Across China: Freezing saline water irrigation may reclaim saline land
BEIJING, Nov. 11 (Xinhua) -- Chinese researchers have discovered that saline land may be reclaimed by the irrigation method of freezing saline water over the soil in winter. In addition, they found that the desalination depth of saline ice meltwater into the saline-alkali soil was greater than that of salt-free ice, according to a recent study paper published in the European Journal of Soil Science.
China has about 1.5 billion mu (about 100 million hectares) of saline-alkali land that lacks enough freshwater resources. This type of land restricts agricultural production and vegetation growth. Scientists have been trying to figure out how to turn barren, salty soil into arable land.
Researchers from the Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences evaluated infiltration and soil desalination under melting saline ice into saline soil. They found that the infiltration of saline ice meltwater went deeper into the saline soil than fresh ice meltwater.
Previously, the researchers developed a saltwater irrigation method to improve cotton yield in saline soils, based on the separation of saline and freshwater by melting saline ice.
They used salty water with less than 15 grams per liter concentration to irrigate the saline-alkali land in winter.
The saline water was frozen into ice on the top of the soil. When spring season came, the saline ice melted and infiltrated into the saline soil gradually.
The continuous infiltration of the meltwater with higher salinity was followed by meltwater with lower salinity.
The following infiltrated rainwater washed the soil salt further, allowing the crop roots to avoid the influence of the salt. Thus, a great desalination effect was received in coastal saline soil.
The soil salt content was reduced to lower than 0.3 percent during the entire season, while the cotton yield reached 200 kg per mu.
The research aims to provide support for improving soil desalting efficiency by using saline ice irrigation.