Soil water resources use limit in the loess plateau of China

Soil water is a key factor limiting plant growth in water-limited regions. Without limit of soil water used by plants, soil degradation in the form of soil desiccation is easy to take place in the perennial forestland and grassland with too higher density or productivity. Soil water resources use limit (SWRUL) is the lowest control limit of soil water resources which is used by plants in those regions. It can be defined as soil water storage within the maximum infiltration depth in which all of soil layers belong to dried soil layers. In this paper, after detailed discussion of characteristics of water resources and the relationship between soil water and plant growth in the Loess Plateau, the definition, quantitative method, and practical applications of SWRUL are introduced. Henceforth, we should strengthen the study of SWRUL and have a better understanding of soil water resources. All those are of great importance for designing effective restoration project and sustainable management of soil water resources in water- limited regions in the future.

Assessment and utilization of soil water resources

Based on the analyses of water interactions and water balance, this paper discusses the issues on the assessment and regulation of soil water resources, which lays the scientific basis for limited irrigation and water-saving agriculture.

Humble View on Soil Water Resources

Soil water is one of renewable water resources.Some properties of soil water concerning with its availability to plant are briefly described.An equation for estimating the amount of soil water resource is presented.Based on the evaporation demand of atmosphere,the evaluation coefficient for soil water resource is suggested.

A STUDY ON THE BALANCE OF WATER AND SOIL RESOURCES IN THE HEXI CORRIDOR,GANSU PROVINCE

1. Actual water resources In the Hexi Corridor, annual precipitation is only 35-200mm, showing semi-desertand desert landscape. But in the Qilian Mountains which are in the south of the Hexi Corri-dor, there is more precipitation. In the Shiyanghe, Heihe, Shulehe River basins average an-nual precipitation is respectively 2.3, 2.7, 3.6 times larger than that of the Hexi

Impacts of Overgrazing and Reclamation on Soil Resources in Rangeland Ecosystems in Huailai Basin, Hebei, China

The soil constituents and relations between the variation of soil resources and plant communities in three adjacent sites representing the overgrazing, reclamation and comparatively undisturbed communities respectively were quantified and examined in study area in Huailai Basin, Hebei Province, China. There have been significantly greater constituent of C, N, P in the soils of shrubland site. Corg, Ntotal, Navail and Pavail were between 1.18 and 3.90 times more concentrated in the soils of shrubland site in comparison with the other two sites. Although the Ptotal concentration was lower in shrubland soils than in overgrazed rangeland soils, the Pavail concentration, however, was significantly greater in the soils of shrubland site, and increased by 59.1% and even 289.6% in the soils of shrubland site comparing to those in the soils of range-land and millet field sites. Among the three sites, CV exceeding 40% were found for SO4, Cl, and F ion. The CV of organic carbon also exceeded 40% but only in the soils of millet field site. The highest CV were found for F, SO4 ion in the soils of shrubland and overgrazed rangeland sites, while for Cl and SO4 ion in those of millet field site. The results also showed that the introductions of shrubs are of vital importance for the accumulation of soil nutrients and maintenance of soil fertilities, and also for the restoration and reconstruction of desertified ecosystems.

Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions,China

Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of HunanProvince, the soil and water resources dynamics, fertility evolution characteristics andland productivity changing situation were studied. Fixed observation results from 1993to 2002 showed that pools covering about 15% of total area could store up 10% of surfacerunoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio ofinterception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in thecatchment area system, and benefited the aquatic culture and helped to resist seasonaldrought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 tkm-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddyfield increased steadily (>10%); water storage enhanced by more than 20% in sloping landand dryland in drought season; crop production increased by more than 20%; and productionof trees, fruits, tea and fish as well as land productivity increased yearly.

A NATION-WIDE SOIL SURVEY RATIONALIZES EXPLOITATION OF VARIOUS SOIL RESOURCES

To tap the production potential of soil resources in China by making a nationwide soil investigation is a precondition for developing the farming production as a means of coping with the current population explosion and providing necessities for people’s livelihood.This article expounds practical methods for the survey and elucidates rational exploitation in line with soil conditions in different localities across the land.

Facts about Cotton and Soil Resources

After the United Nations Climate Change Conference 2009 in Copenhagen,environmental protection and low-carbon have been brought into spotlight.Due to the climate change,people have focused on how to do the green thing. We should live and produce in a low-carbon style.How to do this?You should pay much more attention to materials that were used in the production.

Application of Immune Algorithm to Evaluation of Soil Resource Quality

Based on the geographic information system (GIS) technology, ArcInfo software was adopted to collect, process andanalyze spatial data of Guangdong Province for an evaluation of soil resource quality. The overlay analysis method wasused in combining evaluation factors of Guangdong soil resource quality to determine the evaluation units. Because ofits favorable convergent speed and its ability to search solutions, the immune algorithm was applied to the soil resourcequality evaluation model. At the same time, the evaluation results of this newly proposed method were compared to twoother methods: sum of index and fuzzy synthetic. The results indicated that the immune algorithm reflected the actualcondition of soil resource quality more exactly.

Red Soil Resource Information System and Its Preliminary Application

Red soil is a very important soil resource in southern China. However, due to being simultaneously of high productive potentialities and severely degraded, it needs harnessing urgently. Red Soil Resource Information System (RSRIS) based on remote sensing and geographic information system (GIS) plays an important role in survey, evaluation, utilization and management of red soil resource. RSRIS of Quzhou City) Zhejiang Province (1:250000) and RSRIS of Longyou County, Zhejiang Province (1:50000) have been made respectively on SUN SPARC station and using ARC/INFO. This paper introduces the system design,database creation and system functions, and it particularly focuses on developing applied models, such as red soil resource division and mapping, suitability evaluation, erosion risk evaluation, plant utilization zone etc. The problems on study of RSRIS and its developing strategy are also discussed.

Soil Database Management Software Development for Optimizing Land Resource Information Utilization to Support National Food Security

Since land resource database development in 1987/1988, a large amount of digital data in spatial, tabular and metadata format has been collected and generated. There are some application softwares of soil database to manage such a large amount of data, i.e.: Side & Horizon (SHDE4), Soil Sample Analysis (SSA), and Land Unit in dbf file, while Site and Horizon is in DataEase formats. The database contains soil physics and chemical property data of each soil horizon from surface to effective soil depth, climate, land surface condi- tions, and other parameters required for soil classification. Currently, database management software for land resources is still based on DOS and is stand alone. The system is not efficient and effectively used as Agri- cultural Land Resource Information System. At present, as a key component of this system requires review and development of new database software is compatible with the development of information technology. This paper explains about development of interactive agricultural land resources information system for op- timizing land resources data utilization. Hopefully, the software can give contributions in national Agricul- tural Land Resources System Information development for supporting food security.

Soil Health and Sustainable Land Resource Management Practices at Municipal Level: A Case from Bheri Nagarpalika (Municipality), Jajorkot District, Nepal

The increasing challenges of pressure and ever-growing demands on limited resources in Nepal by diverse actors,land degradation,biodiversity loss and climate change require the rational use of land resources to sustain and enhance productivity and maintain resilient ecosystems for achieving the sustainable and efficient use of resources,taking into account biophysical and socioeconomic dimensions.Regarding this,Nepal Government has realized and taken initiation of scientific and sustainable land use zoning following the National Land Use Act 2019(2076 B.S.)to use land resources in practicable and sustainable manner.Using spatial information techniques such asZ-3 satellite image,remote sensing(RS),global positioning system(GPS)and geographic information system(GIS).Multicriteria decision making(MCDM)methods for acquiring spatial/temporal data,through expert judgment techniques based on field observation as well as laboratory analysis result,it was found that the soil nutrient status of,the municipality varied spatially and has pH with very high acidic to slightly alkaline but most of the soils are slightly acidic(39.58%).Majority of the soil are loam and sandy loam type with very low to high level of organic matter.Most of the municipal area is under medium range of organic matter.Nitrogen content ranges from very low to very high level as to same ranges of phosphorous(37.69%).Potassium level is also in very high to low as 37 percent land area has high level of potassium.Reclamation of acidic soil mainly in leachable soil is recommended with the proper management of Nitrogen with addition of organic matter is needed to manage for improving crop production.

Biocrust-induced partitioning of soil water between grass and shrub in a desert steppe of Northwest China

Maintaining the stability of exotic sand-binding shrub has become a large challenge in arid and semi-arid grassland ecosystems in northern China.We investigated two kinds of shrublands with different BSCs(biological soil crusts)cover in desert steppe in Northwest China to characterize the water sources of shrub(Caragana intermedia Kuang et H.C.Fu)and grass(Artemisia scoparia Waldst.et Kit.)by stable 18O isotopic.Our results showed that both shrublands were subject to persistent soil water deficiency from 2012 to 2017,the minimum soil depth with CV(coefficient of variation)<15% and SWC(soil water content)<6% was 1.4 m in shrubland with open areas lacking obvious BSC cover,and 0.8 m in shrubland covered by mature BSCs.For C.intermedia,a considerable proportion of water sources pointed to the surface soil.Water from BSCs contributed to averages 22.9%and 17.6%of the total for C.intermedia and A.scoparia,respectively.C.intermedia might use more water from BSCs in rainy season than dry season,in contrast to A.scoparia.The relationship between shrub(or grass)and soil water by δ^(18)O shown significant differences in months,which partly verified the potential trends and relations covered by the high variability of the water source at seasonal scale.More fine roots at 0-5 cm soil layer could be found in the surface soil layer covered by BSCs(8000 cm/m^(3))than without BSCs(3200 cm/m^(3)),which ensured the possibility of using the surface soil water by C.intermedia.The result implies that even under serious soil water deficiency,C.intermedia can use the surface soil water,leading to the coexistence between C.intermedia and A.scoparia.Different with the result from BSCs in desert areas,the natural withdrawal of artificial C.intermedia from desert steppe will be a long-term process,and the highly competitive relationship between shrubs and grasses also determines that its habitat will be maintained in serious drought state for a long time.

盐碱地肥沃耕层构建水肥盐综合调控机理与技术研究进展

盐碱地是我国重要的后备耕地资源,我国历来高度重视盐碱地的改良和利用工作,但目前盐碱区淡水资源短缺严重制约了盐碱地的改良利用。如何在水资源约束下,优化调控土壤水肥盐动态是当前盐碱地可持续利用中亟待解决的关键科学问题。近年来,大量研究利用有机培肥、耕作、节水灌溉、田间覆盖、咸水利用等农艺措施,在盐碱地建立“控盐、保肥、保水”的肥沃耕作层,显著改变了水肥盐在土壤-植物-大气连续体中的运移过程,实现了盐碱地质量和产能快速提升,上述内容也日益成为盐碱地改良利用中的重要研究方向。本文系统总结了盐碱地改良和肥沃耕层构建等方面的研究进展,并针对盐碱地肥沃耕层构建下土壤水肥盐综合调控及其与植物生长的协同关系等进行了展望,以期为盐碱地可持续改良利用提供参考。

土壤肥料学实验课操作视频开发探索与实践

土壤肥料学实验是农科类核心专业基础课。本着让学生准确规范地掌握实验操作技能的同时,丰富和完善实验教学资源从而提高实验课的教学效果,为该专业今后的教学、科研和农业技术服务提供高品质的资源保障。作者根据多年课堂实践,总结学生在实验课中常见的错误操作,深入了解学生和实验教师需求,录制开发土壤肥料学实验基本操作视频。视频录制既考虑实验流程的完整性和时效性,又强化实验中关键环节的独立性、规范性和广适性。视频资源的开发和网络推广有效弥补传统课堂模式的不足,以其演示的直观化和内容可再现等特点,既方便学生课前预习,提高学生实验操作技能,又便于学生课后随时复习,巩固实验相关知识,对提高实验教学效果有明显的推动作用。

大豆种质资源苗期耐盐性鉴定评价与筛选

土壤盐渍化严重影响大豆品质与产量,筛选耐盐大豆资源对开展盐碱地综合利用意义重大。为建立大豆苗期耐盐鉴定评价体系,设置淡水和NaCl含量为0.9%~1.8%的10个等差梯度,以蛭石为培养基质,大豆2片真叶始现时开始盐处理。结果表明, 1.2%盐处理16 d时,不同大豆种质资源耐盐等级四分位差值最大,是大豆苗期耐盐鉴定评价的最适条件。利用大豆苗期耐盐鉴定评价体系对来自国内外的504份大豆种质资源进行苗期耐盐性鉴定评价,耐盐等级为1级、2级、3级、4级、5级的大豆资源依次为46份、146份、157份、79份、76份。利用GmSALT3基因的分子标记对1级耐盐资源进行检测,其中40份(86.96%)大豆材料扩增结果与GmSALT3基因的分子标记结果相符合。为分析大豆苗期鉴定过程中盐胁迫浓度的变化趋势,确立了土壤含盐量(Y,%)与电导率(X,mScm^(–1))的回归方程:Y=0.278X–0.0618,预测精准度在95%以上。测定统计了从盐处理开始至调查结束时的培养基质含盐量变化趋势,培养基质含盐量基本维持在13 mS cm^(–1)左右。本研究为大豆苗期规模化耐盐性鉴定和培育耐盐新种质提供了技术体系和基础材料。

基于GPR探测的长江源地区冰川与冻土厚度研究

长江源地区的冰川变化揭示了青藏高原气候变化趋势。冰下地形探测作为冰川发育和运动过程研究的基础,对长江地区水土保持和淡水资源储量研究具有指导意义。长江科学院在长达10 a的江源科考基础上,分别于2022年、2023年采用探地雷达(GPR)技术对长江正源沱沱河发源地格拉丹东主峰的冰川厚度进行精准探测,并对查旦湿地冻土厚度上限进行了探测研究。结合多种冰川和冻土地质模型的GPR波场模拟结果,提高了GPR技术在长江源地区冰川和冻土探测的有效性和精准度。探测结果表明,格拉丹东主峰冰川厚度和查旦湿地冻土厚度上限均有不同程度降低,冰川厚度和冻土厚度上限观测是一个常年积累的结果,后续仍需持续进行观测,积累更多数据,分析变化趋势,以估算探测区域内冰储量,研究气候变化对冰川的影响效果。

基于Theil不等系数IOWAO组合模型的黑龙江省秸秆还田机械化程度预测

玉米、水稻等作物收后秸秆处理一直是农业生产中亟待解决的问题,机械化秸秆还田是作物收后秸秆处理的重要手段,也是保护黑土资源的重要措施。结合相关文献,提出基于协整性检验的单一预测模型选择和基于误差指标最小的最优组合预测模型选择关键环节;运用协整性检验方法确定二次函数模型、ARIMA模型、H-W无季节模型作为秸秆还田机械化程度预测的单一模型;依据误差绝对值和最小法、Shapley法和基于Theil不等系数IOWAO法构建三种组合预测模型,采用误差平方和(SSE)、平均绝对误差(MAE)、均方误差(MSE)、平均绝对百分比误差(MAPE)、均方百分比误差(MSPE)五个误差指标比较模型精度,确定采用基于Theil不等系数IOWAO的组合模型为最优预测作物秸秆还田机械化程度模型。结果表明,2022-2026年黑龙江省秸秆还田机械化程度将稳步提升,平均每年增加4.52%,2026年将达到74.19%,比2021年提升22.62%;2022年以后,黑龙江省秸秆还田机械化程度将进入快速发展期。为制定和实施机械化秸秆处理政策提供理论依据,为保护和恢复黑土资源生产能力提供重要支撑。

交口灌区农业水土资源承载力评价及障碍因子诊断

【目的】评价交口灌区农业水土资源承载力及其障碍因子。【方法】以交口灌区为研究对象,构建包括水土资源、社会、经济、生态环境4个准则层的水土资源承载力评价指标体系,采用组合赋权的TOPSIS模型对交口灌区水土资源承载力进行综合评价,采用障碍度模型诊断制约灌区农业水土资源承载力的主要障碍因子。【结果】2016—2020年,交口灌区水土资源承载力呈稳步提升态势,各区、县的水土资源承载力差距逐渐缩小;灌区不同区、县的水土资源承载力水平差异显著,灌区北部承载力水平高于灌区南部,各区、县承载力指数介于0.257~0.621;水土资源和生态环境系统中的单位耕地农药施用量、水土资源匹配系数、单位耕地施肥量、垦殖率、生态环境用水率、水资源开发利用率是制约交口灌区水土资源承载力提升的主要障碍因子。【结论】水土资源和生态环境是影响灌区水土资源承载力的关键要素,灌区应以可持续发展理论为导向,注重农业发展与生态保护并重,综合提升灌区承载力。

基于耕地资源质量分类监测的土壤条件变化对粮食产量的影响——以河南省兰考县为例

为突出土壤条件变化对粮食产量的影响,采用趋势分析法和对比分析法,以兰考县耕地资源质量分类监测工作为例,分析土壤监测样点不同年份的土壤条件变化对当地粮食产量造成的影响。研究表明,土壤有机质含量的增加和土壤pH在合理范围内的增加都能够提升粮食产量。建议以测土配方施肥为基础,增加有机肥的使用量,提升土壤有机质含量,并针对当地土壤的实际情况和主要作物类型,提出有针对性的改良土壤pH的措施,以提升粮食产量。