Applied Agricultural Research
Year:2015 | Volume:- | Issue:108|Papers Count:19

Alfalfa (Medicago Sativa L.) absorbs large amounts of soil potassium (K) and magnesium (Mg). K fertilization increases alfalfa yield but the changes in the yield as influenced by combined K and (or) Mg fertilization, are not known. Our hypothesis is that K and Mg antagonistic relationship will influence the yield of alfalfa. The objective of this study was to determine influence of K and Mg fertilization on alfalfa yield and yield components during the three yr experimental period. The experiment was a factorial with four K levels (0, 100, 200 and 300 kg K2SO4. ha-1) and three Mg levels (0, 100 and 200 kg MgSO4 ha-1) arranged in the form of a randomized complete block design with three replications. Application of K increased alfalfa dry matter (DM) production. Total K removal in the herbage increased linearly with increasing K rates and reached 1440 kg K ha-1 with the application of 300 kg K2SO4. ha-1 yr-1, compared with 900 kg yield ha-1 in the control treatment. Addition of Mg partially affected DM production. K fertilization depressed plant tissue Mg concentration and Mg uptake. Also, addition of Mg fertilizer decreased plant K uptake. Incremental additions of K increased alfalfa grain yield, K concentration and uptake in the third year after establishment. Mg fertilization did not influence grain yield and Mg content in grains. After harvesting, soil ammonium acetate extractable K (Ke) decreased considerably in check plot (127 mg. kg-1), but it increased with increasing K rates.

Organic matter based on their composition and the C/N ratio can have different effects on nutrient bioavailability in soil. This research was conducted to investigate the effects of various sources of organic fertilizers on bioavailability of Cu and Zn in soil. A silty clay soil sample and three organic fertilizers including animal manure, sewage sludge and municipal compost in two levels of 1.25 and 2.5% W/W bases were included for the experiment. The experiment was conducted in two stages of incubation and greenhouse cultivation of corn (Zea mays L.). Both experiments were in factorial complete randomized design with 6 treatments in 4 replications plus the control. In the first experiment treated soils were incubated at field capacity moisture and 25oC temperature for 8 weeks during which subsamples were taken at 0, 4 and 8 weeks and were analyzed for available Zn and Cu. The results showed that the highest amount of DTPA extractable Zn were 148.4 and 156.7 mg kg-1for the sewdge sludge at the 1.25 and 2.5 percent treatments respectively, and the lowest was related to manure treatment with 103.7 mg kg-1. The highest amount of DTPA axtractable Cu was for the compost treatment with 28.1 and 28.4 mg kg-1in the levels used, and it was 28.4 mg kg-1in the swedge sludge treatment at 2.5% level. Comparison of the changes over time showed that available Zn content decreased but Cu content increased up to 4 week and then decreased. The results of the greenhouse experiment showed that all treatments except sewdge sludge increased some plant growth factors such as yield Zn content and the highest Zn and Cu uptake by plant were in the sewdge sludge treatment with 18.8 and 1.15 mg kg-1.

The objective of present study was to investigate the effect of different rates of super absorbent polymer and different levels of deficit irrigation on physiological and morphological characteristics of sunflower cultivar Master. The experiment was carried out as a factorial based on completely randomized design (CRD) with 15 treatments and 3 replicates under controlled conditions. Factors were deficit irrigation in three levels including irrigation at 0.75, 0.50, and 0.25% of field capacity (FC) and polymer in five levels including application of 0, 0.75, 1.5, 2.25, 3 gr polymer per kg of soil. Pots were weighted every day and irrigated when soil water received to 0.75, 0.50, and 0.25 of field capacity, respectively. The effects of different rates of polymer and different levels of consumed water were highly significant on all of studied characters. Yield diminution in irrigation at 50% of FC was 32% and at 25% of FC was 71% as well as chlorophyll amount diminution at 50% of FC was 8% and at 25% of FC was 42% compared to well watered condition (irrigation at 75% of FC). But, the application of super absorbent polymer moderated the negative effect of deficit irrigation, especially in high rates of polymer (2.25 and 3 gr/kg of soil). The seed yield was obtained from irrigation at 75% of FC and application of 2.25 and 3 gr polymers per kg soil. Concerning to chlorophyll amount the best situation was obtained from irrigation at 50% of FC and application of 3 gr polymer per kg soil. Results revealed that increasing in absorbent polymer lead to elevation in studied characters. Increasing polymer amount to 3 gr per kg soil results in improving WUE and yield until 60% and 31% respectively compared to non polymer application.It seems that absorbent polymer increased irrigation period in sunflower.

This research was conducted to evaluate the effect of simultaneous nitrogen (N) and phosphorous (P) fertilizer application on grain yield and also genetic diversity for absorption efficiency of these two elements and other micro nutrient elements and phytic acid in grain of 18 advanced bread wheat genotypes and two cultivars, i.e. Sardari and Azar-2, as checks, in two successive cropping season (2005-2007) at two fertilizer and non fertilizer application at rainfed conditions in Sararood research station, west Iran, utilizing randomized complete block design with three replication. Also, heritability, genotypic (GCV) and phenotypic (PCV) coefficient of variations and genotypic (GV) and phenotypic (PV) variance were measured for the recorded traits. Based on grain yield at the both condition, grain yield efficiency index (GYEI) were calculated for each genotypes. N, P fertilizer application significantly increased 21 and 14 percentage grain yield in the two cropping seasons. Moreover, NP application enhanced Fe, Zn, and B concentration in seed but reduced N, P, K and ratio of phytic acid to Zn (PA/Zn) which lowers PA/Zn in wheat grain is related to more bio-availability of Fe and Zn in bread. In compare to Azar-2 and Sardari, 9 and 14 genotypes for PA/Zn and 2 and 3 Genotypes for GYEI were superior, respectively. Analysis of variance revealed significant genetic variation for most of the traits.For majority of traits, PCV were more that GCV. The highest PCV and PCG were observed for P content in grain. Grain yield and phytic acid had the highest (h2=60.69%) and the lowest (h2=7.63%) heritability, respectively. Consequently, N, P application had influence on nutritional element concentration in grain and there was a genetic variation among the testing genotypes for nutritional elements absorption efficiency.

In order to study effects of dominant weeds control included wild mustard, wild barley, wild rye and common corn cockle on rapeseed yield and its components an experiment was conducted in Islamic Azad University of Tabriz, Iran. Studied factors were weeds control times included rosette, early stem elongation, early flowering and 50% flowering stages, full season competition and weed free as control; and Okapi, SLM046, Opera crop cultivars. Results showed that rapeseed aboveground biomass in whole season weed-infested plots reduced 40%, as compared with control. Weeds could increase their biomass up to 410 g m-2 when grew with rapeseed along the season. Weeds control at early stem elongation, early flowering and 50% flowering stages with 32%, 44% and 50% reduction value in seed yield, respectively, had significant difference with weed-free plots. When the weeds competition period took a long time, allocation of biomass to seeds decreased. Seed oil percentage was not affected by cultivars and weeds competition periods. Reduction value in oil yield of rapeseed in different levels of weed control were 32%, 4%, 45%, 50% and 55%, respectively. One time weeds control in early stem elongation of rapeseed cultivars is recommended.

The effects of drought stress on yield, yield components and some of drought resistance and sensitivity indices, such as sensitivity stress index (SSI), tolerance index (TOL), means productivity (MP), geometric means productivity (GMP) and stress tolerance index (STI) were evaluated on ten lentil genotypes with an experiment at agricultural and natural research station of Ardabil. The experiment was carried out under dry-land (drought stress) and irrigated (non-drought stress) conditions in a randomized complete block design with three replications. The results of combined variance analysis showed a high diversity in all of traits among studied genotypes. Based on mean comparisons of traits, the native Gazvin, 225-12-C and 418-22-22, 15 genotypes had the highest values of grain yield in both of dry-land and irrigated condition. The results of correlation among the traits studied showed that the number of pod per plant, plant, biological yield and harvest index had the highest positive and significant correlation with grain yield. Correlation among the days to 50 percent of flowering and days to maturity with grain yield was negative and significant, showing that late flowering and late maturity lentil genotypes had lower grain yield. Among geometric means productivity (GMP) and stress tolerance index (STI) with grain yield in both of dry-land and irrigated condition were observed the positive and significant correlation, so can be indentify those as the best optimum drought resistance indices and used for selection of lentil genotypes with high potential yields in both dry-land (drought stress) and irrigated (non-drought stress) conditions. In this experiment the native Gazvin, 225 12-C and 418-22-22, 15 genotypes compared with other genotypes along with high drought tolerance, had higher grain yield in both dry-land and irrigated conditions.

In a field experiment, effects of amount different manure and nitrogen were investigated on quantitative and qualitative Spinach (Spinacea Oleracea) characteristics in Agricultural and Natural Resource Research Center of Tehran Province, Iran. Statistical experiment design was conducted with split plot design under randomized complete block design (RCBD), with three replications during two years (2009-2010). Manure (main plot) was considered in four levels of 0, 10, 20, and 30 ton ha-1 and nitrogen (sub plot) was considered in four levels of 0, 150, 200, and 250 kg Nha-1 as urea source. Stems and leaves fresh weight of spinach and there nitrate was measured after harvest. Combined two years results showed that the main effects of manure factor and nitrogen factor were significant on yield, relative yield, water use efficiency, fertilizer use efficiency, agronomic efficiency and nitrate. The interaction effects of manure and nitrogen were significant different only on relative yield, water use efficiency and fertilizer use efficiency. Fertilizer recommendation was 30 ton manure ha-1 with 150 kg N ha-1 for obtaining optimal yield with regard to legal limit of nitrate in spinach plant.

In order to study response of the seed yield and yield components of canola genotypes to delay in planting, an experiment was conducted as split-plot in randomized complete block design with three replications, during two cropping seasons in zahak Agricultural Research station. Study factors were consisted four sowing dates (Nov 1th, Nov 16th, Dec 1th and Dec 16th as main-plots, and four spring rapeseed genotypes (RGS003, Hyloa401, pp-308/8 and pp-401/15E) as the sub-plots. The Results of combined analysis indicated that planting date and genotype had significant effect on seed yield and traits other, but the effect of year only was significant on oil percent, oil yield and day to initial flowering. With delay in planting, showed decreasing significantly the number of silique in plant, number of seed in silique, weight of 1000 grain, plant height, oil yield and seed yield. The first planting date (Nov 1th) with mean 2989 kg/ha had the highest seed yield and the lowest seed yield obtained with 39 percent decreasing in fourth planting date (Dec 16th). Hybrid Hyola 401 with mean 2701 kg/ha and RGS003 with mean 2453 kg/ha produced maximum seed yield between genotypes. The results of simple correlation of measured traits showed that between yield components, number of silique in plant and number of seed in silique with coefficients (r=0.82** and r=0.62**) and between other traits, oil yield and day to initial flowering with coefficients (r=0.98** and r=0.59**) had most positive correlation with seed yield, respectively. Based on the results, it can be concluded that planting in early Nov and use of hybrid Hyloa401 and RGS003 cultivar was recommendable in Sistan region.

In ley-farming variation system hard-seed is the major ecological trait of annual medic to guaranty the soil seed bank reserve. The trend of hard-seed breakdown is affected by environmental and managerial factors. In order to study, the effect of different nutritional systems, post harvest period and harvest management on hard seed breakdown trend in the annual medic, this experiment was conducted by split plots in time based on complete randomized block design with three replications in two locations (Sararoud dry Agricultural Research Institute and Mahidasht Agricultural Research Stations, Kermanshah) in dry farming system during 2008 and 2009 growing seasons. The results indicated that the highest hard-seed breakdown was periphery 13% in the Sararoud Research Station. After 8 months of post harvest period the mean of hard-seed breakdown reached to 14% in two locations. Also in harvest and non-harvest treatments forage the average hard-seed breakdown were 12.2 and 12.7 percents, respectively.

In order to study Agronomic traits and unknown variables effective on yield of three soybean growth types and select genotypes with high yield, 364 soybean genotypes (35 determinate, 183 Semi determinate and 149 Indeterminate, most of them from 1-4 maturity groups) were studied, based on an augmented design using 3 checks genotypes, in seed and plant improvement institute, Karaj, Iran.24 agronomic traits were studied. The result of Principal component analysis show that 6, 5 and 4 components comprised 89.75, 82.75 and 82.95 % of the total variations in Determinate, Semi determinate and Indeterminate genotypes, respectively. Alianka, Dorekswie A2 and B-121 were Determinate, Semi determinate and indeterminate genotypes, respectively with high yield in component 1 and 2 biplot. For improvement each component should notice related traits because gene or genes which control number of seed per plant, probability control biological yield, seed yield per plant and other economic traits in this component too, and component or gene that control this traits, is similar gene or factor, so result of factor analysis could use in plants breeding and specially in indirect selection.

In order to study the effects of nitrogen fertilizer rates and plant number on yield and yield components of two rice cultivars, a field experiment was carried out in Babol city- during 2010. A split-split plot experiment on the basis of randomized complete block design with 3 replications and 3 factors including fertilizer rate (0, 57.5 and 115 kg.ha-1), plant number per hill (3, 4 and 5) as sub plot and cultivars (Fajr and shiroudi) as sub sub plot were used. Results showed the rates of nitrogen fertilizer had significant effect on grain yield, harvest index, fertile tillers number, panicle number and biological yield. Also, different levels of plant number have not significant effects except of panicle number, grain yield and biological yield. With increasing nitrogen fertilizer application, grain yield was increased significantly compared with control treatment (without nitrogen fertilizer application). Interaction effect between nitrogen fertilizer rate and cultivar was significant at 1% probability levels for grain yield and panicle number in which the highest yield was belong to the nitrogen fertilizer rate of 115 kg.ha-1 and Shiroudi cultivar. Among the mentioned traits, fertile tillers number, panicle number and biological yield had the highest correlation with grain yield.

This study was aimed at evaluating the effect of different row spacings (20, 25, and 30 cm) and competition of weeds at two full-season and non-existence of weeds and potato on potato`s yield and traits. As the last 5 years, Agria variety of potato was planted without using chemical fertilizers, pesticides and herbicides during plantation. The experiment was conducted as split plots in the form of random blocks for one year. The effect of spacing and weed, respectively as the main and secondary factors, on all properties was significant at %1 level, but the interaction of both factors was significant on the yield and weight of the tuber.The maximum yield, like the number of tuber per plant, was achieved at weed-free conditions in 25cm spacing with an average of 10.37 tons/ha. In addition, maximum weight of tuber was achieved at weed-free conditions in 30 cm spacing with an average of 121g. Number of stems per plant and number of main stems per 1meter were increased unlike the height of plant and reduction of density, which were resulted from the increase of spacings. It was also concluded that tuber yield has a significant correlation with the number of tubers per plant (0.952**), which is achieved in narrow spacings if foodstuff is available.

Development of high yielding varieties is the main objective in many wheat breeding programs. However, effectiveness of program depends on relationships between grain yield and its components. In order to investigate the relationships, four varieties of wheat were evaluated for nine traits. Correlation coefficients of simple traits showed the positive and significant relationship of grain yield with harvest index, biological yield, the number of grain per spike and number of grain per m2. The high relationship of grain number per m2, number of grain per spike, weight of thousand grains and number of spiklet per spike with grain yield was also observed in multivariate stepwise linear regression. Path analysis showed positive and direct effect of grain number per m2, number of grain per spike, weight of thousand grains and number of spikelet per spike on grain yield. Grain number is the most important component from grain yield and according to effective role of spikelet number per spike, selection of these two traits will be important to increased grain yield.

A randomized compelete block design in three replication was conducted at the Research Farm of the Faculty of Agriculture, Mohaghegh Ardabili University, Ardabil, Iran, in 2010. The yield and yield components of intercropping of poato (Solanum tubtesum) and safflower (Carthamus tinictorius) in the field were investigated. The treatments include: pure cropping of potato at density of 6 plants m-2, pure cropping of safflower at densities of 6, 12 and 18 plants m-2, and the intercropping of potato (6 plant m-2) with safflower at densities of 6, 12 and 18 plants m-2. The plants were planted as additive method.The results of potato in pure cropping and intercropping with safflower revealed that number of stems m-2 was not significant, but there were significant difference between the number of tubes plant-1 and the tube weight plant-1 at 0.05 probability level and the tube yield at 0.01 probability level. The intercropping of safflower with potato treatment was showed that the number of receptacles plant-1 was significant at 0.05 probability level and the number of seeds per receptacle, seed weight in the receptacle and seed yield were significant at 0.01 probability level.The intercropping of safflower at 12 plant m-2 density with potato at 6 plant m-2 had the highest Land Equivalent Ratio (LER=1.12). This indicated that of intercropping yield compared with pure cropping yield 12% was increased.

In order to the investigate the effect of various organic fertilizers on metribuzin persistence and degradation in soil, an experiment was conducted in completely randomized block design with factorial arrangement with 3 replications in the research fields of Ferdowsi University of Mashhad-Iran. Experimental factors included application of 4 different organic fertilizers (municipal waste compost (MC), poultry manure (PM), cow manure (CM) and sheep manure (SM)), at the rate of 40 ton ha-1 with control treatment (No fertilizer application (NF)) and metribuzin application at two levels (525 and 1050 g ha-1 (WP %75)). For determination of metribuzin residue, soil samples were taken from 0 to 15 cm depth after 2 hrs, 3, 7, 15, 30, 55, 90 and 120 days after application of metribuzin. Metribuzin residue was measured with HPLC. Results show that metribuzin degradation rate increased with the increase of organic fertilizers application. Increasing metribuzin application rate increased residue in soil, but it had no effect on metribuzin half life significantly. So that metribuzin degradation in MC and PM treatments was higher than other treatments. Metribuzin half life when applied at the rate of 525 g ha-1 was 66 days in NF treatment and 46 and 50 days in MC, PM treatments respectively. Based on the present results application of organic fertilizers affect the microbial populations and their activities may have an important role in metribuzin biodegradation in soil.

A randomized complete block design with three replications was performed in Rice Research Institute of Iran, Rasht in 2008, to find the effect of supplement foliar application of nitrogen and potassium on Bahar-1 hybrid rice’s grain yield, concentration and efficiency of nitrogen. Foliar application of 20 kg nitrogen (5 % N) and 15 kg potassium (3 % K2O) in different pre-anthesis stages (maximum tillering, booting, and both stages) was considered as treatments. Foliar application of distilled water was considered as control. Results revealed that the grain yield and grain protein yield were increased in treatments which nitrogen and potassium was applied in pre-anthesis stages compared to control treatment. Foliar fertilization in booting stage resulted to the highest amount of grain and straw nitrogen. No significant effect of foliar fertilization was seen on potassium amount of grains.Foliar nitrogen application had no significant effect on agronomic and physiological efficiency and apparent recovery of nitrogen.However, nitrogen uptake efficiency increased by 14.8 % compared to control treatment in maximum tillering stage. The highest amount of grain protein (11.6 %) was related to foliar application of nitrogen in both maximum tillering and booting stages compared to control. Overall, it could be concluded that maximum tillering and booting stages are the best pre-anthesis time for foliar application of nitrogen and potassium on cv. Bahar-1 hybrid rice.

In order to investigate viability rate of weed seeds in process of dairy cow manure composting, a completely block randomized design with four replications was conducted at Veterinary Research Institute of Tehran University and Weed Seeds Department of Iranian Research Institute of plant protection in 2010. Factors included humidity at 2 levels (with and without), adding straw (hydrocarbonic material) at 4 levels (0%, 1%, 2% and 4%) and sampling time of weed seeds at 5 levels (0, 15, 30, 45 and 60 days).The experiment carried out on 13 weed seeds species and percent of viability was measured. Among 13 species of weed seeds, 10 species were total decay. Adding the straw, and sampling time had significantly effects on percent of viability in field bindweed, dodder and yellow sweet clover but adding humidity had only significantly effect on percent of viability of field bindweed. Interaction effect of adding straw and sampling time were significant at three species weeds, so adding 1% straw in 15th day reduced percent of viability. Adding humidity had less effect on percent of viability among these three factors.

In order to study the effect of different levels of soil nitrogen concentration and water hardness on glyphosate efficacy in redroot pigweed control, an experiment was conducted as a completely randomized design in factorial arrangement with three replications in 2011 at the College of Agriculture, Ferdowsi University of Mashhad. Experimental treatments were included of soil nitrogen content at 5 levels (18, 50, 90, 200 and 300 mg/kg soil), glyphosate doses at 7 levels (0, 75, 100, 125, 150, 175 and 200 % of glyphosate recommended dose for redroot pigweed), and calcium carbonate concentration in water as an index of water hardness at 5 levels (0, 100, 300, 600 and 1200 ppm). Spray solution was applied at 8-10 redroot pigweed leaf stage and 30 days after spray plants survival and shoot dry matter was measured. Results showed, herbicide rate, soil nitrogen content and water hardness significantly affected (P≤0.01) on growth and survival of redroot pigweed. Increasing herbicide doses decreased redroot pigweed survival and growth in pure water spraying. Increasing water hardness decreased glyphosate efficacy in control of redroot pigweed and increased glyphosate ED50 parameter. Minimum (906 gr. a.i ha-1) and maximum (1606 gr. a.i ha-1) glyphosate ED50 for redroot pigweed was observed in 0 and 1200 ppm of water hardness. Increasing soil nitrogen content from 18 to 300 (mg/kg soil) increased glyphosate efficacy in redroot pigweed and glyphosate ED50 decreased from 1745.2 to 896.49 (gr. a.i ha-1).

Cadmium (Cd) is a trace element entering the food chain through crop uptake and animal food intake. A high concentration of Cd in the soil is a serious threat to both the environmental quality and human health over the long-term. So following the availability and mobility of Cd in soil is very important. Soil microorganisms and fauna are factors which may have an influence on the mobility and bioavailability of Cd in soil-plant systems. Specifically, both earthworms and arbuscular mycorrhizal fungi (AMF) have been found to affect Cd chemistry with changes in its immobilization and mobilization in Cd-polluted soils. To examine the effects of these organisms on soil Cd fractionation, chemical forms of Cd were measured in a calcareous soil artificially spiked with Cd (0, 10 and 20 mg Cd kg-1), inoculated with earthworm (Lumbricus rubellus L.), and AMF (Glomus intraradices, and Glomus mosseae species) under sunflower (Helianthus annuus L.) crop for 90 days. Three Cd, two earthworm and three mycorrhizal treatments were applied in a 3×2×3 factorial experiment with three replicates for each treatment. Results showed that the percentage of the total Cd content in exchangeable+soluble (0-5.7%) and organic (0-1.3%) forms were very low. But the percentage of carbonate fraction of the total Cd content was between 54-87%. Earthworm addition increased exchangeable+soluble and organic Cd, while AMF had no influence on these Cd fractions. Both earthworm and AMF species decrease carbonate fraction of Cd but they had no influence on sulfide fraction of Cd.