مجله کشاورزی بوم شناختی
سال پنجم شماره 2 (1394)

In order to evaluate the health of agro-ecosystems in the Birjand region during the yearsof 1991-2011, a studywas conducted between 2011 and 2012. In this study, 38 indices were chosen as health indicators, all of whichwere calculated according to their scientific and quantitative definitions. In order to fitthe relevant equations and observe the variation process, regression analysis was used. At the next step, the relevant positive and negative indices (from to -3) were determined taking into account the positive or negative states of each indicator and the degree of its effect on agro-ecosystem health. Also, after standardizing the datum, the relevant indices have been applied for setting the datum at between zero and one. As a result, the total health index for each year was determined through an algebraic summation of the total indicators’ scores. Finally, the total health index of agroecosystems throughout the 21-year period was calculated from the algebraic summation of the scores finallyachieved. In order to determine the level of quality of the total health index during these 21 years, qualitative classification of the scores was conducted. Based on the findings, the total health index of agro-ecosystems in the Birjand region, obtained from the summation of total scores of 38 indicators during the study years, was placed in a weak health ranking with a score of .92. The health index showed a decreasing trend from the beginning of the study in 1988, when it was closer to the frontier of health and, from then on up to the end of the period, when it reached to the level of an absence of health. The most positive and negative among all the indicators affecting the total health index, were the indicator for agricultural co-operatives and the indicator for damage to agricultural products at .60 and -33.67, respectively.

Field studies were conducted in the research field of the Agricultural Faculty of Islamic Azad University-Astara branch in 2010 and 2011 year in order to evaluate the effect of redroot pigweed (Amaranthus retroflexus L.) on yield and dry matter of corn (Zea mays L.) under different levels of nitrogen application. The experiments were established as a split plot arranged in randomized complete block design with three replications. The main plot was with nitrogen (N) at different rates (0, 100, 160 and 220 kg ha-1) and the sub plot was redroot pigweed in different densities (0, 5, 10 and 20 weeds m-2; 0, 3, 5, 7 and 14 plants m-2 in a corn row, respectively). The results showed that the highest number of seed rows per ear, grain number per ear, 1000 grain weight, grain yield per plant and harvest index of corn were, respectively, 15.6, 691.3, 247.7 g and 41.2% at 160 kg N ha-1 in a weedfree condition and the presence of 5 weeds per m-2 had no significant effect on them. The highest dry matter and grain yield of corn were 15.9 and 12.3 t ha-1 at 220 and 160 kg N ha-1 under weed-free conditions.

Crude oil naturally has large amounts of heavy metals. Heavy metals in soil are non biodegradable and stable. In this research, conducted under greenhouse conditions, Chelate EDTA and sugarcane residual compost were applied for the remediation of soil contaminated with heavy metals. The experiment was designed in a statistical design platform and completely randomized. Soil was artificially contaminated with crude oil to 0, 1, 3 percentage by weight using a soil spray. In the crud-oil polluted soil, compost of sugarcane was applied at two levels, equivalent to 0 and 100 t ha-1 and was added to the pots (1 kg). The treatments included EDTA in quantities of 0, 10, 20 mmol kg-1 added to the pots which were stored in the greenhouse for 60 days. The results showed that EDTA application significantly increased the concentration of Pb, Cd, Ni in uncontaminated soil by 2.11, 2.08, 2.51 times more, respectively, than the control sample. The same was observed for 1% and 3% oil contaminated soils, whereby at 1% contamination the concentrations of Pb, Cd, Ni were 1.96, 2.84, 2.42 times, respectively, greater than in the control sample and at 3% contamination were, respectively, 1.52, 1.9, 1.59 times more than in the control sample. Solubilization of heavy metals in soil was more meaningful at the probable level of 5% than in the control samples. Also, using sugarcane compost significantly decreased concentrations of Pb, Ni, Cd in the soil solution by 1.91, 2.68, 1.77 times, respectively. The soil control had 1.64, 2.11 and 1.85 times the contamination with these elements, respectively, of soil with 1% and 1.29, 1.40, 1.37, respectively, of soil with 3% compared to the control. The results showed that chelate EDTA has the ability to leach heavy metals from oil-polluted soil for its remediation. Also, the addition of sugarcane composting to the soil over the long term can reduce the solubility of heavy elements in soil.

In order to study the effects of biofertilizers, azocompost and nitrogen on the yield of soil properties and yield of the essential oil Dragonhead (Dracocephalum moldavica L.) and the soil properties, a field experiment was conducted as a factorial arrangement in a randomized complete block design with three replications at two locations during 2009-2010 in the research field of the Faculty of Agriculture, TarbiatModares University (location 1), and at the Khoy Agricultural Research Center in West Azarbaijan Province(location 2). Treatments consisted of two genotypes (landrace and SZK-1 cultivars), two seed inoculations withbacteria (with or without bacterial inoculation, including Azotobacter Azosprillum Psedomonas) and five fertilization regimes (100% urea, 75% urea 25% azocompost, 50% urea 50% azocompost, 25% urea 75% azocompost and 100% azocompost). F3 fertilizer increased essential oil yield relative to the control. There was no significant difference between F3 and F1 treatments with and without bacterial inoculation for the former trait. Also, azocompost decreased nitrate leaching and soil pH and increased soil nitrate, soil conductivity, available nutrient elements and soil organic carbon at the two locations. An overlay of the results of this study indicated that integrated treatment (50% urea 50% azocompost) with inoculated and non-inoculated bacteria in a landrace ecotype, by reducing chemical nitrogen and increasing oil yield, could be considered as an appropriate alternative for chemical fertilizers in order to achieve sustainable agriculture.

Crop yield simulation and identification of its determinant factors provides an appropriate tool for planning, management and policy decisions. This study is aimed at estimating the climate response functions for rain-fed crop yields in the north-western Agro-ecological Zone (AEZ) of Iran. For this purpose, a time series was specified as an implicit function of monthly climatic variables for four rain-fed crops (such as wheat, barley, beans and alfalfa) and modelled using the econometric methodology of panel data. The results furnished confirm the existence of a nonlinear relationship between monthly rainfall and temperature and the yield crops showed that spring rainfall, especially in the months of May and June, are the main factors determining of rain-fed crops’ yield. Wheat and alfalfa yield responses to June and July temperature changes are more than in other months. In contrast, this response for barely is the most in April and May. According to previously gathered evidence and projections of future climate change (temperature Increase and rainfall decreases, particularly in spring), it is anticipated that rain-fed crop production in this region will be faced with more drought in the future. Changing planting dates so as to avoid coincidence of flowering growth with moisture stresses in this season can be expressed as an adaptive strategy. This requires further study as a subject of research by crop scientists.

Nowadays, planting cover crops to reduce herbicide use is advised. An experiment was conducted at Ardebil Agricultural and Natural Resources Research Station (at Samian) in the spring of 2012. Experimental design was a factorial arrangement based on a randomized complete block (RCBD) with three replications. The first factor was cover crop types including rye, hairy vetch, berseem clover, green pea and weed control treatment (no cover crop) and the second factor consisted of three levels of management including living mulch, bottom cutting mulch and cover crop topping from 20-30 cm height. Cover crops were planted between rows of KSC400 corn cultivar. The results showed that rye, hairy vetch and berseem clover and green pea could reduce the total density of weeds compared to the control by 76, 68, 65 and 55 percent respectively. The lowest weed biomass was in rye and vetch treatments with an average of 52.94 and 68.34 g m-2 respectively. The highest forage yield was 57500 kg ha-1 in weeding treatments and then 56450 kg ha-1 in hairy vetch. There was no significant difference between other cover crops. The results also showed that the living mulch management was the best in comparison to others with 52700 kg ha-1 forage yield production. The lowest yield was achieved in the control treatment without a cover crop, with 35000 kg ha-1 forage production. The results also showed that the highest fresh ear weight (32600 kg ha-1) was in the weed-free treatment, and then in hairy vetch at 31000 kg ha-1. The highest ear length (39 cm) was in the weed-free treatment too where there was no significant difference between hairy vetch and clover. The lowest ear length (28 cm) was in the control without any cover crop.

Energy management in agroecosystems helps to attain efficient and sustainable use of energy. The aims of this study were to evaluate the energy input, energy output and energy indices in irrigated and dry-land wheat farms under different climatic conditions in Kermanshah Province. Data were collected from irrigated and dry-land wheat growers by using a face-to-face questionnaire during 2012-2013. The results showed that, regardless of climatic conditions, total energy input in irrigated and dry-land wheat farms was 52444 and 15612 MJ ha-1, respectively. Among irrigated wheat farms, the highest and the lowest energy inputswere calculated in aridwarm (60157 MJ ha-1) and wet-moderate (48083 MJ ha-1) climates while, in dry-land wheat farms, these were calculated in semiarid-cold (15295 MJ ha-1) and wet-cold (16263 MJ ha-1) climates, respectively. In irrigated wheat farms the highest energy output was 174289 MJ ha-1 for a semiarid-cold climate and the lowest was 11494 MJ ha-1 for an arid-warm climate while, in dry-land wheat farms, the highest was 70806 MJ ha-1 for a semiaridwarm climate and the lowest was 36955 MJ ha-1 for an arid-warm climate. Energy use efficiency was about 19.9% higher in dry-land farms than in irrigated ones. The highest energy use efficiencyin irrigated and dry-landwheat farms was 3.5 (in a semiarid-cold climate) and 4.4 (in a semiarid-warm climate), respectively. The highest energy productivity in irrigated farms was 0.11 for wet-cold and semiarid-cold climates while it was 0.11 for wet-moderate and semiarid-cold climates in dry-land farms. Based on our results, dry-land wheat farms had higher efficiency and productivity compare to irrigated wheat farms.

Food security is a situation when all people at all times have access to sufficient, safe and nutritious food to maintain a healthy and active life. Measuring food security at the household level is necessary for achieving sustainable food security. Quantitative analysis of the food security situation in Poldokhtar county and the influencing factors that have affected this issue were objectives of this study. To thispurpose, 200 urban and rural households of this county were selected, randomly. Food security status wasmeasured by using an 18-item questionnaire that is provided by the United States Department of Agriculture. Theresults of this study showed that food insecurity was 70.5 % and was greater in rural households compared with urban households. According to the results, food insecurity has a direct relationship with household size and negative relationship with household income. So, food insecurity was reduced with an increase in household income and a reduction in household size. Therefore, we can reduce the food insecurity of this region by appropriate planning and improving its socio-economic situation.

Given the central role played by water in agriculture and the functions of arid plains and the impact of lack of water on agriculture of these areas, a scientifically-based use of water is needed to find asuitable method for sustaining their agricultural function in the future. Hamedan-Bahar plain as among the country’s arid plains andso is not excluded from this rule. Hence, it is important to understand the challenges of and impediments facing water management in this plain. The purpose of this study was to compare water resource managementimpediments from the viewpoint of farmers and experts in the Hamedan-Bahar plain and study the relationship between personal and agricultural traits of the former with their water resource management behaviours. The method of this study is descriptive and includes use of a water resource management theoretical impediments questionnaire and a researcher management behaviour measurement questionnaire. In this investigation, datawas analyzed by the T-Test and multi regression. The results showed that there were no significant differences between training and promotional elements from the points of view of experts and farmers. Also, there were signify differences in the between age, education and earnings elements and the farmers’ management behaviours.

Application of new techniques in precision farming for the determination of soil and plant spatial variability in such matters as soil nutrients, soil physical and chemical properties have received great attention. This study was carried out in order to map the spatial variability of essential plant and soil variables associated with olive yield, through generating maps that can be used in site-specific crop management (SSCM). For this purpose, two orchards with optimum and low yields were selected in the Tarom region of Zanjan province and 65 soil and plant samples were taken during 2014-2015 on a 49-m systematic sampling grid corresponding to a density of four soil samples per ha. All the samples were analyzed using appropriate laboratory methods. In addition, the percentage of fruit set in both years was calculated by counting the number of flowers and fruits. An interpolation map of each variable was created by the inverse distance weighted (IDW) method using ArcGIS. The results showed that nitrogen and potassium accounted for 94.6% of fruit set variations and silt accounted for 93.9%, according to the fitted models using the stepwise regression method. In addition, nitrogen and potassium accounted for 94.6% and silt for 93.9% of the fruit set variations. In aggregate, the main reasons for the differences in fruit set in the olive orchards were including nitrogen and potassium deficiency, high silt, deficiency in available phosphorous, high SAR, TNV and EC. Interpolation maps showed that the spatial distribution of fruit set in both orchards was inversely related to yield limiting variables.