عنوان مقاله [English]
Plants show different morphological and phonological responses to ecological conditions within their tolerable range, which are in fact part of their heredity. These changes have a key role in species survival and ecosystems sustainability. Agricultural ecosystems are very fragile due to the severe limitations of genetic diversity and biodiversity. In an agro-ecological approach, unlike current agriculture, careful consideration of the livelihood stages and other living organisms in the ecosystem is of interest, and so it is attempted to manage production as well as the optimal use of agricultural inputs.
Material and methods:
In order to study the phonological changes in four bread wheat genotypes (Gonbad, Karim, Koohdasht, Morvarid), at different levels of urea fertilizer application (0, 66, 200 kg/ha), a factorial experiment was conducted in a randomized complete block design with three replications in two crop years of 2014 and 2015 at Agricultural Research Station of Gonbad-e-kavoos.
Results and discussion:
The results of this study showed that the length of vegetative and reproductive stages in these two years are different, and the effect of urea content on these stages is not the same in different ecological conditions. Therefore, it was concluded that under different temperature and humidity conditions. it is possible to apply fertilizer management, without having a significant effect on the length of the phonological periods. Observations of this experiment showed that the stalking stage is more stable compared to the previous steps, so that the length of this stage was only 0.63 day in two years, and changes in different levels of fertilizer application did not show any significant difference in two years. It seems that the length of this period is less influenced by environmental factors than the other stages of wheat growth and in other words. it is expected to have a higher inheritance. Changes in the pregnancy stage are also relatively similar to the stalking stage. Even though the consumption of 200 kg/ha urea fertilizer slightly increased the change of the slope, in such a way that 68% slope the increase of the span of the period from the treatment until 66 kg/ha, urea fertilizer is changed into 111.9%, but the amount of this increase is only 0.75 day. It can be concluded that although the length of this stage of plant growth is more affected by environmental factors over the pregnancy stage, in general, the amount of this impact is not high. Observations of this study showed that the studied wheat cultivars (whether they are introduced for dry conditions or supplementary irrigation) during the course of their growth reached the stages of emergence of spike, flowering, and seedling 7.5 to 8.5 days later in the second year (pluvious) than the first year (lower rainfall). So that the difference between these two years for the emergence of the spike on average was 8.33 day, for flowering stage 7.72 day, and for the processing stage 7.56 day. Changes in fertilizer use in these three steps were similar in both years.
This study is important in management and controlling the population of non-cultivated plant species, pathogens (fungi and bacteria), insects and other species in the amount and sustainability of crop production.