Application Rate Influences the Soil and Water Conservation Effectiveness of Mulching with Chipped Branches

Abstract

Core Ideas Soil and water conservation effectiveness of chipped branches mulching was tested. Two simulated rainfall events were applied in the experimental condition. High application rates may not always be ecologically and economically favorable. Mulching with chipped, pruned branches (MB) is an effective land management practice to reduce surface runoff and to control soil water erosion. The use of MB has extra advantages such as material availability and a low cost compared with other mulching materials, especially in orchards. To evaluate the impacts of application rates on the ecological and economical effectiveness of MB, a plot‐scale soil bin experiment was conducted under two representative rainfall regimes. Five treatments were tested: clear cultivation (CC, bare soil without mulching) and four MB application rates of 0.37, 0.74, 1.11, and 1.48 kg m–2. The application of MB reduced runoff generation by 15.5 to 78.6% and sediment yield by 40.7 to 98.6% compared to CC. From an ecological view, the soil and water conservation performance of MB generally decreased with increasing rainfall intensity and application rate with an exception of 1.48 kg m–2 under the heavy rainfall. Different mechanisms, such as soil surface coverage, rainfall interception by mulching, soil permeability, stability of mulching materials, and rill initiation simultaneously affected the effectiveness of MB. From an economical view, this relationship was more complex. The present study confirmed the necessity of determining the proper mulching application rate in the context of site‐specific soil, vegetation, and climatic conditions as well as local social status.