To evaluate the long-term effects of reforestation types on soil erosion on degraded land, vegetation and soil properties under conventional sloping farmland （CSF） and three different reforestation types including a...To evaluate the long-term effects of reforestation types on soil erosion on degraded land, vegetation and soil properties under conventional sloping farmland （CSF） and three different reforestation types including a Pinus massoniana secondary forest （PSF）, an Eucommia ulmoides artificial economic forest （EEF） and a natural succession type forest （NST）, were investigated at runoff plot scale over a six-year period in a red soil region of southern China. One hundred and thirty erosive rainfall events generating runoff in plots were grouped into four rainfall types by means of K-mean clustering method. Erosive rainfall type I is the dominant rainfall type. The amount of runoff and the soil loss under erosive rainfall type III were the most, followed by rain-fall type II, IV and I. Compared with CSF treatment, reforestation treatments decreased the average annual runoff depth and the soil loss by 25.5%–61.8% and 93.9%– 96.2% during the study period respectively. Meanwhile, runoff depth at PSF and EEF treatments was significantly lower than that in NST treatment, but no significant difference existed in soil erosion modulus among the three reforestation treatments. This is mainly due to the improved vegetation properties （i.e., vegetation coverage, biomass of above- and below-ground and litter-fall mass） and soil properties （i.e., bulk density, total porosity, infiltration rate and organic carbon content） in the three reforestation treatments compared to CSF treatment. The PSF and EEF are recommended as the preferred reforestation types to control runoff and soil erosion in the red soil region of southern China, with the NST potentially being used as an important supplement.展开更多
研究不同降水年型施氮量对旱地冬小麦产量、氮素利用及土壤氮素表观平衡的影响,探讨渭北旱塬旱作麦田稳产增效的最佳氮素投入量,为高效施氮提供理论依据。田间定位施氮试验于2017—2020年连续3年在陕西合阳县开展,以长6359为试验材料,设...研究不同降水年型施氮量对旱地冬小麦产量、氮素利用及土壤氮素表观平衡的影响,探讨渭北旱塬旱作麦田稳产增效的最佳氮素投入量,为高效施氮提供理论依据。田间定位施氮试验于2017—2020年连续3年在陕西合阳县开展,以长6359为试验材料,设置5个施氮量处理包括0、60、120、180和240 kg hm^(-2)(分别以N0、N60、N120、N180和N240表示),研究旱地冬小麦产量、氮肥利用率及土壤氮素平衡对降水年型与施氮量的响应。连续3年定位试验表明:(1)降水年型对冬小麦产量和经济收益影响显著,丰水年较平水年和欠水年分别增产33.6%和113.3%,经济收益提高2~3倍以上。冬小麦氮肥回收利用率和农学效率与产量有相似的变化规律,丰水年氮肥回收利用率和农学效率较平水年和欠水年分别提高4.7个百分点、0.6 kg kg^(–1)(平水年)和11.9个百分点、2.5 kg kg^(–1)(欠水年)。(2)无论何种降水年型,冬小麦产量、氮肥回收利用率和农学效率均随施氮量增加呈现先增加后下降的趋势。在丰水年和平水年,均以N180处理下最高,收获期0~100 cm土层土壤硝态氮积累分别为108.9 kg hm^(-2)和113.6 kg hm^(-2);在欠水年则以N120处理下最高,收获期0~100 cm土层土壤硝态氮积累为100.8 kg hm^(-2)。(3)通过最佳经济效益和最高产量来拟定氮素投入阈值,丰水年、欠水年和平水年施氮量分别为158.9~166.5、121.2~130.0和148.1~155.7 kg hm^(-2);通过土壤氮库平衡和最高吸氮量来拟定氮素投入阈值,丰水年、欠水年和平水年施氮量分别为166.5~190.3、109.6~147.7和153.5~198.9 kg hm^(-2)。综合考虑冬小麦高产高效及低土壤氮素损失下得出,渭北旱塬丰水年、欠水年和平水年施氮量分别为158.9~190.3、109.6~147.7和148.1~198.9 kg hm^(-2)时,是兼顾产量和环境效益的适宜施氮量,可供本地区生产中参考。展开更多
基金supported by the National Natural Science Foundation of China(No.30428028)the Innovation Group Project of the National Natural Science Foundation of China(No.40621061)
文摘To evaluate the long-term effects of reforestation types on soil erosion on degraded land, vegetation and soil properties under conventional sloping farmland （CSF） and three different reforestation types including a Pinus massoniana secondary forest （PSF）, an Eucommia ulmoides artificial economic forest （EEF） and a natural succession type forest （NST）, were investigated at runoff plot scale over a six-year period in a red soil region of southern China. One hundred and thirty erosive rainfall events generating runoff in plots were grouped into four rainfall types by means of K-mean clustering method. Erosive rainfall type I is the dominant rainfall type. The amount of runoff and the soil loss under erosive rainfall type III were the most, followed by rain-fall type II, IV and I. Compared with CSF treatment, reforestation treatments decreased the average annual runoff depth and the soil loss by 25.5%–61.8% and 93.9%– 96.2% during the study period respectively. Meanwhile, runoff depth at PSF and EEF treatments was significantly lower than that in NST treatment, but no significant difference existed in soil erosion modulus among the three reforestation treatments. This is mainly due to the improved vegetation properties （i.e., vegetation coverage, biomass of above- and below-ground and litter-fall mass） and soil properties （i.e., bulk density, total porosity, infiltration rate and organic carbon content） in the three reforestation treatments compared to CSF treatment. The PSF and EEF are recommended as the preferred reforestation types to control runoff and soil erosion in the red soil region of southern China, with the NST potentially being used as an important supplement.
文摘研究不同降水年型施氮量对旱地冬小麦产量、氮素利用及土壤氮素表观平衡的影响,探讨渭北旱塬旱作麦田稳产增效的最佳氮素投入量,为高效施氮提供理论依据。田间定位施氮试验于2017—2020年连续3年在陕西合阳县开展,以长6359为试验材料,设置5个施氮量处理包括0、60、120、180和240 kg hm^(-2)(分别以N0、N60、N120、N180和N240表示),研究旱地冬小麦产量、氮肥利用率及土壤氮素平衡对降水年型与施氮量的响应。连续3年定位试验表明:(1)降水年型对冬小麦产量和经济收益影响显著,丰水年较平水年和欠水年分别增产33.6%和113.3%,经济收益提高2~3倍以上。冬小麦氮肥回收利用率和农学效率与产量有相似的变化规律,丰水年氮肥回收利用率和农学效率较平水年和欠水年分别提高4.7个百分点、0.6 kg kg^(–1)(平水年)和11.9个百分点、2.5 kg kg^(–1)(欠水年)。(2)无论何种降水年型,冬小麦产量、氮肥回收利用率和农学效率均随施氮量增加呈现先增加后下降的趋势。在丰水年和平水年,均以N180处理下最高,收获期0~100 cm土层土壤硝态氮积累分别为108.9 kg hm^(-2)和113.6 kg hm^(-2);在欠水年则以N120处理下最高,收获期0~100 cm土层土壤硝态氮积累为100.8 kg hm^(-2)。(3)通过最佳经济效益和最高产量来拟定氮素投入阈值,丰水年、欠水年和平水年施氮量分别为158.9~166.5、121.2~130.0和148.1~155.7 kg hm^(-2);通过土壤氮库平衡和最高吸氮量来拟定氮素投入阈值,丰水年、欠水年和平水年施氮量分别为166.5~190.3、109.6~147.7和153.5~198.9 kg hm^(-2)。综合考虑冬小麦高产高效及低土壤氮素损失下得出,渭北旱塬丰水年、欠水年和平水年施氮量分别为158.9~190.3、109.6~147.7和148.1~198.9 kg hm^(-2)时,是兼顾产量和环境效益的适宜施氮量,可供本地区生产中参考。
