水保所知识产出(1956---)知识库

为了揭示生物炭对黄土区不同质地土壤水分入渗、蒸发特性及硝态氮淋溶的影响规律及差异，该研究选取黄土
区 3 种典型土壤（风沙土、黄绵土和黑垆土），设置质量分数 0、0.5%、1%、2%、3% 和 5%共 6 个比例的生物炭梯度，
进行室内土柱模拟试验。结果表明：湿润锋进程与累积入渗量受生物炭添加量及土壤质地的影响。随着生物炭添加量的
增大，风沙土和黑垆土的水分入渗速度和累积入渗量逐渐降低（P<0.05）；黄绵土水分入渗和累积入渗量呈先增大后减缓
的趋势（P<0.05）。生物炭未显著影响试验条件下黄绵土和黑垆土的累积蒸发量（30 d），但显著改变了风沙土的蒸发特征，
抑制前期蒸发。不同生物炭添加量下，3 种土壤的湿润锋运移距离与运移时间均符合幂函数关系；Philip 入渗模型可描述
添加生物炭土壤水分入渗变化过程。生物炭可减少黄土区 3 种质地土壤的硝态氮淋溶量，表明适量生物炭添加能够增强
土壤氮素固持能力，降低硝态氮淋失及环境风险。该研究结果表明，生物炭作为一种土壤改良剂能够提高土壤持水性和
降低硝态氮淋失，有利于黄土高原旱地作物的生长；同时该研究可为农田选择合理生物炭施用量提供科学参考。

Water scarcity and low use efficiency of nitrogen are the major limiting factors for agriculture sustainable
development in dryland areas of the Loess Plateau. Biochar has been widely proposed as a promising novel alternative of soil
amendment to improve soil quality and increase crop productivity, but limited quantitative work has been addressed on the soil
water infiltration process, evaporation characteristics and nitrate leaching. A better understanding of these characteristics can
provide the solid basis for the evaluation of the effect of biochar amendment on soil hydrology and nitrogen retention in arid
and semi-arid regions. In the present study, by using the soil column simulation investigation, biochar derived from maize
stover (pyrolysis temperature of 400 ) was applied to  ℃ 3 different types of soil samples (aeolian soil, cultivated loessial soil
and dark loessial soil) collected from the Loess Plateau at 6 rates of 0, 0.5%, 1%, 2%, 3% and 5% (w/w) with triplicate. The
wetting process, the cumulative infiltration amount, the permeability and the stable infiltration rate were determined. The water
infiltration analysis showed that the advancement of wetting front and the cumulative infiltration amount changed with the
biochar addition amount and soil texture. The migration rate of water was the fastest in aeolian soil and the slowest in
cultivated loessial soil due to the soil texture and structure. The migration rate of wetting front in aeolian soil and
dark loessial soil was decreased after the biochar addition. As the rate of biochar addition increased, the cumulative infiltration
amount of aeolian soil and dark loessial soil gradually declined. For cultivated loessial soil, the higher biochar addition rates
(3% and 5%) increased the time of the wetting front to the bottom of the column, while the lower rates (0.5%, 1% and 2%)
increased the wetting front migration rate; the cumulative infiltration amount was not decreased at the rate of 0.5%, 1% and
2%, but reduced significantly at the rates of 3% and 5%. Overall, biochar addition reduced the water infiltration capacity and
increased the water holding capacity for aeolian soil and dark loessial soil; the lower rates of biochar addition in
cultivated loessial soil were not conducive to the water retention, while the higher rates of biochar addition favored. There
were extremely significant power function relationships between wetting front distance and infiltration time under different
rates of biochar treatments with the determination coefficient of greater than 0.99. Philip infiltration model was suitable for the
simulation of soil water infiltration process under biochar treatments with the determination coefficient ranging from 0.991 to
0.999. During the successive evaporation of 30 days, biochar addition had no significant effects on the cumulative evaporation
in cultivated loessial soil and dark loessial soil. However, biochar amendment changed the evaporation characteristics of
aeolian soil: the evaporation was inhibited in the early stage; due to the continuous supply of water, the evaporation gradually
increased in the later stage, but not significantly. The nitrate leaching was determined by the volume and the concentration of
the leaching solution. The 2% addition rate of biochar in aeolian soil and the 1% addition rate of biochar in loessial soil had
no significant effects on the total amount of nitrate leaching (P>0.05), when compared with the levels of the control (0%).
Biochar addition reduced nitrate leaching by 18.1%-37.2% in aeolian soil, 33.8%-87.7% in cultivated loessial soil and
13.8%-80.8% in dark loessial soil, which may lead to increase the capacity of nitrogen holding in soil, reduce the nitrogen
leaching risk in environment. Our results suggest that the use of biochar as soil amendment in agricultural soils plays an
important role in increasing soil water holding capacity, improving available nitrogen and helping crop development in dryland
areas of the Loess Plateau. However, more studies are needed to understand the mechanisms through which these benefits are
achieved.