Abstract: A field run-off experiment having five different patterns of hedgerows was carried out to explore effects and mechanisms of the hedgerows conserving soil and water in a red soil sloping farmland in a hilly region of Zhuji, Zhejiang, making use of natural rainfalls, simulated storms, rare earth element tracing technique (REE) and soil erosion resistance index system. Results show that under natural rainfall, the hedgerow of Double rows of Ophiopogon japonicas reduced runoff and soil loss by 39.4% and 65.8% respectively, ranking first among the five patterns in efficiency. The pre-rainfall soil water content could significantly affect occurrence of runoff and soil losses. Regression models were established to simulate the relationships between runoff and soil loss. Changes in soil physical properties under the different patterns were significant and bulk density and porosity were found to be the premier indicators in evaluating effects of the hedgerows controlling soil and water losses. On the basis of the seventeen indices for soil erosion resistance, a comprehensive evaluation index system was established to evaluate red soil erosion resistance as affected by hedgerows. Evaluation using the system indicate that the soil erosion resistance of hedgerows followed the order of double rows of Ophiopogon japonicas (MM) > One row of Ophiopogon japonicas plus one row of Hemerocallis citrina (MM) > double rows of Hemerocallis citrina (HH) > a single row of Ophiopogon japonicas (M) > a single row of Hemerocallis citrina (H) > plot without hedgerow (L). Position of hedgerows on the slope also affects their effect on soil and water losses because the middle and down slopes are the major sources of sediments.

Key words: hedgerows, soil and water conservation effect, soil erosion resistance, red soil sloping farmland, rare-earth-elements tracing technique