M. Dadivar; B. Atarodi
Abstract
Introduction: Because leaf is the main and most important organ of plant metabolism, therefore, its analysis and interpretation of the results using standard methods, can help to provide an optimal fertilizer program. There are different methods for interpreting the results of decomposition of plant ...
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Introduction: Because leaf is the main and most important organ of plant metabolism, therefore, its analysis and interpretation of the results using standard methods, can help to provide an optimal fertilizer program. There are different methods for interpreting the results of decomposition of plant leaves, including critical concentration values and sufficiency ranges. The main drawback of these methods is that only the concentrations of each nutrients are considered and the balance of these nutrients is not considered. The DOP is one of the most up-to-date methods for interpreting the results of leaf decomposition. In this method, the relationship between the concentration of the nutrient and the reference concentration is used instead of the mere concentration of nutrients. Due to insufficient information about the optimal level of nutrients and nutritional status of potato in Khorasan Razavi province, the present study was conducted by using the DOP index to assess the balance of nutrients and to determine the order of nutrient requirement for this plant. Materials and Methods: In order to have a database, 30 potato fields were selected from the major cultivation areas of this crop in Fariman, Torbat-e Heydarieh, and Quchan counties. Among these fields - based on questionnaires completed by farmers - those with good management and high yield (above average) were selected to determine the reference concentration. Accordingly, out of 30 surveyed fields, 16 fields were selected as reference fields and 14 fields as non-reference fields. In each field, before flowering and at the beginning of tuber formation, a composite sample of leaves (from fully developed leaves) was prepared, transferred to the laboratory, rinsed with distilled water and 20 mM EDTA solution, oven dried at 50 °C, ground, digested and analyzed for determining the macro and micro nutrients concentrations by atomic absorption spectrometry (AAS) - (Perkin Elmer, 2380). According to leaf analysis results, some statistical indices, including the maximum, minimum, mean, standard deviation, and coefficient of variation of data in both groups of reference and non-reference fields, were calculated. Furthermore, the reference concentration (Cref) and DOP indices were calculated to evaluate nutritional status of potato and priority nutrients requirement in low-yielding fields. Results and Discussion: The results of this study showed that the coefficient of variation of micronutrients was higher than that of macronutrients, stating that fertilizers containing macronutrients have been used more homogeneously by farmers, compared to those containing micronutrients. Using nutrients concentration in high yielding fields, Cref was obtained for N, P and K nutrients 4.65, 0.32 and 4.28 percent respectively. In addition, Fe, Mn, Zn and Cu Cref values were 190.13, 123.88, 35.19 and 12.44 mg/kg respectively. The results also showed that absolute value of DOP index for all nutrients was greater than zero, indicating imbalance of absorbed nutrients by potato. Due to the fact that the concentration of nutrients in the leaves is a function of the amount of nutrients in the soil, so these data indicate the lack of proper management and imbalance fertilizer application in the studied fields. Among macronutrients, potassium had negative indices in 36% of the studied fields while nitrogen had positive indices in 80% of the studied fields. In other words, most cultivated potatoes of Khorasan Razavi province suffer from K deficiency and excessive N. Due to consecutive cultivation, excessive use of nitrogen fertilizers such as urea and low consumption of potassium fertilizers, higher amount of potassium harvested from the soil as compared with that released from the soil, potassium deficiency is observed in many potato fields. Among micronutrients, zinc had highest negative indices in 57% of the studied fields. After Zn, Fe had the most negative index (highest deficiency) in 35% of fields. Excessive consumption of phosphate fertilizers and lack of sufficient organic matter in soils are the main reasons of iron and zinc deficiency in soils and agricultural products in Razavi Khorasan province. Conclusion: Overall, the results showed an imbalance of all absorbed nutrients by potato and imbalance application of fertilizer in the studied fields. Due to the severe deficiency of K and Zn, fertilization of these two nutrients should be a priority in nutrition management programs in the province's potato fields.
payman keshavars; majid forouhar; masoud Dadivar
Abstract
Introduction: World cereal demand is growing at present in accordance with the global expansion of human populations. Deficiency of micronutrients in cereal cropping is one of the major worldwide problems. Beside of lowering grain yield, it may cause some healthy problems in human populations. Iron is ...
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Introduction: World cereal demand is growing at present in accordance with the global expansion of human populations. Deficiency of micronutrients in cereal cropping is one of the major worldwide problems. Beside of lowering grain yield, it may cause some healthy problems in human populations. Iron is an essential micro element in the soil that mainly had been found as the insoluble (Ferric or Fe3+) form. Although ferric iron is relatively insoluble in water, the solubility of total inorganic iron decreases between pH of 7.4 to 8.5 range which is dominant in calcareous soils. It is estimated that nearly half of the world population is affected from Fe deficiency problem. Major reason for widespread occurrence of Fe deficiency in human populations is very little dietary diversity and high consumption of cereal-based foods with very low amount and poor availability of Fe. Bread wheat is the most widely grown cereal grain with 65% (6.5 million hectares) of the total crop cultivated area in calcareous soils of Iran. Most wheat cultivars currently used have been selected for high yields under optimum fertilizer conditions. Consequently, research is needed to select efficient genotypes that will grow and produce under conditions of lower fertilizer input or soil micronutrients deficiencies. This is especially true for the expansion of wheat cultivation which is often growing in calcareous soil of Iran. These soils are characterized with low fertility, high pH value, low organic matter content and low micronutrients availability. Environmental concerns in wheat production for human population indicate that to improve wheat quality and quantity, the zero or possible lowest amounts of chemical fertilizers would be applied. In this regard, the use of iron-efficient genotypes that have also high yield can be considered as a key strategy.
Materials and Methods: In order to investigate Fe efficiency in various wheat genotypes, a factorial experiments a randomized complete block design was carried out with three replications in agricultural and natural resource research and education center of Khorasan Razavi province, Mashhad (Torough Station), Iran, during 2009-2011. Treatments were consisted of two levels of Fe fertilizer (0 and 10 kg h-1 as Fe-EDDHA) and six genotyps of wheat including: three cultivars and one line of bread wheat (Alvand, Falat, Toos, and C75-5, respectively), two species of wheat known as Thriticosecale and Durum. The trial plots’s size was 9×3.6 (32.4 m2). According to the results of soil analysis, total nitrogen, available forms of phosphorus and potassium were 0.05%, 7.2, and 180 mg kg-1, respectively. DTPA extractable of iron, zinc, manganese and copper were 2.4, 0.52, 3.4 and 0.7 mg kg-1, respectively. Soil texture was silt loam. Soil organic carbon percentage and equivalent CaCO3 percentage (T.N.V) were 0.48% and 18.7%, respectively. The electrical conductivity (EC) and pH measured in saturated extract were 1.4 dSm-1 and 8.1, respectively. At defined phonological stage (SG6 based on Fix’s Index), the Fe concentration in shrub was measured. Moreover, grain yield and Fe uptake by grain were determined at the end of ripening stage. Iron use efficiency, agronomic efficiency and apparent recovery efficiency were calculated and studied as dependent variables.
Results and Discussion: The grain yield is the most integrative trait of a particular genotype. The results showed that Fe application increased significantly grain yield by 9.9% in comparison with control. In our research the highest grain yield increase due to Fe application was found in Durum wheat (17.1%), and the lowest grain yield increase, were found in Toos cultivar (4.1% yield increase). Application of Fe increased Fe concentration and uptake in grain about 5.7% and 16.4%, respectively. In terms of iron uptake by grain, Thriticosecale wheat and C75-5 cultivar had the highest (339.6 g ha-1) and the lowest amounts of Fe uptake (260.3 g ha-1), respectively. Also, application of Fe had no significant effects on Fe concentration in shoot. Fe use efficiency in bread wheat genotype, Durum and Thriticosecale wheat was ranked as: Durum < C75-5 < Alvand < Triticale< Falat < Toos. According to our research results, Toos and Falat cultivars and Thriticosecale have higher iron use efficiency than Alvand and C75-5 cultivars and Durum wheat. The results also suggest that to obtain higher yield in Durum wheat, soil and foliar application of Feis more necessary in comparison with other genotypes especially Toos and Falat.
Conclusion: There were various abilities to uptake and use Fe by different wheat genotypes. Fe-efficient genotypes of wheat were Toos and Falat also Triticale. Moreover, these genotypes also had higher grain yield.
M. A. Khodshenas; J. Ghadbeiklou; M. Dadivar
Abstract
Introduction: Soil test has an important role in plant nutrition management to obtain the economical agriculture system. The nutrient concentration in soils that indicates the division between responsive and non-responsive conditions is termed the critical level. Before any fertilizer recommendation, ...
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Introduction: Soil test has an important role in plant nutrition management to obtain the economical agriculture system. The nutrient concentration in soils that indicates the division between responsive and non-responsive conditions is termed the critical level. Before any fertilizer recommendation, we should be aware of the amount of nutrient critical levels in each region. Soil test results in an area, is not applicable for other agricultural areas. Therefore, these tests should be carried out in the soils of a desired area, so that the soil test could be the base for fertilizer recommendation. Iron is an essential micro element in the soil that mainly was found as insoluble (Ferric or Fe3+) form. Solubility of total inorganic iron decreases between pH 7.4 to 8.5. Bean (Phaseolus vulgaris L.) crop is one of the most widely grown throughout the Markazi province in Iran and has high nutritional value for human. Knowing that bean is a sensitive plant to iron, and because of lack of any information about iron critical level and regional calibration, this study was conducted in Markazi province.
Materials and Methods: Eighteen soil surface samples (0-30 cm) selected with a wide range of soil properties and iron concentration (extracted with DTPA method) from different zone of province and prepared for greenhouse cultivation. Soil physical and chemical properties such as: (texture, pH, calcium carbonate, organic matter, cation exchange capacity, and electrical conductivity) of soil were determined by routine laboratory methods. In this study, bean plant responses were investigated by application of two levels of iron (0 and 10 mg kg-1) in soil as iron sulfate in the greenhouse experiment. All of soil samples received nitrogen, potassium, phosphorus, manganese, copper and zinc as; (150, 100, 25, 5, 5, 5) mg kg-1 as solution in each pot respectively. The greenhouse study was conducted in a factorial experiment with three replications as complete randomized design. Six bean seeds were planted in pots. After the second week three plants of these six seeds were kept.
Soil moisture was maintained at field capacity. At the end of vegetative phase, the shoot bean and iron concentrations were determined in plant samples. At the end of the vegetation period, the shoot parts of plants cut, and plant responses including; (dry matter weight, Fe concentration, total Fe uptake and relative yield) (DMcontrol./DMFe fertilizer*100) were determined.
Results and Discussion: The results showed that available iron content in the soil varied from 1.5 to 20 mg kg-1 of soil with a mean value of 7.75 mg kg-1. The bean plant responded to Fe application and their relationships with physical and chemical properties of soils, which were investigated were effected too. Analysis of variance showed that the effects of soil and Fe fertilizer application were separately significant at 1% level for (weight dry matter, Fe concentration and Fe uptake). The effects of the (soil and fertilizer) interaction were significant at 1% level for the Fe concentration and Fe uptake. The mean comparison test of plant responses was significant as affected by Fe fertilizer consumption. By using Cate-Nelson graphic method, the critical level of iron in soils was five mg kg-1. Amounts of percent relative frequency indicated that eight percent of the soils were less than five mg kg-1 Fe, 63% of soils between 5 to 10 mg kg-1, 16% of soil between 10 to 15 mg kg-1 and 13% of soil above 15 mg kg-1 Fe. Plant Fe concentration in the control treatment (without Fe application) was 439.4 (mg kg-1), but at the Fe treatment (10mg kg-1) increased to (534.4mg kg-1).
The Fe uptake significantly increased from 1.54 to 2.16 mg Fe pot-1 with the application of 10 mg-Fe kg-1. The Fe uptake differences between treatments was due to increase of dry matter weight, and the plant Fe concentration, and this was due to the fertilizer application. Relative yield and dry matter weight showed positive and significant correlation with (clay, CEC and Fe available), but sand revealed negative correlation with the plant's response. The Fe uptake showed positive and significant correlation with Fe available but negative and significant correlation with the sand. The regression equation showed that Fe uptake to be related with CEC significantly.
Conclusion: By using Cate-Nelson graphic method, the critical level of iron in soils was five mg kg-1. The plant parameters were predictable significantly by soil properties such as (clay, sand, silt, soil organic carbon and Fe concentration).
M. A. Khodshenas; J. Ghadbeiklou; M. Dadivar
Abstract
Introduction: Growing irrigation demand for corn production, along side with draws of ground water from stressed water sources, should be limited due to scarce resources and environmental protection aspects. Nitrogen fertilizer applied at rates higher than the optimum requirement for crop production ...
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Introduction: Growing irrigation demand for corn production, along side with draws of ground water from stressed water sources, should be limited due to scarce resources and environmental protection aspects. Nitrogen fertilizer applied at rates higher than the optimum requirement for crop production may cause an increase in nitrate accumulation below the root zone and pose a risk of nitrate leaching. Improving nitrogen management for corn production has a close relation with soil water content. In this study, we investigated the effects of source and rate of nitrogen fertilizer and irrigation on silage corn production and nitrogen concentration, nitrogen uptake and residual soil nitrate in two depths.
Materials and Methods: This experiment carried out as split spli- plot in a Randomized Complete Block design (RCBD) with three replications, in Arak station (Agricultural research center of markazi province, 34.12 N, 49.7 E; 1715 m above mean sea level) during three years. The soil on the site was classified as a Calcaric Regosols (loamy skeletal over fragmental, carbonatic, thermic, calcixerollic xerochrepts). Main plots were irrigation treatments based on 70, 100 and 130 mm cumulative evaporation from A class Pan. Sub plots were two kinds of nitrogen fertilizers (Urea and Ammonium nitrate) and sub sub-plots were five levels of nitrogen rates (0, 100, 200, 300 and 400 kgN.ha-1). Nitrogen fertilizer rates were split into three applications: 1/3 was applied at planting, 1/3 at 7-9 leaf stage and 1/3 remainder was applied before tasseling as a banding method. Phosphorus was applied at a rate of 150 kg.ha-1in each season and potassium at a rate of 30kg.ha-1 (only in first growth season) based on soil testing as triple super phosphate and potassium sulfate, respectively. The corn variety of single cross 704 was planted at 20 m2 plots. The plants were sampled at dough stage from the two rows and weighted in each plot. Plant samples were dried in a forced air oven at 70ºC for at least 3 days before weighting. Total N concentration in the plant samples were determined using kjeldahl method. Nitrogen uptake by plants was calculated based on the total N concentration in plants multiplied by dry matter. Residual nitrate concentrations were determined in soil samples (0-30 and 30-60 cm depths) by diazo method. Combined analysis of variance was accomplished using the MSTAT-C software. Mean comparisons were done using Duncan multiple rang test (DMRT).
Results: The results showed that the main effect of water stress on dry matter yield was negative and significant (P
P. Keshavarz; M. Forouhar; M. Dadivar
Abstract
Introduction: World cereal demand is growing at the present in accordance with the global expansion of human populations.Bread wheat is the most widely grown cereal grain with 65% (6.5 million hectares) of the total crop cultivated area in Iran. Deficiency of micronutrients in cereal cropping is one ...
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Introduction: World cereal demand is growing at the present in accordance with the global expansion of human populations.Bread wheat is the most widely grown cereal grain with 65% (6.5 million hectares) of the total crop cultivated area in Iran. Deficiency of micronutrients in cereal cropping is one of the major worldwide problems. Zinc (Zn) is an essential micronutrient for plants. It plays a key role as a structural constituent or regulatory co-factor of a wide range of different enzymes and proteins in many important biochemical pathways. Nearly half of the world’s cereal-growing areas are affected by soil zinc deficiency, particularly in calcareous soils of arid and semiarid regions. High pH levels and bicarbonate anion concentration in these soils are the major factors resulting in low availability of Zn. About 40% of the soils, used for wheat production in Iran are Zn-deficient, which results in a decrease in growth and wheat grain yield under field conditions. Although application of zinc fertilizers is a common practice to correct Zn deficiency, growing varieties with high Zn efficiency has been reported to be a more sustainable approach. There is significant genetic variation both within and between plant species in their ability to maintain significant growth and yield under Zn deficiency conditions. Plant response to Zn deficiency and Zn fertilization are two distinct concepts. Knowing about these variations, can be very essential and useful for making correct fertilizer recommendation.
Materials and Methods: In order to investigate Zn efficiency in various wheat genotypes, a factorial experiment as a randomized complete block design was carried out with three replications in agricultural research center of Khorasan razavi (Torough Station), during 2009-2011. Treatments consisted of two levels of Zn fertilizer (0 and 40 kg/h as ZnSO4) and six genotyps of wheat including: three cultivars and one line of bread wheat (Alvand, Falat, Toos, and C75-5 respectively), two species of wheat known as Thriticosecale and Durum. The plot size was 9*3.6 (32.4 m2). Soil fertility status showed 0.05% nitrogen, 7.2 mgkg-1 phosphorus, 180 mgkg-1 potassium and 0.52 mgkg-1 DTPA extractable zinc. At defined phonological stage (SG6 based on Fix’s Index) Zn concentration in shrub was measured. Also grain yield and Zn uptake by grain were determined at the end of ripening stage. Zinc use efficiency, agronomic efficiency and apparent recovery efficiency were calculated according to “Graham, et al.”, “Craswell and Godwin” and “Raun and Johnson” respectively. Zinc use efficiency can be defined as the ratio of grain yield or shoot dry matter yield produced under Zn deficiency to that produced under Zn fertilization.
Results and Discussion: Grain yield is the most integrative trait of a particular genotype. The results showed that Zn application increased significantly grain yield by 12.61% in comparison with control. This result is supported by Ziayeian and Malakouti (1999). Who reported that Zn application significantly increased the wheat yield (17%). In our research the highest grain yield increase due to Zn application was found in durum wheat (23.5%), and the lowest grain yield increase, were found in Toos cultivar (1.3% yield increase). Cakmak and et al (1997) also obtained more yield with the application of zinc in durum wheat. Application of Zn increased Zn concentration and uptake in grain, 8.6% and 21.5% respectively. Also, application of Zn significantly increased Zn concentration in shoot (36.5%) over the control. Similarly, Moshiri et al (2010) reported increase of Zn concentration in shoot with application of Zn fertilizer. Zn use efficiency in bread wheat genotype, Durum and Thriticosecale wheat was ranked as: Durum < C75-5 < Alvand < Falat < Triticale ~ Toos. The findings of Khoshgoftarmanesh et al (2004) showed that, Durum wheat is Zn inefficient genotype. According to our research results, Toos and Falat cultivars and Thriticosecale have higher efficiency than Alvand and C75-5 cultivars and Durum wheat. The results also suggest that to obtain higher yield in Durum wheat, soil and foliar application of Zn is more necessary in comparison with other genotypes especially Toos and Thriticosecale.
Conclusion: wheat genotypes were different in their response to Zn deficiency and Zn supply. Thriticosecale and Toos were the most Zn efficient genotypes, whereas Durum and C75-5 were the most responding to Zn supply. So, without considering these differences, accurate fertilizer recommendation cannot be achieved. For organic farming and low input agriculture systems in regions similar to this experiment location (Torough Station), Thriticosecale and Toos could be suggested. However, for improvement of wheat grain yield and achieve desired quality in calcareous soil, most of the time, it is necessary to use the Zinc fertilizers.
