Trip yields meaningful China-Palouse soil comparison
Erosion rates on the Palouse are severe. However, on a recent two-week trip to the Republic of China, a research team from Washington State University realized that they can be worse.
The team visited several areas including Bejing and Yan’an, where the crops, climate and soil composition are similar to the Palouse. Both regions have “loess” soils, which are formed of dust deposited by wind. Besides the similar soil type, the long history of productive agriculture in China made the region of particular interest to WSU researchers.
“Our purpose was to learn about the agricultural systems, crops, soil management and erosion problems and compare them to what we know from personal experience in Eastern Washington,” said Alan Busacca, a WSU soil scientist.
Other trip participants were Thomas Lumpkin, chair of Crops and Soil Sciences; William Pan, a soil fertility specialist; John Aeschliman, a Palouse farmer; Dennis Roe, with the United States Department of Agriculture Natural Resources Conservation Service; Jack Bell, a land management specialist for the Nez Perce tribe; and Paulette Sandene from the Foreign Agricultural Service in Washington D.C.
“We wanted not just university staff, but also members of the Palouse farming community,” Busacca said. The trip was sponsored by the United States Department of Agriculture.
The itinerary included visiting universities, traveling with university scientists and extension agents and making a few tourist stops. Overall, the focus was on sharing knowledge and experiences between farmers and researchers.
The tour revealed numerous differences as well as similarities.
“When we told people in China about our erosion rates, they laughed because their erosion can be 10 times as high,” Busacca said. The Chinese have been farming the same land nearly 60 times longer than Washington farmers have worked the Palouse. The exchange team expected to learn how the Chinese sustain high levels of production on the same land without depleting its resources.
In the past, the Chinese grew one crop a year on the mountain slopes. Now they have moved most of their vegetable cropping to river valleys and field crops to terraced lands. And they are planting trees and grasses on the steepest slopes to reduce erosion. With closer attention to the lands in cultivation and by growing more than one crop a year, the Chinese have boosted productivity and conserved soil.
“Although the agriculture in both places (Palouse and visited areas of China) is based on loess soils, the way that erosion happens is different,” Busacca said. “Water erosion in the Palouse is mainly sheet and rill action, which removes a thin layer of soil from the fields. In China, we saw huge gully systems hundreds of feet deep eroding soil from the slopes into valleys.”
The Chinese loess soil depth is 400 – 500 feet, whereas Palouse soil depth is 20 – 220 feet, according to Roe. “Because their soil is deeper, erosion can take (some of) it without seeming significant,” he said.
China receives 70 percent of its rainfall from June – Oct. whereas the Palouse receives 70 percent of its rainfall from Nov. – Mar., which is why erosion occurs differently, said Roe. “Erosion here is from rain on the soil when it’s frozen, but theirs is from intense rains” during warmer months. The Yellow River in China carries the highest sediment load of any river in the world, primarily due to summer rains.
The Chinese have focused their conservation on reforesting areas and managing the remaining soils. They have concentrated on farming lands that have not been eroded yet and reforesting areas subject to severe erosion.
“It looked like 60 percent of the former cropland area has been put back into forests, and yet they’re producing more off of the remaining acreage,” Busacca said. The Chinese are also reterracing some of their land, using human labor so that it is flatter, which reduces runoff and allows farmers to better control their crops. Erosion control techniques widely used on the Palouse include alternating crops, rotating fields, and tilling methods.
The WSU team also discussed issues relating to disease and pest control, new varieties of different crops, using genetically modified organisms (GMO), and anything else they could think of with local farmers and extension agents.
“It gave us a message to beware of the potential magnitude of erosion in loess soil. We are fortunate because all of our farmers are practicing at least one farming method to reduce erosion.”
To complete the agreement with the USDA for the exchange, the team will submit a two-page report about their experience. “We have so much information to share. They have to limit it to two pages or we academics would give them more than they could use,” Roe commented.
The exchange was successful for Busacca. The USDA program is designed to “let people experience a different kind of agriculture and a different part of the world, while actually meeting the people.”
Roe concurs. “I can’t emphasize enough their hospitality. They went out of their way to make sure we got to do and see everything that we wanted,” he said. “I can only speak for the area we saw, but we didn’t see starving or homeless people. They are a people who are very respectful and patient.”