جستجوی مقالات مرتبط با کلیدواژه « درجه روز رشد » در نشریات گروه « اکولوژی »

Weeds control is very important to achieve optimal yield in agricultural products. The purpose of this study was to determine the critical period for weed control (CPWC).of garlic in chemical and organic nutrition management in Ramhormoz.

A factorial experiment based on randomized complete block design (RCBD) was carried out in 2019—2020 with three replications in Khuzestan-Ramhormoz province. The first factor included nutritional management (chemical and organic) and the second factor included 12 treatments of interference and control period of weeds (0, 20, 40, 60, 80, 120 and 160 days).

Determining the critical period of garlic weed control in two chemical and organic nutrition management revealed that the beginning of the critical period in organic application will be happen later than chemical fertilizers. Also, the end of the critical period in chemical application of was predicted later than fertilizers. Also, the end of the critical period in application chemical was predicted later than organic fertilizers. The length of the critical period for weed control was higher than in chemical than chemical application compared to organic fertilizers. With 5% loss yield, the beginning, end and length duration of the critical period for weeds control in organic management were 202, 1518 and 1316 GDD and in application chemical fertilizers were estimated 210, 1638 and 1428 GDD respectively.

The results indicated that length duration critical period for weed control in organic nutrition management (120 days) will be shorter than chemical management (127 days).

The present study was carried out to compare the phenology of annual ground cherry (Physalis divdricata L.) and its effect on maize yield ‎ ‎.

A field experiment was conducted in the Research Station of Mahidasht in Kermanshah Agricultural and Natural ‎Resources Research and Education Center, in 2017.‎ Different densities of annual ground cherry, including 0, 8 and 16 plants m-2 and corn were planted.  The competition‎ and their phenological stages ‎were recorded based on GDD (growing degree days) for each growing stage. ‎

The results of this study showed that ‎annual ground cherry ends its phenological stages later than corn. In order to complete its life cycle, ‎‎1262.7 growing degree days and 159 days were needed. Thus, complete life cycle of corn required ‎‎1890.7 GDD and 139 days.Both plants passes the early stages of growth and ‎germination concurrently, Maize, however, ‎comleted Vegetative growth and seed ‎ripening more earlier than annual ground cherry. ‎Also, the results of studying the effect of different densities of ‎annual ground cherry on yield and yield components of corn including 1000-seed weight, number of seeds per ear row, corn harvest index and leaf area index showed that all these traits decreased by increasing density of annual ground cherry. However, the number of seed rows per ear, which is genetically-control trait, was not affected by competition with annual ground cherry. In contrary to the above traits, the density of this weed increased with the effect of increasing the height of corn and as a result, increasing the biomass of corn compared to control. In general, weed densities of the 8 and 16 plants m-2 decreased maize yield by 10 and 14 percentages, respectively.

The results of this study suggest that if corn fields are infected with this weed and we do not ‎succeed in combating it in the early stages, earlier harvest of corn in the fall will allow it to be ‎harvested by cultivation methods or using a general herbicide of this weed before its seeds are fully ‎ripen.

The aim of this study was to quantify the effect of managerial factors such as summer planting date on Heat Summation Unit (HSU), phenology and faba bean yield based on number of days and Aggregation Growth Degree Day (AGDD) and to introduce the most suitable genotypes adapted to Mediterranean climatic conditions in the Caspian sea was conducted.   Materials &

In order to investigate effect off-season planting date (Summer) on phenology and yield of faba bean var. Luzde otono using accumulation of thermal units conducted at the Gharakhil Agricultural Research Station in 2014 and 2015. Treatment included four summer sowing dates (July 23, August 7, August 23, September 7) by experiment based on randomized complete block design with three replications.  

The results showed that cultivar Luzde otono in the second planting date (August 7) with 9100 kg which has increased by 124% compared to the last planting date (September 7) had the highest yield (green pod). The unit of heliothermal was more in 2015 (from 0.800 to 1.320) compared to 2016 (from 0.576 to 0.983). On August 7, the efficiency of heliothermal consumption (1.320) increased compared to the first date of August 1 (1.200), which was due to the increase in average air temperature and the number of hours of sunshine. Also, among the studied indicators, the efficiency of heat consumption (HUE) and the efficiency of consumption of sunny hours (RUE) as well as estimated thermal requirement of faba bean Luzde otono cultivar in different cultivation dates and at different stages of development and in this direction, due to having a constant and logical trend, they have a relative superiority over other indicators such as GDD and PTI.  

According to the findings of this study, in order to prevent the coincidence of flowering period and seed filling with heat stress, The summer cultivation of faba bean Luzde otono cultivar has been avoided in June and July and recommended in order to obtain the highest yield (green pod) that cultivation be done in late August.

IntroductionSpecific characteristics of canola and its adaptability to the various climatic conditions, have increased the importance of this product, and has turned it into a hope to supply the edible oil needs of the country. Canola, like other crops, with its own ecological characteristics, with the lack of any of these features lead to the development of the crop in some parts of the country. The total rainfall for the growing season dry land canola about 400-500 millimeters and lack of water and drought at planting and seedling emergence can result in a weak and ultimately reduce performance. The temperature suitable for the development of this plant is 25 to 30 ° C and temperatures over 35 ° C cause prolonged loss of germination ability and the ability of pollening. A study to compare the thermal needs of rape in the provinces of Khorasan came to the conclusion that different parts of the study area in terms of providing optimal temperatures are different for canola. Study as potential climatic zoning wheat cultivation in West Azerbaijan province, it concluded that the role of each of temperature and rainfall, according to the different stages of development in different regions is different.The study also aimed to assess the distribution of suitable rainfall and suitable temperature in the "planting to emergence" of rainfed canola was conducted in various parts of the Khuzestan province.
Materials and MethodsKhuzestan province in the range of 47 degrees and 42 minutes to 50 degrees and 39 minutes east of Greenwich and 29 degrees 58 minutes to 32 degrees and 58 minutes north of the equator is located. According to the climatic classification based on Domarten, the Khuzestan province has three arid, semi-arid and is Mediterranean. Parameters studied were daily maximum and minimum temperature, total daily precipitation, Growth Degree Day (GDD) and land topography condition.
To determine the exact time of the end of "planting to emergence" rainfed canola index GDD was used. Rainfed canola GDD required for this stage is 120.
In order to determine probability of rainfall for the "planting to emergence" of rainfed canola, according to the amount of precipitation for this period is 50 mm, the log-Pearson Type III distribution was used.
To determine probability of suitable temperature stage "planting to emergence" of canola rainfed, normal distribution was used. Suitable temperature at this stage is between 10 and 25 °C, Z=(X-X ̅)/S Z= level probability, X ̅= Average, S= standard deviation, and X as desired temperature us.
The feasibility of canola For this purpose, probability suitable rainfall and suitable temperatures of different stations in the GIS software was used.
Results and DiscussionHumidity is an important factor affecting agriculture, especially in rainfed agriculture, and correct information is useful in precipitation during the last few years. Geographical distribution of the suitable rainfall probability in the "planting to emergence” of canola rainfed was reached. Geographical distribution of the suitable temperature probability in the "planting to emergence" of rainfed canola was reached. The overlay map of the geographic distribution of probability of suitable rainfall, and map of the geographical distribution of probability of suitable temperatures, and land use map of the province, the software Arc Map, map of the geographical distribution of probability of suitable rainfall and temperatures for rainfed canola was obtained.
ConclusionAccording to the results, arable land study area was classified into three parts. Very poor areas, which probability of suitable rainfall and temperatures for the "planting to emergence " is less than 25 percent, and 33.7% of the arable land in the province are included. A poor area, which probability of suitable rainfall and temperatures for the "planting to emergence" is between 25 to 50 percent and 66.2% of the arable land covers the province. A middle-class area, which probability of suitable rainfall and temperatures for the "planting to emergence" of 50 to 75 percent, which is 0.01% of the arable land, covers the province.

In order to evaluate phenologic and thermal time response of three maize hybrids (KSC 704, Maxima and TWC 604) in different rates of nitrogen (0, 92, 220 and 368 kg ha-1), a two-year experiment was laid out as a randomized complete block design with a factorial arrangement of treatments and three replications in 2014 and 2015. Results showed that nitrogen and genotype had a significant effect (p

Salinity is one of the most restrictions in plant growth in dry and semi dry land which effects production of many crops such as sesame. In order to study the phenology and morphology characteristics of 43 ecotypes and line of sesame (Sesamum indicum L.) under salinity of irrigation water (5.2 dS.m-1) a field experiment was conducted at research farm of center of excellence for special crops, Ferdowsi University of Mashhad, Iran, during growing season of 2009-2010 based on a randomized complete block design with three replications. Results showed that four sesame ecotypes could not emerge, 14 sesame ecotypes had appropriate emergence but died before reproductive stage and only 58 % of sesame ecotypes could alive until maturity. There was significant difference between sesame ecotypes for phenological stages and were varied from 64 to 81 days for vegetative and 60 to 65 days for reproductive stages. Plant height, number and length of branches also were different between sesame ecotypes. The highest and the lowest plant height were observed in MSC43 and MSC12 ecotypes, respectively. Number of branches per plant was from 1 to 8 and length of branches in 32 percent of ecotypes was more than 100 cm. There was a considerable correlation between seed weight in plant with reproductive growth (r=0.38**) and plant height (r=0.25). In addition different response of sesame ecotypes to saline water and also better morphological indices in some sesame ecotypes may be show the tolerance of these accessions to salinity. More studies may be useful for selection of sesame salt tolerance resources.