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Effects of Phosphorus Application in Different soil layers on Root Growth, Yield, and Water-Use Efficiency of Winter Wheat Grown Under Semi-Arid Conditions

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Journal of Integrative Agriculture 2014年第9期13卷 2028-2039页

作者： KANG Li-yun YUE Shan-chao LI Shi-qing Sate Key Laboratory of soil Erosion and Dryland Farming on Loess Plateau Northwest Agriculture and Forestry University College of Forestry Northwest Agriculture and Forestry University

Deep phosphorus application can be a usefull measure to improve crops＇ performance in semi-arid regions, but more knowledge of both its general effects and effects on specific crops is required to optimize treatments. Thus, the aims of this study were to evaluate the effects of phosphorus（P） application at different soil layers on root growth, grain yield, and water-use efficiency（WUE） of winter wheat grown on the semi-arid Loess Plateau of China and to explore the relationship between root distribution and grain yield. The experiment consisted of four P treatments in a randomized complete block design with three replicates and two cultivars： one drought-sensitive（Xiaoyan 22, XY22） and one drought-tolerant（Changhan 58, CH58）. The four P treatments were no P（control, CK）, surface P（SP）, deep P（DP）, and deep-band P application（DBP）. CH58 produced larger and deeper root systems, and had higher grain yields and WUE, under the deep P treatments（DP and DBP） than under SP, clearly showing that deep P placement had beneficial effects on the drought-tolerant cultivar. In contrast, the grain yield and root growth of XY22 did not differ between DP or DBP and SP treatments. Further, root dry weight（RW） and root length（RL） in deep soil layer（30-100 cm） were closely positively correlated with grain yield and WUE of CH58（but not XY22）, highlighting the connections between a well-developed subsoil root system and both high grain yield and WUE for the drought-tolerant cultivar. WUE correlated strongly with grain yield for both cultivars（r=0.94, P〈0.001）. In conclusion, deep application of P fertilizer is a practical and feasible means of increasing grain yield and WUE of rainfed winter wheat in semi-arid regions, by promoting deep root development of drought-tolerant cultivars.

关键词： water stress phosphorus application soil layers grain yield root growth water-use efficiency

Effects of soil shrinkage in permanent gullies formation: The case of Benggang erosion in the granite area of southern China

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Journal of Mountain Science 2021年第9期18卷 2328-2344页

作者： HUANG Wan-xia DENG Yu-song CAI Chong-fa JIANG Dai-hua Forestry College Guangxi UniversityNanning 530004China Resources and Environment College Huazhong Agricultural UniversityWuhan 430070China Agricultural College Guangxi UniversityNanning 530004China

soil shrinkage is an important factor in slope destabilization in granitic areas, which is also one of the most important conditions for the formation of permanent gullies. This study explored the effect of soil shrinkage on permanent gullies, and Benggang erosion in granitic areas in southeastern China was used as an example. Three types of Benggang in granitic area were selected to examine the soil shrinkage of three soil layers(the lateritic, transitional and sandy layers) and their effect on the development of Benggang erosion was studied. The results show that the maximum values of COLEH and COLEV(coefficient of linear extensibility in horizontal and vertical directions, respectively) are 3.09% and 1.60% in the laterite layers, 2.71% and 2.13% in transition layers, and 1.10% and 1.82% in sandy layers, indicating that the shrinkage potential of the soil layers exhibits the following order, from highest to lowest: the laterite layer, transition layer, and sandy layer. With a decreasing volumetric water content, the linear shrinkage ratio increases gradually and eventually stabilizes, and in the laterite, transition and sandy layers, the average values of the maximum linear shrinkage are 1.50%, 2.09%, and 1.74%, respectively. Axial shrinkage is most obvious in the transition layers, in which the volume change in the form of subsidence is greater than that in other layers. The soil shrinkage curves fit the trilinear model(R2>0.9), and the soil shrinkage characteristic curves were divided into structural, basic, and residual sections. The correlation analysis shows that the soil shrinkage rate is positively correlated with clay and Fe2 O3 content and negatively correlated with sand content. Clay and sand contents are the most important factors influencing soil shrinkage. soil oxides can influence soil shrinkage by affecting the particle composition of the soil, so soil shrinkage is closely related to soil clay minerals. Our findings can provide a theoretical basis f

关键词： soil shrinkage Permanent gully Granite Benggang soil layers

Fractal analysis for root growth of plant seedlings under doubled CO_2 concentration

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Chinese Science Bulletin 1998年第22期43卷 1891-1893页

作者： WANG Yiqin ZHANG Huijuan YANG Dian’an BAI Kezhi KUANG Tingyun Shandong Teachers’University Jinan 250014China Institute of Botany Chinese Academy of SciencesBeijing 100093China.

Fractal geometry was applied and box dimension was used as an indicator to analyze the effects of doubled CO\-2 concentration on the root growth of plant seedlings. Results showed that doubled CO\-2 concentration displayed different effects on root branching characteristics of C\-3 and C\-4 plants. There was an obvious increase of root branches in spring wheat while there were no significant effects on roots of sweet sorghum. In different soil layers, root branching of spring wheat was stimulated and this promotion was most significant in the second layer (10-20 cm), which denoted that elevated CO\-2 altered the root branching pattern. That means higher CO 2 concentration influences not only root growth but also its differentiation and development.

关键词： doubled CO2 seedling root fractal dimension soil layers branching pattern.

A study on amplification response of soil ground motion in Shanghai using strong motion records

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Acta Seismologica Sinica(English Edition) 2002年第6期15卷 691-695页

作者：徐永林熊里军章纯赵志光 SeismologicalBureauofShanghai

Applying the data recorded from the two minor earthquakes occurred at Zhangjiagang and Nantong, the response of the soft soil in Shanghai was developed. Both the data used here and obtained results are valuable since few of the earthquake data with high signal-to-noise ratio was recorded in China. Therefore, it has practical significance for the seismic zoning, the design and retrofit of the aseismic structures on the soft soil in China. It should also be noticed that the soil layers are nonlinear system especially when the earthquake wave with high amplitude propagating in the soft soil. Although some experts suggested that the soil amplification responses of the ground motion were essentially identical for the earthquake waves with either the higher amplitude or lower amplitude, it is still noticeable that the real soil ground motion response under a near-field strong earthquake may not be totally conformed to the above results. The further effort should be devoted to this problem. Anyway, the results achieved in this paper are of reference value to seismologists and engineers.

关键词： soil ground motion amplification response soil layers intensity

In-Situ Evaluation of Evaporation in Layered soils （Tukulu, Sepane and Swartland）

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Journal of Agricultural Science and Technology(A) 2012年第5期2卷 577-590页

作者： Sabelo Sicelo Wesley Mavimbela Leon Daniel van Rensburg Department of soil Crop and Climate Sciences University of the Free State P.O. Box 339 Bloemfontein 9300 South Africa

Knowledge about the influence of soil layers on evaporation is essential for the optimization of infield rainwater harvesting （IRWH） in the semi-arid areas of the Free State province of South Africa. Among the soils earmarked for 1RWH development include the Tukulu, Sepane and Swartland soil types that have contrasting soil layers. These soils have to capture and store rainwater within the soil profile layers away from the evaporation zone. To determine how the three soils release and deliver soil water at the evaporating site, a 21-day evaporation experiment was conducted on pre-drained monoliths. Instantaneous soil water content （SWC） from in-situ and soil water characteristic curve （SWCC） from laboratory was measured. Separate soil samples of 15 mm thickness were also evaporated under the same conditions to establish the extent of drying and hydraulic gradient at the soil surface. The Darcian evaporative flux and unsaturated hydraulic conductivity （K-coefficient） were also determined. At the surface suctions of magnitude greater than 1,500 kPa were observed from all monoliths. Total contributions to evaporation from the Tukulu, Sepane and Swartland were 43, 51 and 70 mm, respectively. The low contributions were explained by the presence of the prismacutanic C-horizon in the Tukulu and Sepane at respective depths of 600 and 700 mm. This layer was associated with the steepest suction gradient that restrained further upward fluxes by subsequent lowering for the K-coefficient with more than two orders of magnitudes within a narrow range of SWC. However, the presence of the pedocutanic B-horizon at depths of 300 mm undermined this restrictive function through the appreciable capillary activity demonstrated by clays at near evaporating surfaces. The shallowness and deficiency in structure of the Swartland was consistent with the high contribution to evaporation that gave this soil a dry soil water regime. It was therefore concluded that the Tukulu offered soil profile

关键词： soil water soil layers evaporation soil hydraulic characteristics.