فصلنامه پژوهشهای زراعی در حاشیه کویر
سال هفتم شماره 3 (پاییز 1389)

This study attempts to analysis the welfare effects of wheat price increase in North Khorasan province. In this context, compensated variation method was used and net benefit ratio (NBR) was determined. NBR is defined as the value of net sales of a commodity as proportion of income. If NBR is positive (negative), the household is to be net seller (buyer). Net seller (net buyer) households was gain (loose) from wheat price increase. Results indicated that 58.6 percent of the household are net buyer and 41.4 percent are net seller. Whilst, 1.37 percent of the sample households’ income attained form wheat production, 0.46 percent of their income is devoted to bread purchasing. Therefore, North Khorasan households are net seller and wheat price increase will increase their real income. The econometric analysis indicated that households’ real income may increase by 0.12 percent as 10 percent increased in wheat price. Household’ welfare may increase by 0.12 percent in short run but increase by 0.13 in the long run.

In this paper, with use of time series data during 1991-2008 first demand and supply equation for Iran pistachio as a large pistachio exporter by OLS method was estimated then the demand equation for 9 large pistachio importers such as Belgium, China, Hong Kong SAR, France, Germany, Italy, Luxembourg, Spain and United Kingdom with use of panel data model was estimated. The effects of technological progress in pistachio production on consumers and producers welfare and ultimately on total social welfare with 3 scenarios of 2%, 5% and 10% in price decreasing due to technological progress were also determined. Results showed that demand price elasticity for pistachio was 0.53 and supply price elasticity is 0.1 and also the import demand price elasticity for Iran Pistachio was about -0.82. Results also showed that in all scenarios share of producer welfare from total social welfare was about 60% and producers were more satisfied and earned.

To study the effects of cumin (Cuminum cyminum) planting on saffron (Crocus sativus) performance in the first year of intercropping, an experiment was conducted in 2006-07 cropping season at research farm of College of Agriculture, Islamic Azad University of Khorasgan in Khatoonabad, Isfahan using a complete randomized block design whit three replications. Saffron was planted as the main plant and cumin was planted between the saffron rows with different densities of 50, 75 and 100 plants per m2.Yied off flower and stigma, biological yield, number of corm and its depth were recorded for saffron and seed yield and its components for cumin. The results showed that different densities of cumin had not singnificant effects on different characteristics of saffron, butsignificantly affected cumins seed yield and its components. Increasing plant density decreased number of seeds per umber and 1000 seed weight. Planting of cumin in mixture planting with saffron had no negative effect on yield of saffron. Based on the results of the present study, planting of cumin with a normal density (75 plants per m2) with sow broadcast between the rows of saffron could be recommended for production of higher seed yield of cumin.

To study the effect of deficit irrigation and plant density on yield and yield components of the Cotton cultivar Varamin, an experiment was conducted at research farm of Cotton Research Institute, Varamin in 2006, using split- split- plot on the basis of randomized complete, Block design with 16 treatments and three replication. Main plots consisted of plant density in four levels of 80×10, 80×20, 70×10, and 70×20 sub plot consisted of irrigation regimes in two levels of 8 days and 12 days periods on farm's Cotton Research Institute of Varamin (35°19' N, 51°39' E; elevation 1050 m above sea level). Treatments were consists of: Main plot: plant density in 4 levels including (factor A) and Sub plot: irrigation regime in 2 levels including 8 and 12 days period with equal amount of water, and Sub-sub plots were two irrigation methods of Conventional furrow irrigation and fix alternate furrow Irrigation. The results showed that alternate furrow irrigation method had significant effect () on plant height, boll weight and total yield of seed cotton, but its effect on number of sympodial branches and earliness was not significant.Plant density did not effect any of the measured traits. Fiber technological properties were not affected by any of the treatments. yield in alternate furrow method was significantly decreased (25.5 and 27.7 percent) compared to the all furrow irrigation method. The highest seed cotton yield (5319.8 kg.ha-1) was obtained in 70×20 plant density, with 12 days period and all furrow irrigation, and the lowest yield (2718.05 kg.ha-1) in 70×10 plant density with 12 days period and alternate furrow irrigation treatments.

In order to investigate the effects of silicon application and irrigation halting on yield, yield components and bending moment of rice, a field experiment was carried out in split plot in basis of randomized complete block design with three replication at Dashtnaz Agricultural Research field in 2008. Main plot was irrigation halting in four levels including (irrigation halting at start, middle and end of tillering and at 50% flowering stages). Sub plot was silicon application in three levels including (0, 500 and 1000 kg Si ha-1). Results showed that irrigation halting in early tillering stage decreased plant height, panicle length, tiller per hill, fertile tiller, panicle per m2, spikelet per panicle and grain yield (329.22 g.m2) significantly. Irrigation halting in middle of tillering stage also decreased 1000 grain weight (21.11 g). The highest number of tiller per hill, fertile tiller per hill, panicle per m2 and grain yield (408.78 g.m2) were obtained in irrigation halting at 50% flowering stage. Least fourth internode bending moment at irrigation halting were produced in middle of tillering stage with use of 500 kg Si ha-1. Maximum number of panicle per m2 was recorded in response to interaction effects of Silicon and irrigation halting at 50% flowering stage where 1000 kgha-1 Silicon was applied. According to the results obtained in this Study, the beginning of tillering is the most sensitive stage to irrigation halting as caused sever reduction of yield and yield components.

In order to study the effects of mycorrhizal fungi and different levels of zinc on some agrophysiological traits of corn under water stress, an experiment was carried out in research farm of Islamic Azad University of Arak in 2006. The experimental design was factorial based on RCBD with three replications. The treatments composed of mycorrhizal fungus (Glomus intraradices) at two levels (with using and without), zinc at three levels: 0, 25 and 45 kgha-1 and irrigation at three levels: 100%, 75% and 50% water demand of plant. Results showed that irrigation levels had significant effect on traits. The maximum amount of chlorophyll, water use efficiency and biological yield obtained with using 100% water demand of plant, but the maximum root length was obtained from 50% water demand of plant. With using mycorrhiza root dry weight, water use efficiency and biological yield increased non-significantly.Zinc levels had significantl effects on root length and root dry weight. Utilization of mycorrhiza and zinc sulfate 45 kgha-1 with normal irrigation increased most of the characters. The highest biological yield of 18.975 tonha-1 was produced with application of normal irrigation along with mycorrhiza + zinc sulfate 45 kgha-1.Results showed that under drought stress, there is no need to use higher amounts of zinc sulfate, but application of mycorrhizal fungi with lower rates of zinc under optimum irrigation and moderate drought stress can also result in obtaining an acceptable yield.

Efficiency of different wasp parasitoids of Bemisia tabaci was evaluated on different cotton Cultivars in Mazandaran during 2005-2006 using a randomized complete blocks design. The evaluated cultivars were Acala-S-J-2×349, Arboreum, Opal, Bakhtegan, Bulgar-557, Broad leaf and red coloured, Sahel-78, Sahel-79, Sahel-80, Sahel-81, Beli-Izover, Nazili-84, Koker-312, Crema III, Cokurova, Oultan, Zeta-2, Varamin-67, Sindos-80, Sealand, 43200, 43259, 43347, 200, 228, 259, and 818-312. The effect of cultivar on the attraction of 4 parasitoid wasps including, Eretmocerus mundus Mercet, Encarsia formosa Gahan, E. inaron Walker and E. lutea Masi (Chalcidoidea: Aphelinidae) were evaluated by means of yellow sticky traps in the greenhouse. There was significant difference between mean attractions of parasitoids to the different varieties.The maximum attraction was observed on varieties Varamin-67, 228, and Nazili-84. Among the four parasitoid species, Er. mundus and E. lutea were attracted to the traps more than others, significantly. Evaluation of mean percent parasitisms indicated that there was significant difference on different cotton Cultivars. Er. mundus and E. lutea had the highest mean percent parasitism on the varieties. There was negative correlation between mean percent parasitism and pubescence density, but positive correlation to gossypol glands. The highest percent parasitism was determined on Cultivars Acala, Oultan, and Bulgar-557 which have the fewest pubescence and the highest gossypol glands on leaves. There was not defined and significant correlation between mean percent parasitism and length wave of leaves.

In order to study the competitive effects of redroot pigweed (Amaranthus retroflexus), lambsquarters (Chenopodium album), bermuda grass (Cynodon dactylon) and small bindweed (Convolvulus arvensis) on yield and yield components of sunflower (Helianthus annus L.), cv. Allstar, an experiment was conducted in Islamic Azad University of Tabriz, Iran, during 2007 with 7 treatments based on randomized complete block design in three replications. Sunflower density was 8.3 plants m-2 and treatments were weeds competition from 2, 4, 6, 8 and 18 weeks after sunflower emergence until late growth season, full-season competition and weed-free plot as control. Data were analyzed with MSTAT-C and means were compared with LSD test. Results revealed that reduction value of leaf area index in full-season weeds interference was 54%, compared with control. The highest hollow seed percentage (11%) obtained from full-season weeds competition, and when sunflower grew weed-free or weeds were controlled up to 10 weeks of early growth period, hollow seed percentage were the lowest (6%). Weed control in early 52 days of sunflower growth period, could not increase 100 seeds weight of sunflower. Seed yield reduction value in full-season interference of weeds was 27.5%, in comparison with control. Oil yield in control was similar to treatment that weeds were controlled in early 10 weeks of sunflower growth period. The highest oil yield (43%) measured in full-season weeds competition treatment, compared with control. With considering of 10% permissible yield loss resulting from weeds, the weeds if present must be controlled at 8 weeks of early growth period of sunflower.

To optimize the use of fertilizer on nitrate contents and yield of common bean cv. Sunray, an experiment was conducted in research farm of Agricultural College of Varaminin 2010, using a splite polot design based on RCBD with three teplications. The main plots were three Urea fertilizer levels 1) 250 kgha -1,2) 300 kgha -1 and 3) 350kgha -1, and sub plots were three K and Zn fertilizer combinations 1) 120 kgha -1 k,2) foliar spraying of 6/100 Zn and 3) 120 kgha -1K+6/1000 Zn. The hight nitratr content in bean pods was detected in treatment of 350 kghh –a Sulfur coated urea + 120 kgh -1 a k and the lowest nitrate content in treatment of 250 kgh -1 a urea + 120 kgh -1 a k + Zn spraying. The highest zn content of seeds was obtained from treatment of 250 kgh -1 a urea + k and Zn fertilizers. The highest pod and yield was also obtained from the latest treatment whereas the lowest yield belonged to the treatment of 350 kgh -1 a urea + 120 kgh -1 a k. The highest CGR in R5 growth period (22086 gm-2) was measured in 250 kgh-1 a urea and the lowest in 350 kgh-1 a urea treatments, respectively. Consumption of K and Zn spray had the highest CGR in P5 period (25.36 gm-2 perday). The highest NAR was recorded in V1 period (26.37 gm-2 per day) in treatment of 250 kgh –a urea while consumption of 350 kgh-1 a urea had the lowest NAR.