水稻均衡营养肥对杂交稻生长发育的影响及养分吸收特性

研究了水稻均衡营养肥对杂交稻生长发育的影响及养分吸收特性,以为精准施肥及秸秆还田养分循环利用提供必要的科学参数。结果表明,水稻均衡营养肥处理的株高、总粒数、实粒数、结实率、穗质量和产量均高于常规施肥处理,稻谷中的总钾、S~(6+)和Fe~(2+)含量均高于常规施肥处理,但总磷、Ca~(2+)和Mg~(2+)的含量低于常规施肥处理,总氮含量则基本相同;常规施肥处理的秸秆中总氮、总钾、Mg~(2+)和S~(6+)含量均高于水稻均衡营养肥处理,总磷、Ca~(2+)和Fe~(2+)含量基本相同。均衡营养肥处理氮、磷、钾利用率分别为67.8%、60.0%和95.5%,农民常规施肥处理分别为32.3%、86.0%和100%。可见,水稻均衡营养肥能均衡的为杂交稻生长提供必需的养分,大幅度提高肥料利用率。     

连续翻耕秸秆粉碎还田土壤物理性状及水稻产量

通过连续5年田间定位试验,研究了翻耕秸秆粉碎还田对稻麦两熟农田土壤物理性状、水稻产量及其构成因素的影响。结果表明,水稻收获时,翻耕秸秆粉碎还田处理能够有效降低耕层土壤容重、紧实度和土壤中固相部分所占比例,增加耕层土壤毛管孔隙度和土壤中气相部分所占比例。就水稻产量而言,翻耕秸秆粉碎还田处理较秸秆不还田处理有不同程度的提高,5年平均增产428 kg/hm~2,增幅为4.50%,主要是通过增加有效穗数和穗粒数来提高水稻产量。总之,本试验条件下,翻耕秸秆粉碎还田措施有利于改善耕层土壤物理结构,提高水稻产量。     

Utilizing a DUALEM‐421 and inversion modelling to map baseline soil salinity along toposequences in the Hunter Valley Wine district

In the oldest commercial wine district of Australia, the Hunter Valley, there is the threat of soil salinization because marine sediments underlie the area. To understand the risk requires information about the spatial distribution of soil properties. Electromagnetic (EM) induction instruments have been used to identify and map the spatial variation of average soil salinity to a certain depth. However, soils vary with depth dependent on soil forming factors. We collected data from a single‐frequency and multiple‐coil DUALEM‐421 along a toposequence. We inverted this data using EM4Soil software and evaluated the resultant 2‐dimensional model of true electrical conductivity (σ – mS/m) with depth against electrical conductivity of saturated soil pastes (EC_p – dS/m). Using a fitted linear regression (LR) model calibration approach and by varying the forward model (cumulative function‐CF and full solution‐FS), inversion algorithm (S1 and S2), damping factor (λ) and number of arrays, we determined a suitable electromagnetic conductivity image (EMCI), which was optimal (R² = 0.82) when using the full solution, S2, λ = 3.6 and all six coil arrays. We conducted an uncertainty analysis of the LR model used to estimate the electrical conductivity of the saturated soil‐paste extract (EC_e – dS/m). Our interpretation based on estimates of EC_e suggests the approach can identify differences in salinity, how these vary with parent material and how topography influences salt distribution. The results provide information leading to insights into how soil forming factors and agricultural practices influence salinity down a toposequence and how this can guide soil management practices.     

施石灰和秸秆还田对双季稻产量和氮素吸收的互作效应

红壤稻田面临土壤酸化和肥力偏低的双重挑战。施石灰和秸秆还田分别是稻田土壤酸化改良和培肥的有效措施,但二者的互作效应尚不清楚。本研究连续4年(2015—2018年)在江西省开展施石灰和秸秆还田双因素田间定位试验,旨在探明施石灰和秸秆还田对红壤双季稻田水稻产量和氮素吸收的互作效应。结果表明,施石灰和秸秆还田均显著提高了早、晚稻的产量和氮素吸收,且二者具显著的协同促进效应。秸秆还田下,施石灰使早稻产量和氮素吸收分别增加10.7%和15.5%;而在秸秆不还田下,增幅仅分别为4.4%和9.7%。秸秆还田下,石灰使晚稻产量和氮素吸收分别提高18.7%和24.6%;但在秸秆不还田下,增幅则分别为10.5%和5.7%。施石灰对早、晚稻产量和氮素吸收的促进效应随试验年限的增加而减弱。石灰对土壤pH值的提升效应随试验年限的延长显著降低。试验4年后,石灰对土壤有机质和全氮含量均无显著影响;秸秆还田显著提高了土壤有机质含量,而对全氮含量无显著影响。因此,秸秆还田配施石灰能够协同实现双季稻增产、土壤酸化改良与培肥。本研究表明在此酸性的红壤双季稻田上每4年左右施用一次石灰为宜。     

Soil risk maps – Interpreting soils data for policy makers,agencies and industry

Surface runoff, erosion, compaction and the leaching of potential pollutants from land can degrade the soil resource and damage the water environment, reducing crop yields, causing loss of valuable nutrients and organic matter, together with increasing flood risk. Increasingly, it is recognized that scientific information must be translated into practical tools to change practices and protect the soil and water resource. Working alongside agencies in Scotland, we applied a suite of simple, transparent, rule-based models to identify areas most at risk of exporting sediment and pollutants that may degrade water quality based on field-scale (1:25,000) soil maps. The maps have been used by Scottish Environment Protection Agency, Scottish Water and Scottish Government to assess soil risks to waters from field to regional scale. The work brought scientists together with policy makers, agencies and the water industry to pool their knowledge to apply these practical tools for decision-making. It highlights the need to apply existing knowledge to answer salient questions. All three examples described show that providing the right type of information, which is based on fundamental soils data, can directly influence the implementation of policies, investment and monitoring decisions and provide evidence in support of government. However, this requires both researchers and agency scientists to develop skills as knowledge brokers and to normalize the use of soil data in everyday agency settings.     

全国水土保持功能年度价值评价研究

依据《中华人民共和国水土保持法释义》对水土保持功能的定义,分析了水土保持设施、地貌植被所发挥或蕴藏的有利于保护水土资源、防灾减灾、改善生态、促进社会进步等作用的内涵。在借鉴国内外先进经验和研究成果基础上,结合我国水土流失特点、水土保持现状,界定出水土保持功能价值概念。采用生态经济学计量方法,结合实际调研情况,分析各个指标之间的逻辑关系,建立了水土保持功能价值评价模型。按照国家水土保持区划一级分区,适当考虑二级分区和三级分区,以及全国水土流失动态监测站网分布概况,收集39个典型县(市、区)2016年度的土壤、水文、气象等观测资料,测算出其水土保持功能价值,进而推算至全类型区,再从8个水土保持一级分区的水土保持功能价值推算出2016年度全国水土保持功能价值,并在对测算结果进行分析讨论的基础上,对国家制定水土保持生态文明对策提出了建议。     

基于土壤微波辐射布儒斯特角反演土壤含水率

在利用被动微波遥感技术进行裸露地表土壤含水率(Soil Moisture Content,SMC)的反演中,土壤粗糙度是制约反演精度的最关键因素。该研究利用改进的积分方程模型(Advanced Integral Equation Model,AIEM)进行地表多角度微波发射率的模拟,探索地表微波辐射多角度信息用于提高地表SMC反演精度的可行性。基于不同SMC和不同粗糙度地表多角度V极化发射率数据的变化趋势提取土壤介质布儒斯特角,结果表明,土壤布儒斯特角对SMC具有较高的敏感性,C波段(6.6 GHz)不同含水率土壤的布儒斯特角分布在60°～80°范围内。基于AIEM模拟数据的分析发现,土壤布儒斯特角正切值与SMC具有较好的线性关系,线性拟合决定系数为0.94,均方根误差为0.027cm~3/cm~3,并得到了基于布儒斯特角的裸露地表SMC反演算法。基于模拟数据的算法验证结果表明,算法的SMC预测值与理论值的决定系数为0.95,均方根误差为0.024 cm~3/cm~3。算法在不同土壤粗糙度自相关函数下均表现出稳健的特性,SMC预测精度最大均方根误差为0.027 cm~3/cm~3,最小为0.023cm~3/cm~3。基于布儒斯特角的SMC反演算法利用的是多角度土壤发射率的相对变化而非其绝对数值,该研究为SMC的多角度被动微波遥感提供了一种不同的研究思路。     

Soil Organic Carbon and Soil Physical Characteristics as Affected by Land Uses under Semiarid Irrigated Conditions

ABSTRACT

Rice-Wheat rotation is the dominant land use in the state of Punjab, resulting in over exploitation of ground water resources. Thus, it is necessary to evaluate other land uses that requires less water and are sustainable. The present investigation was planned with four land uses viz., fallow (FLU), rice-wheat (ALU), grasses (GLU) and pear (PLU) with respect to their effect on soil organic carbon and soil physical characteristics in surface and subsurface depth in district Ludhiana, Punjab. The soil organic carbon (SOC) content was higher by 10, 30.9 and 24.9% under rice-wheat, grasses, and pear than that under fallow. The grasses showed higher soil moisture characteristics curve (SMCC) and lower bulk density (Db) than that under rice-wheat. The larger mean weight diameter (MWD) were observed under pear, grasses and fallow than that under rice-wheat by 0.21, 0.51 and 0.41 mm, respectively. The saturated hydraulic conductivity (K_s) was higher in magnitude by 56.1, 55.4 and 28%, respectively under PLU, GLU and FLU over ALU. Of the evaluated land uses, pear and grasses proved to be more sustainable by retaining more moisture, maintaining better soil physical characteristics and SOC under semiarid irrigated conditions in the state on long term gradual response.     

基于土壤水分下限的宁夏枸杞滴灌灌溉制度试验研究

以宁杞7号枸杞为研究对象,在宁夏同心县开展2 a田间试验.设置4个关键控水期、3个控水水平共8个处理,研究枸杞不同生育期不同水分下限条件下根区土壤含水率、叶片光合生理指标、产量与品质变化;分析其耗水规律与水分利用效率,提出基于土壤水分下限的宁夏枸杞滴灌灌溉制度.结果表明:不同水分处理枸杞根区20~60 cm土层土壤含水率最大;叶片气孔导度随土壤下限升高而增大,高水分下限处理的蒸腾速率相对较大,叶片水分利用效率则相反;生育期耗水量随土壤水分下限升高而增大,2 a增幅分别为10.8%和12.8%,平均耗水量为386.6~463.2 mm,夏果期耗水量最大且差异具有统计学意义,是关键需水期.2 a均为处理S5的产量最大分别为2 208.15和2 571.30 kg/hm²,水分利用效率最高为0.39 kg/m³;水分处理对蛋白质含量影响差异不具有统计学意义,低土壤水分下限的枸杞多糖含量相对较高;全生育期分为6个灌水期,其中萌芽期灌水(春水)为375 m³/hm²;春梢生长期、花期、夏果期、秋果期的土壤质量含水率下限分别为50%θ_f(θ_f为田间持水率),65%θ_f,65%θ_f,55%θ_f,而上限为95%θ_f;休眠期冬灌量为450 m³/hm².     

全膜双垄沟双幅覆膜覆土联合作业机设计与试验

为进一步提升全膜双垄沟覆膜种床机械化耕整作业效果与作业效率,基于全膜双垄沟种床双幅覆膜覆土农艺技术栽培模式,设计全膜双垄沟双幅覆膜覆土联合作业机,实现了全膜双垄沟种床构建过程中的旋耕、起垄、施肥、双幅覆膜覆土及镇压的一体化作业。在设定联合作业机传动系统的前提下,对样机关键部件进行设计与选型,确定其旋耕刀组、排肥装置、提土-种床覆土装置的工作参数与功耗,同时解析了刮板式提土装置、水平双向螺旋输土装置作业过程,得到满足双幅覆膜种床各部位覆土的必要条件。应用离散单元法对提土-种床覆土装置"提土-输土-覆土"动态作业过程进行数值模拟,分析了各工作环节输土、覆土特性,对影响覆土作业效果的相关因素进行了探讨。田间试验结果表明,当全膜双垄沟双幅覆膜覆土联合作业机前进速度为1. 10 m/s时,采光面地膜机械破损程度为39. 8 mm/m~2、种床膜边覆土宽度合格率为94. 5%、大垄垄体中心覆土宽度合格率为91. 6%、种床覆土厚度合格率为97. 5%、种床起垄高度合格率为93. 2%,试验指标均符合国家与行业标准要求,试验结果满足设计和实际作业要求,田间试验工况与仿真结果基本一致。