قابل توجه دانشجویان درس زبان تخصصی زراعت
The role of weeds in nematode management
Weeds are alternative hosts for plant-parasitic nematodes and have long been recognized for their ability to maintain nematode populations targeted for suppression by various management strategies. The impact of weeds as alternative hosts depends largely on nematode feeding behavior, which is determined by the level of host specialization required for the parasite to feed successfully. Besides serving as alternative hosts, certain weeds can protect nematodes from pesticides and the environment, provide nematode suppression through antagonism, contribute to changes in future nematode biotic potential, or exert indirect effects through competition with crops or by the effects of weed control strategies on nematode populations. Weed–nematode interactions in agricultural production systems may be more complex than the simple function of weeds as alternative hosts. The challenge that faces weed scientists and nematologists is to identify effective, compatible IPM strategies that address weed and nematode management collectively
Pistachios SOIL AND WATER REQUIREMENTS
Pistachio trees grow in virtually all soils. However, they grow better in deep, sandy loam soils. Tree density should be increased in poorer soils. This will permit maximum production earlier than in orchards planted with more space between trees, and in about the same time as those planted in good soils. Pistachio trees are long-lived, tap-rooted and can grow to 20-30 feet tall. Pistachios are drought tolerant, but for commercial crop production there must be adequate soil moisture during late winter, spring and early summer. Critical stages during these times require not only good nutrition but good soil moisture. Within a month after pollination, pistachio trees will grow vegetatively and will form flowers for the following year. Pistachio trees are highly tolerant to saline conditions.
What is modern organic farming
Modern organic farming is an integrated farm management system where natural biology and balanced soils are developed to give sustainable yields without synthetic chemicals.
Integrated weed control without the use of herbicides gives good results with timely management. Techniques include soil improvement, rotational cropping, controlled grazing, green manuring, mowing, mechanical cultivation and harrowing.
With no-tillage planting, weed control with herbicide is essential for satisfactory production of the second crop. Wheat stubble ordinarily contains many weed seedlings that must be controlled. When competition from the wheat is removed, these weed seedlings will develop rapidly and compete severely with soybeans. Herbicides selected and rates of application used for weed control in double-crop soybeans should kill the weeds present at planting time and provide residual control of weeds emerging from seed. The use of Roundup Ready soybean varieties for weed control almost guarantees perfect weed control.
Agronomy: Branch of agriculture that deals with field crop production and soil
management. Agronomists generally work with crops that are grown on a large
scale (e.g., small grains) and that require relatively little management. Agronomic
experiments focus on a variety of factors relating to crop plants, including yield,
diseases, cultivation, and sensitivity to factors such as climate and soil.
Crop: In agriculture, a plant or plant product that can be grown and harvested
extensively for profit. By use, crops fall into six categories: food crops, for human
consumption (e.g., wheat, potatoes); feed crops, for livestock consumption (e.g.,
oats, alfalfa); fibre crops, for cordage and textiles (e.g., cotton, hemp); oil crops, for
consumption or industrial uses (e.g., cottonseed, corn); ornamental crops, for
landscape gardening and industrial and secondary crops, for various personal and
industrial uses (e.g., tobacco).
Managing Wheat by Growth Stage
Management decisions in wheat production are growth-stage dependent. Applying fertilizers, herbicides, and fungicides are most effective and profitable when applied at specific times during wheat development. If certain chemicals are applied at the wrong growth stage, they may be ineffective or even damage the crop. Understanding how to correctly identify wheat growth stages can help producers make timely and profitable management decisions.
Winter wheat plants must survive the many stresses of winter. Roots and leaves that develop in the fall are often killed off during the overwintering period. However, as long as the crown remains alive, new roots and leaves can be regenerated. Therefore, plants that enter the winter with well developed crowns have the best chance of winter survival.
Grain yield can be expressed as the product of three variables (yield components):
Grain yield = (number of heads) * (kernels per head) *(kernel weight).
The impact of each yield component on final grain yield is determined at different stages during the growing season. The number of viable seeds planted and the number of tillers produced per plant sets the upper limit on the number of heads that can be produced by a wheat crop. Tiller production is favored by moist, warm weather and good soil fertility, especially nitrogen fertility, prior to the stem elongation stage.
Integrated Pest Management (IPM) is an effective and environmentally sensitive
approach to pest management that relies on a combination of practices. IPM
programs use current, comprehensive information on the life cycles of pests and
their interaction with the environment. This information, in combination with
available pest control methods, is used to manage pest damage by the most
economical means, and with the least possible hazard to people, and the
IPM is an abbreviation for Integrated Pest Management. Integrated Pest
Management is a process involving sound solutions for treating and controlling pests.
These solutions incorporate three basic steps: 1) inspection, 2) identification and 3)
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