AGROECOLOGY (بوم شناسی کشاورزی)
Year:2010 | Volume:2 | Issue:1|Papers Count:20

Biodiversity is an important component in sustainability assessment of agroecosystems. Along with increasing or decreasing of biodiversity, ecosystem services in agroecosystems will be varied. Agricultural experts take into account different factors which affect agroecosystems variation. In this study, farming systems of two areas including a protected mountainous area and also a plain – hilly area in southwestern Iran from agrobiodiversity aspects are studied. In case of field crops species richness, plain – hilly area (average 4.35 versus 3.25 in mountainous ecology) and in horticultural systems, mountainous protected area (average 2.76 versus 0.9 species in plain area) had better situations. Shannon – Weiner index had the scores range from 1.25 to 1.87 in different villages which was harmonious with former estimations in Iran. Simple regression showed that mean horticultural species richness raised significantly with increasing altitudes, however in other systems, no significant trend were observed. It seems that in mountainous areas, investment on sustainable rural livelihood should be concentrated on gardening development. Homegardens species richness reduced significantly, in villages thar were far from urban centers. Results showed that there is significant and positive correlation between agronomic and horticultural systems regarding species richness and relative household income from these sectors which is an implication for non-dominance of large scale commercial cultivations in the area.

Efficient use of agricultural wastes due to their recycling and possible production of cost effective materials, have economic and ecological advantages. A biological method used for degrading agricultural wastes is a new method for improving the digestibility of these materials and favoring the ease of degradation by other microorganisms. This research was carried out to study the possible biodegradation of wheat straw by different species and isolates of Trichoderma fungi. Two weeks after inoculation of wheat straw by different isolates, oven drying in 75oC, the samples were weighted and (Acid Detergent Fiber) ADF and NDF (Neutral Detergent Fiber) reductions of each sample under influence of fungal growth were compared with their controls. The results showed that biodegradation of wheat straw were closely related to fungi species and also its isolates. The Reductions in NDF and ADF of wheat straw by T. reesei and T. longibrachiatum were more pronounced compared to others, although T. reesei was superior in ADF of wheat straw reduction. It is concluded that for improving in digestibility and also shortening the timing of composting process, it is recommended to treat the wheat straw with Trichoderma fungi and especially with T. reesei and T. longibrachiatum that performed well and had excellent efficiencies.

Incorporation of plant residue in soils is considered as an important agricultural practice for maintaining soil fertility in sustainable agricultural system. CO2 levels, nitrogen fertilization and plant residues are factors which highly affect decomposition of added organic matter to soil. In this research controlled chambers were used to investigate the effects of elevated atmospheric CO2 concentrations (350 vs.760 CO2 ppm) under two N fertilization levels (0 vs. 500 kg N ha-1) and two replicates on decomposition of wheat and alfalfa residues in two calcareous (32.66 % CaCO3) and non calcareous soils (3.4% CaCO3) at 6 times (0, 10, 20, 40, 60 and 90) under laboratory condition. Soil moistures were adjusted at 70% of field capacity. The results showed that elevated CO2 significantly increased decomposition of residues in both calcareous and non calcareous soils. In the samples that received N fertilizer, decomposition of wheat straw and alfalfa residues increased in both soils. From the obtained results, we concluded that in all treatments the amount of decomposition of wheat straw and alfalfa residues in calcareous soil were higher than non calcareous soils.

In order to evaluate the effect of intercropping with replacement and additive series for hemp (Cannabis sativa L.) and sesame (Sesamum indicum L.), a field experiment was conducted during growing season 2006-07 at the Agricultural Research Station of Ferdowsi University of Mashhad, Iran. A randomized complete block design with three replications was used. Treatments included different combinations of intercropping with replacement (75% sesame+25% hemp, 25% sesame+75% hemp, 50% sesame+50% hemp) and additive (50% sesame+100% hemp and 100% sesame+50% hemp) series and their monoculture. Results indicated that the highest and the lowest leaf area index (LAI) and dry matter (DM) accumulation of hemp were observed in 50% sesame+50% hemp (2.99 and 1921.7 gm-2) and 50% sesame+100% hemp (1.06 and 929 gm-2), respectively. The highest and the lowest LAI and DM accumulation of sesame were observed in monoculture (1.34 and 551.27 gm-2) and 50%sesame+100% hemp (0.23 and 51.73 g.m-2), respectively. The maximum crop growth rate (CGR) of hemp and sesame were observed in 50% sesame+50% hemp (76.58 gm-2day-1) and monoculture (22.78 gm-2day-1), respectively. It seems that the intercropped sesame with hemp reduced the growth indices of sesame due to increasing shading on it and decreasing the absorption of radiation.

In order to compare of ecological management of weed control on economical income, yield and yield components of cotton (Gossypium hirsutum L.), a Randomized Complete Block design with 12 treatments and four replications was conducted in Mahvelat of Khorasan Razavi province, Iran. Treatments consisted of weeding, harrowing, burning, two times weeding, weeding+harrowing, weeding+burning, harrowing+ harrowing, harrowing+weeding, harrowing+burning, weeding+harrowing+ burning, weed free and weedy as a check treatment. Investigated traits were plant height, number of boll in plant, 20 boll weight, 20 boll cotton lint weight, cotton lint yield per plant, cotton yield, number and biomass of weeds, outcome, net and gross income. The result showed that treatments had significant effect (p<0.01) on all traits. Treatments including weeding simultaneous with harrowing caused 80 and 97 percent decrease in density and weed biomass, respectively. The highest yield (4051 and 4087 Kgha-1) and net income (7.80 and 8.58 million Rials per ha) obtained from weeding+harrowing+burning and weed free treatments, respectively. The highest expensive weed controls also concern with two these treatments. The lowest yield (1923 Kgha-1) and net income (410,000 Rials) were confirmed by check treatment. Results of this study showed that weeding+harrowing+burning is the best method in cotton weed control.

Plant dry matter accumulation has a linear relation with accumulative photo synthetically active radiation (PAR). Intercropping could be a strategy for increasing light absorption in agronomic systems and it may improve radiation use efficiency (RUE). Thus this study was conducted in order to evaluate radiation absorption and use efficiency in potato (Solanum tuberosum L.) –corn (Zea mays L.) intercropping. The experimental treatments were consisted of monocropping corn (MC), monocropping potato (MP), strip intercropping (S), intercropping with three different patterns (I25, I50 and I75 are 25%, 50% and 75% overlaps of corn and potato rows in strip treatment, respectively) and row intercropping (R). Results showed that corn RUE increased in all intercropping treatments compared with mono-cropping plots while potato RUE reduced in the intercropping plots. Mean of corn RUE in growing season was from 2.65 g.MJ-1 in the MC up to 3.27 g.mJ-1 in the R. Mean of potato RUE was from 1.27 g.MJ-1 in the R to 1.47 g.MJ-1 in MP treatment. With shifting row intercropping, where row spacing was doubled compared with mono-crop corn plots, towards strip intercropping, where distance of rows was similar to mono-crop corn plots, RUE decreased. This could be due to decreasing the number of rows that their distances were double of mono-crop plots. Moreover, with shifting from strip intercropping towards row intercropping (i.e. I25, I50, I75 and R treatment, respectively), the number of potato rows that were under the corn direct shading increased and this resulted to decreasing potato RUE. Further studies on the effects of various densities of potato and corn plants and delayed intercropping systems for these crops are required.

In order to perform each component of agricultural practices, its plan should be rationalized economically and technically. In a study for recognition patterns of energy inputs and outputs in saffron fields of Southern Khorasan, Iran, during a five years exploitation period, two questionnaires were prepared, one for the first cultivation year, and another for crop management and harvest during four subsequent years. In each questionnaire some questions were included to obtain direct and indirect inputs and outputs of energy flows in saffron fields. About seventy questionnaires were filled by direct interview with farmers. Results showed the highest energy input in the first year is supplied by farm manure which approach to 91.16% of total used energy. During four next years, however, nitrogen fertilizer (mainly as urea form) was the main energy input with 37.67% of total used energy. The daughter corms and crop shoots consist the main sources of energy outputs, as energy efficiency was 41% for a five exploitation period, which is similar to some annual crops such as tomato and lettuce in USA. Although energy efficiency of saffron production is very low in Southern Khorasan, but most of saffron fields is cultivated ecologically, with low external inputs, and this crop play an important role in rural livelihood, because of its high economic efficiency and employment than other local cultivated crops.

In order to have a sustainable agriculture it is necessary to use environmental friendly inputs to improve ecological aspects of environment. Basil (Ocimum basilicum L.) is a medicinal and vegetable crop which is cultivated in different parts of the world. An experiment was conducted at Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in year 2009. A complete randomized block design with six treatments, and three replications was used. The treatments were: control (no fertilizer), cow manure, sheep manure, hen manure, vermin-compost and NPK fertilizers. Results showed that all studied organic manures were high in measured characters in compare with chemical fertilizer.The highest plant height, leaf yield, fresh and dry matter were obtained at vermicomposting. Treatments have no significant effect on Essential oil percentage. The highest essential oil yield was obtained in cow manure treatments.Third cut and the first cut had the maximum and the minimum of leaf yield, fresh and dry shoot yield, respectively. Essential oil percentage in the first cut was significantly more than other cuts, but essential oil yield, were the highest in third cut because this cut produced highest leaf yield. There was no significant difference between chemical fertilizers and control treatment in all characters except green area index and fresh and dry leaf weight in a plant.

In order to study morphological traits, yield and yield components of 34 hybrids of corn, an experiment was carried out based on of randomized Complete Block Design with three replications under normal irrigation condition in Khorasan Razavi Agricultural Research and Natural Resources Center, Mashhad, Iran on 2009.Results of analysis of variance showed that there were significant differences between hybrids for all of traits. Results of hybrid means comparison showed that KSC500 hybrid was better than others in yield trait. Result of simple correlation between traits showed that ear diameter and kernel depth had the highest correlation with grain yield, respectively. In other to study relationship of traits in regression model with grain yield, path analysis showed that number of ear per plant had the highest direct and positive effect on grain yield. Principle component analysis was performed for corn hybrids. Seven components have been extracted, which describe 85% of traits variations. Also factor analysis (with Varimax rotation) was performed. Cluster analysis with Ward’s method, arranged hybrids into five different groups.

In order to study radiation use efficiency and radiation interception in intercropping of herb sweet basil (Ocimum basilicum L.) and common bean (Phaseolus vulgaris L.), an experiment was conducted at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran during growing season of 2008. Treatments were 1) sole crop of bean, 2) sole crop of sweet basil, 3) strip intercropping of bean and sweet basil (four rows bean and two rows sweet basil), 4) strip intercropping of bean and sweet basil (two rows sweet basil and four rows bean), 5) row intercropping of bean and sweet basil. Sweet basil was harvested at two times during the course of experiment. For this purpose a complete randomized block design with three replications was used. Results showed that in intercrop the fraction of intercepted radiation (F) was higher than the sole crop F. radiation use efficiency (RUE) of sweet basil in intercrop treatments was increased compared to sole crop and highest RUE of sweet basil obtained in secondary harvest of row intercropping (3.4 g.MJ), and the highest RUE of bean obtained in row intercrop too (2.4 g.MJ). Light extinction coefficient of bean was obtained as 0.55 and sweet basil 0.47, respectively. The highest Leaf area index (LAI) in bean was obtained in sole crop (4.3) and the highest LAI in sweet basil in first harvest was in strip intercropping with 4 rows sweet basil (3.2) and secondary harvest was in sole crop sweet basil (2.5).

Early watergrass (Echinochloa oryzicola (Ard) Fisher) is an aggressive specie of Echinochloa and have mimicry chareterstics of rice. In order to evaluate competitive effect of aggressive specie of Echinochloa on Rice, an experiment was conducted at the Rice Research Institute of Rasht during 2007. The experimental design was complete randomized block with three replications. The treatment included weeds density at three densities (10, 20 and 40 plant/m2) and Rice was transplanted with local normal density (20 bunch.m2 and each bunch included three plants).Result indicated that early water grass decreased grain yield, the number of panicle per plant, biologic yield and harvest index were significantly at possible area 1%. When density increased until 40 plant.m2, grain yield lossed was 70%. Loss of number seed per panicle in densities 10, 20 and 40 plant/m2 was 34, 41 and 43 present and loss of number panicle per plant of rice in competition to Echinochloa was 62, 64 and 62 present respectively. Densities of 10, 20 and 40 plant.m2 decreased average of rice height to 49, 67 and 61 present, respectively. Rice in densities 40 plant.m2 of weed had less highest and in densities 0 plant.m2 the highest.

Remote sensing techniques are known as very useful methods for studying land use management in arid and semi-arid areas, where undeveloped soils are dominant. These techniques can be used for determining different environmental characteristics including soil and vegetations. In this study ETM+ band ratios and Principal component analysis (PCA) were used for monitoring of vegetation cover and its disparity in relation to soil characteristics. Neyshabour area was selected as the study area. The results showed that using of vegetation indices and PCA increased regression coefficients for the model. It was also found that when the analysis is restricted to more homogenous areas, the regression coefficients were improved significantly. It was also concluded that it is possible to develop some statistical models for using of ETM+ images for monitoring vegetation cover in arid areas which are covered dispersedly.

Agroecology emphasizes the use of organic materials in agriculture. The organic acids are important sources of organic materials. In order to study the effect of different levels of humic acid on yield and yield components of corn (Zea mays L.) an experiment was conducted at Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during 2009. The experiment was conducted with different levels of humic acid (0, 500, 1500, 2500, 3500 and 4500 gha-1) based on randomized complete block design with three replications. Results showed that different levels of humic acid imposed a significant effect on the yield parameters such as grain yield, biomass, leaf area index, leaf area duration, height, row number and ear length, but there were no significant effects on harvest index, 1000-grain weight, ear diagonal, and grain number per row did not have significant effect. According to the results, the highest and lowest grain yield belonged to 3500 g.ha-1 humic acid and control treatments respectively. The highest biomass production observed to 4500 gha-1 humic acid treatment. While the highest row number and ear length belonged to 3500 gha-1 humic acid treatments. Generally, it seems that application of humic acid due to having nutritional ingredients and different physiological effects improves corn performance and reduces environmental pollution and it could be used as a natural material to increase and stabilize field crop production.

In order to investigate the effects of nitrogen fertilizer on yield and yield component of potato, (Solanum tuberosum L.) and researching for direct and indirect effects of some important agronomic traits, an experiment was conducted based on randomized complete blocks design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during 2008.Chlorophyll meter was used to identify the required precise time of potato to nitrogen fertilizer application. Nitrogen topdress fertilizer was applied at two levels (of 100 and 150 kgN.ha-1) and during two nitrogen index of 90 and 95 percent. Results of analysis of variance showed that 95 percent nitrogen index versus 90 percent nitrogen index has a better efficiency in increment of potato crop yield, but in 95 percent index, nitrogen fertilizer levels of 100 and 150 kgN.ha-1 did not showed significant difference in tuber yield. Results of path analysis indicated the traits of leaf nitrogen and large tuber percentage had the most positive direct effect on tuber yield and the traits of tuber specific gravity and tiny tuber percentage had the most negative direct effect on tuber yield. Supplying of nitrogen despite decrement of tuber specific gravity, increased tuber yield by increment of large tuber percentage. Assessment of correlation coefficient indicated that there are high correlations between SPAD reading, leaf nitrogen percentage and large tuber percentage and also there are high correlations between these traits and yield of potato. In general, it appeared that nitrogen fertilizer application by using chlorophyll meter, in addition to producing desirable yield of tuber, leads to make desirable quality of tuber and economy in nitrogen fertilizers application.

In order to study compatibility of 30 white bean genotypes under Karaj climate, an experiment was conducted based on randomized Complete Block Design with four replications.Evaluation and statistical analysis was performed for 18 important traits.Analysis of variance results showed that there are significant differences between varieties for all traits. Results of genotypes means comparison with Duncan’s multiple range test showed that genotype No. 29 was better than others in plant height, yield, and biological yield, seed no. per plant and pod weight traits. Simple correlation coefficients were significant between yield and weight of pod, biological yield, number of seed per plant, number of pod per plant, plant height, width of pod and number of seed per pod. Only pod length was negative correlated with yield between all investigated traits. Cluster analysis with UPGMA method arrangement genotypes into three groups. According to this experiment results we can recommend 29 and 30 genotypes for Karaj condition.

In this study 18 corn hybrids consist of 15 new early and mid mature foreign hybrids and three commercial Iranian corn hybrids (KSC704, KSC647 and DC370) as controls were evaluated at two RCBD with three replications at the Khorasan Razavi Agricultural Research and Natural Resources Center, during 2008-2010. Results showed that hybrid EXP1 and DC370 with 16.5 and 12.1 tonha-1 were the best and the worst hybrids, respectively. Also, the EXP1 hybrid was better than others for no. rows, kernel depth, ear length and stem diameter. The results of simple correlation showed positive and significant correlations between grain yield with plant height, ear height, No. rows kernel depth, days to physiological maturity, ear length and leaves no. Also, we estimated negative correlation between grain yield and cob percentage. Results of cluster analysis by Wards’ method based on two years data showed that these corn varieties can be divided in four clusters.

A study was conducted to evaluate the effects of moisture limitation on yield and dry matter distribution between shoot and root of triticale genotypes. This study was performed using a factorial experiment based on completely randomized design with four replications, in Agricultural College of Ferdowsi University of Mashhad greenhouse during 2009. Treatments were two available soil water including irrigated after 50% and 75% depletion of moisture from root zoning (as a check and moisture limitation, respectively) and four triticale genotypes (ET-82-8, ET- 82-15, Et- 79-17 and Juanillo-92). Results showed that the significant (P≤0.01) decrease in grain yield due the drought stress about 32 percent, but the effects of genotypes and interaction of moisture limitation and genotypes were not significant. Total above ground dry weight, leaf plus shoot and spikelet dry weight decreased with drought moisture limitation. Moisture limitation had significant (P≤0.01) decrease in root depth about 16 percent. Also genotypes and treatment's interactions had significant effects on root depth (P≤0.01 and P≤0.05 respectively). Moisture limitation and genotypes showed significant effects (P≤0.01) but interactions were not significant. About 46 percent decrease on root dry weight was due from moisture limitation. Experimental treatments and their interactions had significant effects on total root area. Genotypes and interactions were significant effects (P≤0.01) on root/shoot ratio, but the effect of moisture limitation was not significant. Finally, results showed that while the ET-82-8had the better growth characters, its drought susceptibility index (DSI) was lower which indicate the lower susceptibility and high yield stability of this genotype under stress conditions.

Twenty local and foreign maize (Zea mays L.) hybrids in five different maturity groups were evaluated in Mashhad, Iran for two years (2007-2009). Three planting dates (5th May, 20th May and 5th June) and hybrids were arranged in a randomized complete block design as split plot arrangements, with three replications. The planting dates were in main plots and hybrids in subplots. The results indicated that late maturing hybrids will have high risk in region. In 5 June planting, non of hybrids except early maturing group, failed to reach proper maturity. Results revealed that KSC 704 can be replaced by early hybrid, KSC 260 in 20 May and 5 June plantings, as well as medium-early hybrids such as KSC 400 in 5 May and 20 May plantings. Hybrid KSC 260 in 5th June sowing, produced 13.886 and 11.698 t/ha grain with proper harvestable moisture in 2007 and 2008 respectively, while, late hybrid KSC 704 produced 13.007 and 16.243 t/ha grain with very high moisture, without significant grain yield.

In conventional agricultural systems application of fungicide and pesticides for seed treatment had been extended in wide range. This study was conducted to evaluate the effects of seed treatment on seed vigor indices on back cross Roshan of wheat cultivar in vitro status during 2007. The experiment was done in a completely randomized factorial design with eight replications. Treatment were including wheat seed in two levels (contaminated with common bunt teliospores and health seeds), fungicides in four levels (Real, Vitavax, dividend and control) and seed storage time following treatment in three levels (30, 60 and 90 days) were tested in the experiment. Results revealed that contamination and fungicide affected shoot and root lengths significantly (p≤0.01). Seed storage had significant effect (p≤0.01) on germination percentage, seedling dry weight, root and shoot lengths. Interaction between contamination and fungicide was not significant for germination rate, seed germination percentage, seedling dry weight and root length. According to these laboratory results seed treatment with fungicide not only lost seed vigor but also damaged bioenvironmental indices could be expected. Whenever seeds contaminated by common bunt and epidemic of disease are definitely by emphasis on field experiment results and different reaction of wheat varieties to common bunt, utilization of favorite fungicide will be useful and yield loss and bioenvironmental hazard will be decreased.

In order to evaluate the effect of using zinc granulated phosphorous biofertilizer on yield and yield components of white bean (Phaseolus vulgaris L.), a field experiment based on a randomized complete block design with three replications was performed. Experimental treatment were included of using phosphate and triple super phosphorous chemical fertilizer at five levels (without using of chemical fertilizer, use of %25 phosphorous chemical fertilizer, use of %50 phosphorous chemical fertilizer, use of %75 phosphorous chemical fertilizer, use of %100 phosphorous chemical fertilizer) and bio granulated phosphate fertilizer including zinc in 2 level (without using bio phosphorous fertilizer, without bio phosphorous fertilizer). Characterizations such as seed yield, the high of bush, the number of tributary branches, dry weight of bushes, whole dry weight, percentage of phosphorous and protein of seed, whole biomass and yield components were measured. Results shows that there is an significant deferent between use and not using of biological fertilizer from the view of yield components at %5 statistical level and the most yield component with producing of 2275.3k on 1000m2 was belong to use of biological fertilizer. There is a significant deference between the various amounts of phosphate chemical fertilizer at %1 statistical level. This shows the effect of various amounts of phosphate chemical fertilizer on yield components, that most yield components was obtained by using of %75 of chemical fertilizer with amount of 2468kg for 1000m2. in the survey of the reciprocal effects between fertilizer and bio fertilizer from the yield components view and depend on using of bio fertilizer and %50 phosphate chemical fertilizer treatment, seed yield was 2683 kg in 1000m2, that comparing with other level of fertilizer and irrigation treatment become significant. Reciprocal effects of bio fertilizer treatment and the level of using fertilizer for some characterizations such as weight 1000 seed, high of bush, number of branches in the bush, number of pod in the bush, seed number harvested index at yield components and present age of pertain were significant.