Showing 57 results for Corn
A. H. Ghanei, A. R. Hosseinpur,
Volume 8, Issue 1 (4-2004)
Abstract
Iron oxide-coated strips (Pi) can serve as a sink to continuously remove P from solution. In this way, probably, P extraction is analogous to P absorption by plant root. The objective of this study was to evaluate the iron oxide-coated paper strips to estimate the availability of soil P of corn (Zea mays) grown under greenhouse conditions in some soils of Hamadan Province. Sixteen soil samples with different physico-chemical properties were examined for available P by Olsen, Colwell, Mehlich1, 0.01 M CaCl2, AB-DTPA, 0.1 M HCl methods and two (Pi1, Pi2) Pi methods. Furthermore, the effects of two P levels ( 0 and 250 mg P Kg-1 soil) on the plant responses (P uptake, P concentration, and relative yield) were studied in the greenhouse experiment using 12 soil samples. The results showed that the amount of extractable P decreased in the order: 0.01 M Cacl2 < Pi2 < AB-DTPA < Pi1 < Olsen
Pourreza, M.r. Ebadi,
Volume 9, Issue 4 (1-2006)
Abstract
In a completely randomized design with 3×5 factorial arrangement, the metabolizable energy and nutrients digestibility of three varieties of sorghum grains (low, medium and high tannin) with and without supplemental phytase were determined and was compared with corn and wheat. Three varieties of sorghum were selected from the 36 varieties according to their tannin content and were grown togther with corn and wheat under the same environmental conditions. Supplemental phytase was added at three levels (0.0, 500 and 1000 FTU/kg) to each grain. The metabolizable energy (ME) and nutrients digestibilities were determined by the mature male Leghorn with the method of Sibbald. The results indicated that different grains had different ME, apparent and true digestibilities regarding dry matter, nitrogen and phosphorus. Medium tannin sorghum had the highest apparent and true metabolizable (AME and TME) energy, whereas the high tannin sorghum showed the lowest AME and TME. The apparent and true dry matter digestibilities of corn was more than the other grains (P<0.001). Medium tannin sorghum had the highest apparent and true nitrogen digestibilies than the other two varieties (P<0.001). Difference between tested grains regarding apparent and true phosphorus digestibilities were not significant. All measured criteria were the lowest for the high tannin sorghum. Adding 500 FTU/Kg phytase caused an improvement (P<0.001) in AME, apparent and true dry matter digestibilities and true nitrogen digestibility. Although added phytase improved apparent and true phosphorus digestibilities and true nitrogen digestibility, but the differences were not significant. The differences between 500 and 1000 units phytase was not significant and the results indicated that 500 FTU/Kg phytase was sufficient to improve the nutritional value of grains under study.
M. Soleimani, M. Shahedi,
Volume 10, Issue 2 (7-2006)
Abstract
Isotherm curves are useful for the designing of dryer as well as controling of the seed moisture content during storage and drying process. To study the curves, this research was performed on the basis of two factorial experiments including three factors: (1) hybrid at two levels (Three Way Cross 647 and Single Cross 704) (2) temperature at 6 levels (from 5 to 55°C) and (3) Relative Humidity (RH) at 5 levels (from 10 to 90 percent) for the analysis of the adsorption and desorption phenomena. For maintaining RH at the above mentioned ranges, glycerol solutions with different concentrations were used. The results showed that the relationship between solutions concentration and their RH was non-linear and somewhat related to temperature. Also, statistical analysis displayed that for 3 factors of tepmerature , RH and hybrid, the effects on Equilibrium Moisture Content (EMC) in both adsorption and desorption phenomena were significant at α=1%. Comparisons of means showed that hybrid 704 had higher EMC values than did hybrid 647 under the same conditions, in other words, hybrid 704 produced lower aw than did hybrid 647 at the same moisture content. Fitting experimental values on non-linear models (Henderson, Chung-Pfost and Oswin) showed Oswin as the best model for adsorption and desorption curves for hybrid 704 and also for adsorption curve for hybrid 647 , but the best model for desorption curve for hybrid 647 was Chung-Pfost.
M. A. Nazari, H. Shariatmadari, M. Afyuni, M. Mobli, Sh. Rahili,
Volume 10, Issue 3 (10-2006)
Abstract
Sewage sludge and effluents, as cheap sources of irrigation water and fertilizer, can supply plants with water and nutrients however, contamination of these sources with heavy metals and the possibility of human food chain contamination using these sources should be considered. In this research, the effects of industrial sewage sludge and effluents on concentration of some nurtients, heavy metals and sodium and dry matter yield of wheat (Triticum aestivum), barley (Hordeum vulgare) and corn (Zea mays) were investigated. The experiment was carried out in a greenhouse using a complete randomized design with four replication. The treatments comprised well water, well water + sewage sludge(50 tons/ha), and three industrial effluents from Iran Polyacryl factory including the cooling tower, the over flow and the factory outlet effluents. Chemical analysis showed the following results: The concentration of the elements in the sludge and the effluents were below the critical contaminating levels. The application of the treatments did not supply enough nitrogen for corn the cooling tower effluent could not supply enough nitrogen for wheat and barley all the treatments supplied enough P for wheat. None of the treatments could supply enough P for corn. The cooling tower, over flow and the factory outlet effluents could not supply enough P for barley, the micronutrient and heavy metal concentrations in the plant tissues using the effluents and the sewage sludge were higher than those for well water the dry matter yield of plants’roots and shoots was highest using well water + sludge and in comparison with the well water, effluents could increase the shoot dry matter yield.
R. Karimizadeh, H. Dehghani, Z. Dehghanpour,
Volume 10, Issue 3 (10-2006)
Abstract
To facilitate the interpretation of data from a genotype by environment experiment (GE), a cluster method is proposed to group genotypics according to their response to the environments especially when the GE interaction is large. The interaction structure of two-way classification data often can be identified if the data stratified into homogeneous subsets. In this paper four GE interaction cluster methods are proposed for this purpose. The stability of the 10 maize hybrids including 9 hybrids that were the best hybrids in yield trials and KSC 301 (check hybrid) were evaluated for 2 years in 4 locations of Iran. The randomized complete block design with 4 replications was conducted for each environment with different layouts. Simple analysis of variance revealed significant genetic differences between hybrids for grain yield. The results of combined analysis of variance indicated that genotype × year, genotype × location, and genotype × year × location interaction effects were significant (P < 0.01). Results also showed that models 1 and 3 and models 2 and 4 had the same responses. Hybrids 8 (K1263/1 × KE8212/12) with high yield stability in both models 1 and 3 were in one group and other hybrids were in another group. In models 2 and 4 results led to 3 groups: Group1 included hybrids 3, 7 and 9 that were very stable and had high yield group 2 included hybrid 1 alone that had medium stability and yield and group 3 included other hybrids that had low stability and yield.
Gh. Riazi,
Volume 11, Issue 1 (4-2007)
Abstract
Isolating and cloning of plant protease inhibitor (PIs) genes and transforming them to the genome of other plants have paved the way for producing resistant transgenic plants against pests. Knowing that cystatins act as inhibitor factor against cysteine protease, short and long cystatin genes were isolated from maize mRNA. By using specific primers, cDNA of these genes were constructed and cloned in pUC19 and pGEX 2T plasmid vectors. The recombinant plasmid vectors were then transformed to E. coli (strain DH5 α) competent cells using electroporation. The competent cells harboring the clones were grown in suitable medium and cystatin proteins fused to Glutation-S-transferase (GST) were purified by glutation agarose bead filter. In each step of the procedure the presence of cystatin genes were confirmed through electrophoresis. Further evaluation proved the inhibitory effect and a mild stability of at least one of the corn cystatin (CC II) when incubated with cysteine protease.
P. Sharifi, M. Tajbakhsh,
Volume 11, Issue 41 (10-2007)
Abstract
To evaluate the effect of plant density and detopping on grain yield, protein content biological yield harvest index, growth indices, number of cob in each plant, No. of row per ear, No. of grain in each row, thousand seed weight of corn (Zea mays L. ar. SC 704), an experiment was conducted at the experimental statues of Research Center of Uremia Agricultural College in 2004. The Treatment design was split plot in randomized complete block design with four replications. The main plots included plant density at three levels (53000, 66000, and 88000 Plants/ha) and the subplets comprised three levels: (1) no detopping (control) (2) removing canopy only and (3) removing canopy and three leaves above the node. Analysis of Variance of data showed that both detopping treatment and plant density influenced the number of kernel per ear ,1000 grain weight, ear weight, total dry weight of biomass, seed yield and harvest index. Canopy detopping led to a marked increase in photo assimilateion import grains. The highest plant density evaluated, 88000 plants per hectare with detopping of three above leaves had the highest number of cobs per square meter. In plant density of 53000 plants per hectare and canopy detopping treatment, the number of grain per ear was greater than other densities. The efficiency of harvest index increased under corn detopping compared with control, and this increase with an increase in photosynthesis contributed to grain yield. It was concluded that major increase in grain yield under high plants density and tassel detopping was due to improvement of physiological indices.
E. Dehghan, A. Naderi,
Volume 11, Issue 41 (10-2007)
Abstract
This study included two experiments conducted in 2000-2001 for surveying the effects of saline water irrigation on yield and yield components in corn varieties. Experiments were conducted in a silty-clay soil in Ahwaz Agricultural Research Center. First experiment was conducted as a split plots and randomized complete blocks design in three replications. Main plots included salinity levels 2, 4, 6 and 8dS/m and subplots included three single cross hybrids of corn 704, 711 and 647. In the other experiment the effects of saline water 8dS/m at different growth stages including the stage of planting to plant establishment. (G1), flowering and pollination (G2) and grain filling (G3), were evaluated. The results of the first expriment showed that there was very significant difference among water salinity levels for yield, thousand kernel weight, percentage of corn fertility and percentage of plants containing corn. The highest and lowest grain yield were obtained for salinity levels 2 and 8dS/m treatments respectively. Differences among varieties and interaction of treatments were significant for grain yield, and highest grain yeild was obtained for 704 and 711 varieties on saline water 2dS/m. The results of the other expriment showed that highest and lowest tolerance to irrigation with saline water on corn were G3 and G1 growth stages respectively. Consequently, hybrids 704 and 711 were more sensitive than the 647, but the obtained yield, suggests that 704 and 711 hybrids can be cultivated under these conditions.
A. Jalalian, M. Rostaminia, S.h. Ayoubi, A.m. Amini,
Volume 11, Issue 42 (1-2008)
Abstract
Extension of cultivation areas becomes gradually impossible due to ever-increasing population growth and urban area development in Iran. Therefore, it is very important to use the existing cultivated lands more efficiently. Land suitability evaluation makes the sustainable use of the lands feasible. The objective of this study was qualitative, quantitative and economic suitability evaluation of irrigated croplands for wheat, maize and sesame in Mehran plain, Ilam Province. Soil survey in the field, laboratory analysis of the soil samples, qualitative, quantitative and economic evaluation were different successive stages of this research. In qualitative evaluation, climatic, topographic and soil suitability classes were determined according to the degree of the matching with plant requirements, by parametric (square root) method. Quantitative and economic evaluations were done based on observed, potential and marginal yield analysis. Results of the qualitative land evaluation showed that most of the land units were classified moderately suitable for given crops because of soil limitations. Qualitatively, most of the land units were classified in the same classes as, or in lower classes than quantitative suitability classes for wheat and maize production, due to high management level at the farms. Whereas quantitative classes of sesame were determined lower than qualitative classes induced by low management level for this crop. Economic land suitability classification showed that the wheat production was the most economic land utilization type. Results of the economic assessment suggested that the cultivation of wheat in rotation with sesame would produce the most income for different units and could be increased in future using improvement in management level in the study area for sesame cultivation.
F.s. Biabanaki, A.r. Hosseinpur,
Volume 11, Issue 42 (1-2008)
Abstract
Phosphorus (P) after nitrogen limits agricultural production in most region of the world. Information about P release rate is limited in Hamadan soils. The objective of this research was to study P release in 10 soils from Hamadan province by successive extraction with 0.5 M NaHCO over a period of 1752 h and the correlation of P release characteristics with soil properties and corn plant (Zea mays) indices. The results showed that soil P release began with a fast initial reaction, followed by a slow secondary reaction until 1752 h. The amounts of soil P released after 1752 h ranged from 309 to 586 mg kg-1. The cumulative P release was evaluated by six kinetics equations. Statistical analysis showed that phosphorus release kinetics were described by parabolic diffusion law, first order and power function equations. The correlation study indicated that soil P release coefficients such as rate constant of first order, parabolic diffusion law, power function equations, P released after 168 and 1752 h were significantly correlated with some soil properties such as Olsen-P, calcium carbonate equivalent, sand and silt. The correlation studies between plant indices and constants of kinetics equation showed that rate constant of first order equation was not significantly correlated with plant indices. Equation constants of parabolic diffusion law, power function and P release after 1752 h were significantly correlated with plant indices. The results of this research indicated that release rate of P is different in soils and is an important factor in supplying available P to plants.
A. R. Melali, H. Shariatmadari,
Volume 11, Issue 42 (1-2008)
Abstract
Application of slag and converter sludge, major by-products of Esfahan Zob Ahan factory, to enrich two organic amendments for corn nutrition, was investigated. Farm manure and its vermicompost mixed with different rates of slag and sludge were incubated in 3 Kg pots at field capacity moisture and home temperature for three months. The applied rates of slag and sludge were 0, 5 and 10 percent (w/w) of pure iron from these compounds to the organic amendments. Iron sulfate with the above ratios was also examined for comparison. Sub-samples of the incubated materials were taken after 0, 10, 25, 45, 65 and 90 days of incubation and examined for DTPA extractable Fe, Mn, Zn and Cu. After the incubation, the enriched amendments were applied to a soil sample to grow corn. Three Kg soil samples, taken from Chah Anari experimental farm, Esfahan University of Technology, were mixed with 17 gr of the amendments (50 ton/ha) placed in 3 Kg pots. In each pot two corn seeds (single cross 704) were planted and after 70 days crop yield and concentration of Fe, Mn, Zn, Cu in the plant tissues were determined. Results showed that the use of iron sulfate strongly increased DTPA extractable Fe and Mn of the amendments. In enrichment by converter sludge, the best result was obtained in the mixture of 10 percent pure iron with the vermicompost on 60 days of incubation. Treatment of 5 percent pure iron from slag mixed with the manure increased DTPA extractable Fe and Mn with the time, but the 10 percent treatment was not much effective in this regard. The highest rates of iron uptake by the plants occurred in the iron sulfate and 10 percent converter sludge treatments, respectively however, the highest rate of the plant Mn uptake was observed in 5 percent iron from converter sludge mixed with vermicompost. In general, 10 percent pure iron from converter sludge was the most effective enrichment treatment, increasing the plant uptake of Fe, Mn, Zn and Cu micronutrients.
A. Moalemi Ore , S.h. Karparvarfard,
Volume 11, Issue 42 (1-2008)
Abstract
This study was undertaken to investigate the effects of soil compaction due to wheel traffic on corn growth and yield, in summer 2004 and 2005 at the Badjgah Research Station, Shiraz University located in North West of Shiraz, Iran. The treatments consisted of axial load in two levels and wheel traffic location treatments at four levels, including none, between rows, on rows and on entire plot area. The corn growth rate, root density and yield were not significantly influenced by axial load, but they were significantly affected by wheel traffic in all plots. Corn yield with wheel traffic on entire plot area averaged 3.97 Mg/ha which was significantly lower than the yields with the other treatments which averaged 6.65 Mg/ha with no traffic.
M. A. Ebrahimizade, A. M. Hassanli ,
Volume 12, Issue 44 (7-2008)
Abstract
Root depth is one of the main parameters affecting soil moisture availability held within the plant root zone. This study was conducted to evaluate the trend of corn root development during the growing season in different irrigation methods with two water qualities, and distribution of roots in soil profile. The experiment was a split plot design with three main treatments (subsurface drip(SSD), surface drip(SD) and furrow irrigation(FI)) and two sub main treatments (municipal effluent and fresh water) in two consecutive years conducted in Korbal plain, Fars province. Root monitoring was carried out with the observation of soil profile root depth measurement. Samples were taken during the growing season 16 times, each with a 7 day interval. Measurement of root weight in different soil layers was carried out using monoliths of soil washed with water pressure using 50 mesh sieves. Although the longest roots were observed in plots irrigated with SSD and the shortest in FI, the final root length was not significantly affected by irrigation methods and water qualities. In this research, a model showing the trend of root length average growth was developed and tested in the experiment conditions. The average final main root depth for all treatments was 77 cm. Irrigation volume using root depth monitoring could be reduced compared to linear model, Borg & Grimes and CROPWAT model for root depth estimation. Irrigation water on the base of soil moisture deficit within the root zone in each irrigation event could be reduced when the real root depth is considered compared with the conventional general models giving a final root depth. Results showed the total dry root weight in SSD was more than that in SD and FI methods. However, water quality did not show a significant effect on dry root weight. The most root concentration in SSD was measured in depth of 20-40 cm, while in SD and FI the most concentration was in surface layer (0-20 cm). In the SSD, the roots were distributed more evenly compared with SD and FI methods. The concentration of roots in all treatments below 65 cm was not significant.
M. Majidian, A. Ghalavand, N. Karimian, A. A. Kamgar Haghighi,
Volume 12, Issue 45 (10-2008)
Abstract
In order to investigate the effects of moisture stress, nitrogen fertilizer, manure and integrated nitrogen and manure fertilizer on yield, yield components and water use efficiency of SC 704 corn (late maturing, non-prolific and dent). In 2005, a field study was conducted in agricultural experiment station of the college of agriculture, Tarbiat Modares University. The type of design was randomized complete block with factorial arrangement and three replications. For the study, four levels of nitrogen fertilizer (0, 92, 184 and 276 kg N ha-1), integrated fertilizer (46 kg N ha-1 + 2/5 ton ha-1 FYM, 92 kg N ha-1 + 5 ton ha-1 FYM and 138 kg N ha-1 +7/5 ton ha-1 FYM ) and organic Farm Yard Manure (5, 10 and 15 ton ha-1 FYM ) along with three levels of irrigation (optimum irrigation (control), water stress 75% optimum irrigation and water stress 50% optimum irrigation) were used as treatments. The results showed maximum seed yield was produced with 92 kg N ha-1 + 5 ton ha-1 FYM and average of seed yield was 7976 kg ha-1. Maximum corn seed yield resulted when optimum irrigation water was applied and average seed yield was 7041 kg ha-1. When water stress was imposed in 50% and 75% of optimum irrigation, seed yield was decreased by 33 and 12%, respectively. The best seed yield was obtained with interaction of 5 ton ha-1 FYM and optimum irrigation. Also, maximum water use efficiency was obtained in using 50% of optimum irrigation. Maximum water use efficiency was obtained with interaction of 92 kg N ha-1 + 5 ton ha-1 FYM and imposition of water stress in 50% optimum irrigation. Results showed that adequate nitrogen fertilizer slightly increased corn seed yield under stress, and integrated (nitrogen and manure) fertilizer increased corn seed yield under stress. But seed yield greatly increased with optimum irrigation. Integrated fertilizer application increased seed yield even with severe moisture stress. Application of integrated chemical fertilizers and manure produced better seed yield and also decreased the amount of chemical fertilizers and improved soil physical and chemical characteristics.
A Masjedi, A Shokohfar, M Alavi Fazel,
Volume 12, Issue 46 (1-2009)
Abstract
The increasing cultivation of corn in Ahwaz and the direct relation between the increase of the summer corn yield and its perfect irrigation in sowing period all together have made the research regarding this crop necessary. Deciding over the suitable irrigation scheduling of corn (hybrid SC.704) in summer by utilization of class A evaporation pan is the focal point of this research. Accordingly, a project was conducted in the form of stadistical perfect accidendal block in four repetitions and four treatments in 1383 on Ahwaz Azad university research land situated in Choneibeh. The irrigation treatment had four levels of T1,T2,T3 and T4 in class A evaporation pan containing of four levels of 50,75,100 and 150 mm, carried out in split plot. The suitable irrigation period was chosen according to the best treatment performance and its components, and the total amount of water in the taking period defines the depth of irrigation. The soil texture is clay lomy silty and the internal soil is silty clay. According to the amount of the accumulated evaporation from class A evaporation pan and taking the plant coefficient (Kc) into consideration, the amount of needed evapotrans piration was calculated and the amount of needed water for plot was measured by water counter. Then a comparison between the means by the use of Donken multi domains test was made and in this way the superior treatment was selected. Accordingly, the most suitable time for irrigation of summer corn in Ahwaz was after 50 mm of accumulated evaporation from class A evaporation pan which equals ten irrigation in the growing period. So in order to acquire 12 tons of seed yield in each hectare, at least 9600 m^3 of water for every hectar is needed. However, given the equal amount of water, with 3 times decrease in irrigation in treatment T2 in comparison with T1, a performance near 11 tons and with five times decrease in irrigation and ten tons in treatment T3 a performance near 10 tons can be attained.
M Gorji, H Eshghizadeh, A Khosh Goftarmanesh, A Ashrafi, A Moalem, N Poursakhi, N Pourghasemian, A Miladi,
Volume 12, Issue 46 (1-2009)
Abstract
Iron deficiency is a worldwide nutritional constraint in agricultural lands especially in calcareous soils. Cultivation of crops tolerant to Fe-deficiency is an approach to combat Fe deficiency. The aim of this investigation was to evaluate Fe-efficiency of selected important crops in Iran. A completely randomized block design in triplicates was conducted at IUT research greenhouse in fall 2006. Sweet corn (Hybrid K.S.C. 404), grain corn (Hybrid S.C. 500), safflower (cvs. S3110, S-411), sunflower (Hybrid Hyson) and durum wheat (cv. Shuga) were grown in a nutrient solution at two Fe levels (1 and 10 µM Fe-EDTA). The results showed significant (P < 0.01) variation among the studied crops in Fe-efficiency. Corn hybrids were more sensitive to Fe deficiency (FeE = 26%) as compared to other studied crops, and the greatest reduction was observed in their shoot dry matter at 0.1 mM Fe- EDTA treatment. In contrast, the lowest decrease in root and shoot dry matter weight under Fe-deficient condition was found for durum wheat (FeE=94%). Comparing the calculated Fe-efficiency using different indices showed that Fe concentration and content in the whole plant, shoot and root had no relationship with crop tolerance to Fe deficiency.
H Shariatmadari, Y Rezainejad, A Abdi, A Mahmoudabadi, M Karami,
Volume 12, Issue 46 (1-2009)
Abstract
Many researchers have reported positive effects of converter sludge and slag, two by-products in Isfahan iron melting factory. In this work, the optimum rate of application and the availability of some essential elements (for plant growth) in the converter sludge and slag for corn were investigated. The converter sludge contains about 64% Fe ІІ and ІІІ oxides and some other essential elements for plant growth. The slag also contains 17% iron oxides, 52.8% calcium oxide as well as considerable amounts of some other elements. Treatments included a control, Fe-EDTA foliar spray with 5 in 1000 concentration, application of sludge in 4 levels (L1, L2, L3 and L4 equal to 5.83, 13.33, 20.83 and 26.67 ton/ha, respectively) and application of slag in 4 levels (S1, S2, S3 and S4 equal to 3.20, 7.28, 11.36 and 15.44 ton/ha, respectively) which supply 1, 2, 3 and 4 times as much as soil test recommends, based on AB-DTPA extractable Fe in the soil. Corn (Zea mays) single cross 704 was planted for the experiment. Applications of the two compounds increased the soil extractable Fe and Mn, decreased Mg but the treatment did not change the soil-extractable Zn, Cu and Ca. The corn yield also increased due to the applications of the two compounds and the maximum yield was related to L3, L4, S3 and S4 treatments. The foliar application treated the leaf chlorosis and increased the silage, grain and leaf + stalk yields however, this was not as efficient as sludge and slag application. Also applications of the two compounds increased the Fe, Mn, Zn, Cu, Ca and Mg uptake by corn. The L3 and S3 treatments can be recommended as the proper levels of these compounds as iron fertilizer.
R S.sharifi, A Javanshir, M Shakiba, K Ghasemi Golezani, A Mohamadi, Y Raei,
Volume 12, Issue 46 (1-2009)
Abstract
In order to study yield component and determinate the contribution of stem reserves to corn yield under effect of different densities and interference periods of sorghum, a factorial experiment based on randomized complete block design with three replications was conducted in 2002 on the Research Farm of the Faculty of Agriculture Tabriz University. Experimental factors were sorghum interference at different periods (0,14,28,42 days after corn emergence and also during plant life corn) with three densities (4,8,12 plants m-2). Characteristics of study were yield, yield component and the contribution of stem reserves to corn grain yield. The results showed that with increasing sorghum density and interference, corn yield components (except the number of grain rows) were decreased, due to shading and competition between plants for using available resources. Maximum grain yield and grain number per ear was obtained at pure corn plantation. With increasing sorghum density and interference periods grain yield decreased, and maximum corn yield loss was 38%, which occurred at the highest sorghum density and interference. Dry matter remobilization and contribution of stem reserves were significantly influenced by sorghum densities and interferences in corn grain yield. The highest contribution of dry matter remobilization and stem reserves to corn yield was obtained at maximum density and complete interference of sorghum. The least contribution of reserves was shown in pure corn plantation. This might be related to shading and competition between plants for light and other resources.
B Salari, M Shamsedin Said, A Askarian Sardari,
Volume 12, Issue 46 (1-2009)
Abstract
In order to study the effect of NaCl priming on some agronomical and physiological traits of corn (single cross 704), an experiment was conducted at Agricultural Research Station of Bahonar University of Kerman in 2005. The experimental design was completely randomized designs with 3 replications. Treatments were a combination of all different levels of two factors including salinity levels (1, 4, 8, 12, 16 dS/m) and salinity solution for NaCl priming (1, 4, 8, 12, 16 dS/m). Results showed that salinity and NaCl priming had significant effects on total emergence, mean time to emergence, root and stem length, number of leaf, relative water content, ion leakage and K+/Na+. Mean comparison showed that increasing salinity decreased all plant characteristics (with the exception of mean time to emergence and ion leakage) by %49.5, %33.49, %23.97, %18.64, %14.05 and %40.20, respectively. However, increasing salinity led to 1.2 and 1.3 increase in mean time to emergence and ion leakage of leaves, respectively. Mean comparison also showed that NaCl priming decreased negative effects of salt stress, and all mentioned traits under NaCl priming increased as compared with control. The results showed that NaCl priming is a useful method for increasing salt tolerance in corn plant.
N Shahmirzaee, S Kamgar,
Volume 13, Issue 47 (4-2009)
Abstract
One of the most important goals of precision farming is preparing yield map. Recently in Iran, planting of corn has received special attention. Therefore, among the different methods of yield measurement such as using impact sensor at the outlet port of forage harvester (chopper), displacement sensors at feed rollers of forage harvester, continuous measurement of discharged material to trailing wagon and using the torque meter, the present study made use of the torque meter method. This method consisted of a torque transmitting shaft equipped with laser-based encoders to monitor twist in a real time mode. The unit output could be exported to a computer via a microcontroller installed into the interface device. For calibration of the torque meter output with material feed rate in lab conditions, a conveyor was used to feed homogenous amount of material at a specific rate to the chopper. The experiment was conducted at 3 feed rates of silage corn and at 3 feed roll speeds of the chopper with 3 replications. Correlation between the feed rate and recorded power at different gears of the chopper was established. Relationships between feed rate and recorded power of the chopper at gears 1, 2 and 3 were linear with calculated R2 of 0.95, 0,98 and 0.98, respectively.
