فصلنامه علوم زراعی ایران
سال هفدهم شماره 2 (پیاپی 66، تابستان 1394)

To study the effect of different planting beds and amount of Humi-ferthi as supplementary organic fertilizer on quantitative and qualitative traits of min-ituber of two potato cultivars، an experiment was carried out under greenhouse conditions in Ardabil، Iran، in 2012. A 2×3×3 factorial experiment was conducted using completely randomized design with three replications. Experimental factors included two potato cultivars (Agria and Savalan)، three planting beds (forest leaf composts of Fandoglo of Ardabil+ perlite، forest leaf composts of Andabil of Khalkhal + perlite، and Mixkaar peat mass + perlite) as second factor and three levels of organic fertilizer of Humi-ferthi consisted; zero (control)، 2‰ and 4‰. Results showed that cultivar effect was significant on mini- tuber weight per plant and plot and concentrations of P، K and Ca nutrients in min-ituber tissue. Effect of organic fertilizer on concentrations of P، K، N and Ca nutrients on mini-tuber tissue was also significant. Cultivars × planting bed interaction effect on mini-tuber number per plant and mini-tuber weight per plot as well as the cultivars × organic fertilizer interaction effect on mini-tuber weight per plot were significant. Mini-tuber weight per plant and plot and concentrations of P، N and Ca nutrients in mini-tuber tissue were significantly influenced by planting bed and organic fertilizer interaction. The highest number of mini-tubers per plant (7. 8 mimi-tubers) was obtained from Agria cultivar in Mixkaar peat mass + perlite. Andabil forest leaf composts with 2‰ of organic fertilizer (Humi-ferthi) had the highest mini-tuber weight per plant (223. 7 g). The highest nitrogen، phosphorus and potassium contenets of mini-tuber were obtained in combination of 2‰ Humi-ferthi + Fandoglo leaf composts. Considering the importance of number of mini-tuber in mini-tubers production stsytem، it is concluded that planting micro-tubers of Agria cultivar in media of leaf composts of Andabil + perlite and application of Hiumi-ferthi (2‰) is suitable and economically reasonable for producing mini tuber. As well as in all of the qualitative characteristics، Miksskar peat mass + perlite were suitable planting bed، which could improve the quality characteristics of both potato cultivars with using 2‰ or 4‰ supplementary organic fertilizer.

To study the effect of plant density and harvest time on forage yield of Chicory (Cichorium intybus L. cv. Grasslands Puna)، an experiment was conducted at Research Farm of Ferdowsi University of Mashhad، Iran، over two years in 2006 and 2007. Experimental design was split-split plot based on complete randomized block design with three replications. Different plant densities of ‘Grasslands Puna’ chicory (Cichorium intybus L. cv. Grasslands Puna) (10، 20 and 40 plants. m-2)، three harvest time (10% flowering، 50-60% flowering and full flowering) and three cutting frequency (due to plant re-growth) allocated to main، sub and sub-sub plots، respectively. Results showed that10% flowering and full flowering stages of ‘Grasslands Puna’ chicory were achieved at 113 and 140 days after sowing، respectively (2160 and 2729 growing degree-days). Total fresh forage، dry forage and leaf yields of ‘Grasslands Puna’ chicory were significantly increased (more than 59، 29 and 28%، respectively) by increasing the plant density (from 10 to 40 plant. m-2). The lowest dry leaf yield (452. 2 kg. ha-1) and leaf to biomass ratio (355. 4 g. kg-1) were observed in the third harvest (full flowering stage). In general، planting density of 40 plants. m-2 and harvesting in of 50 % flowering stage produced a satisfactory forage yield in ‘Grasslands Puna’ chicory in climatic condition of the experiment site.

To evaluate the effect of improvers and water deficit on seed yield and irrigation water use efficiency of sunflower (Helianthus annuus L.)، a field experiment was conducted as split-factorial in randomized complete block design with three replications in Isfahan and Tehran، Iran، during the 2012 growing season. Experimental treatments were 1- water stress at three levels; 60، 120 and 180 mm evaporation form class A pan were assigned to main plots، 2- soil improvers at three levels; control (no application)، zeolite (4. 5 t. ha-1) and super absorbent polymer (100 kg. ha-1) and 3- plant improvers at theree levels; control (zero)، calcium silicate (400 mg. l-1) and Hexaconazole (2 g. l-1) as factorial were randomized in sub-plots. Water deficit significantly decreased seed yield (45%) and oil yield (20%)، biological yield (22%)، seed number per plant (32%) and 1000 seed weight (29%). Application of zeolite and hexaconazole led to higher seed yield. Water deficit at 180 mm level reduced the oil yield by 58%. Application of super absorbent polymer and calcium silicate reduced the effect of water deficit stress by 19%. Application of zeolites and hexaconazole had the highest irrigation water use efficiency (IWUE). IWUE increased with application of combination of soil and plant improverby 25% to 59%.

To investigate the effect of delayed plantine date and timing of foliar application of nitrogen on seed yield، yield components and quality of canola، a field experiment was conducted as split plot using randomized complete blocks design with three replications at research farm of Agriculture and Natural Resource University of Ramin، Iran، in autumn of 2013-2014 growing season. The experimental treatment consisted of three sowing date; 27 November، 17 December، 30 December which were assigned to main plots and the timing of of nitrogen foliar application in four levels; control، rosette، budding، flowering، were randomized in sub-plots. Results showed that the highest seed yield (3406. 6 kg. ha-1) and oil yield (1481 kg. ha-1) were obtained from the first sowing date. With delay in sowing date، seed yield، pod per unit area، 1000 seed weight، oil yield، growing degree days (GDD)، day to flowering and duration of flowering to maturity decreased significantly. Moreover، with delaying sowing date seed oil content decreased، but the canopy temperature increased. The effect of nitrogen foliar application on seed yield، yield components and oil yield of canola was significant. The highest seed yield، pod per unit area، 1000 seed weight and dry mater were obtained from nitrogen foliar application in budding stage، however، with nitrogen foliar application oil content significantly decreased. In conclusion، the first sowing date and nitrogen foliar application in budding stage produced the maximum seed and oil yield، therefore it was considered the most suitable treatment. In general، results showed that nitrogen foliar application in budding stage could compensate for the reduction in seed yield and oil content، due to delay in planting date and heat stress، by 31% and 34%، respectively.

To study the effect of sowing time and on the isabgol- ajwain intercropping a field experiment was performed in split plot arrangement using randomized complete block design with three replications at Zabol University، Zabol، Iran in 2013. Experimental treatments consisted of: two sowing time; January 10 and February 9 which were assigned to main plots، and six isabgol and ajwain additive ratios; (sole isabgol، sole ajwain، 25% isabgol+100% ajwain، 50% isabgol+100% ajwain، 75% isabgol+100% ajwain and 100% isabgol+100% ajwain) were randomized in sub-plots. Results showed that the highest seed yield and secondary metabolic of both species obtained from sowing time of January 10. The highest seed yield of two species (2363 kg. ha-1)، land equivalent ratio (LER = 1. 53)، System Productivity Index (SPI=10237) was obtained at mixed cropping of 50% isabgol+100% ajwain. Ajwain in intercropping of 25% isabgol+100% ajwain had the highest crowding coefficient (Kajwain=2. 38) and dominance (Kajwain=0. 54). By increasing the density of intercropping isabgol was dominant species. Competition Index (CI) for all intercropping treatments was lesser than unity، indicating yield advantage in intercropping over monocropping systems. These findings suggest that intercropping of ajwain- isabgol at 25 isabgol+100% ajwain and 50% isabgol+100% ajwain can be considered for yield advantage in hot and dry areas of experiment site conditions.

To investigate the effect of zinc sulfate spraying on seed and oil yields of two safflower cultivars، a field experiment was conducted in Ramin Agriculture and Natural Resources University of Khouzestan، Ahvaz، Iran، in 2012-2013 growing season، as factorial arrangement in randomized complete blocks design with three replications. Experimental factors consisted of two safflower cultivars; Soffeh and Local Isfahan and zinc sulfate foliar application at differenet growth stages at five levels; control (without spraying)، spraying at early stem elongation، branching، flowering and seed filling. Results showed that zinc sulfate spraying had significant effect on seed Zn and P contents، chlorophyll a، chlorophyll b، chl-a: chl-b ratio، SPAD value، seed and oil yields and yield components. Spraying of zinc sulfate in different growth stages increased Zn content in seed، however، seed P content decreased. The Zn foliar application significantly increased chl-a، chl-b، chl-a: chl-b ratio، SPAD value، seed oil content and yield، however، there was no significant difference between Zn foliar application in different growth stages. Cultivar × Zn spraying interaction effetc was significant on seed oil content and chl-a. Highest seed oil content in cv. Soffeh obtained in Zn spraying in stem elongation satge and in Local Isfahan in flowering and branching stages. Zn spraying increased head number per unit area and thousand seed weight، with no significant effect on grain number per the head. In general، Zn spraying at all growth stages increased the seed yield، but the differences between growth stages were not significant. Oil yield increased in Zn foliar application compared to control، except for application in seed filling stage. Both of safflower cultivars showed similar response to Zn spraying، but the differences were not significant.

Soil and water salinity have been increasingly threats for arid and semi-arid regions such as Iran. Salt stress، as one of the most important factors reducing agricultural production، has been subject of numerous worldwide researches for more than 100 years. Review of literature in Iran revealed that filed crops production improvement and breeding research in saline conditions have been widely conducted at Universities and Research Institutes during the last half century. In this study، published Iranian salinity researches from 1977 until present time were investigated and analyzed، and the challenges were discussed and finally some approaches have been suggestd for the future. It seems that lack of well defined strategic plan، shortage of research resources، lack of team-work and poor knowledge of salinity concepts are among the most challenges in salinity research in Iran. Research planning in the field instead of growth chambers and greenhouse experiments، selecting suitable crops for salt affected conditions based on its relative salt tolerance and water use efficiency، and research on emergence and establishment growth stages of crops as a sensitive phase could be some of the applied approaches for improvement of field crops yield in salt affetced conditions. It is hoped that this article can help to the updating of knowledge of researchers and brings new attitudes and visions in salinity research in Iran.