Deep Roots

MANILA: Why study roots? Because the invisible half of the plant is as important as the visible part. Because "physiologically vigorous root systems are as essential as vigorous shoots for successful plant growth," PJ Kramer says, "because root and shoot growth are so interdependent that one cannot succeed without the other" (dspace.udel.edu). Because, DB Kell says, deeper roots give "much greater steady-state trapping of carbon, and also of nutrients and water, leading to improved drought and flooding tolerance, greater biomass yields, and better soil structure and steady-state carbon sequestration" (2011, nipccreport.org). More biomass formed, more nutrients and water trapped, more tolerance to drought and flooding, higher yields, and better soils.

Today I chanced upon Neil Palmer's 1.5-year old report of a high anticipation for a successful genetic modification of IRRI's rice variety IR64 that will produce deep roots and establish itself well during a drought (October-December 2013, Rice Today,  irri.org/rice-today). The original of the image above is from the Palmer's story. An international team led by scientists of the National Institute of Agrobiological Sciences (NIAS) in Japan, with members from the Centro Internacional de Agricultura Tropical (CIAT) in Colombia, had discovered a deeper rooting (DR01) gene in rice that induces the roots to grow downward instead of outward from the base, reaching moisture held deeper in the soil, allowing the plant to grow and prosper despite a drought. Roots seek the water's level.

"It's a very exciting discovery," CIAT's Manabu Ishitani said. "We've known for some time that deeper roots can buy farmers extra time during drought, but, until now, we haven't known which gene in rice is responsible for root architecture, or how to control it." Deeper roots tap more water and, therefore, more nutrients from the soil, not only to survive a drought but thrive.

Masa Iwanaga, President of the Japan International Research Center for Agricultural Sciences (JIRCAS), welcomed the discovery and said:

The Green Revolution in the 60s and 70s was made possible by the introduction of short-stature, shallow-rooted cereals capable of producing high yields. The DR01 gene confers (a) deeper root system architecture to crops, which will surely mark the start of an "underground revolution" in crop improvement, which will be essential for meeting the increasing worldwide demand for food.

Those short and shallow-rooted rices, represented by IR8, were high yielders under abundance of irrigation; in the next Green Revolution, the next short and deep-rooted rices, represented by IR64, hopefully would be good yielders under water stress.

We need all the rice we can grow. And all the water. That would be Deep Roots IR64. According to Palmer:

Rice feeds around half of the world and production needs to increase by around 40% in order to meet the demand of more than 9 billion people by 2050. But, each year, drought affects some 23 million hectares of rainfed rice in South and Southeast Asia alone. In parts of India, water scarcity can cut rice yields by more than a third, equal to losses of US$ 800 million annually. Water scarcity is also expected to increase because of climate change and increased demand for water for industrial and urban use.

If you could raise by 1 ton the production of those drought-stricken ricefields by deep-root rice, that would give us an additional yield of 23 million tons of rice, equivalent to US$ 8.7 Billion at the current price of $382/metric ton. If you distributed that amount equally to 2 million farmers, each would receive $4,350, or P 191,400, a lot of money!

The paradigm that rice scientists use, that of IRRI included, in solving the problem of productivity under problematic conditions is:

Change the plant.

Change the architecture of the plant so that it takes advantage of the adverse situation, like growing deeper roots to reach the moisture deep down there. Roots scavenging for water below the surface of the soil. JL Maeght, B Rewald & A Pierret say, "Deep roots provide important functions for individual plants such as nutrient and water uptake but can also shape plant communities by hydraulic lift" (13 August 2013, ncbi.nlm.nih.gov). The nutrients and water that deep roots bring to the surface of the soil can also improve the growth of other plants. Makes sense.

Differently, the paradigm I have always been using is:

If you can't solve the problem, change the problem!

I probably got that crazy idea from Edward de Bono whose book The Mechanism Of Mind (1968) changed my way of thinking creatively forever. The copy of that book that I got in 1975 was a gift from my good friend Orli Ochosa – may God bless his soul!

As an alumnus of the College of Agriculture of the University of the Philippines, I wish those deep roots scientists luck; they will need it, as it will take them years to come up with positive results. And genetic modification of crops is quite logical but yes, it's all Greek to me.

In this case, since I'm not a plant breeder but only an armchair farmer, 50 years ago I decided to change what I could: the soil, not the plant. That is what I now call The New Organic, turning the very topsoil into compost all over the field, organic matter rotting where it should, not only contributing to the fertility of the soil but also building it up to provide a rich environment for crops, water and plant nutrients and all (see for instance my essay, "The New Organic. It's A Revolution!" 06 June 2015, The New Organic, blogspot.com). Lorenzo Casasus, our relative, the one who has been practicing it all those years, will swear to it – his yields are higher than his neighbors, and he does not spray.

So, while waiting for IRRI's Deep Roots, we can practice Frank H's Shallow Soil. Right after harvest of rice, or any crop, while the leftover hills are alive still, we rotavate the field lightly, passing the blades not deeper than 2 inches into the soil. What happens is that the soil and vegetation, including the weeds, are cut and mixed together, thereby starting the decomposition process. The crop refuse, which has all the water in it, and the plant nutrients, will then begin to yield back to the soil what it has gotten from it naturally. What could be more beautiful than that?!