Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources
Not a member yet
7916 research outputs found
Sort by
Amination of biorefinery technical lignin by Mannich reaction for preparing highly efficient nitrogen fertilizer
No full textTo develop a novel lignin-based highly efficient nitrogen fertilizer, the amination of the biorefinery technical lignin was conducted by Mannich reaction synergy with phenolation pretreatment. Subsequently, the structural transformations of lignin samples and the reaction mechanism were investigated in detail. The soil column leaching experiment was also performed to research the nitrogen release behavior of aminated lignin in soil. The results indicated that the amounts of active sites in lignin were significantly increased to 8.26 mmol/g from the original 2.91 mmol/g by phenolation. In addition, the Mannich reaction was highly selective for occurring at ortho- and para-positions of phenolic hydroxyl groups in the phenolated lignin, in which the latter was favored. Moreover, the nitrogen content in the aminated lignin was highly depended on the types of amination reagent instead of the proportion of reactants in this study. Under an optimal condition, aminated lignin with a high nitrogen content (10.13%) and low C/N ratio (6.08) could be obtained. Besides, it was especially noteworthy that the prepared APL in this study has a favorable nitrogen release behavior in soil. Thus, it is believed that these aminated lignin derivatives could be used for the preparation of various lignin-based highly efficient nitrogen fertilizer.</p
Changes in Soil Iron Fractions and Availability in the Loess Belt of Northern China After 28 Years of Continuous Cultivation and Fertilization
No full textIron (Fe) deficiency in calcareous soils of the Loess Plateau of China is a wide spread issue and primarily affects agricultural production due to the relatively higher soil pH and carbonate content. Understanding the relationships between Fe distribution in soil fractions, Fe availability, and their responses to cropping and fertilization could provide essential information for assessing Fe availability in soils and managing soils to improve Fe availability. A long-term field experiment was established in 1984 in a split-plot design using cropping systems as main plots and fertilizer treatments as subplots on a farmland in the Loess Plateau. The cropping systems included fallow, continuous wheat cropping, continuous alfalfa cropping, continuous maize cropping, and a rotation system that included a legume. Various fertilization treatments using chemical and/or manure fertilizers were included in each cropping system. Soil samples were collected from 0–10 and 20–40 cm depths in 2012. Long-term planting of crops significantly increased the concentrations of available Fe in the soils. The largest increase was observed in the continuous alfalfa cropping system. Long-term cropping significantly increased the concentrations of Fe associated with carbonates and organic matter, but decreased the concentration of Fe associated with minerals in the soils. The effect of fertilization on the distribution of Fe in the soil fractions varied with cropping system and soil depth. The fertilization treatment with manure generally increased the concentrations of Fe associated with the soil fractions. Long-term cropping and fertilization in the highland farmland significantly affected the availability of Fe and the distribution of Fe fractions in the soil.</p
Effects of vegetation and slope aspect on soil nitrogen mineralization during the growing season in sloping lands of the Loess Plateau
No full textSpatial analysis of soil aggregate stability in a small catchment of the Loess Plateau, China: II. Spatial prediction
No full textAs indicators of soil degradation vulnerability, soil aggregate stability indices play important roles in representing soil resistance to water erosion, and their spatial variability provides both agriculturally and environmentally important information. The spatial variability of aggregate stability indices is synergistically affected by the soil, topography, vegetation, and human factors. To understand the formation processes of aggregates by a spatial analysis, a prediction model combining soil properties with natural and human factors should be developed to improve the accuracy of the spatial interpolation of soil aggregate stability indices. In this study, the mean weight-diameter (MWD, mm), water-stable aggregates greater than 0.25 mm (WSA>0.25, %) and soil erodibility factor (K factor) were satisfactorily predicted by multiple stepwise regression (MSR) and regression kriging (RK) based on soil properties and natural and human factors (0.436≤ R2 ≤0.578). In addition, spatial variability and prediction modeling of aggregate stability indices were highly dependent on the quantification of land use type and landscape structure (the spatial structure of landscape elements and the connections between the different ecosystem types or landscape elements). It has received little attention in previous studies. The exclusion of all soil variables did not affect the predictions of K factor, and for MWD and WSA>0.25, even though the performance of the models may appear relatively low, but also significant (0.183≤ R2 ≤0.312), indicating that the prediction of the spatial distributions of aggregate stability indices with easily available auxiliary data is practicable and effective. Residual maps showed that high residuals are distributed around built-up land (transportation land and residential land) or farmland, indicating that anthropogenic factors increase the uncertainty of the models. The spatial distribution maps of MWD, WSA>0.25 and K factor can be useful in landscape planning and decision making to minimize water erosion risks.</p
黄土丘陵区草地植被群落优势种叶片 功能性状对氮磷添加的响应
No full text以黄土丘陵区草地植被群落 3 种优势种白羊草、长芒草和达乌里胡枝子为对象，采
用裂区试验设计，设置 0、
50 和 100 kg N·hm－2·a－1 3 个氮处理和 0、
40 和 80 kg P2O5·hm－2·
a－1 3 个磷处理，于生长旺盛期测定了各植物的叶长、叶宽、比叶面积、叶片干物质含量、叶片
氮、磷含量和氮磷比等指标，分析不同优势种叶片功能性状对氮磷添加的响应差异．结果表
明: 与未施肥相比，
50 和 100 kg N·hm－2·a－1 处理下白羊草叶长和叶宽分别显著增加 35．3%
和 64．4%，而长芒草仅有叶长显著增加 58．8%，达乌里胡枝子仅有叶宽显著增加 33．9%，但三
者叶片干物质含量分别显著降低 10．7%、
15．3%和 11．2%，白羊草和长芒草叶片氮含量分别显
著增加 23．0%和 99．2%，氮磷比分别显著增加 45．8%和 96．9%; 40 和 80 kg P2O5·hm－2·a－1处
理下达乌里胡枝子叶长、叶宽和比叶面积分别显著增加 56．9%、
41．4%和 19．6%，叶片干物质
含量显著下降 14．9%，三者叶片磷含量分别显著增加 96．7%、
110．9%和 238．4%，氮磷比分别显
著降低 45．8%、
42．8%和 53．7%．50 kg N·hm－2·a－1 处理下，与未施磷相比，
40 和 80 kg P2O5·
hm－2·a－1 处理后仅达乌里胡枝子叶长和叶宽显著增大，
3 种植物叶片磷含量显著增加，白羊
草和长芒草叶片氮含量显著降低; 100 kg N·hm－2·a－1 处理下，施磷后白羊草和长芒草叶长、
达乌里胡枝子叶宽显著增大，三者叶片磷含量显著增加，白羊草叶片氮含量显著降低．综上表
明，
3 个优势种植物叶片功能性状对短期氮磷添加的响应存在明显差异，这些差异与物种属性
和施肥水平有关，不同优势种对氮磷添加响应的差异对维持草地群落多样性和稳定性具有重
要作用．</div
基于水敏性设计理论的西安市水生态环境治理
No full text指出了随着西安市城镇化节奏加快，城市生态环境问题也与日俱增，城市发展带来的水污染问题影
响着城市的水生态环境。针对西安市发展中的水环境问题，基于水敏性城市设计（ＷＳＵＤ）理论，对 其 水 生
态环境进行了治理。以“八水绕长安”中所指的八条河流作为主要治理对象，总结了相应的治理措施。</div