جستجوی مقالات مرتبط با کلیدواژه « forage » در نشریات گروه « اکولوژی »

Vetches are especially important due to their resistance to cold and water-deficient stresses, and due to the high amount of crude protein and detergent fibers, they have the same nutritional value as alfalfa and clover. Planting vetch can increase soil nitrogen due to the symbiosis of its root nodes with Rhizobium bacteria. No-tillage reserves more moisture in the soil than other tillage systems. No-tillage and reduced tillage significantly increase mycorrhizal fungi in soil compared to conventional tillage. Increased leaf area index (LAI) and dry matter in plants under reduced and no-tillage systems have been observed, too. Also, increases in chlorophyll concentration, decreases in canopy temperature, increases in plant height and improvements in forage quality in plants under a no-tillage system have been reported. This experiment evaluated the effects of different types of tillage on morpho-physiological traits related to yield and quality of vetch forage to protect the soil and select the best tillage system.

This experiment was carried out in Saral Rainfed Agricultural Research Station located 55 km north of Sanandaj county, Kurdistan province, in the west of Iran. The effects of reduce tillage (RT), no-tillage (NT) and conventional tillage (CT) systems were evaluated on rainfed vetch in rotation with wheat during two years (2018-02019). Sowing date was 18 and 9th of October in the two experimental years respectively. All sampling of rhizobium nodules, relative leaf water content, leaf area index, chlorophyll and carotenoids, chlorophyll fluorescence, canopy temperature, enzymes, proline, hydrogen peroxide, malondialdehyde, leaf soluble proteins and carbohydrates, leaf elements took place in early seed filling stage. The combined (2-year data) analysis of variance (ANOVA) was performed using SAS software by the general linear model (GLM). The means value were compared using Duncan’s range test at P ≤ 0.05.

In this study, the yield of dry forage in reduced and no-tillage systems increased by 14 and 24%, respectively, compared to CT. A significant relationship (R = 0.75*) was obtained between the relative leaf water content and dry forage yield. According to the results, vetch in the no-tillage system had the highest percentage of colonization (30.16%), the number of fungal spores (179.8), and rhizobium nodes (12.16) on the roots. The high symbiosis of mycorrhizal fungi in RT and NT compared to CT was probably due to higher water uptake and higher RWC. In the present study, vetches under the NT system probably had higher chlorophyll a and b concentration due to more moisture and higher nitrogen and phosphorus in leaves. The results showed that the tillage treatments had significant effects on the activity of reactive oxygen species (ROS), which was directly related to the amount of plant moisture and antioxidant enzymes. The lowest activity of enzymes was in vetches under a no-tillage system. 

In this experiment, reduced and no-tillage systems increased yield compared to conventional tillage. Significant increases in relative leaf water content and canopy temperature difference were observed in different types of tillage. Chlorophyll content and carotenoids in plants grown in the conventional tillage were lower than in reduce and no-tillage systems. The percentage of colonization, sporulation of mycorrhizal fungi, and the number of rhizobium nodes were higher in no-tillage system. The levels of antioxidant enzymes, hydrogen peroxide, malondialdehyde, and proline increased in CT compared to RT and NT. Types of tillage in rainfed conditions due to biological and structural changes in the soil cause positive morpho-physiological changes and forage quality in rainfed vetch seem to be effective in increasing yield and improving growth conditions.

Crop simulation models are very useful tools for the evaluation of plant growth and development processes. Crop-simulating models may be used to estimate yield and evaluate climatic, plant, and management parameters on yield. Also, it may be used to predict crop water requirements under different conditions. Crop models should be evaluated and parameterized to simulate crop growth and development. Parameterization is used for precise simulation of crop growth and development and can estimate the best and most appropriate values for model parameters obtained via observed data or calibration. The objectives of this study were to describe the SSM-iCrop2 model, determine plant parameters, and evaluate alfalfa (Medicago sativa L.) in its major production regions using the SSM-iCrop2 model in Iran.

SSM-iCrop2 crop simulation model is a simplified form of SSM crop models which is suitable for the simulation of growth, development, and yield of different crops under different environmental conditions and large-scale estimation of crop production, especially in the evaluation of nutrient availability and climatic effects. This model includes sub-models of phenology, leaf expansion and senescence, dry matter production and distribution, and soil water balance. Daily weather data, agronomic management, soil properties, and plant parameters are required for simulation in this model. The present study investigates the performance of the SSM-iCrop2 model regarding the prediction of single cuts and overall cuts, phonologic stages, and water requirement of alfalfa under changing climatic conditions in Iran. To simulate the growth, development and yield of alfalfa using SSM-iCrop2 model in Iran, the major irrigated alfalfa production provinces, including East Azarbaijan, Hamedan, West Azarbaijan, Sistan and Baluchestan, Khorasan Razavi, Esfahan, Kordestan, Ghazvin, Ardabil, Markazi, Fars, Zanjan, Chaharmahal and Bakhtiyari and Tehran were identified based on the data available in Ministry of Agriculture statistics. Then, field experiment data required for model parameterization and estimation were collected from these provinces.

According to the results of the SSM-iCrop2 model parameterization, two cultivars with different leaf area indices (high-yielding and low-yielding) were identified in major alfalfa production provinces. The model was evaluated using independent experimental data that had not been used for parameterization. The evaluation results for alfalfa yield showed that the observed single-cut forage yield ranged from 112 to 640 g.m-2 with an average of 330 g.m-2; the observed total annual forage yield ranged from 646 to 4042 g.m-2 with an average of 1717 g.m-2; and the water requirement of alfalfa obtained from the NETWAT software was between 5140 to 12690 m3 ha-1 with an average of 8746 m3 ha-1. The predicted single-cut forage yield, predicted total annual forage yield, and alfalfa water requirement ranged from 189 to 457 g.m-2 with an average of 351 g.m-2, 693 to 3296 g.m-2 with an average of 1654 g.m-2, and 4093 to 16874 m3 ha-1 with an average of 10940 m3.ha-1, respectively. Overall, in the evaluation of observed versus simulated alfalfa forage yield, 31 points were obtained for single-cut yield with a correlation coefficient (r) of 0.79, root mean square error (RMSE) of 88.3 g.m-2, and coefficient of variation (CV) of 26.78%; and 21 points were obtained for annual yield with an r of 0.90, RMSE of 344.4 g.m-2, and CV of 20.05%. The evaluation results also showed that the observed versus simulated alfalfa water requirement had an r of 0.43, RMSE of 3503 m3 ha-1, and CV of 40%.

The results obtained from parameterization and evaluation of the SSM-iCrop2 model show that the mentioned model presents a logical prediction and accurate estimation of model parameters for yield and water requirement of alfalfa crops in Iran. Thus, this model may be used for the prediction of alfalfa yield under different climates and management conditions.

The global approach in agricultural production is to increase the quantitative and qualitative yield of plants through management methods such as the use of organic fertilizers and reducing the use of chemical fertilizers. This experiment was conducted as a split factorial arrangement with three replications in two folds in Bandarabbas during 2018 and 2019. The main factor included irrigation intervals at three levels (irrigation 80, 60, and 40% of field capacity) and the subfactor was different fertilizer sources at three levels (poultry manure, sheep manure, and chemical fertilizer based on the results of soil and plant test) and different species of Atriplex (A. canascens, A. leucoclada and A. lentiformis). The results showed that increasing drought stress increased ion and malondialdehyde leakage and decreased relative leaf water content and leaf chlorophyll content of Atriplex. In irrigation of 60 and 40% of field capacity, the use of poultry and sheep manures reduced ion and malondialdehyde leakage of leaves. At 40% of field capacity, plant height in poultry and sheep manures increased by 28% and 38% compared to chemical fertilizer. Also, in 40% of field capacity, biological yield in poultry and sheep manures compared to chemical fertilizer showed a 4 and 8% increase. Increasing the total phenol content in sheep manures compared to chemical fertilizer in irrigation was 40% of field capacity. Overall, the results showed that the use of organic fertilizers by improving physiological traits to some extent increased the resistance to drought stress. Also, in drought stress conditions, organic fertilizers were more effective than chemical fertilizers. In general, based on the findings of this research, it can be concluded that the use of organic fertilizers in order to provide all or part of the nutritional needs of Atriplex maintains the optimal yield of Atriplex plants under water stress conditions.

This research was aimed to evaluate seven perennial Astragalus species including Astragalus subsecondus, Astragalus lilacinus, Astragalus vegetus, Astragalus brachyodontus, Astragalus effusus, Astragalus cyclophyllon, Astragalus brevidens, with multiple accessions to select the best accession in Homand Absard Rangeland Research Station. After seedbed preparation, the accessions were cultivated with three replications on two rows (lines) of two-meter length with row spacing of 0.5 m for each accession and 0.75 m for different accessions. Forage production, canopy cover percentage, canopy cover diameter, height, seed yield, and the number of flowering stems were evaluated. Collected data were analyzed statistically in a completely randomized design. Analysis of variance and Duncan's Multiple Range Test were performed for mean comparisons. Results showed there was significant differences in terms of the measured traits and accessions. According to the results of forage production, canopy cover percentage and etc. species and accessions such as A. vegetus (Kordestan), A. brevidens (torogh and tandure) A. brachyodontus (zereshk) and A. effusus (dare shohada) are recommended for the improvement and development of rangelands and abandoned dry land farming with the same weather conditions of high rainfall of 300 mm, the average temperature of 11°C , poor in organic matter and medium to semi- heavy texture in Homand Absard station.

Intercropping is an example of a sustainable system in agriculture that has such purposes as creating ecological balance, higher utilization of resources, increase in the quantity and quality of the product and reducing pests, diseases and weeds (Koochaki and Zand, 1996). Persian clover (Trifolium resupinatum L.) is a plant native to Asia and Iran and contains both early (single cut) and late (multiple cut) ecotypes (Taylor, 1985). One new method in intercropping, namely the interspecies intercropping of different cultivars of Persian clover that causes an increase in the yield. However, little known about this method in the litreture (Prasad et al, 1990). The objective of this study was to investigate the effect of intercropping of early (single cut) and late (multiple cut) ecotypes Persian clover cultivars on quantitative and qualitative forage yield and determe the best seed rate and seed mix in the Karaj region
In order to evaluate the effect of interspecies intercropping with Persian clover cultivars on increased forage yield, an experiment was carried out at the Seed and Planting Improvement Institute as a factorial design (base on a randomized completely block design (RCBD) with two factors (mixed seed at 5 levels, including 0-100,100-0,50-50,40-60,and 60-40 and seed rate at 3 levels of 10,15 and 20 kg ha-1) over two years (2012-13).
The results of combined analysis of variance showed that the effect of year, seed rate and seed mix rate on the forage and dry matter yield and protein percentage, and the interaction of seed mixed × seed rate for just the protein percentage, were significant at 1% probability levels. Mean comparison of seed mixed × seed rate showed the highest forage and dry matter yield with 68.19 and 12.02 t ha-1 were obtained, respectively, from the treatment of 60% Persian clover (single harvest) and 40% multiple harvest Persian clover and seed rate 15 k ha-1. Also, the lowest forage and dry matter yields of 42.52 and 5.18 t ha-1 were obtained from the treatment of 100% multiple harvest Persian clover and the seed rate of 10 kg ha-1, respectively. The quality results showed that the highest crude protein at 24.77% was obtained from the treatment of 100% multiple cut harvest Persian clover and a seed rate of 10 kg ha-1. Evaluation of the land equivalent rate (LER) showed the highest evaluation efficiency at LER=2.85 was obtained from the treatment of 60% Persian clover (single cut) and 40% multiple cut harvest of Persian clover and a seed rate 10 kg ha-1, and for crude protein from the treatment of 40% Persian clover (single cut) and 60% multiple cut harvest Persian clover and a seed rate of 15 kg/ha with LER= 2.17, respectively.
The results of this study indicate that interspecies mixed cropping of early and lately cultivars of Persian clover resulted in inceased forage yield compared to pure cropping. Since early cultivars have high a growth rate and suitable water and soil resources for utilization and high biomass production, in intercropping with late cultivars resulted in increased forage production in time and place units. The highest forage of 68.19 and LER=2.68 for forage yield, 12.02 t ha-1 and LER=2.85 for dry matter yield were obtained from the treatment of 60% Persian clover single cut and 40% multiple cut Persian clover and a seed rate of15 k ha-1. This mixed cropping model could be an agro-ecological approach for high forage production in crop systems.

Because Iran is in an arid and semi-arid area¡ lack of water is considered as a serious crisis in the country; so using agronomic techniques such as irrigation¡ use of low quality water resources (brackish and saline) and the use of dry-friendly herbs and halophytic herbs is of great importance in agricultural production. Deficit irrigation is an optimal solution for agricultural production whereby the removal of excess irrigation and reduction in water use at every turn has no negative effect on net profit but increases water use efficiency (Sohrabi et al.¡ 2006). Currently¡ an alternative crop resistant to drought compared with conventional forage plants has been kochia whose rapid deployment in the soil¡ in addition to creating a short lived protective cover¡ can be used as an alternative forage especially in areas that are confronted with lack of forage production (Jami Ahmadi et al.¡ 2004). Kochia is a drought resistant annual plant and can be a valuable source of forage in ecosystems under drought conditions. Its rapid growth of kochia and drought resistance shows that this plant has a high potential for designation as an important forage crop in arid and semi-arid areas (Jami Ahmadi and Kafi¡ 2007).
In order to investigate the effect of plant density¡ height of harvest and consumption of nitrogen fertilizer on yield of dry matter and some agronomic traits of Kochia¡ an experiment was conducted in a factorial arrangement based on a randomized complete block design with three replications in spring and summer of 2011 in a research field at Neishabour city. The treatments consisted of plant density at three levels (20¡ 30 and 40 plants in 1 m2)¡ height of harvest at two levels (10 and 20 cm from level of soil) and nitrogen fertilizer at two levels (consumption of 150 kg ha-1 Urea after the first cutting and non consumption nitrogen fertilizer).
The results indicated that the effect of plant density was not significant on the leaf dry weight and the ratio of the leaf dry weight to stem in the first and second cutting¡ while its effect on the yield¡ stem dry weight and the leaf area index in the first and second cuttings was significant; also¡ by increasing the plant density¡ these traits increased significantly. The effect of the height of harvest on studied traits¡ also the consumption of Urea after the first cutting on the yield of dry matter¡ stem dry weight and the leaf area index in the second cutting was not significant¡ but its effect on leaf dry weight and the ratio of the leaf dry weight to stem in the second cutting was significant.
Generally¡ it seems that the plant density of 30 plants per m2¡ the height of harvest of 20 cm from level of soil and the consumption nitrogen fertilizer after harvest of the first cutting are effective factors to obtain desirable yield and quality in produced forage of Kochia.