J. Ghaderi; F. Nourgholipour
Abstract
Introduction: Due to the compatibility of canola with different conditions, economic value, its price and importance of rotation with cereals, it has the highest level of cultivation area among the oilseed crops in Iran. Phosphorus (P) deficiency is a widespread macronutrient deficiency and is one of ...
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Introduction: Due to the compatibility of canola with different conditions, economic value, its price and importance of rotation with cereals, it has the highest level of cultivation area among the oilseed crops in Iran. Phosphorus (P) deficiency is a widespread macronutrient deficiency and is one of the major limiting constraints for canola production. Despite its importance, it limits crop yield on more than 40% of the world’s arable land and 70.2% in Iran. Moreover, global P reserves are being depleted at a higher rate and according to some estimates, there will be no economic P reserve by the year 2050. This is a potential threat to sustainable canola production. Most of the P applied in the form of fertilizers may be adsorbed by the soil, and would not be available for plants lacking specific adaptations. It is widely accepted that the most realistic solution to the problem of P deficiency is to develop new plant cultivars that adapt to P-deficient soils. Phosphorus efficiency is a term that generally describes the ability of crop species/genotypes to give higher yield under P-limiting condition. Plant species as well as genotypes within the same species may differ in P efficiency. This study was conducted to determine the effect of phosphorus fertilization on the grain yield and phosphorus efficiency indices in different canola cultivars.
Materials and Methods: The present study was carried out at the research farm of the Mahidasht Agricultural Research Station located 20 km away from Kermanshah (with elevation of 1265 m). This experiment was conducted as factorial in a randomized complete block design with three replications with 2 factors including canola varieties and different amounts of phosphorus fertilizer. The first factor consisted of five triple superphosphate (TSP) levels (0, 16, 32, 49, and 61 kg per ha) and the second factor consisted of three cultivars (Okapi, Opera and Zarfam). This research was conducted on soil where the amount of available phosphorus was lower than the critical level required for canola (15 mg kg-1). Prior to sowing, all phosphorus treatments with 30 kg ha-1 of zinc sulfate fertilizer as well as one-third of nitrogen fertilizer (100 kg ha-1 urea) were applied during planting and mixed thoroughly with the soil. The remaining urea fertilizer was applied at two stages of stem growth (120 kg ha-1) and early flowering (100 kg ha-1). Each experimental plot had an area of 12 m2. Irrigation method was sprinkler. Grain and straw yield were determined after the harvest and seed samples (harvesting stage) were taken and rinsed with distilled water, oven dried at 70 °C, ground, digested and analyzed for determining the P concentration. Analysis of variance was performed using SAS software and mean comparisons performed by Duncan’s multiple range tests (P ≤ 0.05).
Results and Discussion: The results showed that the interaction effects of phosphorus fertilizer rate and canola cultivars on leaf P concentration, grain and straw yield, grain P concentration and uptake, and P efficiency indices were significant. In average of the two-years, the highest grain and straw yields (3203 and 4613 kg ha-1, respectively) were obtained from 300 kg ha-1 P fertilizer rate for Okapi cultivar. Under the P deficiency condition, no significant difference was observed between cultivars in terms of grain yield. Significant differences were observed among three cultivars in terms of P efficiency. Opera cultivar was efficient in absorption (0.84) and Zarfam cultivar was efficient in phosphorus utilization (152 kg grain / kg fertilizer), but Opera was phosphorus efficient. With application of phosphorus fertilizer, phosphorus use efficiency decreased and the highest amount was found for the control treatment which produced 169 kg seeds per kg of phosphorus. The lowest amount of this characteristic was obtained for 300 kg phosphorus fertilizer treatment. Considering the correlation between phosphorus stress factor and P uptake efficiency, it seems that P efficiency was dependent on P uptake (R2 = 0.477 **) rather than P utilization (R2 = 0.076 ns).
Conclusion: Phosphorus uptake efficiency can be used for selecting P efficient cultivars of canola under farm condition. Application of Opera and Okapi cultivars with 80 kg of fertilizer per ha in similar conditions of this experiment would be advisable and excess phosphorus fertilizer application would not significantly increase grain yield. Selecting suitable varieties could decrease application of chemical fertilizers in the soil.
Y. Azimzadeh; H. Shariatmadari
Abstract
Phytoremediation is one of the lowest-cost methods for remediation of soils contaminated with heavy metals. This study was conducted to investigate the phytoremediation potential of corn and canola, grown under single and mixed culture systems. Thus, a pot experiment was carried out on a calcareous ...
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Phytoremediation is one of the lowest-cost methods for remediation of soils contaminated with heavy metals. This study was conducted to investigate the phytoremediation potential of corn and canola, grown under single and mixed culture systems. Thus, a pot experiment was carried out on a calcareous soil contaminated by Pb and Zn. Treatments included single culture of corn, single culture of canola and mixed culture of corn and canola. Results showed that bioavailability of metals, lead, zinc, nickel and copper increased with decreasing soil pH and increasing DOC as influenced by root activity. Root uptake of metals; lead, zinc, copper and nickel in mixed culture, was more than that of in canola and lower than that of in corn. Zinc and nickel uptake by shoots of canola and mixed culture, were more than corn. Also, the results concerning the uptake of metals in the total biomass (sum of roots and shoots) showed uptake of copper and nickel in corn was more than mixed culture and it was more than canola while, uptake of lead and zinc in corn and mixed culture was more than canola. Also, the total yield of corn and canola in mixed culture increased. Therefore, it seems use of mixed culture system may extract metals, zinc and nickel more than corn, and copper more than canola, in single culture systems.
A. Shahnazari; Mirkhaleg Ziatabar Ahmadi
Abstract
One of the important components of suitable operation of subsurface drainage systems is its envelope. Several researchers have evaluated the efficiency of dry land drainage, but the operation of these materials in subsurface drainage systems of paddy fields has not been investigated. In this research, ...
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One of the important components of suitable operation of subsurface drainage systems is its envelope. Several researchers have evaluated the efficiency of dry land drainage, but the operation of these materials in subsurface drainage systems of paddy fields has not been investigated. In this research, the effects of two mineral and artificial envelopes on flow rates of drainage system in paddy fields of Sari Agricultural Sciences and Natural Resources university lands have been investigated. For this purpose, a drainage system consisting of 4 drain lines at 0.65 m depth and 15 m spacing was installed. For two drain lines, mineral envelopes and for other two drains artificial envelopes were used. During one canola growing season, the drain discharges were measured daily. There was significant difference (p=1%) between the mean discharge of drains so that the average drain discharge of drain with artificial envelope was 88 percent higher than the corresponding value of drain with mineral envelope. Based on the drainage water depth-rainfall relationship, the average of daily discharges of drains with artificial and mineral envelopes was equivalent to 2.5 and 1.8 mm rainfall, respectively. Also, comparison of the total costs of the two drainage systems showed that the drainage system with artificial envelope was 30% less expensive than drainage system with mineral envelope.
