ارائه نکات طلایی گیاهان زراعی به طور کامل در کتاب (( 1100 نکته زراعت)) تالیف اینجانب   در  در 120 صفحه با شابک: 5-63-8735-964-978در شهرستان اهواز، کتابفروشی رشد در اختیار عموم قرار دارد. اما عده بسیار زیادی از عزیزان در اقصی نقاط کشور درخواست ارسال کتاب 1100 نکته زراعت را نموده اند. 

با توجه به اینکه قیمت پشت جلد کتاب 2000 تومان بوده است، هزینه ارسال به عهده خریدار محترم می باشد. بدین ترتیب لطفاً ابتدا به ازای خرید هر جلد کتاب مبلغ 8000 تومان  به عنوان علی الحساب هزینه پستی به شماره حساب زیر واریز نمایید. در اینصورت کتاب (ها) به علاوه مابه التفاوت مبلغ هزینه پست به همراه فیش رسید پستی در اسرع وقت به آدرستان ارسال خواهد شد. توجه داشته باشید که :

اعتبار این پست تا پایان سال 1393 می باشد و پس از آن قبل از خرید و یا واریز حتماً ابتدا درخواستتان را ایمیل نمایید.

 

جهت خرید:

 با واریز مبلغ  100000 ریال به حساب شماره 4286260261  و یا

کارت عابر بانک به شماره 7303 0832 3371 6104 بانک ملت به نام نیما فربد اقدام و

1 -  شماره پیگیری یا شماره فیش واریزی

2 -  نام و نام خانوادگی به همراه آدرس دقیق پستی /کد پستی و یک شماره تلفن همراه را

به آدرس ایمیل اینجانب ROPINHAJ@YAHOO.COM ارسال فرمایید.



تاريخ : یکشنبه بیست و سوم شهریور 1393 ا 7:12 بعد از ظهر نويسنده : NIMA ا

  The curve can be shown appearing slowly along the line and stabilizing.

During the initial stage, i.e., during the lag phase, the rate of plant growth is slow. Rate of growth then increases rapidly during the exponential phase. After some time the growth rate slowly decreases due to limitation of nutrients. This phase constitutes the stationary phase. growth curve is a typical sigmoid curve The curve obtained by plotting growth and time is called a growth curve. It is a typical sigmoid or S- shaped curve

.


برچسب‌ها: منحنی , رشد , Growth , Curve ,

تاريخ : یکشنبه شانزدهم شهریور 1393 ا 2:57 قبل از ظهر نويسنده : NIMA ا


Zinc is one of the essential micronutrients required for optimum crop growth. Plants take up zinc in its divalent form. At this time it still remains unclear whether this uptake is facilitated as diffusion through membranes specific for zinc ion or whether it is mediated by specific transporter(s). It has been concluded that both mechanisms operate, and about 90.5% of the total zinc required by plants moves towards the roots by diffusion. This lateral movement of zinc is highly dependent upon the soil moisture, and this may be the reason why, particularly in arid and semi-arid areas, zinc deficiency is more frequently seen.

The vast majority of zinc is present in the lattice structure of the soil and therefore, unavailable to meet the plant’s nutritional requirements. Available soil zinc is dissolved in the soil solution in ionic or complex form and may be found on the exchange sites of clay minerals and organic matter. Zinc can also be found as adsorbed divalent cation, zinc hydroxide, or zinc chloride. The solubility of zinc is highly dependent upon soil pH. Presence of calcium carbonate decreases the availability of zinc due to higher soil pH. The poor zinc availability in alkaline calcareous soils is precisely due to the formation of zinc carbonate. High levels of soil phosphorus are also commonly responsible for zinc deficiency. Presence of excess amount of copper can also reduce zinc availability because the absorption of both cations is through the same mechanism, which causes interference in the uptake. On the contrary, application of magnesium can enhance zinc availability and uptake by the roots.

Zinc is transported in the xylem tissues from the roots to the shoots. However, high levels of zinc have been detected in the phloem tissues, which indicates that zinc moves through both transport tissues, and maybe remobilisation of zinc towards the grain during ripening. Substantial translocation of zinc takes place from the older leaves to the younger ones during grain development phase. Plants deficient in nitrogen do not show the retranslocation of zinc from the older leaves, indicating that the deficiency symptoms of zinc are more pronounced in the nitrogen deficient plants.

Using zinc in the fertility program

Both soil and leaf tissue tests are accurate evaluations of zinc requirements. If a crop is “zinc responsive” and a high yield program is being used, some zinc is often inexpensive insurance for the higher yield goals. Zinc is sometimes applied broadcast to correct the zinc level in soils in one treatment. Zinc oxide and oxy-sulphates are slow release forms for build-up purposes. However, for in- row applications or for immediate uptake zinc sulphate or chelated and /or complexed zinc must be sprayed or applied to the soil. As indicated above, zinc must be present in soil solution in soluble form, a form that can only be possible with the application of zinc sulphate or complexed zinc. Zinc oxide, though, a very high analysis source of zinc, is not soluble in water, consequently the zinc is not released in the soil solution for roots to absorb. Moreover, spray application of zinc oxide on a standing crop will not be profitable as only a very minute percentage of applied zinc can penetrate the leaf tissue. Rest of the zinc goes waste during threshing as it still adheres to the foliage. This may limit the zinc requirement of a crop and reduce the yields. Zinc oxide forms a thin film over the leaf surface, which may reduce the canopy light interception and consequently reduce photosynthesis. Zinc oxide should always be applied through the soil for correcting zinc pool for the subsequent crops. However, the amount of zinc released depends upon the subsequent soil moisture conditions, as dry topsoil can still limit the zinc availability for the next crop. For immediate requirements the growers should use a soluble form of zinc such as Smartrace Zinc or zinc sulphate. Zinc applied using these fertilisers is rapidly absorbed by the leaves, and is translocated to the grain. The growers must correctly ascertain the amount of zinc required by the crop as excessive amounts of zinc sulphate can cause severe leaf fall.

Zinc deficiency

Deficiency of zinc is widespread among crops grown in calcareous soils and highly weathered acid soils. The deficiencies in the calcareous soils are often associated with iron deficiency as well. Zinc deficiency symptoms in wheat appear between three to five weeks after emergence, and in rice about two to four weeks after transplanting. In severely deficient zinc soils, wheat and corn germination is poor and in these situations, seed treatment with Smartrace Zinc-Manganese or Smartrace Zinc can substantially improve seed germination and seedling vigour. Spray application of soluble zinc such as Smartrace Zinc during grain filling can improve the zinc level in seeds for better germination in such soils. The deficiency symptoms of zinc are;

1. dusty brown spots of upper leaves of stunted plants
2. uneven plant growth and patches of poorly established plants in the field
3. decreased tillering, spike or spikelet sterility and interveinal chlorosis on l eaves
4. dicots shows drastic decrease in leaf size, loss of lustre and shoots die off.
5. premature leaf fall, chiefly in apples.


Metabolic roles of zinc

Zinc plays an important role in many biochemical reactions within the plants. Plants such as maize and sorghum and sugarcane shows reduced photosynthetic carbon metabolism due to zinc deficiency. Zinc modifies and/or regulates the activity of cabonic anhydrase, an enzyme that regulates the conversion of carbon dioxide to reactive bicarbonate species for fixation to carbohydrates in these plants. Zinc is also a part of several other enzymes such as superoxide dismutase and catalase, which prevents oxidative stress in plant cells. Following are the various other roles of zinc in plants;

  1.production of auxin, an essential growth hormone
2. regulates starch formation and proper root development
3. formation of chlorophyll and carbohydrates
4. enable plants to withstand lower air temperatures
5. helps in the biosynthesis of cytochrome; a pigment, and maintains plasma membrane integrity, and synthesis of leaf cuticle.

While zinc is essential for every plant, these crops have been found to be especially responsive: corn, rice, wheat, sweet corn, cotton, citrus, most orchard crops and sorghum.


برچسب‌ها: تغذیه , روی , zinc , nutrition ,

تاريخ : شنبه پانزدهم شهریور 1393 ا 12:57 بعد از ظهر نويسنده : NIMA ا



تاريخ : چهارشنبه دوازدهم شهریور 1393 ا 1:13 قبل از ظهر نويسنده : NIMA ا



تاريخ : چهارشنبه دوازدهم شهریور 1393 ا 1:10 قبل از ظهر نويسنده : NIMA ا

فرض کنید دو ژنوتیپ دارای LAI برابر هستند و لی یکی دارای برگ های با زاویه افقی و دیگری دارای برگ های با زاویه عمودی تر می باشد. در واقع زمانی که خورشید از بالا به برگ ها می تابد (نگاه می کند) مقدار کمتری از برگ دارای زاویه عمودی را می بیند ولی در ژنوتیپ دارای برگ های افقی، تمام برگ را می تواند ببیند. زاویه برگ را با حرف K نشان میدهیم تا LAIموثر را محاسبه کنیم.

LAI effective= LAItotal . K

در فرمول فوق:

اگر K برابر با یک باشد آنگاه برگ کاملاً افقی است

اگر K برابر با صفر باشد آنگاه برگ کاملاً عمودی است

بنابراین تغییرات k  بین صفر و یک می باشد. پس تمام LAI  برای فتوسنتز موثر نیست  و فقط بخشی از آن برای محاسبات آنالیز رشد محسوب می شود.

Beer-Lambert Law

قانون بیر: در یک محلول نسبتاً رقیق هر مولکول رنگیزه حل شده، بخشی مساوی از تشعشع تابیده شده را جذب می کند (به این معنی که میزان جذب تشعشع به غلظت رنگیزه ها بستگی دارد و هر چه غلظت رنگیزه بیشتر باشد جذب تشعشع هم بیشتر است).

قانون لامبرت: اگر در یک محیط لایه لایه شدت تابش اولیه Io  باشد، هر لایه با ضخامت مساوی بخشی مساوی از این انرژی تابشی را جذب می کند (هر لایه ای وقتی مقداری از تشعشع را جذب کرد، مقدار تشعشع کمتری برای لایه بعدی باقی می ماند و در حقیقت با یک حالت استهلاک یا انقراض نوری  مواجه هستیم که نور دریافتی توسط لایه بعدی مرتباً با یک ضریب کم و کمتر می شود).

با تلفیق این دو قانون قانون بیر- لامبرت خلق می شود. خلاصه این قانون می گوید:

مقدار جذب تشعشع برابر است با تعداد مولکول رنگیزه ای که در یک طول مسیر معین وجود دارد. از آنجا که این مقدار تشعشع متباً کاهش می یابد لذا آن را در یک ضریب (ضریب خاموشی یا ضریب استهلاک نوری که با حرف ابسیلون یا K نشان داده می شود) ضرب می نماییم.

Ln Ii/Io= -K.LAI

در فرمول فوق:

Ii = شدت نور در لایه I ام جامعه گیاهی.

Io = شدت نور در بالای جامعه گیاهی.

K= زاویه برگ ها.

LAI = شاخص سطح برگ.

این فرمول به ما می گوید مقدار  نوری که به لایه I ام می رسد با LAI نسبت عکس دارد و ضمناً به زاویه برگ ها نیز بستگی دارد.

نحوه محاسبه ضریب استهلاک نوری یا K:

K= Ln Io/Ii / LAI

توسط دستگاه نور سنج یکبار شدت نور را در بالای جامعه گیاهی (Io) و یک بار بر روی زمین (زیر کانوپی گیاهی Ii) اندازه می گیریم. با محاسبه LAI می توان فرمول فوق را محاسبه نمود. (توضیح اینکه می توان در لایه های مختلف Ii را اندازه گرفت د ر این صورت لایه بالایی می شود Io و لایه پایینتر می شود Ii).

برای درک بهتر این قانون مثال زیر را می آورم:

در دو جامعه گیاهی A و B ، جامعه A دارای شاخص سطح برگ 3/6 بوده و 12% از تشعشع به زمین برخورد می کند (Ii) در حالی که در جامعه B شاخص سطح برگ 2/9 بوده و 4% از تشعشع به زمین برخورد می نماید. ضریب استهلاک نوری (K) را برای این دو جامعه گیاهی محاسبه کنید؟

در جامعه A:

Io = 88% و Ii = 12%

در نتیجه:

K= 1.99/6.3 = 0.32

در جامعه B:

Io = 96% و Ii = 4%

در نتیجه:

K= 3.18/9.2 = 0.35

تفسیر: جامعه B دارای برگ های با زاویه افقی تر و جامعه A دارای برگ های با زاویه عمودی تر بوده و در نتیجه با افزایش LAI توانسته درصد بیشتری از تشعشع را جذب کرده و با ضریب استهلاک نوری کمتر، تشعشع بیشتری  به لایه I ام جامعه گیاهی برساند. در نتیجه در جامعه A می توان با افزایش تراکم عملکرد محصول بیشتری به دست آورد.



تاريخ : شنبه هشتم شهریور 1393 ا 8:33 بعد از ظهر نويسنده : NIMA ا



تاريخ : شنبه هشتم شهریور 1393 ا 8:31 بعد از ظهر نويسنده : NIMA ا
در شکل زیر مقایسه 4 غله دانه ریز گندم، یولاف، چاودار و جو را مشاهده می کنید.


برچسب‌ها: گندم , چاودار , جو , یولاف , مقایسه ,

تاريخ : شنبه هشتم شهریور 1393 ا 8:5 بعد از ظهر نويسنده : NIMA ا

June 27, 2014
By: Ben Potter, Farm Journal Technology Editor
Wet, Drowned Corn


Exact predictions are difficult, but these guidelines will help you determine if you need supplemental N following heavy rainfalls.

Did you know that wet soils in June are much more conducive to nitrate loss, as compared to early spring? That’s because soils are warmer, and losses can mount as saturation and tile flow continues, according to John Sawyer, Extension soil fertility specialist with Iowa State University.

"One way to determine N loss is to calculate an estimate," he says. "Predicting the exact amount is difficult as many factors affect losses. However, estimates can provide guidance for supplemental N applications."

Estimating N loss is a two-step process, he says. Step one is to estimate how much ammonium has converted to nitrate-N. It’s a safe assumption that late-fall anhydrous ammonia and manure ammonium has by now nearly completely converted to nitrate. Preplant N applications will also have a majority to nitrate, although you should factor in whether you used a nitrification inhibitor. On the other hand, ammonium applications within the last two weeks will still be predominately in the ammonium form, especially for anhydrous ammonia.

Step two is to estimate how much nitrate-N has leached away. Some factors that can accelerate N loss include soil type (coarse-textured soil leaches N much more quickly than silt loam or clay loam soils), whether or not the field is tiled, and of course length of soil saturation. Research indicates an average 4% to 5% N loss per day that soils are saturated.

Here’s an example. Say you made a preplant application of UAN solution at 120 lbs per acre. Estimate that 95% of that application has since been converted to nitrate and soils were subsequently saturated for 10 days. The N loss estimate calculation looks like this:

(120 lb N per acre x 95% nitrate/100) x (4% per day/100) x (10 days) = 45 lbs of N per acre loss

Increase the loss estimate for tile-drained fields, or fields with sandier soils. In fact, on very coarse-textured/sandy soils, a rainfall of 4" to 6" on already moist soils could easily result in all nitrate leaching out of the crop rooting zone, Sawyer says.



تاريخ : جمعه سیزدهم تیر 1393 ا 2:11 بعد از ظهر نويسنده : NIMA ا

here are many advantages to triticale as a forage over wheat or oats in the High Plains, according to Jason Baker, Texas A&M AgriLife Research senior research associate in Amarillo, who has been conducting trials since 2002.

Baker has worked with forage trials in both the Lockett and Chillicothe areas, first while he was stationed at the Texas A&M AgriLife Research and Extension Center in Vernon and continuing now with the AgriLife Research wheat breeding program at Amarillo.

Triticale is a cross between wheat and rye, Baker explained. It was first developed in the late 1800s, but the first commercial releases were not available until the 1960s. Triticale grows taller and remains green longer than wheat.

"We’ve been working several years here to make better varieties for the Rolling Plains," he said during a recent field day near Chillicothe. "We don’t see triticale competing for the wheat acres. It’s really a complement to dual-purpose wheat. We are trying to use the triticale more for grazing and not put as much pressure on our wheat, allowing us to use the wheat more for grain and triticale for forage."

"Anyone who grazes wheat or uses wheat for hay might want to at least have some triticale in their program," he said. "You can plant the triticale earlier and turn cattle in and save the wheat for grain later on. If you have a lot of growth, you can graze the wheat some, but use the triticale as your main focus for grazing."

Working with about 20 experimental lines and 100 commercially available triticale lines in breeding trials at Vernon, Baker said he also has compiled eight years of forage yields data comparing triticale, wheat, oats and barley.

The most recent three-year total average resulted in the triticale varieties yielding 2.09-2.11 tons per acre dry matter, compared to 1.69-1.93 tons per acre for wheat, 1.61-1.79 tons per acre for oats, and 1.54-2.01 tons per acre on barley.

In 2014, the triticale – after three clippings – yielded considerably better under drought and late freeze conditions, he said. The triticale yields were 1.92-2 tons per acre compared to wheat at 1.26-1.58 tons per acre, oats at 0.88-1.17 tons per acre and barley at 1.13-1.44 tons per acre.

"Triticale tops that test here in the Rolling Plains," he said at a recent field day near Chillicothe. "Our breeding plots have oats and wheat planted next to the triticale, and you can look at the difference – oats had a lot of freeze damage. The wheat is shorter and just produces less forage."

Baker said the two Texas A&M AgriLife varieties in the forage trial are TAMcale 6331 and TAMcale 5019, "but if you took any good commercial triticale variety, you will get the same results for grazing, hay or silage. They produce a much greater quantity."

"Many triticale varieties have disease and insect resistance that wheat and oats don’t have, allowing us to plant a little earlier in the year," he said. "We can get cattle on sooner by taking advantage of some of the late summer rains that we might get and go ahead and get it in the ground and get a good stand."

In addition to the earlier stand in the fall, Baker said triticale offers two to three weeks longer grazing time in the spring.

Source: Texas A&M AgriLife Research



تاريخ : جمعه سیزدهم تیر 1393 ا 2:7 بعد از ظهر نويسنده : NIMA ا
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