When farming in arid regions, the lack of soil moisture can be dealt in the following ways: either by enhancing the resistance to drought via plant breeding, or through an employment of irrigation. What are the advantages and/or disadvantages of each approach?
Soil protection from evaporation through mulching is a viable agronomic technique to avoid further moisture loss from arid land. Also, relying on plants and animal species that adapted already to survive, or even thrive in dry conditions. Permaculture can assist to design farms that also in these marginal conditions could become biologically diverse and, eventually capable of generating some viable agricultural output (e.g.: food).
Drought Tolerance in crops should be looked at in terms of sustainable grain production with less water and if we could bring Dryland Agriculture under irrigation that could be the next green revolution
The quality of the irrigation water needs to be very high with very low salinity to avoid the accumulation of salts within the rootzone. Under dry land conditions, there is usually not enough water to wash the salts below the rootzone. As a result the accumulated salts within the root zone will lead to salinization of the soil which will become unproductive. There are ample evidences in history on the collapse of civilizations because of salinization of soils leading to crop failure and famine.
I think all the answer you have been given are good. I would like to add to them with regards to the cons. When you add water to the soil you are also adding salts. To manage the salt in the rootzone leaching is required which means adding more water than the crop requires. This means unless are drainage system is also included and an outlet for the drainage water then salt will accumulate in the regolith and or groundwater. This can lead to the groundwater rising and waterlogging and/or salinisation occurring. If evaporative basins are used then the area taken up by these will become a salina and eventually the problem of groundwater salinity returns (over a much longer time frame). Isn't the real problem human population growth?
If we use drought resistant crops to grow more food without at the same managing population growth. Then all that will happen is the issue is put off into the future.
Thank you so much Dr. Borsari, Sri Rajan, John Cook, Ahmad and you all. I am soo happy to get some excellent information dealing with crop resistant to drought. Currently I am working on Integrated Sweet Sorghum Crop- Livestock Production Systems on Dryland Farming in Lombok Indonesia. We are looking at how we are able to improve WUE of sorghum crop in a sandy soil particularly the use of water from rainfall. We will share with you some of our longterm reseach project on this area and please suggest to us if you have some works going on in this areas.
Kindly regards
Drought resistant crops are very essential, particularly during a bad rainfall year, when food & nutritional security for humans & livestock is required.
Irrigation in drylands needs to be introduced with care, so that the scares resources are not over-exploited and extracted, and equitably distributed, and heavy duty crops unsuitable for the ecology are not taken-up.
I have worked on WUE in sandy loam condition. if we r able to give irrigation based on AET , alternate row irrigation , plastic or straw any mulch , it founds requirement of crop water irrigation decrease up to 30 percent.
Drought resistance = higher Water Use Efficiency (WUE). Irrigating dry land = increased yield according to the photosynthetic equation.
Thanks very much . can anybody sending me the publication on photosynthetic equation.
I find also very interesting and innovative the approach to arid lands cultivation by Salvatore Ceccarelli and his co-workers. What they call: "evolutionary breeding" implies the growth of the same crop, in the same field with a variety of seed of different cultivars that has been grown and saved by local farmers, within the same geographic region. This high genetic diversity within the crop population will select for higher resistance against drought. Also, as soon as the soil is able to host a few plants and as its restoration process has begun. This process will begin to store carbon and with it the conservation of soil moisture will increase. Agroforestry (especially alley cropping) where herbaceous species are grown simultaneously with shrubs and trees is the design for the fields that I would think becoming successful in dry areas of the world. The adaptation of the topography to reduce water run off and design water collection pools through a key line is another important component of the design process in dry lands.
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