Showing 6 results for Phenology
M. Basirat, H. Seyedoleslami,
Volume 4, Issue 1 (4-2000)
Abstract
In 1996 and 1997 pistachio orchards in Isfahan Province were surveyed to determine the presence and damage levels by Eurytoma plotnikovi Nikolskaya and Megastigmus pistacia Walker. In order to investigate seasonal population fluctuation of E. plotnikovi, larval, pupal and adult stages were monitored in three orchards. In each orchard, 200 nuts with more than 50% infestation to overwintering larvae were dissected and examined twice weekly. In 1997 in one orchard, at intervals of one week, 100 randomly selected fresh nuts were examined to determine oviposition trend and damage development. In this field, the biology of the pest was also compared to developmental stages of pistachio trees. In most orchards visited, E. plonikovi was present and was the dominant species in relation to M. pistacia and its damage varied between 0.8-75%. In 1997, start, peak, and end of pupal stage were observed on April 4th, May 7th and May 21st. Start, peak and end of adult emergence occurred on May 4th, May 18th and June 4th. In two other orchards, almost a similar trend was observed. Start, peak and end of oviposition were also observed on May 18th, May 28th and July 2nd. Development of pistachio tree was divided into nine stages and the above mentioned dates were compared to that.
E. plotnikovi had one generation every one or two years. Only one egg was found in each infested fruit and first stage larvae had a long prefeeding period. The use of the information obtained from this study in the management of these pests is discussed.
H. Matinkhah,
Volume 10, Issue 4 (1-2007)
Abstract
Phenology is the study of time and sequence of recurring stages in the life history of an organism. The occurrence fashions of the phenophases form different phenological behavior patterns. Despite the importance of phenology and wide applications of knowing phenophases, few studies have been done on the wooden species in Iran. The goals of this study are identification and designation of the phenophases occuring time and their successions, phenological behavior patterns and finally phenological patterns assay of 35 fruitful and fruitless woody species in the northeast of Esfahan during 2003-2005. Leaves, flowers, fruits, buds, bark and color changes were observed weekly or every other week. Analysis of the obtained charts and tables shows that with respect to the environmental and climatic condition of the area, observed phenological behavior patterns are two- leaf, two-flower and two-fruit emergent patterns two-flower peak patterns three-fruit perpetuity patterns and three leaf shed patterns. Finally, there are three comparative successions, six-flower and three-leaf phenological patterns. Based on the findings, blooming and leaf shed calendars were also achieved.
A. R. Valdiani, M. Tajbakhsh,
Volume 11, Issue 1 (4-2007)
Abstract
A total of 25 advanced rapeseed (Brassica napus L.) varieties were evaluated under cold weather conditions using Randomized Complete Block design (RCBD) with four replications in Dr. Nakhjavani Agricultural Research Station, 35 km North-East of Urmia the capital of West Azerbaijan province in 2000-2001. The results showed significant differences among the varieties (P ≥ 0.01) for all the phenological stages including days to germination, days to rosette completion, days to initiation of stem elongation, days to flowering initiation, pod formation stage and days to maturity. The spring varieties Sarigol (PF7045/91), Hyola 42 and SYN1 and autumnal varieties Alice, Eurol, Fornax, VDH 8003-98, Consul, Licord and Zarfam (Regent× Cobra), showed early maturity. On the other hand, Mohican, Olara, Colvert, L-1 and Akamar were late mature varieties. In fact, the most prolific varieties, DP.94.8, Zarfam (Regent ×Cobra) Cocktail, Consul and SLM046 (control variety) had the highest ability survive in the cold conditions and they completed their rosette stage sooner than the other varieties. There was positive and significant correlation between duration of pod formation stage and seed yield. Maturity date of varieties was positively and significantly correlated with harvest index, number of seed per pod, days to germination, days to rosette completion, days to stem elongation, days to flowering, and days to pod formation. Negative and significant correlations were found between days to maturity and duration of flowering and pod formation stages. It can be concluded that delay in initiation or completion of each growth stages could delay maturity of the rapeseed varieties.
H. R. Eshghizadeh, M. Kafi, A. Nezami, A. H. Khoshgoftarmanesh, M. Karami,
Volume 19, Issue 73 (11-2015)
Abstract
This study was conducted to determine some mineral content concentrations in soils and plants of three elevation classes (1500, 2200 and 3000m) and two phenological stages of flowering and seedling in north facing slopes of Sabalan rangelands. Soil samples from the depth of 20cm and plant samples using 1×1m plots with 10 replications were collected. After sample preparation, the concentrations of minerals such as calcium, phosphorous, sodium, potassium, ion, copper, zinc and magnesium were determined using spectrophotometer and flame photometer. Data was analyzed by SAS9.1 software using a Completely Randomized Design with a Generalized Linear Model procedure. Results showed that elevation had a significant effect on Ca, Fe, Cu, Zn and Mn of soil and P, Na, K, Mg and Mn of plants in the study areas (P&le0.05). Growing stages had a significant effect on all elements of plants except Ca (P&le0.05). Moreover, results showed that in three elevation classes the high demand minerals' concentrations were higher at the starting seedling stage in comparison with the flowering stage. In contrast, the low demand minerals' concentrations in three elevation sites were higher in the flowering stage in comparison with seedling stage. Interaction effect of elevation and growing stage was also significant in relation to all elements except Ca (P&le0.05).
R. Valizadeh Yonjalli, F. Mirzaei Aghjehgheshlagh, A. Ghorbani,
Volume 19, Issue 73 (11-2015)
Abstract
This study was conducted to determine some mineral content concentration in soil and plant of three elevation classes (1500, 2200 and 3000m) and two phenological stages of flowering and seedling start in north-facing slopes of Sabalan rangelands. Soil samples from the depth of 20cm and plant samples using 1×1m plots with 10 replications were collected. After sample preparation, the concentrations of minerals such as calcium, phosphorous, sodium, potassium, ion, copper, zinc and magnesium were determined using spectrophotometer and flame photometer. Data was analyzed by SAS9.1 software using Completely Randomized Design with a Generalized Linear Model procedure. Results showed that elevation had a significant effect on Ca, Fe, Cu, Zn and Mn of soil and P, Na, K, Mg and Mn of plants in the study areas (P&le0.05). Growing stages had a significant effect on all elements of plants except Ca (P&le0.05). Moreover, results showed that in three elevation classes the high demand minerals’ concentration was higher at the starting seedling stage in comparison with the flowering stage. In contrast, the low demand minerals’ concentration in three elevation sites was higher in the flowering stage in comparison with seedling stage. Interaction effect of elevation and growing stage was also significant in relation to all elements except Ca (P&le0.05).
H. Sadoghi, T. Rajaee, N. Rouhani,
Volume 24, Issue 4 (2-2021)
Abstract
Identification and investigation of changes in the area under cultivation of various crops seem to be essential for the management supply of crop production. In this study, r to identify and investigate change of the area under cultivation in major crop Hoseynabade Mishmast region in Qom province, we used the time series images of OLI and ETM sensors of landsat 8 and 7satellites, according to the crop calendar of this region. By using the vegetation index (NDVI) in the decision tree algorithm, the thresholds of this index were adjusted according to the major crops of this region; then a map of the cultivation pattern of the crop of this region was prepared. In order to evaluate the results, the statistics of the provinces agricultural jihad were used during 2005, 2009, 2014 and 2019 crop years. The results showed that by using the threshold of NDVI index, crops in this region in 2005 included wheat and barley and alfalfa, and their areas had an error of 17/1 and 6/1 percent in comparison with the statistics of agricultural Jihad, respectively; in 2009, wheat and barley, alfalfa and corn had an error of 0/5, 9/6 and 0/1 percent. Also, in 2014, wheat and barley, alfalfa, corn and sophie crops had an error equal to 4/9, 0.4, 11/4 and 2/4 percent, and the same crops in 2019 had an error 0/04, 11/6, 1/4 and 17/5 percent; that error was not significant. According to the results, the appropriate efficiency NDVI index in estimating crop cultivation area was determined by their phenology. Also, in 2009 and 2014, corn and sophie crops were added to the regions crops, and the area under crops cultivation in 2019 was increased, as compared to 2014.
