جستجوی مقالات مرتبط با کلیدواژه "forage sorghum" در نشریات گروه "کشاورزی"

 The metabolizable energy represents a part of the gross energy of the feed, which after the deduction of the amount of feces and urine energy and the gases. One of the laboratory methods for determining the metabolizable energy of feedstuff is the gas method. This method is based on the measurement of the amount of released gas at the specified time. The estimated energy obtained from this method has a very high correlation with the amount of energy derived from the live animal method (in vivo). The direct determination of the energy available of feeds requires a great deal of time and cost, and since the available energy has a positive and high relationship with some of the chemical constituents of the feed, livestock nutritionists use fiber components such as NDF, ADF and lignin to estimate the available energy of feeds. Another approach is using equations to obtain the ADF for metabolizable energy of forages. It was reported that the amount of determination coefficient (R2) for estimating the metabolizable energy of forages from ADF levels was from 0.52 to 0.92. This study conducted to determine the nutritional value and introduce regression equations for estimating the available energy of some forage sorghum.

 Eighteen sorghum varieties planted in May 2016 at the research and educational farm in Karaj province of IRAN. Experimental varieties were harvested in September. Three samples of each sorghum forage cultivar, which planted in three separate rows, after crushing into 3 to 5 cm pieces, totaling about 54 samples, collected. Nutrient compositions including crude protein, crude ash, ADF, NDF, water-soluble carbohydrates, starch and lignin analyzed by AOAC official methods. The amount of crud ash determined by burning samples in an electric furnace and crude protein. To determine the concentration of ADL and to dissolve cellulose present in ADF, ADF samples placed in 72% sulfuric acid for three hours. The digestibility of the samples determined by gas test method. The amount of ME calculated using the volume of gas produced from fermentation of 200 mg of dry matter over a period of 24 hours. ME = 2/2 + 1357/0 (GP) + 0057/0 (XP) + 00002859/0 (XP) 2 , Where ME is the metabolizable energy (MJ per kg of dry matter), GP, the volume of produced gas (ML in 200 mg dry matter per 24 hours incubation) and XP, crude protein (g / kg dry matter). For fitting the equations for estimating metabolizable energy based on NDF, ADF and lignin, SPSS software used to fit the linear, quadratic and exponential equation, and selected the independent variable that had the best R2.

 The average dry matter of total 54 experimental samples is 19.54, and it is less than minimum required for high-grade silage (25%). The amount of sugar and starch are enough, which is an important part for the preparation of stable and quality silage. Determined metabolism energy was 2.40, which is higher than that announced by researchers, which could be the reason for the presence of BMR hybrids in this experiment. The mean of NDF, ADF, lignin and metabolizable energy of forage sorghum was determined to be 60.36, 31.16, 1.78 and 2.40, respectively. The whole equations obtained from NDF, ADF, lignin had an acceptable coefficient of determination, but the equations obtained from the ADF value, as an independent factor, have a higher coefficient of determination and the accuracy of the equations is moderate and acceptable. Among the equations, the linear equation derived from ADF suggested for estimating metabolizable energy due to the simplicity and approximation closer to actual ME of forage sorghum measured. Compared to the international linear equations, which ADF were independent factor, the Menke and Steingas metabolizable energy from ADF equations do not have any significant difference with the estimated ME of forage sorghum in this study.

 The results of chemical analysis and determination of ME of sorghum by gas test showed that the amount of ADF and ME of sorghum was 31.16% and 2.41 Mcal/kg of dry matter, respectively. The best correlation for estimating ME, which ADF was as independent factor, was the following proposed linear equation. ME (Mcal/Kg DM) = 3.320 - 0.029 (ADF %).

In order to investigate the role of mycorrhiza inoculation and Biochar application on the phosphorus availability, growth, and yield of sorghum and some chemical properties of soil, a pot experiment were conducted as a factorial experiment in completely randomized design, with three replications. In this research, application effects of biochar (0 and 1.5 % by weight), mycorrhiza (inoculation and non-inoculation of mycorrhiza fungi) and phosphorous (four levels of triple superphosphate: 0, 55, 110, and 165 mg .kg-1 soil) on sorghum were studied. The results showed that phosphorus and biochar application significantly (P<0.01) increased foliage and roots weights, roots volume, and also nitrogen, phosphorous and potassium uptake. Furthermore, the application of phosphorus in combination with biochar and inoculation of plant roots with mycorrhiza increased the above-mentioned traits to a higher level. Application of phosphorus or biochar alone increased soil salinity, but their combined application together with the plant root inoculation using mycorrhiza decreased it. Application of phosphorus decreased soil organic carbon, whereas biochar and mycorrhiza significantly increased it. The maximum dry foliage (24.4 g.pot-1) and the maximum phosphorous uptake (79.9 mg.pot-1) were obtained from combined application of mycorrhiza, biochae and 55 mg.kg-1 triple superphosphate. The results showed that biochar and or mycorrhiza application affect the amount of phosphorus consumed[H1] , but it should be noted that prolonged use of biochar could increase soil salinity.

The aim of this study was to investigate the concentration of Prussic acid and Nitrate as main anti-nutrients in 18 varieties of sorghum forages. The sorghum varieties include four domestic Iranian sorghums named: Pegah, Speed-feed, KFS-2 and KFS-18 and 14 imported varieties named: CSSH.1, FGCSI09, FS 1 BMR, JS BMR SSH.1, JS BMR SSH.2, S, T, PHFS-27, PFS-21, FGCSI10, FGCSI12, SP BMR, HFS1 and JS 2. All sorghum varieties were cultivated in the farm of Seed and Plant Improvement Institute. General condition such as irrigating, fertilizing, light and temperature were the same for all varieties. Samples were harvested at blooming stage and concentration of prussic acid and nitrate was determined. Statistical analysis was performed using one-way ANOVA. The highest concentration of prussic acid detected in FS 1 BMR (481 ppm) PHFS-27(408 ppm) and FGCSI10(381 ppm). and the highest concentration of nitrate was detected in JS 2 (2416ppm) and JS BMR SSH.1(2088 ppm). By comparing the concentrations of prussic acid and nitrate in these 18 varieties of forage sorghum with the tables of anti-nutrition hazard level, it was found that the concentration of anti-nutritional substances in all of these varieties was lower than the level of dangerous for livestock.

The research in order to identify the best function salinity of sorghum forage yield and harvest time was carried out in the Sistan region.Testing in three levels of salinity (2, 5 and 8 ds/m) and four levels of irrigation water (50, 75,100and 120% water requirement) were conducted at three time points and four linear production function, cob-douglas, quadratic and transcendental evaluated. for each harvest production function was evaluated separately.Then, considering the time of harvest, evaluated and the best function was determined. After determining the best function to separate effects of salinity and irrigation water from the final production indicators of the depth and salinity of water, Marginal rate of technical replacement for salinity and water irrigation , the final output value of the irrigation water depth and salinity were used in each drawing. Final manufacturing index showed the depth of irrigation water for irrigation to increase water depth of one centimeter per impression, first impression least change operation (1.22) and third harvest the maximum amount (2.9) had. Final Manufacturing Index showed to salinity Reduction in salinity low performance in the second and third were less than first impressions and is the second largest fresh forage yield The final replacement rate the quality and quantity of water than fresh forage yield of forage sorghum showed For the performance does not change with increasing salinity units, should be 5.86 inches in the first harvest, 1.97 and 1.72 second harvest third harvest irrigation water depth increases.

In order to study the effects of irrigation water (50, 75 and 100%) and potassium fertilizer (0, 50 and 100% required potassium fertilizer) on the dynamic of root, yield and shoots of sorghum varieties (Pegah (P), KSF2 (KS) and Speedfeed (S)), a research was conducted in the Agricultural and Natural Resources Research Center of Semnan Province (Shahrood) in 2014. In this study the factors were irrigation water (W), potassium fertilizers (K) and varieties (V) of forage sorghum. The experimental treatments were arranged based on split plot factorial design using a randomized complete block design with three replications. Irrigation water was calculated with Penman-Monteith method. Drip irrigation was used as irrigation system. Sampling was carried out from the roots in three phases during the season. The root volume was determined with immersion in water method. Shoots parameters such as leaf area, leaf dry weight, stem dry weight and shoot weight were measured. The results showed that the effects of irrigation water, potassium fertilizer and sorghum varieties on the forage of yield, volume and dry weight of roots and shoots plant were significant. The highest yield was obtained from the W100K100 treatment for Pegha variety. The maximum water use efficiency was obtained from the W75K100Vp treatment. The W75K100Vp treatment was identified as a superior treatment. The final production value of forage varieties were obtained 1920000, 3180000 and 3980000 rials for Speedfeed, KSF2 and Pegha, respectively.

To evaluate the drought tolerance in forage sorghum promising lines, a filed experiment was conducted as split plot arrangement using randomized complete block design (RCBD) with three replications at the Research Farm of Seed and Plant Improvement Institute, Karaj, Iran, in 2011 and 2012 growing seasons. Main plots consisted of three irrigation regimes (irrigation after 60, 120 and 180 mm evaporation from class-A Pan) and sub-plots included five forage sorghum promising lines (KFS2, KFS3, KFS12, KFS17 and KFS18). Combined analysis of variance showed that the effect of irrigation regimes on fresh and dry forage yield and plant height was significant (P ≤ 0.01). Under sever drought stress the highest forage yield was obtained from KFS3, KFS2 and KFS18 lines (112.3, 97.5 and 95.9 t.ha-1 respectively). Results revealed that stress tolerance index (STI), geometric mean productivity (GMP) and mean productivity (MP) indexes had significant positive correlations with forage yield under stress and non-stress conditions and were identified as suitable indices for screening of forage sorghum promising lines. The results of biplot analysis indicated that KFS3 line with the highest STI (1.18) had high forage yield potential and low susceptibility to drought stress. The results of multivariate biplot analysis and correlation of indices using forage yield data under stress and non-stress conditions showed that MP, GMP and STI were the suitable indices for predicting forage yield of sorghum promising lines and superior genotypes could be selected based on these indices. KFS3 promising line was identified as highly adpated forage sorghum genotype to drought stress condition.

In this study, to evaluate the seed vigor tests associated with the emergence and yield of forage sorghum, three separate experiments consisted of standard germination test and seed deterioration test in a completely randomized design with four replications in Islamic Azad University, Ahvaz and culture in the city of Shoushtar were conducted. 8 genotypes of forage sorghum in a randomized complete block design with three replications was conducted in 2014.Analysis of variance showed that there were significant differences between genotypes in all three experiments for all traits except seedling length in standard germination test. The results showed that seed deterioration test reduces seed germination percentage (39%), germination rate (38%), seedling length (11%) and fresh weight (40%) and dry weight (13%).In terms of percentage and rate of germination and emergence in three experiments, genotype KFS18 was superior genotype. The maximum of the dry forage yield of 9.5 tons per hectare belonged to genotypes KFS2 and KFS18. So it became clear that superior genotype was KFS18.The results showed that the correlations between the percentage of germination and emergence and biomass production in field experiments with standard germination test and seed deterioration test were significant. The seed deterioration test and standard germination test could predict emergence of sorghum in the field.

To determine the effects of plant density on quantitative and qualitative yield of five forage sorghum hybrids, an experiment was conducted at Agricultural Research Station of Anbarloum in 2010 and 2011. The experiment was in factorial based on RCBD with four replications. The first factor was five hybrids of forage sorghum and the second factor was plant density with three levels (167000, 208000 and 278000 plantha-1). The results of analysis of variance showed that the effects of plant density and hybrids were significant on all of assesse traits. Mean comparison of the traits showed that with decrease in plant density, number of tillers per plant and stem diameter were increased. The highest number of tiller plant (3 tillerplant-1) was obtained from 167000 plant per hectare. In all hybrids, with increase in plant density, dry forage and protein yield were increased and the highest dry forage yield and protein yield were obtained from Speed Feed and ICRISAT 625 × R165 hybrids. Speed Feed produced the highest dry forage (18.5tha-1) and protein yield (132.5 kgha-1) in treatment with 287000 plant per hectare. Based on the results of this experiment, Speed Feed and ICRISAT625×R165 hybrids with 208000 plantha-1 dencity can be recommended for sowing in this region.

Sorghum is a forage crop that produces high yield of dry matter. Forage sorghum is used for production of silage and dry folder. To evatuate forage yield potential of forage sorghum genotypes in different planting dates, this experiment was carried out in Shahrekord during 2013 and 2014. The experiment was arranged in split plot with three replications in that, main plots were three planting dates (26 may, 10 June and 25 June) and sub plots were four sorghum genotypes (cvs. Pegah and Spead Feed and lines KFS1 and KFS2). Forage yield and different traits were recorded during the growth period. The results indicated that fresh and dry fodder yields in two years were not significantly different. The highest fresh and dry fodder yields were obtained from the first planting date treatment (78.86 and 16.89 tha-1, repectively). The highest plant height and diameter of stem were also belonged to the fisrt planting date. The higest fresh and dry fodder yields were Produced by line KFS1 (73.08 and 16.30 tha-1, respectively) which were not significantly different from those of Pegah cv. (P ≤ 0.05). Significant difference was not observed for protein contents in different planting dates. The highest protein contents and lowest NDF and ADF were obtained from cv. Speed Feed. Generally, the results revealed that in three planting dates, sorghum genotypes could produce reliable forage yield, even that, the third planting dates produced less yield than other two planting dates.

In order to evaluate the most appropriate method of planting and harvest times of forage sorghum Speedfeed, Strip plot in the form of randomized complete block design experiment with three replications in 1394-1393 at the ResearchCenter for Agriculture and Natural Resources Balochistan is located in the city of Iranshahr. Two different methods of planting furrow cultivation, napa, row, and different harvesting times Different harvesting times of 50, 60 and 70 days after planting, respectively, in the main plots and sub-groups. Traits such as growth habit, leaf and shoot dry weight, nitrogen, and protein content was measured Fsfrvptasym. The results showed that the effect of different planting methods on fresh and dry weight, shoot dry weight was statistically significant, but no significant difference in the percentage of nitrogen, phosphorus, potassium and protein was observed. Harvest time is also significantly more weight and leaves, fresh weight and dry, nitrogen and protein impressed. According to test results, treatment, planting furrow, row, and 70 days after planting harvest time to increase the quality and quantity of forage sorghum recommended Speedfeed Iranshahr conditions.

In order to investigate the effect of nitrogen fertilizer, manure and integrate fertilizer on quantitative and qualitative yield of two forage sorghum cultivars (Pegha and Esphidfid) under Guilan climatological conditions a field study was conducted in 2010 cropping season at Rasht. Treatment consisted of four levels of nitrogen fertilizer (0, 46, 92 and 138 kg N.ha-1) and organic Farm Yard Manure (5, 10 and 15 ton.ha-1 FYM) and integrated N of chemical and biological (23 kg N.ha-1 2.5 ton.ha-1 farm yard manure (FYM), 46 kg N.ha-1 5 ton.ha-1 FYM and 69 kg N.ha-1 .5 ton.ha-1 FYM). A randomized complete block design with factorial arrangement in three replications was used. Traits included plant height, stem diameter, plant dry weight, forage yield, protein percent, dry matter digestibility and ash. Stem diameter, protein percent, dry matter digestibility, water soluble carbohydrates percentage, NDF, total ash effected by Nitrogen significanty, and maximum traits was obtained with 69 kg N.ha-1 7.5 ton.ha-1. Based on the results obtained from this study integrated treatment was best and Pagha cultivar with 69 kg N.ha-1 7.5 ton.ha-1 suggested in Rasht reign conditions.

Prediction of germination time is one of the main goals of seed researchers. Therefore in order to evaluation the cardinal temperatures and the investigation response of promising forage sorghum lines to temperature, this experiment was conducted as factorial in a completely randomized design with three replications, 15 forage sorghum lines and nine fixed temperatures 10, 15, 20, 25, 30, 35, 40, 45 and 50˚C at Seed Technology Laboratory of Islamic Azad University Shoushtar Branch in 2013. Results of analysis of variance showed that investigated germination components for factor line, temperature and interaction line × temperature were significant. The maximum germination percent-age in temperatures 20, 25 and 30˚C and the most speed rate, uniformity of germination and the minimum duration time till 95 percent the maximum germination (D95) in temperature 40˚C was obtained. With temperature drop from 40˚C, germination speed rate and D95 gradually decreased and increased, respectively. The base temperature (Tb) of forage sorghum lines from 9.36˚C (KFS11) to 14.28˚C (KFS2), optimum temperature (To) from 23˚C (KFS2) to 37.2˚C (KFS11) and maximum temperature (Tc) from 40.7˚C (KFS2) to 49.76˚C (KFS15) varied. Cluster analysis with ward’s method in the basis 7 studied traits led to three clusters formation. Third cluster included the lines KSF6, KSF7, KSF9 and KSF10 with the maximum percentage, rate and uniformity of germination and the minimum D95 jointly in temperatures 25˚C, 30˚C, 35˚C and partially 40˚C therefore these lines are recommended for supplementary researches.

The objectives of this study were to analyze genotype by environment(GE) interactions on the forage yield of 15 sorghum lines by the additive main effects and multiplicative interaction(AMMI) model and to evaluate genotype(G), environment(E) and GE interactions using stability parameter i.e., AMMI stability value(ASV) and Wrick, s ecovalance (W2 i). The trials were conducted at two research station(Neyshabur and Torogh Mashhad) for three successive years2007-2009(). The result’s of AMMI analysis for forage yield indicated that the Genotype main effects, environment, and GE interactions as well as two first interaction principal components (IPCA1-2) were significant. AMMI biplot was able to distinguish stable genotypes and environments with high and low genotype discrimination ability. The genotypes 5 and 15 with higher mean yield than total mean were to be most stable genotypes, while the genotype 1 and 3 with the highest contribution to GE interaction, were to be the most instable. The result of recommended genotypes based on AMMI analysis showed that the genotypes 1 and 3 were highly adapted to Neyshabur and genotypes 5 and 15 were adapted to Mashhad environments during this study.

Nowadays, implementation of simple and efficient methods for determining nitrogen needs has been considered in various plants. The simplest and most efficient methods for appreciate nitrogen requirement determination is leaf color chart (LCC). To determine of nitrogen fertilizer requirement in forage sorghum using leaf color chart, an experiment was conducted as factorial arrangement based on complete randomized block design with three replications at Agriculture and Natural Resources Research Station of Sabzevar in 2012 growing season. The factors were nitrogen rate in four levels including conventional (150), 25, 50, and 75 kg.ha-1 N and LCC scores was less than 4 and 5. The highest plant height, leaf dry weight, number of leaves per plant, biological yield and protein percentage were obtained in 75 and 50 kg.ha-1 nitrogen application. Using different amounts of nitrogen with reduction of LCC to 5 led to higher plants, more leaf dry weight, leaf numbers per plant, biological yield and protein content than using nitrogen with reduction of LCC to 4. On the whole, 50 kg.ha1 nitrogen with reduction of LCC to 5 was the best treatment for the highest quantity and quality yield achievement for forage sorghum. Also, LCC can be applied easily to determine sorghum nitrogen equipment.

In order to study different characteristics، 10 new varieties of forage sorghum in two cutting in a split plot in time، based on a randomized complete block design in four replications، were tested in Karaj. All of the varieties are pure line variety; including: KFS1، KFS2، KFS3، KFS6، KFS8، KFS9، KFS12، KFS15، KFS17 and KFS18. Important factors such as the number of leaves، plant height، stem diameter، were recorded each timely. Combined analysis of variance showed significant differences between varieties (except tiller number)، cuttings and variety * cutting interactions (Only plant height) for all study traits at 1% level probability. The highest and lowest leaf area mean were produced from KFS6 and KFS18 with 512/84 and 353/25cm2. The highest stem diameter obtained from KFS3 with 1/ 75 cm and the lowest with 1/53 cm from KFS12. The highest and lowest number of tillers، belonged to KFS3 with 3/19 and KFS1 with 2/28 respectively. The highest and lowest of leaves obtained from KFS2 and KFS15 with 14/56 and 11/75 respectively. The highest total dry matter yield varieties KFS18، KFS1، KFS3 respectively 66/21، 24/20، 16/18 tons per hectare produced. KFS6 lowest Dry forage yield variety with 70/13 ha in total، two cutting produced.

In this study, three cultivars (named varieties include a new line and 2) the names of forage sorghum Speedfeed, MFS1 and MFS2 using statistical design randomized complete block basis to determine the most appropriate in terms of yield and compatibility with climatic conditions of North Khorassan (Bojnourd), three replicates were analyzed Garmkhan region. Consumer characteristics included yield more dry matter, plant height, tiller number, leaf chlorophyll content, leaf area index (the most important indicators of growth), leaf and stem dry weight at different times and China were measured and harvesting operation unit area were performed. The aim of the plan to identify the best and most efficient forage sorghum varieties (as one of the first indicators of forage plants) in the arid and semi arid areas, consider the limitations of water resources and forage production is. Based on the estimated variance analysis showed that all these indices affected by genotype, at least at the 5 percent level were significant. The highest yield of dry forage varieties Speed feed, respectively 17, 800 and 3782 values of g m was obtained. Considering the significant positive correlation between growth traits and performance among cultivars was there, so cultivars Speedfeed significant superiority compared to two other lines that nearly had similar characteristics, there. According to the results of late varieties in cultivation Speedfeed region being due to fast growing and having more Speedfeed is recommended.

In order to study the effects of weeding and plant density on forage yield of two sorghum cultivars، an experiment was conducted in 2011 at Bahonar University of Kerman Research field station. The experiment was designed as a randomized complete block with a factorial-split treatment arrangement and with three replications. Treatments were included four levels of weeding (whole season wedding، whole season interference، twice and three times weeding) and three levels of sorghum density (20، 25 and 30 plants per m2) and two forage sorghum cultivars (Pegah and Speedfeed). The results showed that the competition of weeds with forage sorghum significantly influenced all of the measured parameters. The maximum reduction in yield was observed in weed-infested treatment (full season competition). Increasing in plant density led to the reduction of stem diameter، and increased plant height. The highest fresh fodder، dry matter and leaf to stem ratio was obtained in the density of 30 plant per m2. The maximum dry matter of 6. 352 ton per hectare was obtained in Speedfeed which was a superior hybrid over Pegah cultivar. Increasing plant density enhanced yield and yield components and competition power of crop plant which led to decreased weed dry matter production.

In this study 34 forage sorghum pure line varieties which improved in sorghum breeding program in Iran, were conducted to determine of the most suitable variety, on a randomized complete block design (RCBD) in three replications at Karaj, in 2005. Ammonium phosphate on the base of P2O5 was applied at 115 Kg/ha. and total nitrogen was used 183 Kg/ha. at four times. Four traits including green fodder, dry matter, plant height and tiller number were measured in each cutting. Harvesting was conducted from 8.4 m2 area. Data were analyzed in split plot on time based on RCBD and the means comparised with Duncan multi rang test (DMRT) method, analysis of variance showed significant differences between cuttings, varieties and cutting * variety interaction at 1% of probability. Comparison of the means by DMRT showed that KFS3 and KFS6 were produced the highest and lowest green fodder with 179.56 and 83.54 t/ha. respectively. In aspect of dry matter KFS18 and KFS6 were produced the highest and lowest dry matter with 39.84 and 20.02 t/ha. Respectively. The 84/1384 produced the highest plant height, 271.7 cm and KFS14 the lowest plant height, 129.7 cm at second cutting. 144/1384 was produced the highest tiller number per plant with 6.33 tiller at second cutting and KFS14 was produced the lowest tiller number with 1.00 tiller at first cutting. According to all traits especially main traits to forage production, totally 15 varieties were chosen for investigation of regional adaptation of new forage sorghum varieties at different conditions.

In order to investigate effect of nitrogen fertilizer on yield and quality of three forage sorghum cultivars under Guilan climatological conditions a field study was conducted in 2010 cropping season at Rasht. A randomized complete block design with factorial arrangement with three replications was used. Treatment consisted of four levels of nitrogen fertilizer (0, 50, 100 and 150 kg N ha-1 from urea source) along with three sorghum cultivars (Pagha, Esphidfid, KSF2). Plant characteristics measured were forage yield of dry and forage yield, Stem dry weight, leaf dry weight, Plant height, stem diameter, Crude protein, Dry matter digestibility, Total ash and Acid detergent fiber were calculated. The result showed that nitrogen fertilizer had significant effects on forage yield and quality traits also cultivars had significant effects on forage yield, protein percentage, total dry matter, and Acid detergent fiber (ADF). Maximum forage yield (dry and fresh weight) in sorghum was obtained with 150 kg N ha-1 and KSF2 cultivar. Based on the results obtained from this study in order to increasing forage yield, dry matter percentage and minimum ADF was obtained in KSF2 cultivar should be applied with 100 kg N ha-1 in condition Rasht reign and If our objective is forage quality, was suggested Pagha cultivar with 150 kg N ha-1 in Rasht reign conditions.

In order to study the effect of plant density and nitrogen fertilizer different rates on sorghum forage yield, an experiment was conducted in Agricultural Research Farm of Bojnourd region, Iran on Summer 2010. Experiment was carried out in split plot factorial based on Randomized Complete Blocks Design with 4 replications. Sorghum cultivars included speed feed and MFS1 cultivars in main plots and sub plots were combination of plant density 25, 30 and 35 plant/m2 and nitrogen application rate of Urea source included three levels 0, 100 and 200 kg N /ha. The result of analysis of variance showed that an increase in plant density on the surface unit leads to the reduction tillers. But it could increase plant height and LAI. The highest fresh and dry forage yield obtained in 350000 plants per hectare. Also results showed that nitrogen rate affected all the quantity traits si gnificantly except tiller number per plant, and plant height, in such a manner increased N use from 0 to 200 Kg N /ha increased 9, 12.96 percent in speed feed cultivar and in MFS1 line 10.91, 15.07 of fresh and dry forage yield respectively. The maximum fresh and dry forage yield obtained in speed feed cultivar. Finally it could be stated, maximum fresh forage (82.93 ton/ha) and dry matter yield (14.38 ton/ha) were obtained using 200 Kg N/ha and in density of 350000 plant/ha for speed feed early maturing cultivar.