leaf area index

In the sustainable agriculture system, the use of plant hormones has received more attention in recent years due to the potential for reducing the use of chemical fertilizers and increasing the quantity and quality of the produced crops. To investigate the effects of cytokinin foliar application on the physiological and yield characteristics of cowpea cultivars, a split-plot experiment was conducted in randomized complete block design with three replications in the two crop years of 2018 and 2019 in Dezful city. The main factors included Mashhad, local, and Arabic cultivars, and the secondary factor was foliar application of cytokinin hormone at 100 and 200 ppm. Hormonal foliar spraying was done at the beginning of the flowering stage. The results of combined variance analysis showed that there was a significant difference between cultivars for all traits, except for the harvest index. The correlation between seed yield and protein percentage, hundred seed weight, and biological yield was positive and significant, with the highest correlation related to seed protein percentage (0.958). The highest seed yield (with an average of 2281 kg/ha) belonged to the Mashhad variety, and the lowest yield (with an average of 1386 kg/ha) belonged to the Arab variety. The highest and lowest seed yields were obtained from the use of 200 ppm of cytokinin hormone and the control treatment (with an average of 2319 and 1327 kg/ha, respectively). Increasing the use of cytokinin improved quality traits such as chlorophyll index and seed protein. In general, it was found that the selection of high-yielding Mashhad variety and foliar spraying of 200 ppm of cytokinin hormone, in addition to increasing yield, could improve quality traits in cowpea.

Available water is the main factor limiting crop growth and production in arid areas. In this regard, in order to investigate the effect of silicon application on morphological, physiological and yield characteristics of sunflower under different moisture levels, an experiment was conducted in the crop year 1397-1398 in Gonabad. This study was conducted as a split plot in a randomized complete block design with three replications. The main factor of irrigation with different moisture levels based on water requirement includes four levels (100% water requirement, 80% water requirement, 60% water requirement and 40% water requirement) and the secondary factor of silicon consumption time. There were four levels (no application (control), application in vegetative stage, application in reproductive stage, application in vegetative stage and reproductive stage). The results showed that reducing the moisture level from 100% to 40% of water requirement reduced the quantitative traits studied; So that the lowest seed yield (1730.8 kg / ha) and oil yield (583.41 kg / ha) were obtained in the treatment of moisture level of 40% of water requirement. Also, the application of silicon under low moisture levels based on water requirement improved the effects of reducing moisture levels in all evaluated traits and seed yield. The highest seed yield (7572.96 kg / ha) was obtained in the treatment of 80% water requirement and application of silicon in the vegetative and reproductive stages and the lowest value (1193.54 kg / ha) was obtained in the treatment of 40% water requirement and without the use of silicon. Also, the application of silicon in the vegetative and reproductive stages compared to the non-application treatment (control) increased 2.5, 1.5 and 2.5 times the oil yield at different levels of moisture, including 80, 60 and 40% of water requirement. In general, the results showed that the use of silicon in the vegetative and reproductive stages at a moisture level of 80% of the water requirement compensated for the adverse effects of reducing the moisture level in the studied traits.

In order to Assessment of the role of growth reduction factors on some morpho-physiological and yield indicators of rice cultivars an experiment in the year 2018 was conducted as split plot in a randomized complete block design with three replications. Experimentation factors included various rice varieties: Champa, Chermez-anbori and Hoveizeh in the main plot and reducing growth factors include: control (without cutting), consumption of half a liter of medax top in 45 days after planting, cut 65 days after planting to a height of 35 cm and cut 85 days after planting at a height of 35 cm in the subplot was. the results showed difference between levels of reducing growth factors in terms of stem height, panicle number, number of hollow seed per panicle and seed yield were at 1% probability and 1000-seed weight at 5% level. the difference between cultivars in terms of number of hollow seed per panicle at 1% level and 1000 grain weight at 5% probability level. highest number of hollow seed per panicle was in the control and the lowest in the cut 65 days after planting. the highest grain yield was obtained in the application of medax top with average of 4.7 tons/h and the lowest grain yield with average of 3.19 tons/h was obtained by cutting in 85 days after planting. so it can be cut by 65 days after the planting and use of the medax top or using the hoveizeh cultivar to reach the desired results in the region.

In order to effect of humic acid on yield, yield components and physiological parameters of wheat in deficit irrigation conditions this research was done as split plot in randomized complete blocks design with three replications. main plots consisted: full irrigation, no irrigation at the beginning of stem elongation, and no irrigation at the pollination stage and sub plots included different levels of humic acid fertilizer (0, 100, 200 and 300 mg/L). Results showed that interaction of irrigation and humic acid on number of seeds per spike and 1000 grain weight at 1% probability level and number of spikes per unit area and harvest index was significant at 5% probability level. Grain yield under the effect low irrigation and humic acid was significant at 1% probability level. The highest leaf area index and crop growth rate were affected in full irrigation and 300 mg.L-1 humic acid and least of them were obtained in low irrigation stress conditions in different periods and no foliar application of humic acid. The highest grain yield was obtained in full irrigation (5035 kg.ha-1) and foliar application with 300 mg.L-1 humic acid (4462 kg.ha-1). The lowest grain yield was obtained in no irrigation at the pollination stage (2355 kg.ha-1) and no-humic acid (2667 kg.ha-1). As a result, foliar application 300 mg.L-1 of humic acid in different periods of low irrigation stress improved the physiological indices and increased yield components compared to control (no foliar application).

In order to investigate the effect of acid modifiers in lands with high pH on improving morpho-physiological characteristics of wheat, a factorial experiment was conducted in a randomized complete block design with three replications. The factors included, sulfur sulfate in three levels (0, 250 and 500 kg ha-1) and thiobacillus in three levels (0, 5 and 10 kg ha-1). The results showed that the effect of sulfur fertilizer and thiobacillus bacteria on total dry weight, leaf area index, crop growth rate, net assimilation  rate and plant height were significant at 1% probability level. The interaction between sulfur and thiobacillus fertilizers on total dry weight was significant at 1% probability level and on plant height at 5% probability level and was not significant for other traits. The maximum crop growth rate were obtained by 12.5 and 11.6 g m-2 under 500 kg ha-1 sulfur fertilizer and 10 kg ha-1 thiobacillus, respectively and the minimum by 9.7 and 10.6 were under non-application of sulfur fertilizer and non-application of thiobacillus. The maximum plant height (94.3 cm) was observed under application of 500 and 10 kg ha-1 of sulfur and thiobacillus fertilizer and the minimum by 74.6 was under non-application of sulfur fertilizer and thiobacillus. In general, the results of experiment showed that the application of sulfur fertilizer and thiobacillus bacteria in lands with high pH improved morpho-physiological characteristics of wheat, which could be interest to researchers and farmers.

Application of bio-fertilizers in Sustainable Agriculture perform important role at increasing of crop pro-duction and improving soil fertility. In order to investigate combine application of biological and chemical phosphorus fertilizers and micronutrients on morpho-physiologic characteristics of barley, present research was conducted via split plot experiment according randomized complete blocks design with three replications in Ramhormoz during 2016-17. The main treatments consisted of phosphorus fertilizers and bio-fertilizers in four levels (Non use phosphorus fertilizer or control, bio-fertilizer “Barvar2”, bio-fertilizer “Barvar2” with 150 kg.ha-1 superphosphate fertilizer and 200 kg.ha-1 superphosphate fertilizer) and spray micro-nutrient (included micronutrients of zinc, iron and manganese) at three levels (no spray micro-nutrient or control, spray micro-nutrient at 0.002 and 0.004 concentration) belonged to sub plots. Results of analysis of variance indicated effect of combine application of biological and chemical phosphorus fertilizers and micronutrients on measured traits was significant. Mean comparison result of phosphorus fertilizers showed that bio-fertilizer “Barvar2” with 150 kg.ha-1 superphosphate fertilizer had maximum peduncle length (9.46 cm), awn length (11.95 cm), leaf area index (4.5), chlorophyll index (40.26) and days to rippening (185 day) also spray micro-nutrient at 0.004 concentration achieved maximum rate of mentioned traits. According mean comparison results of interactions of treatments the highest seed yield (400.1 g.m-2) and main spike weight (2.89 gr) belonged to bio-fertilizer “Barvar2” with 150 kg.ha-1 superphosphate fertilizer and spray micro-nutrient at 0.004 concentration. Generally to achieved optimum yield use bio-fertilizer “Barvar2” with 150 kg.ha-1 superphosphate fertilizer and foliar application micro-nutrient at 0.004 concentrations for Ramhormoz weather conditions can be advised.

In order to investigate the effects of different mycorrhizal fungi and phosphorus fertilizer on growth traits and grain yield of wheat, an experiment was conducted in factorial experiment in a completely randomized design with three replications. The first factor included mycorrhizal fungi application as non-use of fungi (control), Glomus intraradices, Glomus mossea and Glomus fasciculatum and the second factor included various levels of phosphorus fertilization included non-application of fertilizer (control), 40, 80 and 120 kg ha-1. The results showed that the effect of fungi, phosphorus fertilizer and interaction between the application of fungi and phosphorus fertilizer on leaf area index, dry matter, root dry matter and grain yield were significant. In all treatments of mycorrhizal fungi with increasing of phosphorous fertilizer level, leaf area index, total dry matter, root dry matter and grain yield increased. Maximum values in all studied traits were observed under the application of Glomus intraradices and Glomus mossea. Glomus mossea and Glomus intraradices at 80 kg ha-1 fertilizer level was the best condition for all traits. But in Glomus fasciculatum, the maximum of traits was obtained at 120 kg ha-1 fertilizer. In general, using Glomus mossea and Glomus intraradices can reduce the use of phosphate fertilizers, which could be a new approach to achieve sustainable agriculture.

In order to determine the effect of humic acid and potassium fertilizer on the fresh and dry weight of heath and root dry weight , Length of root and Leaf Area Index (LAI) of mention plant, there was an Experiment using the plan of Compeletly Randomized Block Design with 3 replications and 12 treatments raised on factorial.the factors was 4 level of humic acid (0,5,10,15 kg/ha) and 3 level of potassium sulfate (0,50,100 kg/ha). During the experiment , Leaf Area Index, as well as plant fresh and dry weight , Length of root and root dry weight was measured and analyzed. Results showed that the positive effect of humic acid and potassium on Leaf Area Index by plant and increase dry and fresh weight ,root dr weight and Length of root . That treatment who had received the most amount of humic acid had significant difference in comparision of other treatments. Comparing treatment who had received the most amount of "Potassium" had significant difference too. Comparing interaction between treatments, also indicate that treated plants with the highest amount of humic acid and putassium, had significant difference in comparision of other treatments.