نشریه بوم شناسی گیاهان زراعی
سال پانزدهم شماره 4 (پیاپی 58، زمستان 1398)

This study was conducted to develop a binomial (presence-non presence) sequential sampling model for saving time in determining population density of greenbug, Schizaphisgraminum (Rondani) in broom corn fields. For this purpose, 50 broom corn stems were sampled every three days for counting the aphid number. The mean and variance of population at each sampling date were used to estimate spatial dispersion parameters. Then, Taylor’s Power Law parameters were used to prepare binomial sequential sampling models at two precision levels of 0.10 and 0.25. The spatial distribution of S. graminum in the field was clumped and its mean population at different sampling dates ranged from 0.14 to 25.45 aphids per stem. Comparison of models showed that sample size required for estimating aphid population increased significantly by reducing the precision level from 0.25 to 010. Therefore, the binomial sequential sampling model at the precision level of 0.10 was very time consuming and was not suitable for estimating aphid population density. However, the model at 0.25 precision level reduced the required sample size compared to the fixed sample size method. Overall, using binomial sequential sampling model at 25% precision level, the proposed precision level for pest management programs can reduce sampling time in comparison to the fixed sample size method and is recommended for estimating the pest population in integrated pest management programs in broomcorn farms

To investigate the effect of triacontanol on the yield and yield components of the two chickpea Landraces, a completely randomized factorial design was conducted with three replications. The treatments were designed at four levels of hormone consumption including 0, 5, 10 and 15 mg/L in the form of leaf and soil applications on two chickpea Landrace of Mashhad and Kermanshah. The total treatments included 24 pots for each Landrace. In this experiment, traits such as grain yield, biological yield, number of pods per plant, number of grains per pod, height of plant, 100-grain weight, and total biomass of chickpeas were examined. The results revealed that the effects of triacontanol application and method of application on chickpea Landraces were not significant. The results also showed no significant effect for biomass. Moreover, analyzing the effects of interaction between the amount of hormone consumption and method of consumption and type of chickpea mass on the yield and yield components showed that all properties were significantly different with an exception of the number of grains per pod and 100-grain weight. Increasing the doses of hormone by leaf application on Mashhad Landrace resulted in significant improvement of yield and yield components of the chickpea. The triple interaction effects of triacontanol application, method of application and chickpea Landrace on the measured traits were significant in all treatments. In the triple interaction, the highest yield was observed in 15 mg/L triacontanol application on the leaves of Mashhad Landrace chickpea, which increased the yield by 45% compared to control treatment. It was concluded that the increase of yield and yield components by increasing doses of triacontanol application on leaves was mainly due to their effects on aerial parts of the plant through decreased rates of flowers, pods and falling leaves. On the whole, application of biochemical triacontanol hormone resulted in increasing chickpea yield by its positive effect on the metabolism activities of the plant.

The purpose of this research was to study the morphological, physico-chemical and mineralogical properties in different physiographic units of rangeland soils of Parishan lake  area in Kazeroon, Fars province with soil temperature and moisture regimes of ustic and hyperthermic, respectively. To this end, four representative soil profiles were selected on plateaus, hills, piedmont plain and low land physiographic units. Laboratorial studies were carried out on each soil sample after being air- dried, compacted and sieved by a two-millimeter sieve. Based on the laboratorial data, the soils of the area were classified as Entisoils and Inceptisoils with ochric epipedon and calcic and gypsic subsurface horizons. The result showed that soil factors have not had a significant impact on soil evolution and development in the lands under study in Parishan lake, which are located in four physiographic units and under rangeland use due to the low rainfall and calcareous soils.  It seems that among the five soil forming factors, topography and time have played more prominent role. The XRD data for the less than 2 μm fractions of the studied soils indicated that the soils were similar in their clay mineralogy, mainly consisted of illite, smectite, chlorite and palygorskite but were different in content. Illite and chlorite were higher in plateau and higher content of smectite was observed in low land unit due to low drainage condition. The source of smectite mineral of the  area soils can be inheritance, neoformation and transformation. Chlorite, illite and quartz are inherited and the resource of palygorskite is mainly inheritance and neoformation in the presence of gypsum and calcit. Finally, most of the soil's chemical properties, including organic matter, EC and gypsum, have had an increasing trend from the plateau physiographic unit to the low land.

To investigate the effect of different amounts of wheat residues on growth and yield of barley cultivars in cold regions, a strip plot design based on a randomized complete block design with three replications was done in two years at Dry land Research Institute of Iran, Maragheh Station. In this study, the amount of wheat residues at three levels of 0.0, 1.5 and 3 ton/ha as horizontal factors and barley cultivars including Sahand, Abidar, Reyhan03 and Usef as vertical factors were evaluated. The experiment was carried out on a wheat- barley rotation farm. Residues of the wheat were added to the experimental plots and distributed uniformly on the surface of the soil. Plant residues of 3 tons per hectare had positive effects on early establishment of seedlings in the field, cold tolerance, yield and yield components of barley. The results also showed that Abidar cultivar had the highest positive reaction to the addition of wheat residues in the amount of 3 tons per hectare in terms of seedling emergence rate and percentage, thousand kernel weight, grain yield, biomass yield, productivity rate and precipitation efficiency index. Therefore, the maintenance of wheat residues of 3 tons per hectare can improve the yield of barley in cold regions

Selenium, known as a key ingredient for human and animal health, can play an important role in the antioxidant mechanism in plants. Unfortunately, many plants fail to have enough selenium, which  has led to selenium enrichment. The aim of this study was to investigate the effect of selenium combined with fulvic acid and humic acid on nutritional value of dill. To this end, an experiment based on a completely randomized factorial design with three levels of fulvic acid and humic acid (0, 50 and 150 mmol/L) and selenium application at 5 levels (0, 6, 8, 12 and 16 mg/L) with three replications was conducted in a greenhouse. The results of this experiment showed that the effect of 50 mmol/L fulvic acids + 12 mg/L sodium selanate, was significant on morpho-physiological traits such as shoot and root dry weight, plant height, chlorophyll, essence,  amount of selenium,and antioxidant enzymes. The results indicate that selenium along with the acids increased and improved essential oilconstituents such as alpha-pinene (3.129%), beta-myrcene (2,231%), alpha-phellandene (46.14%) and carvone (74.83%).

Assessment of energy and environmental pollutants of production process is important in terms of providing solutions to reduce energy consumption and emissions. The purpose of this study was to investigate and predict the yield and profit to cost ratio and environmental effects in sugar beet production to improve energy consumption and reduce global warming. The Cobb-Douglas model was used to investigate the effect of inputs on performance and profit-to-cost ratio. Environmental impact assessment was performed using Simapro software based on CML2 baseline2000 method. The required data were collected through questionnaires and face-to-face interviews with sugar beet growers in Khorasan Razavi, Fars, Khuzestan and Isfahan Provinces. The results showed that with a one percent increase in manpower inputs, diesel fuel, chemical fertilizers, electricity and seeds, the yield was increased or decreased 1.84, -0.59, -0.19, 0.13 and 0.39 percent, respectively. With a one percent increase in the costs of machinery, chemical fertilizers and seeds, 0.23, -0.39 and 0.98 percent were increased or decreased in terms of profit to cost, respectively. Fertilizers and chemical toxins (more than 90%) have the greatest effects on organic matter depletion and open water toxicity. Electricity consumption was also more than 20% effective in reducing inorganic matter and ozone depletion. The effects of open water poisoning and depletion of organic matter had the greatest environmental impact. The total emission of greenhouse gases into the atmosphere was 745.79 kg .ha-1. Analysis of soil parameters and proper management of agricultural machinery use can minimize energy consumption and environmental pollutants from production.