Dear @Girija Prasad Patnaik It is very difficult to create a "real" drought situation to perform selection for drought resistance in any plant species under actual field condition. In dry climate/season, controlling irrigation water has been one of the ways used extensively to perform screening for drought tolerance. However, under such a situation we have no control over relative humidity (RH). In a crop like rice, which is usually grown during rainy season when RH of air is very high, automated rain out shelters are used to create "drought-like" situation to perform screening. But rainy days, and other variables of rainy weather (clear vs cloudy days) imposes further ceiling on the applicability of results of field screening. You can go through a similar discussion at RG by accessing the link given below:

https://www.researchgate.net/post/How-to-create-and-maintain-drought-condition-in-crop-field

Best wishes, AKC

Actually, plants responses to stress in two major categories: stress avoidance and stress tolerance. Quinoa crop has a well-adaptive mechanism to cope with the stress of water in the field. It can grow in arid and semi-arid conditions. It can possess an exceptional innate ability to cope with water shortage based on its intrinsic low water requirement, and the aptitude to resume rapidly its former photosynthetic level and its specific leaf area after a period of drought, and farmers need only the seasonal rain to grow this crop.

If you grow the Quinoa crop in a reliably very dry zone the incremental addition of water can create a crop response curve.

In more rainfall zones the idea will be the creation of zones where the rainfall is intercepted by an elevated sheeting and the gutters take the water away from the soil.

Then the incremental irrigations can give the water response curve for the experimental purpose

Crop shelter provides greater research portability

by American Society of Agronomy

📷Drought tolerance in wheat experimental plants growing under rainout shelters. Credit: Surya Kant

In many parts of the world, lack of sufficient water makes it difficult - or impossible - to grow crops. Even in areas with enough water for farming, droughts can drastically lower the yield and quality of crops.

One way to grow crops in dry and drought-prone regions is to breed crop varieties that are better able to tolerate water stress. These crops can expand available arable land and increase food production.

Plant breeders and geneticists are continuously developing new crop varieties. But field-testing these new crop varieties to test whether they can actually tolerate water stress is challenging. Part of the challenge is that it is difficult to predict the timing and amount of rainfall, which can complicate experiments in the field.

So researchers turn to rainout shelters. These are structures designed to exclude rainfall from specific areas on agricultural fields. This allows experimentally-controlled water stress to be applied to the crops being grown in those areas.

In a new study, researchers from Agriculture Victoria in Australia describe a fully-automated, portable, and energy-independent rainout shelter. This new design will allow researchers to more effectively field test crop varieties for their tolerances to water stress.

📷Plastic road barriers, filled with water, and steel arch frames create the skeleton for this portable rainout shelter. Credit: Surya Kant.

"Developing tools to enable precise testing under natural field conditions is key for breeding water stress-tolerant crops," says Surya Kant, the lead author of the study. Field testing new crop varieties is vital. Experiments under more controlled conditions - such as in greenhouses - cannot always replicate the variable conditions found outdoors.

"There are always variations between field and greenhouse experiments," says Kant. "That is especially the case for drought tolerance research."

During field studies researchers often have to account for various soil types. In contrast, greenhouses often use premade potting mixes or a single kind of soil. There are also differences in plant density, competition with weeds, insects, pests and diseases. All of these differences add up and "results from greenhouse experiments can potentially be unreproducible in the field," says Kant.

The rainout shelters designed by Kant and his colleagues are built using steel arch frames and polyethylene covering. "This lightweight, robust design allows the structures to be portable," says Kant. "It also means that the shelters maintain durability in all weather conditions, especially high winds."

The rainout shelters are mounted on plastic road barriers. These barriers can be filled with water to act as foundations. They can be emptied for maximum portability when the shelters need to be moved.

📷Solar power, rain sensors, and surveillance cameras complete the setup. Credit: Surya Kant.

"Most rainout shelters run on rails that are fixed to the ground, and are therefore non-portable," says Kant. "In contrast, our rainout shelters are portable. They can be relocated to another research station to allow for crop rotation and experimental site changes."

Availability of electric power supply is another issue for researchers using rainout shelters. This is especially the case when experimental sites are located in remote areas. Kant and his colleagues incorporated a portable solar power system in their design to ensure that all power is generated onsite. Independent power generation can minimize potential failures due to issues with existing power infrastructure.

The new rainout shelters also have other customized features, such as rain sensors and surveillance cameras. The rain sensors automatically deploy the shelters in the event of rain, such that no rainfall event is missed accidentally. The surveillance cameras allow researchers to monitor their experiments remotely.

The unique features on these rainout shelters can expand their use into more remote areas. This will potentially allow researchers to test crops for drought-tolerance and growth in previously unusable land.

Irrespective of the crop, the use of moisture probes and rainout-shelters can help induce drought under field conditions. For salinity, this is better to do extensive soil sampling and do the experiment where soil salinity level is in the target/desired range.

Agree with Paul Reed Hepperly

In long term experiments the long term drought response can be assessed in real life conditions.l Monitoring the environment the irrigation can be applied per soil sensors to eliminate all drought and response to periodic drought can be determined by monitoring also.

Many soils have 2% or less organic matter and the soil limitation can be addressed through the raising of the organic matter level because of the fact that the carbon is fundamental in water dynamics.

The low organic matter condition can be modified to 2, 4 and 8% and the responsponse curves can give an appreciation of the fundamental role of soil organic in avoiding periodic drought or in moderating the need for supplementation irrigations.

conclusive increase of cultivated soils pasture and frrest lands can play a critical role in reversing the person day global warming scenario.

Methods to apply drought in field conditions... My head is trying to search for technological devices to measure the water potential in soils, water availability, field capacity, leaf turgor pressure probes (ZIMM Probes*), etc. From this approach, you can control the degree of water stress in any crop.

*Have a look at my paper, material and methods, Pressure Probes.

Article Chloride nutrition improves drought resistance by enhancing ...

To induce water stress condition under field environments, if you will use moisture probes and rainout-shelters so it can help you to attain good results. While salinity related experiment , you can mange it in any high saline area.

Rainout-shelters can help in the field. Otherwise, pots experiment in the glasshouse.

It is better and easy to conduct drought stress experiments in controlled environments for accurate results. But can also be conducted in field conditions and the easy way is rainout shelters.