Iranian Journal of Soil Research
Year:2009 | Volume:23 | Issue:2|Papers Count:12

A factorial completely randomized block design experiment with 3 replications was carried out in the greenhouse to evaluate cereals genotypic variation in phosphorus acquisition and utilization during 2006. Treatments consisted of 8 bread wheat (Triticum aestivum L.), 3 durum wheat (Triticum durum L.), 3 barley (Hordeum vulgare L.), 1 rye (Secale cereale L.), 1 oat (Avena sativa L.) and 1 Triticale (X Triticosecale L.), and two levels of P (0 and 84 mg P/kg soil). Genotypes showed significant differences in number of tillers, shoot P concentration and content, and dry weight. Also, P efficiency (taken as the relative above-ground yield) significantly differed among genotypes and ranged from 0.42 for a barley line (M-80-16) to 0.97 for bread wheat cultivar (Azadi) with the average of 0.71. Application of P significantly increased shoot P concentration and content from 0.19% and 13.24 mg P/pot to 0.47% and 46 mg mg P/pot, respectively. In treatment P0, durum wheat (Yavaroos) with 20.15 mg P/pot and a barley line (M-80-16) with 5.85 mg P/pot had the highest and lowest P uptake, respectively. Oat produced the highest dry weight per unit of P uptake and, hence, was considered to be very efficient in P utilization. Azadi and Yavaroos with 0.45 and 0.43 had the highest relative P uptake, respectively. Therefore, these varieties were efficient in P acquisition. There was no correlation between P efficiency and shoot P concentration of genotypes, but the relationship between P efficiency and shoot P content was highly significant (r=0.66**).

In order to evaluate the effect of different nitrogen application methods on yield and yield components of winter wheat, a field experiment was conducted with split plot arrangement in completely randomized blocks with four replicates in 2006. Basal N was applied at three levels (no basal dressing, band application, and surface distribution) in the main plot. In the sub-plots, top dressing was applied at six levels (1-at tillering only, 2-at tillering and before spike appearance, 3- foliar application with herbicide application before spike appearance, 4-two foliar application at tillering and before spike appearance, 5-two application: at tillering and one foliar application before spike appearance, 6- three foliar application at tillering, before spike appearance, and at milking stage). The amount of fertilizer in strip application was 2/3 of distributing method. In the split application, the amount of applied fertilizer was two third of that used in the broadcasting method. Based on fitted peak equations, the maximum leaf dry matter estimated for no basal nitrogen fertilizer treatment was 30% lower than the mean of maximum leaf dry matter estimated for band and broadcasting application of basal nitrogen fertilizer. Band and broadcasting application of basal nitrogen fertilizer increased leaf dry matter per plant 46 and 64%, respectively, in comparison to no basal treatment. Basal nitrogen application, band or broadcasting, increased wheat stem dry matter by 31%. The highest stem dry matter per plant recorded for one top dressing at tillering (2/3 traditional treatment) plus one foliar application before spike appearance, that was 27.6% higher than traditional treatment. Wheat tiller number for broadcasting and band application of basal N was significantly higher than that for no basal nitrogen treatment by 20.5%. Top dressing at tillering (2/3 traditional treatment) plus one foliar application before spike appearance had the highest tiller number and flag leaf dry weight.

The objective of this study was to evaluate the effect of zinc and salinity levels on some growth parameters and chemical properties of Pistachio (cv. Ghazvini). A factorial greenhouse experiment was carried out as a completely randomized design with three replications. Treatments were 4 levels of Zn (0, 5, 10 and 15 mg kg-1 soil as ZnSO4.2H2O) and 5 levels of salinity (0, 800, 1600, 2400 and 3200 mg NaCl kg-1 soil) and their combinations. Results showed that growth parameters decreased with increasing soil salinity so that the treatment 3200 mg NaCl kg-1 soil resulted in the mean dry weight reduction of the shoot, root, plant's height and the leaf area to the amounts of 33, 76, 14 and 35 percent respectively in comparison to control. Application of 10 mg zinc kg-1 soil increased an amount of 20, 71, 31 and 41 percent in the mentioned parameters respectively. With increasing salinity, shoot zinc and calcium concentrations significantly decreased by an amount of 48 and 30 percent, respectively, and shoot sodium concentration increased more than 7 times in comparison with the control treatment. As salinity increased, root zinc concentration increased from 17.56 in the control to 21.27 mg kg-1 in the highest salinity level. Shoot Ca concentration increased about 30 % at the third salinity level, but, at the highest salinity level, it was significantly reduced. Zinc application increased shoot zinc and calcium concentrations by, respectively, 60 and 34 % and reduced root Na concentration by 20 %. Also, salinity significantly decreased shoot and root K/Na and Ca/Na ratios, however, application of 10 mg zinc kg-1 soil significantly increased shoot Ca/Na ratio and had no significant effect on K/Na ratio.

Date palm bunch wilting and drying disorder has been the most important problem of Iran palm producers in recent years. Reduction of relative humidity and increased air temperatures are known as the major causes of this disorder. Calcium decreases plants injuries due to environmental stress, though its movent in plants is slow. Increase in cell sap concentration with calcium injection can increase cell resistance when temperature increases suddenly, thereby preventing fruit injury .In order to investigate  the effect of calcium salts trunk injection on this disorder, an experiment was conducted since 2003, using four replicatios of a randomized complete block design with 7 treatments: Check , injection of saturated solution of calcium sulfate , %1 solution of calcium nitrate and chloride in two times  (second half of Feb and Apr ). Every plot contained one tree in two garden that had been infected with this disorder in recent years. A hydraulic pump was used to inject the solution into tree trunks. Results showed three different groups of disorder injury. The first group consisted of the check (76.3% injury) , calcium chloride, and sulfate treatments, indicating that these two salts had no significant effect on reduction of disorder injury . The second group was injection of calcium nitrate in the second half of Feb that had significantly decreased disorder injury in contrast to the first group (48.5 %) .The least disorder injury was observed in the two-stage injection of calcium nitrate (38.5%).Correlation of mean leaf calcium concentration and disorder injury was significant in one of the experimental sites (R=-0.88**).Calcium concentration of bunch and leaf increased significantly with high pressure injection method, indicating that, in similar conditions, this method can be used to provide nutrients to the palm trees.

Measuring cation exchange capacity (CEC) of soils is both time consuming and expensive. CEC can be estimated, indirectly, from some readily and cheaply measured chemical and physical properties of soils. The objective of this study was to develop a proper pedotransfer function (PTF) for predicting CEC in soils of Guilan by particle size distribution, organic carbon percentage and acidity (pH). A total of 1676 data from the soil chemical laboratory of Rice Research Institute of Iran database in Rasht, Guilan, were used to develop the predictive CEC model: 1260 data were used for model calibration and 416 data were used for validation. The variables were selected by using stepwise regression method. The developed model (CEC=15.524+0.32 Clay+7.863 OC0.5 - 1.453 pH) was compared with the other existing models and was selected as the best predictive model on the basis of the greatest R2adj and the smallest ME and RMSE. The results showed that 42.8 percentages of CEC variations can be interpreted by clay, organic carbon and pH variables, with the clay variable having the largest impact according to the greatest b coefficient.

This experiment was conducted to study different chemical forms of Zn (native and applied Zn) in some selected paddy soils of Mazandaran. Twenty soil samples with the widest range of physicochemical properties, especially with respect to the levels of available Zn and P, were selected out of some 40 surface soils (0-30 cm) collected in rice paddies of east Mazandaran. A completely randomaized block factorial experiment (20×2) with two levels of Zn (0 and 10 mg Zn/g soil as ZnSO4.7H2O) and three replications was carried out on the 20 soils in the greenhouse. Different chemical forms of Zn i.e., exchangeable, sorbed, organic, carbonate, and residual were fractionated by 0.5M KNO3, XH2O, 0.5M NaOH, 0.05M Na2EDTA and 4M HNO3 extractants, respectively in order to determine the amount and chemical form of Zn fractions. The extracted Zn was determined by atomic absorption and ICP-AES instruments. The results showed that KNO3-Zn (exchangeable Zn) was determined as non detectable (ND) zinc. Total Zn, in untreated soils (native Zn) ranged from 49.3 to 84 mg/g with a mean of 63.4 mg/g. Distribution of native Zn in different soil chemical fractions were in the fallowing order: Residual >>> Carbonate> Organic> Sorbed> Exchangeable Most of the applied ZnSO4 was converted to residual and carbonate forms as much as 40.4 and 34.9 percent respectivily. Redistribution of Zn fractions as affected by 10 mg Zn/g soil were in the fallowing order: Residual > Carbonate> Organic> Sorbed> Exchangeable.

Distribution of soil magnetic susceptibility (χ) and Fe compounds were studied in 14 soil profiles, reflecting key climatic conditions, land use, and drainage classes in Fars Province. Magnetic susceptibility was measured both on oven-dry basis (χod) and minerogenic basis (compensating for mobile diamagnetic materials such as carbonates and gypsum, χm). Magnetic susceptibility of eluvial horizons was greater than that of the illuvial horizons in most of the soils. This is probably a result of eluviation of diamagnetic materials as well as pedogenic formation of ferrimagnetic minerals in soil surface. Poorly and somewhat poorly drained soils had distinctly lower χm than well-drained soils. There was a positive significant correlation (P<0.01) between crystalline pedogenic Fe (Fed-Feo) and χm. Similar relationship was noticed between mean annual rainfall and χm.

In order to isolate and characterize the Iranian indigenous Azospirilla, 404 soil and plant samples were collected from 12 provinces. One hundred and fifty isolates capable of forming a veil-like pellicle in a semi solid medium, free of N and with bromethymole blue (NFB), were subjected to primary isolation and characterization. Seventy six isolates were tested and classified into 4 species, based on their growth in a 3% medium of sodium chloride, biotin requirements, consumption and production of acid from glucose and production of polymorphous cells in a NFB medium. The   phenotypic specification of indigenous species were compared with those of A.lipoferum, A.brasilense, A.irakense and A.halopraeferense .The highest number of isolated species belonged to Golestan (25 isolate), Fars, and Khozestan Provinces, respectively. Despite the higher area and number of sampling at Khorasan province, the lowest number of isolates belonged to this province. This may be attributed to the low level of organic matter and unfavorable agricultural condition at this province. Most of the isolated species (80%) were collected from rhizosphere of the gramineous plants, especially wheat. Among the identified species, A.lipoferum was the highest in number, followed by A.brasilense and A.irakense. Only one isolate was morphologically and physiologically similar to A.halopraeferense.

Recent use of wastewater, some chemical fertilizers, and pesticides at agricultural farms have caused problems such as accumulation of heavy metals in soil and agricultural products. One way to solve this problem is to use biologic methods. In a greenhouse experiment, tomato (C.V..Soltan) was inoculated with two species of VA mycorrhiza (Glomus verci form and Glomus etunicatum) or left uninoculated as control plants in sterilized sand. The plants were then treated with three levels of phosphorus (5, 20, 40 mg P/kg), and three levels of Cadmium (0.02, 1, 5 mgCd/L) . A factorial RB design was used with four replications. Statistical analysis indicated that the percentage of root length colonized (RLC) was increased significantly but Cd concentrations of root, shoot, and fruit was decreased significantly (P<0.01) with phosphorus. Percentage of (RLC) was decreased significantly and Cd concentration of fruit, root, and shoot increased with increasing cadmium (P<0.01). The main effect of Fungus not only had positive significant effect on percentage of(RLC) and Cd concentration of root, but also had negatively significant effect on Cadmium concentration of fruit and shoot (P<0.01). The effect of (fungus * Cadmium) was significant on percentage of (RLC), (P<0.01) and Cadmium concentration of fruit and shoot (P<0.01). The effect of (Fungus * P) was significant on percentage of (RLC), (P<0.01). The effect of (Cd * P) was significant on Cadmium concentration of fruit and shoot (P<0.01). Correlation analysis between  measured parameters indicated that percentage of (RLC) had negative correlation with cadmium concentration of fruit and shoot (P<0.05). Also positive correlation was observed between Cd concentration of fruit with Cd concentration of shoot and root (P<0.01). Cadmium concentration of root positively correlated with Cd concentration of shoot (P<0.01). Considering these results, VA mycorrhiza inocolum may be used on polluted soils to reduce toxicity of heavy metals in plants. Second level of phosphorus, which is 20kg P/ha less than the recommended rate for tomato, can be recommended without any reduction in the quality of fruit or mycorhizal activity in tomato roots, but after farm testing.

There are definite relations among growth of plants and function of roots and shoots. Interactions between shoot and roots can also be characterized and quantified by allometric relationships. In order to study the effect of phosphate solubilizing bacteria and other phosphate fertilizers effects on allometeic relationship for root and shoot of rice, an experiment was conducted in randomized complete block design with three replications. The filed experiment was conducted at the Rice Research Institute located in Tonekabon-Iran. Fertilizer treatments included microbial biophosphate, phosphate solubilizing bacteria (PSB), rock phosphate (A), triple super phosphate (TSP), triple superphosphate %50 (TSP50%), triplesuper phosphate%50 + PSB and rock phosphate + PSB. Root and shoot characteristics including root dry weight (RDW), leaf dry weight (LDW), shoot dry weight (SDW), total dry weight (TDW) and rate of root/shoot were determined. Analysis of variance showed that the effect of different treatments on the allometric coefficient was significant (P<0.05). Shoot dry weight and total dry weight were the highest in A+PSB treatment. The highest rate of RDW and rate of root/shoot were obtained in A+PSB treatment while the highest LDW was observed in TSP50% treatment. Allometric coefficient was the highest in A+PSB treatment.