Mushroom hunting by Dr. Peyvast

برآورد سطح برگ کدو¬ها توسط اندازه¬گیریهای خطی

روشهای دقیق و غیر­مخرب تعیین سطح برگ گیاهان ابزاری مناسب در مطالعات فیزیولوژیکی و اگرونومیکی است. تعیین سطح برگ منفرد گونه­های cucumis مانند Cucumis moschata L. و Cucumis pepo L. (شامل کدو خورشتی، کدوی زینتی و کدو تخم کاغذی) و کدو تنبل (Cucumis maxima L.) دربرگیرنده اندازه­گیری پارامتر­های برگ، مانند طول و عرض برگ یا برخی ترکیبات این پارامتر­ها می­باشد. این تحقیق طی سال 1387 در شرایط مزرعه جهت یافتن معادله­ای برای تخمین سطح برگ کدو­ها انجام شد. بررسی رگرسیون بین سطح برگ و طول و عرض برگ معادلاتی را جهت تعیین سطح برگ کدو­ها ایجاد نمود. رگرسیون خطی دارای عرض برگ به عنوان متغییر وابسته بیشترین دقت را دارا بود. معادله LA = a + bW بیشترین دقت و کارایی محاسبه سطح برگ کدو­ها را دارا بود.

اثر غلظت آمونیوم و مولیبدن در محلول غذایی بر غلظت نیترات در دو رقم خیار گلخانه¬ای

نیترات شکل متداول نیتروژن مورد استفاده گیاهان است اما غلظت بالای آن منجر به ایجاد ترکیبات خطرناک و مضر برای انسان می­شود. از عوامل تاثیر گذار بر غلظت نیترات میزان آمونیم و مولیبدن موجود در محلولهای غذایی است. در این تحقیق اثر سطوح مختلف آمونیوم(0 ، 1/0 و3/0میلی اکی­والان گرم در لیتر) به شکل نیترات آمونیم و مولیبدن (05/0، 1/0، و 15/0 میلیگرم در لیتر) به شکل مولیبدات آمونیم در محلول­های غذایی در دو فصل کشت بهاره و پاییزه بر غلظت نیترات در میوه خیار رقم­های "سلطان" و "روبا-اس" مورد بررسی قرار گرفت. طرح به صورت فاکتوریل کرت­های خرد شده در قالب طرح کاملا تصادفی در گلخانه انجام گرفت و در هر فصل کشت دو برداشت برای نمونه گیری صورت گرفت. نتایج تجزیه مرکب نشان داد که غلظت نیترات در گیاهان تغذیه شده به وسیله محلول غذایی حاوی 3/0 میلی اکی والان گرم در لیتر آمونیوم (37/0 درصد در ماده خشک) در مقایسه با گیاهان تغذیه شده با محلول غذایی 1/0 میلی اکی والان گرم در لیتر (4/0 درصد در ماده خشک) کاهش یافت اما کمترین غلظت نیترات در تیمار بدون آمونیوم (25/0 درصد در ماده خشک) به دست آمد. در بین سطوح مختلف مولیبدن نیز بیشترین تجمع نیترات مربوط به 15/0 میلیگرم در لیتر محلول غذایی (38/0 درصد در ماده خشک) می­باشد و بین دو سطح دیگر اختلاف معنی­داری مشاهده نشد. دو رقم از نظر میزان غلظت نیترات اختلاف معنی­داری نداشتند. بین برداشت­های اول و دوم و همچنین دو فصل کشت اختلاف معنی­داری مشاهده شد و در برداشت اول تجمع نیترات کمتری مشاهده شد و همچنین غلظت نیترات در کشت بهاره نسبت به پاییزه کمتر بود.

Three red cabbage variety comparisons and their leaf area estimation from linear measurements

Cabbage is one of the most important and widely grown vegetables in the world. It’s a staple in many people’s diets. However, many red varieties are gaining popularity as part of various pre-packaged salad mixes. The red cabbages used in this study including: Red Dynasty, Red Rookie and Schwarzkopf 2 was similar in measured parameters and in spite of different producer company it’s seem that they have similar parents. Estimation of individual leaf areas was another goal of this research. Accurate and nondestructive methods to determine individual leaf areas of plants are a useful tool in physiological and agronomic research. Determining the individual leaf area (LA) of red cabbage involves measurements of leaf parameters such as length (L) and width (W), or some combinations of these parameters. This study was carried out during 2008 (on three red cabbages) under open field conditions to test whether an equation could be developed to estimate leaf area of red cabbage. Regression analysis of LA vs. L and W revealed several equations that could be used for estimating the area of individual red cabbage leaves. A linear equation having W as the independent variable provided the most accurate estimate of LA. The linear equation (LA = a + bW2) exhibited a high accuracy and precision in estimating LA.

Feasibility Decrease Use of Fertilizer on Greenhouse Cucumber Production in Soilless Culture

In order to evaluate the effect of different substrates on growth, yield and quality of greenhouse cucumber cv. ‘Rubah-R’, two greenhouse experiments were conducted at the Agricultural Faculty of Guilan University in Rasht, Iran (37°16'N), during 2006 and 2007. Four growing media were used in 2006 including peat, perlite, rice-hull and a mixed substrate (perlite and rice-hull 50:50 v/v) and four other substrates such as peat + carbonized rice hull (50:50, v/v), peat + wood chips (50:50, v/v), peat + bark (50:50, v/v), and perlite 100%. Results of 2006 showed that substrates had a significant effect on the plant growth, total fruit yield, marketable fruits, fruit weight and number of fruits per m². Furthermore, no significant differences were found between substrates in term of fruit quality parameters such as fruit length, fruit diameter and total soluble solids. Results of 2007 experiment showed that tested substrate (peat + carbonized rice hull (50:50, v/v) (T1), peat + wood chips (50:50, v/v) (T2), peat + bark (50:50, v/v) (T3), and perlite 100%) could affect the most cucumber quality components, but plant elements analysis showed a negative correlation between the different substrates especially between calcium and magnesium. It is also a positive correlation between the roots and cucumber fruits in term of nutrient uptake. The analysis showed also a positive correlation between the calcium amount in root and fruit, but no differences were found between leaves and fruits.

Effect of Municipal Solid Waste Compost on Yield and Quality of Lettuce (Lactuca sativa L.)

The work was conducted at the experimental field of the Agronomic Faculty, University of Guilan, Rasht, Iran in 2008. The aim was to study the effect of compost on lettuce (Lactuca sativa cv. Great Lakes) growth, yield and yield components. No supplementary fertilization was applied until commercial harvest. Results revealed that compost used at 100 Mg. ha^-1 did affect the yield of lettuce which was statistically different from other treatments with the lower compost. The significant differences were also found on plant weight and leaf numbers. In addition to head yield, it was shown that crop maturity was positively affected with compost application. However, Pearson correlation analysis showed that plant weight, leaf number and yield had significant correlation and in fact measure similar characteristics while other measured characteristics do not have significant correlation with other.

Cabbage and broccoli leaf area estimations from linear measurements

Accurate and nondestructive methods to determine individual leaf areas of plants are a useful tool in physiological and agronomic research. Determining the individual leaf area (LA) of Brassicaceae family such as red cabbage (Brassica oleracea var. cappitata L. f. rabra ), cabbage (Brassica oleracea var. cappitata L. F. alba) and broccoli (Brassica oleracea var. italica L.) involves measurements of leaf parameters including: length (L) and width (W), or some combinations of these parameters. This research was carried out during 2008 (on eight cabbage, six broccoli, and three red cabbage genotypes) under open field conditions, to evaluate whether an equation could be developed to estimate leaf area of cabbage and broccoli across genotypes. Regression analysis of LA vs. L and W revealed several equations that could be used for estimating the area of individual cabbage and broccoli leaves. A linear equation having W as the independent variable provided the most accurate estimate of red cabbage and cabbage LA. The linear equation (LA = a + bW2) exhibited a high accuracy and precision in estimating red cabbage and cabbage LA. For broccoli a linear equation having LW as the independent variable provided the most accurate estimate of LA, but doubled the time required for leaf measurement.