JOURNAL OF AGROECOLOGY (کشاورزی بوم شناختی)
Year:2011 | Volume:1 | Issue:2|Papers Count:8

Sustainable agroecosystems production depends on conservation of agrobiodiversity. Despite the ecological role of biodiversity in the stability and functional characteristics of agroecosystem, there are not enough studies in this topic in Iran. Therefore, the aim of this study was to evaluate agrobiodiversity and its relationship with climate in Iran. Data collected from 30 provinces of Iran. Agricultural productions classified to 8 groups of horticultural products, cereal, industrial crops, pulses, medicinal plants, forage and vegetable. Result showed that there were high differences between different provinces in terms of area planting of different agricultural crops and agrobiodiversity. Cereal (56.2%) and horticultural crops (20.6%) showed the highest planting area. The highest species richness was in Fars, Khorasan Razavi and Sistan-o-Baluchestan provinces and the lowest was obtained in Bushehr and Horrnozgan provinces, respectively. Regardless of medicinal plants, the horticultural (1.95) and forage (0.60) crops showed the highest and the lowest Shannon index, respectively. The highest agrobiodiversity was obtained in Fars and Khorasan Razavi provinces. Results showed that there was a positive and significant relationship between Shannon index and evenness index in this study. Hot and dry climate of central Plateau of Iran showed the highest beta diversity.

Determination of the best amount of nitrogen (N) fertilizer application in maize that results in high grain yield under weed competition is of great importance. In order to study the effect of weed competition on maize performance and identifYing whether or not N application rate affects by weed species, an experiment was conducted in 2008 at the Research Field of Tarbiat Modares University. The experiment was established as a randomized complete block design with factorial arrangement of treatments and three replications. First factor was N fertilizer at the three following rates: 138, 184 and 230 kg N ha-1. Second factor consisted of two weed species; i.e. redroot pigweed and proso-millet. Third factor was planting each weed species at low and high densities. Yield and yield components of maize was assessed at final harvest. Results indicated that weed competition significantly reduced maize grain yield compared to 230 kg N ha-1 control treatment. The highest grain yield (1077 g m-2) was achieved in treatment 230 kg N ha-1 while the lowest yields belonged to high densities of redroot pigweed and proso-millet fertilized with 184 and 230 kg N ha-1, respectively (643 and 565 g m-2. Increasing millet density resulted in significant loss of maize grain yield only. Maize grain yields in competition with low densities of proso-millet and pigweed were 800 and 795 g m-2, respectively which reduced to 693 g m-2 when weed densities increased. Difference in N application rate did not cause significant differences in yield components of maize under weed competition. However, high densities of proso-millet and redroot pigweed resulted in significant reductions of the number of rows per ear and the number of grains per row, respectively. Overall, results indicated that in fields where a nitrophile species is the dominant weed species, increasing N application rate beyond the optimum rate not only does not increase maize grain yield but also reduces its yield and causes pollution of environment.

Pot marigold (Calendula officinalis L.) belongs to Asteraceae family is a medicinal herb which its flowers have diverse pharmaceutical, cosmetic and nutritional uses. In order to study the effect of organic fertilizers on agronomic performance, yield and quality characteristics of pot marigold, a field experiment was conducted based on randomized complete block design with three replications in Research Station of Faculty of Agriculture, College of Agriculture and Natural Resources, University of Tehran, Karaj, in 2010. Treatments were vermicompost (15 t ha-1, municipal waste compost (20 t ha-1), cattle manure (25 t ha-1, mushroom compost (15 t ha-1 and control (without fertilizer). Quantitative and qualitative criteria such as plant height, number of branch per plant, number of flower per unit area, flower diameter, herbal fresh and dry weight, 1000 seed weight, flower and seed yield and content of essential oil and extract were measured. Results revealed that among different organic inputs, vermicompost performed better and  significantly increased plant height, number of branch per plant, number of flower per unit area, 1000 seed weight, herbal fresh and dry weight and flower and seed yield. Whereas there were no significant difference between cattle manure and municipal waste compost in plant height and also with vermicompost in 1000 seed weight Application of cattle manure resulted in highest flower diameter and extract content Although, there were no significant difference between cattle manure and vermicompost in flower diameter and extract content improvement. Yield and all plant criteria were decreased with mushroom compost application. In general, this study indicated that vermicompost could be an alternative organic input instead of chemical fertilizers in sustainable production system of C. ojjicinalis.

The objective of this investigation is to study the vegetable diversity in villages at Varamin plain, situated in north of Iran, using qualitative research methods, focused group discussion, key informant interview, informal discussion and using local knowledge. The findings showed that the diversity of vegetables in this area is severely affected by socio­ economic factors and among different factors, water accessibility and land size were two determinant factors which showed negative and positive significant correlation with species richness, respectively. As in this region most farmers cultivate diverse species for reducing the risk of production and small land size was an important problem which farmers introduced it as a main reason for diversity reduction. Then it can be said that accessibility to different inputs is a determining factor in crop diversity.

In recent years, environmental issues and management practices have increasingly paid more attentions particularly in the limited natural resources. To increase acreage and biological products is required to achieve sustainable agriculture areas suitable for development, recognition and be selected. The purpose of this study assess the talents of natural areas for ecological construction of the orchard and farm samples, considering factors and climatic conditions, geology, soil science and more. In fact land suitability determines proportion of land characteristics matching with the requirements of particular uses. Evaluation of pedo-climatic in this study was carried out according to the FAO method. According to field study and soil samples analysis, soil properties were determined. Evaluation of effective factors on plant establishment shows apple and walnut trees and wheat and barley crops are suitable for cultivation in this region.

Fertilizer N residual use in agriculture is recognized worldwide as an alternative fertilizer and to a sharp decrease of the nitrate concentration in seepage water recharging the groundwater. In order to evaluate recovery of residual fe1tilizer-nitrogen by canota in a canota-forage maize agroecosystem, a field experiment was conducted at research farm of Shahrekord University, 2008-2009. Experimental design was a randomized complete block with four replicates. Treatments include residues of 0, 100, 200 and 300 kg N ha-1 in the form of urea and broiler litter which that this soil amendments were applied in spring for maize as prior crop. Canola was planted in mid­ September following forage maize harvest. The results showed that broiler N residual increased pod/plant, seed/pod, 1000 seed weight, grain yield, dary matter, oil concentration and oil yield compared with the N residual of urea. The greatest pod/plant, 1000 seed weight, grain yield, oil concentration and oil yield were obtained with 300 kg N ha-1 from source of poultry litter, but 200 kg N ha-1 from broiler Jitter produced the highest seed/pod and biological yield. In conclusion, utilization N residual after maize harvest would help to minimize the use of high cost synthetic mineral fertilizers for canola production and represents an environmentally and agronomically sound management strategy.

According to identify and survaying the effect of plant Growth Promoting phyllospheric Bacteria Foliar Application on nutrient uptake of corn, this experiment was done. Therefore, leaf samples were taken from corn plants growing around karaj, Iran and total bacteria inhabiting plant surfaces were determined. Nitrogen-fixing and auxine producing bacteria were isolated from the leaves. Amount of N2-fixation and auxin production were determined by gas chromatography and spectrophotometry methods, respectively. Results showed that there were 104 to 106 bacteria on the leaves. Among 39 isolates, 10 were selected for greenhouse experiment. Bacteria suspensions were sprayed on the leaves four times in two-week intervals. Plants were harvested after 75 days and morphological indices and nutrient uptake were measured. Results showed that application of bactena increased plant height, fresh and dry matter and stem diameter compared to control plants. Spraying of bacteria affected length, volume, dry matter and surface area of the roots. Nutrient uptake was also increased due to foliar application of the bacteria.

The purpose of this study was to assess natural sustainability in peasant farming system and its determinants. The target population in this research was include all farmers in Behbahan county (7314) with less than 10 hectare land that a number of 208 people were selected by systematic sampling method among farmers of 38 villages of this county. A questionnaire used for collected data. The result of study showed that there are positive correlation between farmers' literacy, extension participation, off-farm income, weeding lands, human capital, social capital and natural sustainability. According to study findings, there are negative correlation between farmers' age, family size, land pieces index and amount of natural sustainability. Result of regression showed that variables "farm lands fertilized by manure", “consumed pesticides”, “rotated lands”, “lands cultivated by chisel”, “drained lands”, “total managed lands” and “amount of chemical fertilizer” entered in equation and explained 44.7% of dependent variable variance.