مجله کشاورزی بوم شناختی
سال پنجم شماره 1 (1394)

Agricultural systems around the world face the challenge of providing the needs of a growing human population. To meet this demand, agricultural systems have intensified to produce more crops at the expense of greater energy inputs. Agricultural intensification, while yielding more crops, generally has detrimental impacts on energy use efficiency. The aim of this study was to compare of wheat production in dry-land (low input) and irrigated (high input) farms in Kermanshah in terms of energy ratio, benefit/cost ratio and amount of energy use. Data were collected from 60 irrigated and 60 dry-land wheat farms selected using a random sampling method in 2013. The total energy requirement under low input was 14520.8 MJ ha-1, while 41921.8 MJ ha-1 was consumed under high input conditions, so that three times higher energy input was used on irrigated than dry-land farms. The energy ratios of 1.88 and 1.56 were achieved under dry-land and irrigated systems, respectively. The results showed that the greatest energy consuming input for the different operations investigated were chemical fertilizers, especially nitrogen (35.6% in dry-land against 25.9% in irrigated systems), and the total energy equivalent of diesel fuel consumption was placed second among the energy inputs (25.9% in dry-land against 13.4% in irrigated systems). Economic analysis indicated that the benefit–cost ratios were 1.87 in dry-land and 1.85 in irrigated wheat production systems. Based on the results of the present study, dry-land farming can have a significant effect on energy-related factors, especially in the arid climates of Iran.

To evaluate the effects of organic and chemical fertilizers on the leaf area index, yield and yield components of pumpkin, a field experiment was conducted based on RCBD with three replications during the 2010-2011 growing season at Gorgan University of Agricultural Sciences and Natural Resources, Iran. The treatments included N: (control), N1: 66-66-99 kg ha-1 NPK, N2: 132-132-198 kg ha-1 NPK, N3: 300-200-200 kg ha-1 NPK, H: 30 t ha-1 manure, HN1: (1/2 H + N1), HN2: (N2+ 1/2 H), HN3: (N3+ 1/2 H), C: 30 t ha-1 municipal compost, CN1:(1/2 C + N1), CN2: (1/2 C + N2), CN3: (1/2 C + N3) and HN: (1/2 C + 1/2 H). In this study, total dry weight, leaf area index, number of fruits per plant, number of seeds per plant, 1000-seed weight and seed yield were measured. The results showed that the application of chemical fertilizer (N3: 300-200-200 kg ha-1 NPK) decreased seed yield. The effect of manure and solid waste compost application was positive on both physiological indices and seed yield. Application of Chemical and combined fertilizers (N2: 132-132-198 kg ha-1 NPK and HN2: (N2: 132-132-198 kg ha-1 NPK + 15 t ha-1 manure) had a positive effect on all traits. The use of chemical fertilizer with FYM (HN2: (132-132-198 kg ha-1 NPK + 15 t ha-1 manure) produced the highest value of physiological indices and seed yield. In total, the results showed that the application of an NH2 treatment instead of chemical fertilizers, in addition to the considerable reduction of chemical inputs, can be a step towards achieving sustainable agriculture.

Rosa damascena Mill. is one of the most important aromatic plants in Iran and throughout the world. In order to investigate genetic variations between different accessions of Rosa damascena Mill., a cytogenetic study was performed. The accessions were studied for several karyotypic characteristics, including long and short arm length, by which the total length of the chromosomes, long arm to short arm and short arm to long arm, ratios were calculated. Analysis of variance of mitotic data in a factorial experimental design based on a completely randomized design, showed significant differences (p<0.01) between the studied accessions for all of the traits (p<0.01). Duncan tests were carried out in order to classify the accessions and their chromosomes. All of the sixteen accessions had 14 chromosome pairs, without any sat-chromosome and B-chromosome. The minimum total length of chromosomes belonged to the Yazd2 population and the maximum total length of chromosomes belonged to the Khuzestan1 accession. Most of the chromosomes were sub-metacentric based on Levan’s classification and karyotypic symmetry measurements showed that most of the accessions have asymmetric chromosomes.

In order to find an approach for controlling hoary cress using gall mite (Aceria draba (Nal.) (Acari: Eriophyidae), various studies were conducted in three regions of Shirvan, northern Khorasan Province (Iran) during spring 2011. Preliminary studies that included collecting, identifying and screening bio-control agents for hoary cress were carried out. For this purpose, 40 plants (20 infected and 20 healthy) were transplanted to the pots. After establishment, the control plants were sprayed with an acaricide and others infested with the gall mite at three stages. At the end of the growing season, plant height, stem diameter, shoot fresh weight, shoot dry weight and seed number of the hoary cress were measured, accordingly. The host-range results showed that the mite did not feed from any of the plants except for hoary cress. The effect of gall mite on the vegetative and reproductive characteristics of hoary cress was significant (p≤0.01) and could reduce the seed number of hoary cress by 98% compared with the control. This mite was able to reduce the vegetative and reproductive organs and seed number of hoary cress.

In order to evaluate the effects of biological fertilizers and crop rotation on yield and the yield components of wheat (Triticum aestivum L.), an experiment was conducted as a split-plot factorial arrangement based on a randomized complete block design, with three replications, in the field during the 2010-2011 growing season. Two crop rotations as alfalfa-wheat and fallow-wheat were assigned to the main plots. Two wheat varieties (Falat and Parsi) and biological fertilizer at four levels, including Nitroxin, Mycorrhizal fungi and Nitroxin+ Mycorrhizal together, and with a control were randomized in subplots. Growth indices, the number of tillers, yield and yield components and the grain glutenin content of wheat were recorded. Results showed that in the wheat-alfalfa rotation all studied traits except the harvest index increased. Parsi increased in plant height and grain yield more than Falat, but seed glutenin content in both varieties was the same. Biological fertilizers increased the leaf area index, dry matter accumulation and crop growth rate. Also, the impact of biological fertilizers on the chlorophyll meter reading, grain yield, grain number per spike and glutenin content of wheat were significant. In contrast, the effects of biological fertilizers on plant height, number of fertile tillers, dry matter yield and straw yield were not significant. The maximum yield was gained with 435 g m-2 in the alfalfa-wheat rotation, Parsi variety and Nitroxin+Mycorrhizal fertilizer.

Although developing countries have a good potential for establishing and expanding organic farming, most such countries are faced with a number of challenges to increasing organic acreages. In fact, farmers have been faced with many challenges when they wish to convert to organic. This paper aims to assess the factors affecting the conversion of tomato producers in Alborz Province to organic production. The statistical population constituted tomato producers in the 2010-2011 crop year. The collected data was analysed using a descriptive, statistical test and discriminant analysis. The results indicated that the average willingness of tomato farmers to organic product is low. They also indicated that familiarity with organic farm management, education, health issues and positive attitudes to environmental variables all have a positive and significant relationship and that age, and chemical fertilizer and pesticides variables have a negative and significance effect on willingness to convert to organic cultivation. The results indicate that, despite of most production methods and technologies, economic factors alone are not the main factor in the adoption and diffusion of organic practices. Thus, for developing organic farming the role of other factors like awareness and information, personal attitudes and interest, technical, technological and managerial skills, social issues, institutional factors like law, regulations, markets and government support must be taken into consideration by government and policymakers.

In order to investigate the impact of the sowing date on yield, yield components and physiological growth indices of grain maize (Zea mays L.) cultivars, a field experiment was conducted at the Faculty of Agriculture of the University of Lorestan in 2011 as a randomized complete block design with factorial arrangement of treatments and three replications. Treatments consisted of two sowing dates (21st May and 13th June) and six maize cultivars, namely T.V.C.767 and S.C.704 from a late maturing group, cultivars T N.S640 and Maxima from a mid maturing group, and cultivars Koppany and D.C.370 from early maturing group. Results indicated that the main effects of the experimental factors were statistically significant in terms of 1000-kernel weight, number of kernels per ear, number of kernels per row, number of rows per ear and harvest index. The interaction between sowing date and cultivar was only significant in the case of biological and grain yields, ear length and plant height. In the first sowing date the highest and lowest grain yields belonged to cultivars S.C.704 and D.C370 (12.7 and 7.5 t ha-1, respectively). In the second sowing date, N.S.640 from mid maturing group was ranked first in this regard (13.37 t ha-1). Higher grain yield in S.C704 and N.S640 compared to other cultivars, could be attributed to their higher leaf area index, leaf area index duration and crop growth rate. In total, planting late maturing group cultivars is not recommended for the second sowing date.

The appropriate concentration of micronutrients is not only necessary for normal growth and yield of plants, but also for the growth and health of animals and humans in the food chain. So, in order to evaluate the effects of chemical fertilizers and organic manure, and their combinations, on micronutrient concentration and uptake of fenugreek (Trigonella foenum-graecum) -black cumin (Nigella sativa L.) under different planting patterns, a factorial experiment was conducted in a randomized complete block design with three replications at Shahrekord University research farm in 2013. Five planting patterns were used, namely sole cropping of fenugreek, sole cropping of black cumin, fenugreek: black cumin (2:1), fenugreek: black cumin (1:1) and fenugreek: black cumin (1:2); three fertilization sources consisting of chemical fertilizer, broiler litter and integrated fertilizer (chemical fertilizer: broiler litter) were evaluated. The results showed that micronutrient concentrations were as follows: iron, zinc and manganese concentration of black cumin > fenugreek and copper concentration of black cumin < fenugreek. Under chemical fertilizer application, intercropping only increased the zinc and manganese concentration in black cumin. Black cumin/fenugreek (1:2) treated with integrated fertilizer and black cumin/fenugreek (2:1) under broiler litter had the highest uptakes of iron and zinc (242 and 269 g ha-1), respectively. However, the highest uptakes of manganese and copper resulted from sole cropping of black cumin and sole cropping of fenugreek, respectively. Overall, it can be stated that the use of intercropping treated with organic manure is an appropriate strategy for increasing the uptake efficiency of some nutrients in calcareous soils.

In order to study the effect of black plastic mulch and bio-fertilizers on weed biomass and yield of naked-seed pumpkin under different irrigation regimes, a field experiment was conducted at the research station of Bu-Ali Sina University (Hamedan region of Iran). The experiment was carried out in a randomized complete block design with a split-factorial arrangement of treatments and three replications. The main plots included two irrigation intervals (7 and 12 days), and the subplots included covered with black plastic and un-matched, and four fertilizer regimes (25% chemical fertilizers + bio-fertilizers, 50% chemical + bio-fertilizers, 75% chemical + bio-fertilizers and 100% chemical fertilizers). Different traits including the seed yield and yield components of naked-seed pumpkin, total biomass of all weed species and weed density were investigated. Also leaf, stem, inflorescence and plant weight of redroot pigweed as a dominant weed species were all measured. Results indicated that seed yield and components were affected by a three-way interaction of factors. The highest seed yield (1559 kg ha-1) was obtained with a 12-day irrigation interval, using black plastic mulch and application supplying 75% of plant requirements from chemical sources + bio-fertilizers. This treatment led to a 67% increment compared to a 7-day irrigation interval in un-mulched plots which received 100% of plant requirements from chemical sources. Using mulch at a 12-day irrigation interval and reduced chemical fertilizers replaced by bio-fertilizers led to a considerable reduction in total weed biomass. In general, a 12-day irrigation interval, using black plastic mulch and the application of 75% of plant requirements from chemical sources + bio-fertilizers is recommended. Under the circumstances of this treatment, chemical fertilizer could be decreased by 25% and weeds controlled non-chemically and a high seed yield could be produced with lower water input.

Recently, the planting of narrow lead cover crops has had a noteworthy effect in reducing the use of herbicides. This experiment was carried out during 2011-2012 at the Natural Resources research station in Samian (Ardabil Province) as a factorial study in a randomized complete block design with 3 replications. The first factor included three types of cover crops, rye (Secale cereal), barley (Hordeum vulgare) and wheat (Triticum aestivum) with two controls: (1) without cover crops, with complete weeding and (2) without cover crops and without weeding. The second factor involved management at two levels (live mulch and non-living mulch) and the third factor was with two levels of cover crop planting date (synchronic with planting sunflower and 45 days after planting sunflower). Results showed that the effect of cover crops was significant on sunflower seed yield, protein percent and yield, shoot dry weight, head dry weight and height. The highest seed yield was obtained at control 1 (4053.3 kg ha-1) and in wheat and rye cover crop traits were 3916.7 and 3798.3 kg ha-1, respectively. The highest protein (42.51%) and protein yield percentages (1.69 t ha-1) were observed in control 1 (without cover crops, with complete weeding). Also, the maximum height (173.73 cm) was related to synchronic planting of cover crops with sunflower. The highest single seed weight mean was observed in live mulch management in synchronic planting (0.087 g m-2) and in dead mulch management at 45 days after planting (0.089 g m-2). The interaction of cover crops and planting date had significant effects on weed density and dry weight so that the minimum density and total dry weight of weeds were observed in the cover crops of rye, wheat, barley respectively and at the same planting date. The maximum density and dry weight of weeds were observed in control 2 (without cover crop, without weeding).