ارزیابی اثر تنش خشکی بر ویژگی‎های زراعی و فیزیولوژیکی خربزه تحت شرایط کاربرد کود دامی و بنتونیت

به منظور ارزیابی اثر تنش خشکی بر صفات خربزه تحت شرایط کاربرد کود دامی و بنتونیت آزمایشی به صورت اسپلیت- فاکتوریل در قالب طرح بلوک‎های کامل تصادفی با سه تکرار طی سال زراعی 1398 و 1399 اجرا گردید. کرت اصلی شامل آبیاری پس از تخلیه 25، 50 و 75 درصد رطوبت خاک و کرت فرعی شامل کاربرد بنتونیت در سطوح 2، 3 و 4 تن در هکتار و استفاده از کود دامی به میزان 20، 30 و 40 تن در هکتار بود. ﻧﺘﺎﯾﺞ نشان داد عملکرد میوه در شرایط آبیاری پس از تخلیه 50 درصد رطوبت خاک با کاربرد 4 تن در هکتار بنتونیت همراه با 20 تن در هکتار کود دامی در سال اول آزمایش با میانگین 20/2 تن در هکتار و 74/1 درصد نسبت به شاهد افزایش نشان داد. غلظت پرولین به میزان 0/422 میکرومول بر گرم وزن تر برگ با 83/17 درصد افزایش نسبت به شاهد در هر دو سال با مصرف 20 تن در هکتار کود دامی و فعالیت آنزیم‎های کاتالاز و پراکسیداز به ترتیب به میزان 32/60 و 4/15 od.g-1.fw.min-1 با 99/69 و 92/78 درصد افزایش نسبت به شاهد در سال اول با مصرف 40 تن در هکتار کود دامی در شرایط آبیاری پس از تخلیه 75 درصد رطوبت خاک و کاربرد 2 تن در هکتار بنتونیت مشاهده شد. به منظور دست‎یابی به عملکرد میوه بالاتر، آبیاری پس از تخلیه 50 درصد رطوبت خاک، کاربرد 4 تن در هکتار بنتونیت و 20 تن در هکتار کود دامی برای کشت در منطقه هیرمند پیشنهاد می‎شود.

evaluation of the effect of drought stress on agronomic and physiological characteristics of melon under application of animal manure and bentonite

introduction: a large part of iran is affected by arid and semi-arid climate and drought has caused many problems in the agricultural sector. the present study aimed to investigate the characteristics of melon under drought stress conditions using animal manure and bentonite.materials and methods: this experiment was conducted as a split-factorial based on a randomized complete block design with three replications in hirmand city, iran, during the two cropping years of 2019-2020. experimental treatments include irrigation after 25, 50, and 75% soil moisture discharge as the main plot and application of bentonite at levels of 2, 3, and 4 t.ha-1 and application of animal manure at the rate of 20, 30, and 40 ton.ha-1 were considered as subplots. according to the results, in the first year of the experiment, fruit yield increased by 2.02 times compared to the control under 50% soil moisture discharge with the application of 4 t.ha-1 of bentonite with 20 ton.ha-1 of animal manure.results and discussion: the results showed that the fruit yield in irrigation conditions after draining 50% of soil moisture with the application of 4 t.ha-1 of bentonite along with 20 ton.ha-1 of animal manure in the first year of the experiment with an average of 2.20 ton.ha-1 and 74.1% compared to the control showed an increase. in order to achieve higher fruit yield, irrigation after draining 50% of soil moisture, application of 4 t.ha-1 of bentonite and 20 ton.ha-1 of animal manure are suggested for cultivation in hirmand region. in this experiment, the greater effectiveness of fruit weight and yield in the first year can be attributed to the faster growth of shoots and the availability of more nutrients due to the release of manure elements for plant use and the effect of soil interactions in the first year, and the improvement of physical conditions and soil and plant chemistry in the second year under irrigation conditions after draining 50% of soil moisture. the reason for the higher fruit yield due to the consumption of animal manure can be the result of the vegetative growth caused by the increase in the availability of nutrients, which causes photosynthesis and the production of more photosynthetic substances, followed by the presence of more vascular elements to transfer the cultivated substances to the fruit of the plant. based on the obtained results, the increase in drought stress increased the activity of catalase and peroxidase enzymes, and the animal manure increased the activity of enzymes to defend the plant under drought stress conditions, in other words, the plant decomposes hydrogen peroxide and increases tolerance against radicals.conclusion: the effect of animal manure on plant growth can be largely attributed to mineral nutrients, especially absorbed nitrogen. in addition to this, increasing the decomposition of organic materials and mineralization of phosphorus in organic materials and converting them into usable form for plants plays a key role in the soil phosphorus cycle, and along with the use of bentonite, it strengthens the physical, chemical and biological structure of the soil, and finally by increasing the amount of water and the availability of nutrients available to the plant, it has a positive effect on the process of photosynthesis and can increase the length and width of the fruit. according to the results of the experiment, in order to achieve the desired results, irrigation after draining 50% of the soil moisture, application of 4 tons per hectare of bentonite and 20 tons per hectare of manure are suggested for cultivation in hirmand region.