This is a good question for which empirical studies will be helpful in arriving at a answer, but the answer is not likely to be uniform across countries or for different irrigation management options.

The simplest explanation which I would from 20+ years of working with the System of Rice Intensification (SRI) across more than 50 countries is the following. Most systems for water-saving have focused just on the single variable of water provision, not taking account of the full range of agronomic practices that bear upon the success of irrigated rice cultivation.

SRI has had its own disappointments in terms of rate of adoption, although it is probably being used by over 20 million rice farmers, both irrigated and upland, in over 60 countries, but while SRI water management in general reduces water needs by 25-50%, it also raises average yield, reduces costs of production, increases farmers' net income per hectare, and produces crops that are more resistant to the hazards of climate change.

AWD, for example, can reduce water requirements would reducing yield, or with little yield reduction. That is not very rewarding for a farmer who must make some greater investment of labor to manage his/her water supply more sparingly. While his/her greater effort is beneficial for other (downstream) farmers, the cost is borne by the water-saving farmer.

If AWD was become part of a more holistic strategy of rice crop management, as it is in SRI, changing things like age of seedling, plant density (seed cost), soil fertilization to get greater crop productivity, and lower costs overall, I think that it would be more attractive, not as a stand-alone innovation.

For many years, SRI has been stereotyped as 'too labor-intensive' to be attractive and practical for farmers. This classification stems from the initial journal article on SRI and on a lot of anecdotal complaints that get amplified by persons who are resisting SRI for whatever reasons. In fact, many large-scale studies have shown SRI to be labor-saving (over current practice) or labor-neutral.

When SRI was being introduced in Madagascar, it had to compete with a very labor-extensive traditional system of rice cultivation, and any intensification would require more investment of labor. But even there, within 3-4 years of use, as farmers gained experience and confidence in the new methods, SRI began to save even these farmers labor, 4-10% according to Barrett et al. (2004) in the AMERICAN JOURNAL OF AGRICULTURAL ECONOMICS.

In Asia, where 90% of the world's rice is produced, most rice production has been labor-intensive already, and in Asian countries, even in the first year, there is labor-reduction with SRI practices even from the first year. More on this can be found in my book SYSTEM OF RICE INTENSIFICATION: RESPONSES TO FREQUENTLY ASKED QUESTIONS (2015), available also in Spanish, Chinese and Burmese. PDF version is free at: http://sri.cals.cornell.edu/aboutsri/SRI_FAQs_Uphoff_2016.pdf

A Kindle version is at: https://www.amazon.com/System-Rice-Intensification-Responses-Frequently/dp/1515022056 -- for $2.99 from Amazon.

Norman Uphoff

Cornell University ([email protected])

Dr. Uphoff, I remember those days of 2005-06 when you visited different demonstrations in undivided Andhra Pradesh, ANGRAU, Hyderabad. At that time I was in farm journasim and I covered the benefits of SRI. Later, in the banner of ETV we made a CD on SRI for the farmers in different Indian languages, namely, Hindi, Bengali, Telugu, Kannada, Marathi and Odia. Our CDs reached to a large number of farmers. But unfortunately it was observed that due to promotional support only SRI popularized in some pockets in India. When supports were withdrawn, SRI disappeared.

I still hope rice growers of India and other developing countries must realize the scarcity of water. Rice is our staple and we can't quit rice farming. But we can change the water gazler face of rice. We must look into the maximizing water productivity in rice farming. And we must adopt alternative rice farming practices.

Dr Uphoff, want to listen from you about your vision on aerobic rice. Regards.

If its yield is as important as that of irrigated rice as Norman points out, it should be popularized.

It is important to do our categorizations of phenomena clearly; rice loves water! Drought at tillering or flowering is deadly. Breeding for drought tolerance is a major effort to raise genotypes that are efficient in water utilization and a lot of progress has been made in identifying QTLs for this trait. We need to select for early varieties with drought tolerance and plant at optimal periods(can even be multiple plantings for very early varieties) in the growing seasons to ensure good yield and higher productivity. This is also a kind of water management: putting the available water to maximum use in a growing season.

@Julius, thanks for your valuable comments.

In addition to the methods informed, it is also practiced, a method viz.Ratoon croping, developed by Dr. Mahadevappa, former Vice Chancellor of Dharwad Agricultural University. I worked with him, for detecting scent in leaf stage in Scented Rice Breeding Programme.

@Dr Vasudevae, Nice to hear from you. Thanks for your valuable comments.

I think there is an idea that adapted by farmers which is Rice needs flooding!

During my Ph.D. study, I saw rice plants grew and yielded by using drips!

@ Firas, I have also seen some experiments on growing rice under drip and mulching. We need to focus on water-saving technologies in agriculture because water is a very scarce natural resource and in future the scarcity will be more crucial.

Thanks for your valuable input.

@ Dr. Vasudeva, what's your idea about System of Assured Rice Production (SARP)?