leaf and chlorophyll a concentration showed reduction. By increasing irrigations intervals the positive effect of nitrogen application on increasing nitrogen percentage of the ear leaf and chlorophyll a concentration was considerably decreased. The increase of density especially in sever drought tension conditions caused increase in leaves rolling percentage, the effect of drought tension, nitrogen and plant density on grain yield was significant. Grain yield increased by increasing nitrogen application. The positive effect of nitrogen consumption on grain yield reduced due to decreasing of availability of water in soil. The grain yield increased by increasing density. The results showed that due to high sensitivity of physiological traits to water deficiency from one hand and the relation between these traits to grain yield from the other hand, prohibition of irregulated irrigation or any water deficiency especially at corn sensitive growth stages is necessary.

Sustainable agriculture focuses on the quality and soil organic matter and one of the major sources of soil organic matter is crop residue. In order to investigate the effect of different planting methods, crop residue management and nitrogen foliar application methods on quantitative traits of mung bean this experiment was carried out as a strip- split plot using randomized complete blocks design with three replications at research station of Islamic Azad University Khoramabad branch in summer 2009. Tillage as strip in two levels of furrowed plots and no tillage in the main plots, residue management methods in two levels with straw and straw mulching and burning straw and straw mulching and foliar application of urea fertilizer in four levels without foliar application, one time foliar application in the rapid stage growth, one time foliar application before flowering and one time foliar application in the stage of rapid growth + flowering, by the concentration of three x 1000 with urea fertilizer in sub plots was assigned. Results showed that the effect of different planting methods on grain yield and plant height at one percentage level was significant. Also the effect of crop residue management was significant on productivity degree and plant height at five percentage level and dry weight at flowering stage in one percentage level. Results showed the superiority of grain yield and branch number in plant in no-tillage method in compared to furrowed plot method. Totally, planting method of no- tillage with straw and straw mulching foliar application in the stage of rapid growth + flowering stage by producing 782 kg.ha-1 grain yield was considered as superior treatment combination in this research.

In order to investigate the effects of drought tension and plant density on quality and quantity characteristics of Brassica napus L. cultivars, this experiment was conducted as split-split plots in randomized complete blocks design with four replications in Boroujerd Agricultural Research station in 2009-2010 cropping year. In this experiment, the drought tension was investigated in three levels included without tension (control), irrigation cut in the stages of after rosette and before flowering initiation and irrigation cut in the stages of after rosette, before flowering initiation and filling pod in the main plot and plant density in three levels 6, 10 and 14 kg consumed seeds in hectare in the sub-plot and cultivars of Brassica napus L. included Zarpham, SLMO46 and Okapi in the sub-plot. The results showed the effect of drought tension, plant density and their interaction on quality and quantity characteristics of Brassica napus L. cultivars was significant. The highest oil and grain yield was obtained in the treatment of irrigation cut in the stages of after rosette and before flowering initiation and seed density 10 kg/ha in Zarpham cultivar that seems it is related to 1000-grain weight, the number of pod in plant, harvest index and its more oil percentage. Zarpham cultivar was the most appropriate cultivar in the drought tension conditions and by investigating all of the indices, it was the best cultivar in usual conditions and had minimum yield reduction in tension conditions.

In order to investigate the early growth response and sodium and potassium ions concentration in ten barley (Hordeum vulgare L.) cultivars under effect of salinity tension, an experiment was conducted at a controlled environment at Agriculture collage of Shiraz University. In this greenhouse research ten barley cultivars including Eram, Karoon, Kavir, Jonoob, Makoei, Afzal, Shirin, Gohar, Nosrat and Reyhan were investigated in two irrigation regimes by tap water (0.62 dS m-1, as control) and salt water by electrical conduct 20 dS m-1 in a sand culture system. The results showed that salinity significantly decreased emergence percentage and rate, leaf area, shoot and root dry weight, potassium concentration and the ratio of potassium to sodium and increasing sodium concentration. The response of cultivars to salinity was different. The ratio of potassium to sodium (40.7 percentage reduction) and root length (4.6 percentage reduction) showed the most and the least reactions to salinity. On average, salinity tension decreased 24.3 percentage shoot dry weight of barley cultivars; that the most and the least reduction percentage were observed in Shirnin (31.6 percentage) and Afzal (16.3 percentage) cultivars, respectively. The traits of mergence percentage, potassium concentration and root dry weight in optimum conditions and root dry weight and the ratio of potassium to sodium in salty conditions were identified as the most effective traits on shoot dry weight. According to this, Afzal and Kavir cultivars can be associated as the tolerant cultivars and Shirnin and Reyhane cultivars as sensitive cultivars to salinity. The results of this research showed that although emergence rate and percentage traits appeared to be essential for better plant growth, but has no direct effect on salinity tolerance.