Irris river valley and Ansai station compound
Loess erosion in Ansai county
Crop terraces in the Ansai demonstration watershed
Ansai station experimental terraces and slope research plots above loess erosion
Experiments on slope effects on erosion
Some experiments varied slope lengths, slope shapes, and steepness, others changed fertilization or crop rotation
For each experimental plot, sediment and runoff is captured and measured
Intercropped corn and soybeans in the Ansai demonstration watershed show the researcher's efforts put to work in the fields

Originally published in The Journal of Soil and Water Conservation July/August 1995

China: Soil Studies at Ansai
by O.R. Jones and Wendy Despain

Deep in the hills of central China is a research station devoted to studying soil erosion, land use, and ecosystem restoration.

Seven hundred kilometers from Beijing, on the Loess Plateau, 31 scientsts live on the side of a mountain. A complex with 1900 square meters of buildings with living quarters and offices for 30 full-time staff and guest researchers surround six laboratories, all nestled in the hills and deep gullies of central China. It's a research station devoted to studying soil erosion, land use, and ecosystem restoration. The station has been in operation since 1973, first as a research station for the Northwest Institute of Soil and Water Conservation, Chinese Academy of Sciences (CAS) and Ministry of Water Resource, and since 1992 as a leading station of the Chinese Ecosystem Research Network (Cern) of CAS.

The station is located in the temperate forest-steppe zone, but the steppe land vegetation has been replaced - primarily by crops and shrub land. Ansai station is in the Heilutu soil region, but most of it has been lost to erosion, so the primary soil at Ansai is loess. The high hills and deep ravines are the result of the erosion of the 180 meter deep loess, more of which is lost every year. Ninety-three percent of the land in that county is farmed, and the semiarid climate requires that farmers use dryland techniques or irrigation.

The steep slopes make farming even more challenging and erosion even more of a problem. Villagers have increased their production by building terraces into the hillsides and using chemical fertilizers.

The Ansai research station's main purpose is to determine the structure and function of conservational eco-agriculture systems in the hilly area of the Loess Plateau; study the energy flow, the law of soil erosion and its control, and rational use of natural resources; and creat a model of sustainable, highly efficient eco-agriculture.

To carry out these goals, several experiments are underway. One experiment studies fertilization management for sloping lands. A soybean crop is grown with varying fertilizers, but the same tillage on all plots. Runoff and erosion are checked for nitrogen, potassium, organic matter, and other water quality indicators.

Ordie R. "Reggie" Jones, a soil scientist with the USDA-ARS, visted Ansai last September and toured some of their experiments. He said the experiments on the effect of slope on erosion are "amazing in scope.... These plots should provide valuable data for calibrating erosion prediction models." The experiment investigates the effects of differing slope lengths, slope shapes (convex, concave), and steepness.

Another experiment has 40-meter square plots with five crop rotations using potato, foxtail millet, and sweet clover. The plots have slopes ranging from 0 to 38 degrees, and varying fertilizer treatments. In all experiments, most of the sediment and part of the runoff is captured and tested.

One resident research associate is studying the effects of different crops on erosion, runoff, sedimentation, and soil water balance. The crops involved are lespedeza, sanfoin, alfalfa, and sweet clover. Each plot is on a 33 degree slope. Jones said, "The plots are well established and instrumented and should provide a wealth of information regarding cropping, fertility, and erosion management for steep lands."To further the goals of creating a model of sustainable, highly efficient eco-agriculture, the Ansai station is also associated with a nearby village in the Zhifang gully watershed as a demonstration watershed. The research is put to use by the 500 villagers on their family plots, including crop rotation and intercropping. There is a noticeable difference in the quality of agriculture practiced in the demonstration waterhsed as opposed to the surrounding area.

At the research station, almost every slope has vegetation. Not so with the shrubs that struggle to survive outside the watershed in the semi-arid, loose loess soil. With the old ways, 18 mu/person (a Chinese unit of measurement. One mu = 1/6th acre) of cropland produced 450 kg of food. With the help of the research station, production in the village at Ansai is 500 kg/person on a third as much cropland. The remainder of the land is used as pasture or forest.

With vegetation on every slope, erosion was cut by more than half. Where the erosion used to be 15,000 Mg/km2 it is now 6,000 to 7000 Mg/km2, but it didn't get that way without help. Because of the remote location, the teraces were built with only a cart, shovels, and a small tractor. It takes four people working four days to build 1 mu of level bench. From what he saw on his visit to the Ansai research station, Jones said, "The Chinese do move mountains with only a shovel and a hand cart.... Although our agriculture differs vastly from that of the Chinese, there is much we can learn from each other. Their agriculture is over 5,000 years old and is more productive than ever. Will U.S. agriculture still be productive in 5,000 years?"

O.R. "Reggie" Jones is a soil scientist at USDA-ARS, Conservation and Production Research Laboratory, Bushland, Texas. He travelled in China in September 1994. This photo essay was prepared with the help of SWCS staffer Wendy Despain.