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| Effects of soil crust on runoff, sediment yield and nutrient loss on slope of southweast Hengduan Mountains |
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| Abstract: |
| Simulated rainfall experiments were conducted to investigate the effects of soil crust on hillsloperunoff, sediment yield and nutrient loss process of Hengduan Mountains. The experimental design included two kindsof soil surface (crust and non-crust), one rainfall intensity (60 mm/h) and two gradients (5and 10). Results showedthat the runoff of crust slope occurred earlier than that of non-crust, but runoff yield was similar. Compared withnon-crust slope, sediment yield of 5slope with crust decreased by 54%, while the sediment yield of 1slope withcrust increased by 16%. These results suggested that crust had less effect on runoff yield; however, it had great effecton sediment yield. The declining process of phosphorus and potassium losses with runoff and sediment was a powerequation, and the losing velocity of phosphorus and potassium was the fastest for no crust land. With the differentdevelopment status of soil crust from no crust to heavy crust, the dominant position of sediment extractable potassium(SEK) loss was replaced gradually by the dissolved potassium loss, but the sediment extractable phosphorus(SEP) losswas dominant all the time. Compared with no crust hillslope, the total amount of K+, DP, SEP and SEK lossdecreased by 62.39%, 33.33%, 37.10% and 78.36%, respectively. It implies that soil crust may make soil nutrientloss decreased and control soil quality degeneration tendency. |
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