| The long road |
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| Written by Adam Barclay | ||||
| Wednesday, 31 December 2008 | ||||
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Forty-five years of painstaking research have shown that modern, intensive rice farming is sustainable and can even improve soil health
Just outside the town of Los Baños, around 60 kilometers south of Manila, sits a one-hectare patch of land that is, quite possibly, some of Asia’s most valuable real estate. It’s not for sale and, even if it were, you wouldn’t build a house, or a car park, or a shopping mall on it. But, for the past 45 years, this patch of land has revealed an extraordinary thing. In recent years, people have begun to argue that modern, intensive agriculture is unsustainable—that it degrades the soil and, eventually, renders the land incapable of supporting worthwhile crops. However, new evidence tells us that, when it comes to rice, this is far from true. 
Since 1963, the International Rice Research Institute (IRRI) has grown first two, then, from 1968, three crops of rice per year on that one hectare, in what is known as the Long-Term Continuous Cropping Experiment (LTCCE). As Rice Today went to press, the 134th crop is under way. The time between harvesting one crop and planting another has been minimal (2 to 3 weeks), and crop residue has been removed after harvest, rather than incorporated into the soil. What did IRRI’s researchers find? The answer flies in the face of what many people now believe. In short, with appropriate fertilizer management, not only can yields be maintained, but soil health can be improved as well. A recent paper1 by Roland Buresh, Mirasol Pampolino, and Eufrocino Laureles from IRRI, and Hermenegildo Gines from the Philippine Rice Research Institute (PhilRice), summarized the decades of LTCCE information in a report on the soil health in four long-term trials managed by IRRI, including two at the Institute’s Los Baños headquarters. According to the paper, “The results suggest that continuous cultivation of irrigated rice with balanced fertilization on submerged soils maintained or slightly increased soil organic matter and maintained soil nitrogen (N)-supplying capacity.” Soil organic matter—which comprises living organisms and the decomposing remains of once-living organisms, including animals, plants, and microorganisms—is a vital component of healthy soil. High amounts of soil organic matter enhance the soil’s water- and nutrient-holding capacity and improve soil structure for plant growth. Healthy soils can also reduce the severity and costs of such problems as drought, flood, and disease. Over a 15-year period (1983-98), the study also found no decline in the amount of N able to be supplied to rice plants by the soil. |
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