基于最小数据集的不同有机物料还田黑土土壤质量评价

【目的】研究不同种类有机物料还田对黑土质量的影响,并对土壤质量进行量化评价,为黑土资源的可持续利用提供理论依据。【方法】基于黑土区中部多年定位试验,选取无肥（CK）、单施化肥（NPK）、化肥配施玉米秸秆（NPK+JG）、化肥配施堆肥（NPK+DF）、化肥配施牛粪（NPK+NF）、化肥配施鸡粪（NPK+JF）和化肥配施猪粪（NPK+ZF）7个处理,研究不同种类有机物料还田后耕层（0～20 cm）土壤基本理化指标的变化,建立了土壤质量评价全量数据集,通过主成分分析法和皮尔森分析法筛选出最小数据集,计算各处理土壤质量指数（SQI）。【结果】不同种类有机物料对土壤基本理化指标的影响各异,NPK+DF处理土壤有机质与活性有机质含量显著高于其他处理,土壤全氮和全磷含量的最高值分别出现在NPK+DF和NPK+JF处理。土壤质量评价最小数据集是由全磷、容重和阳离子交换量三项指标组成。基于最小数据集计算出的土壤质量指数高低表现为：NPK+JF(0.780)> NPK+ZF(0.765)>NPK+DF(0.741)> NPK+NF(0.735)> NPK+JG(0.699)>...     

基于最小数据集的吉林省黑土耕层土壤质量评价

黑土作为吉林中部平原粮食主产区主要土壤类型,其质量的优劣直接影响区域生态安全和农业可持续发展。该研究以吉林省典型黑土耕层土壤作为研究对象,采集1 401个土壤样本,测定8项土壤理化指标及玉米产量。采用最小数据集法筛选评价指标,对于黑土耕层土壤进行质量评价,并综合土壤质量指数和产量提出评价指标的适宜范围。结果表明:吉林省黑土耕层土壤质量评价最小数据集由耕层容重、有机质、速效磷、pH构成,由全量数据集(Total Data Set,TDS)、重要数据集(ImportantDataSet,IDS)和最小数据集(MinimumDataSet,MDS)分别计算的土壤质量指数之间存在显著正相关关系,R~2分别为0.716、0.771,表明MDS可以替代TDS对黑土耕层土壤质量进行评价。黑土玉米种植区耕层土壤质量指数分布在0.22～0.75之间,均值为0.53,呈现东部高西部低的趋势。土壤质量指数随产量先增加后降低。黑土耕层保持较高土壤质量及产量的评价指标适宜范围分别为:容重为1.23～1.43 g/cm3,酸碱度(pH值)为4.74～6.96,有机质为33.14～35.81 g/kg,有效磷为122.46～136.06 mg/kg。该研究结果可为吉林省黑土耕层土壤质量诊断、提高黑土肥力及选择适合农田管理措施提供理论及参数支撑。     

基于聚类及PCA分析的红壤坡耕地耕层土壤质量评价指标

为准确评价红壤坡耕地耕层土壤质量特征,该文采用聚类分析法(CA)和主成分分析法(PCA)分别建立了南方红壤丘陵区坡耕地耕层质量诊断最小数据集(minimum data set,MDS),并利用最小数据集土壤质量指数(soil quality index-CA,SQI-CA和soil quality index-PCA,SQI-PCA)和全量数据集土壤质量指数(soil quality index-total,SQI-T)对坡耕地耕层特征进行分析。结果表明:1)红壤坡耕地耕层土壤质量变化特征差异明显,其中耕层平均厚度(19.93±4.9)cm,接近作物生长适宜水平;土壤有机质、全氮平均含量分别为(17.43±8.71)和(0.97±0.42)g/kg,处于中度贫瘠化水平;土壤有效磷和速效钾含量丰富,平均含量分别为(26.1±22.22)和(155.46±88.35)mg/kg;p H均值为(5.34±0.77),土壤呈弱酸性。2)红壤坡耕地耕层土壤质量评价最小数据集由耕层厚度、土壤容重、土壤贯入阻力、土壤有机质、p H值和有效磷组成。基于不同数据集的耕层土壤质量评价结果差异明显,土壤质量指数变化范围、均值表现为SQI-TSQI-CASQI-PCA,变异系数表现为SQI-TSQI-CASQI-PCA,SQI-CA与SQI-T的Nash有效系数和相关度高于SQI-PCA,而相对偏差系数和平均相对误差则低于SQI-PCA,这表明基于聚类分析最小数据集(MDS-CA)较基于主成分分析最小数据集(MDS-PCA)更适合替代全量数据集(total data set,TDS)对耕层土壤质量进行评价。3)从保水、保土、保肥及增产潜力角度看,红壤坡耕地合理耕层诊断指标适宜性阈值为耕层厚度≥20.39 cm,土壤容重0.92~1.21 g/cm3,土壤贯入阻力≤1.21 kg/cm3,土壤有机质含量≥18.82 g/kg,p H值5.04~5.38,有效磷≥28.83 mg/kg。合理深松是构建合理耕层的有效措施之一。该研究结果可为南方红壤丘陵区坡耕地耕层质量恢复、农作物生产适宜性调控和坡耕地水土流失阻控提供参考,有利于红壤丘陵区坡耕地资源持续利用。     

基于最小数据集的黄淮海旱作区耕层土壤质量评价及障碍分析

为探究黄淮海旱作区耕层土壤质量特征,基于土壤物理、化学及剖面特征,建立黄淮海旱作区耕层土壤质量评价指标体系,运用主成分分析法构建耕层质量评价指标的最小数据集（minimum data set,MDS）,结合障碍因子诊断模型揭示黄淮海旱作区耕层土壤质量特征及其障碍因素。结果表明：1）研究区耕层土壤质量评价最小数据集由土壤有机质、土壤阳离子交换量、土壤pH、耕作层厚度、耕作层穿透阻力和耕作层压实度构成,基于最小数据集和全指标数据集的耕层土壤质量指数间显著正相关（R²=0.61,P＜0.05）,Nash有效系数和相对偏差系数分别为0.601和0.181,表明最小数据集的指标能够代替全部数据集指标对黄淮海旱作区耕层质量进行评价;2）研究区耕层土壤质量总体处于中等水平,质量指数为0.25～0.61;适宜耕层各项指标如下：耕作层厚度不小于17.20 cm,耕作层穿透阻力不大于896.10 kPa,耕作层土壤压实度不大于78.01%,pH值为8.01～9.37,有机质不小于17.87 g/kg,阳离子交换量不小于21.13 cmol/kg;3）黄淮海旱作区存在明显的障碍类型,耕层障碍可分为薄化紧实与养分贫瘠障碍耕层、养分贫瘠耕层、土壤紧实型耕层3类。其中有机质含量低、阳离子交换量低、耕作层压实度过高是黄淮海旱作区耕层质量主要障碍。研究为黄淮海旱作区耕层土壤质量提升和改善提供理论支撑。     

基于耕作指数评价耕作措施对东北风沙土耕层土壤质量的影响

为准确评价构建风沙土合理耕层的土壤质量特征,采用聚类分析方法建立了东北风沙土耕层质量诊断最小数据集(MDS),利用最小数据集的耕作指数(TI-MDS)定量评价了耕作措施对东北风沙土农田耕层土壤质量的影响,旨在为科学选择风沙土区耕作措施提供依据。试验始于2017年,在黑龙江省杜尔伯特蒙古族自治县第一粮种场,设化肥、秸秆还田和有机肥3种施肥模式,常规、旋耕、翻耕、深翻和超深翻5种耕作方式,共15个处理。测定了玉米收获期0～20 cm耕层土壤pH值、有机质、碱解氮、有效磷、速效钾、全氮、全磷、全钾、阳离子交换量(CEC)、团聚体平均重量直径(MWD)、容重、硬度、含水量、田间持水量、孔隙度和渗透速率16项评价指标。结果表明,全量耕作指数(TI-TDS)与TI-MDS的相关系数r为0.928,Nash有效系数Ef为0.761,偏差系数Er为0.079,TI-MDS取值范围为0.26～0.85,与玉米产量呈显著正相关(r=0.767),故TI-MDS可作为定量评价土壤质量的指标。施有机肥处理土壤耕作指数达到Ⅱ级水平;秸秆还田耕作指数达到Ⅲ级水平;施化肥耕作指数达到Ⅲ级水平,这表明风沙土区施用有机肥是构建合理耕层有效培肥方式,秸秆还田对合理耕层构建效果不明显。翻耕施用有机肥耕作指数最大,为0.85,达到I级;深翻+秸秆还田和超深翻+化肥措施土壤质量严重下降,降为Ⅳ级。在风沙土区应用翻耕+有机肥措施是构建合理耕层的有效措施。     

基于最小数据集沂蒙山区不同治理模式下的土壤质量评价

沂蒙山区是北方土石山区水土流失治理重点区域,定量评价不同治理模式下的土壤质量,进而优选适宜的生态恢复措施,是推进沂蒙山区生态环境建设的关键。以沂蒙山区4种治理模式(乔草混交、土坎梯田+果树种植、撂荒、封禁植草)为研究对象,基于主成分分析、相关性分析和Norm值计算,对土壤养分、孔隙、水分、容重4类9项土壤属性指标进行筛选,构建土壤质量评价最小数据集。结果表明：(1)治理模式对土壤理化性质具有明显影响,硝态氮属于极敏感指标,全氮为高度敏感指标,而有机质、全磷、无机磷、田间持水量与饱和含水量属中度敏感指标,土壤容重为低度敏感指标;(2)影响沂蒙山区土壤质量的最小数据集指标包括全氮、土壤孔隙度、容重,经总数据集验证所构建的最小数据集可体现沂蒙山区土壤质量有效信息、准确性较高;(3)沂蒙山区不同治理模式下土壤质量指数介于0.41～0.53,土壤质量属于中等水平,且0—5 cm和5—10 cm土层的土壤质量指数较10—20 cm分别增加136.20%和37.60%。土壤质量表现为乔草混交>土坎梯田+果树种植>撂荒>封禁植草。综上,在水土流失严重、土壤较为贫瘠的沂蒙山区,生态恢复...     

基于最小数据集的青藏公路沿线土壤质量评价

为明确青藏公路沿线土地土壤质量的基本特征,通过采集沿线3种不同土地利用类型(农地、草地和沙地)的土壤样品,采用主成分分析法(PCA,Principal Component Analysis)筛选最小数据集(MDS,Minimum Data Set)指标,并构建土壤质量指数(SQI,Soil Quality Index)定量评价其土壤质量。结果表明:(1)相较于农地和草地,沙地的土壤肥力较为贫瘠,其土壤有机质、全氮和有效磷的土壤肥力等级均为6级。9个土壤指标均为中低度敏感指标,沙地土壤黏粒和粉粒含量具有更强的空间分异性。(2)沿线土壤质量评价最小数据集由全钾、全磷、有机质、黏粒和粉粒组成,最小数据集能够较好地替代全数据集进行土壤质量评价(p<0.01)。(3)沿线农地的土壤质量指数SQI(0.535±0.043)高于草地SQI(0.499±0.044)和沙地SQI(0.449±0.066)。该研究发现沿线农地土壤质量为中等水平,沿线草地和沿线沙地土壤质量处于较低水平,土壤有机质是影响青藏公沿线土壤质量的主要因素。     

基于最小数据集的宁都县不同整地方式下果园土壤质量评价

为探究不同整地措施下梯田果园土壤质量的变化,以赣南宁都县小洋小流域脐橙果园开发示范区内的3种典型坡面(优化整地T_y、传统整地T_c、撂荒地CK)为研究对象,采用主成分分析法(principal component analysis,PCA)筛选最小数据集指标,对该地区土壤质量进行评价。结果表明:(1)由全量数据集(total data set,TDS)和最小数据数据集(minimum data set,MDS)计算的土壤质量指数存在显著正相关关系,R²=0.604,表明MDS可以代替TDS对宁都县脐橙果园开发示范区进行土壤质量评价;(2)3种典型坡面的土壤质量指数(soil quality index,SQI)表现为优化整地(SQI=0.477)>撂荒地(SQI=0.436)>传统整地(SQI=0.220),其中T_y与CK之间无显著差异,T_y的SQI相较于T_c提升1.16倍,表明优化整地措施下土壤质量有显著提升;(3)果园不同土层总体表现为表层(0—10 cm)土壤质量指数大于深层(10—20 cm)土壤,通过土壤质量指数分级发现,优化整地梯田和撂荒地土壤质量优于传统整地。研究结果可以为我国红壤丘陵区的坡地资源利用管理以及梯田修建后水土保持措施布设提供科学依据。     

基于最小数据集的塔里木河上游绿洲土壤质量评价

以塔里木河上游绿洲阿拉尔垦区为靶区,综合考虑表征土壤物理、化学和生物学性质的14个土壤指标,利用数理统计方法确定最小数据集并评价土壤质量,同时与不含土壤酶指标的土壤质量评价结果进行对比分析。结果表明:(1)研究区土壤质量评价适用的最小数据集(MDS)包括:土壤水分、全盐、全氮和过氧化氢酶活性;(2)研究区棉田、新开垦农田、果园和林地等大部分耕地土壤质量属于中等及以上水平(SQI≧0.5的占78.12%),大部分分布于河岸及绿洲区域;(3)不包含土壤酶活性指标的土壤质量评价使土壤全盐含量的权重降低,且导致土壤质量评价结果偏低。     

典型喀斯特山区无籽刺梨基地土壤质量评价

以贵州省兴仁县回龙镇无籽刺梨种植基地为研究对象,综合考虑表征土壤物理、化学和生物学性质的16个土壤指标,利用数理统计方法确定最小数据集并评价土壤质量,同时根据划分样方所在坡位的不同,对其相应的土壤质量评价结果进行了对比分析。结果表明:(1)研究区土壤质量评价适用的最小数据集(MDS)包括土壤有机质、pH值、全钾、水解氮、真菌和磷酸酶;(2)研究区上坡位、中坡位和下坡位土壤质量属于中等及以下水平,SQI依次为0.544,0.408,0.503;(3)影响该地区土壤质量的重要指标为土壤有机质和土壤真菌数量。     

基于最小数据集和模糊数学法的水旱轮作区土壤肥力质量评价

基于湖北省水旱轮作区133个土壤样点数据,利用主成分分析及参选指标相关关系法确定了该区域土壤肥力质量评价的最小数据集,分别为土壤有机质、碱解氮、速效磷、速效钾、有效硼、有效钼、有效锌。利用模糊数学隶属度函数法对该区域土壤肥力质量进行了评价,结果表明:湖北省水旱轮作区的赤壁、洪湖、荆州、麻城和沙洋5个市(区、县)的土壤肥力质量以中等(III)为主,差(Ⅳ)等级次之,其中赤壁市和沙洋县土壤肥力质量以良(II)等级的比例(12.5%和9.5%)大于其他县市,5个县市土壤肥力质量均无优(I)和很差(V)2个等级。     

Field survey study on the difference in Cd accumulation capacity of rice and wheat in rice-wheat rotation area

Purpose

In the rice-wheat rotation area, Cd contamination affects food safety of rice and wheat. However, there have been conflicting results and different conclusions on the difference in Cd accumulation capacity of rice and wheat, and the factors that led to the difference were not clear.

Materials and methods

A field survey study was conducted by collecting 60 soil and grain samples in pairs during rice and wheat harvest in 30 long-term rice-wheat rotation areas with clean and mild Cd contamination in Jiangsu Province, China. The soil physicochemical properties, total Cd, soil available Cd, and grain Cd were determined, and the factors affecting Cd accumulation in rice and wheat were analyzed.

Results and discussion

The soil pH during wheat season (22 sampling points) was slightly higher than that during rice season; thus, soil available Cd in wheat was generally lower (with an average three times lower) than that in rice soil. The mean Cd content in rice grain was only half of that in wheat grain, and the Cd concentration in rice and bioconcentration factor of rice at 26 sampling points (86.7% of total samples) were lower than those of wheat, indicating that Cd accumulation capacity of wheat was stronger than that of rice. Pearson correlation coefficient and multivariate linear regression models revealed that the main factors affecting the difference of Cd accumulation in rice and wheat were soil pH and available Cd content in soil.

Conclusions

The Cd accumulation capacity of wheat was higher than that of rice, especially in neutral and alkaline soil, and the Cd contents in rice and wheat grain depended on the soil pH and available Cd content. The food security risk of wheat was more noteworthy than rice in rice-wheat rotation area.

     

青藏高原典型沙化区草地土壤质量评价

为了探究青藏高原沙化区草地土壤质量变化,采用主成分分析法筛选具有代表性的土壤质量指标构建最小数据集,计算土壤质量指数SQI(Soil Quality Index),评价了青藏高原海晏县、共和县、贵南县3个典型沙化区不同沙化程度下的土壤质量变化特征。结果表明:(1)随着沙化程度的减弱,3个典型沙化区草地的地上生物量均值由0增大至(0.8±0.18)kg/m²; 土壤有机质、全氮、全钾、全磷、速效钾、速效磷、碱解氮等养分含量增大,土壤阳离子交换量(CEC)增大了87.28%; 土壤容重减小了33.62%;(2)3个典型沙化区内不同沙化程度下,贵南县森多镇土壤质量最好,其次为共和县铁盖乡,海晏县三角城镇土壤质量最差;(3)最小数据集与全数据集的土壤质量指数呈现极显著相关关系,表明采用最小数据集法代替全数据集法评价典型区沙化草地土壤质量是行之有效的。综上所述,沙化区草地的土壤质量随沙化程度的加剧逐渐降低,不同沙化区草地土壤质量存在空间差异性。     

Long‐term effects of fertilizer and manure applications on soil quality and yields in a sub‐humid tropical rice‐rice system

Widespread yield stagnation and productivity declines in the rice–rice cropping system have been reported and many of the associated issues are related to soil quality. A long‐term experimental study was initiated in 1969 to assess the impact of continuous cultivation of rice as a single crop grown in wet as well as dry seasons using varying levels of chemical fertilizer and manure applications on soil quality indicators (physical, chemical and biological), a sustainable yield index (SYI) and a soil quality index (SQI). The treatments comprised chemical fertilizers and farmyard manure (FYM) either alone or in combination viz. control, N, NP, NK, NPK, FYM, N+FYM, NP+FYM, NK+FYM and NPK+FYM, laid out in a randomized complete block design with three replications. Soil samples were collected after the wet season rice harvest in 2010 and were analysed for physical, chemical and biological indicators of soil quality. A SYI based on long‐term yield data and SQI using principal component analysis (PCA) and nonlinear scoring functions were calculated. Application of NPK fertilizers in combination with FYM significantly increased the average grain yield of rice in both wet and dry seasons and enhanced the sustainability of the system compared to the control and plots in receipt of fertilizers. The SYI for the control was higher in the wet season than in the dry one, whereas the reverse was true for NPK+FYM treatment. The value of the dimensionless SQI varied from 1.46 in the control plot to 3.78 in the NPK+FYM one. A greater SYI and SQI in the NPK+FYM treatment demonstrated the importance of using a chemical fertilizer in combination with FYM. For the six soil quality indicators selected as a minimum data set (MDS), the contribution of DTPA‐Zn, available‐N and soil organic carbon to the SQI was substantial ranging from 59.4 to 85.7 per cent in NPK+FYM and control plots, respectively. Thus, these soil parameters could be used to monitor soil quality in a subhumid tropical rice–rice system.     

Soil‐quality‐index model for assessing the impact of groundwater on soil in an intensively farmed coastal area of E China

Soil quality is important in measuring sustainable land‐use and soil‐management practices. It is usually assessed by evaluating important physical, chemical, and biological soil properties. For this study, a site‐specific 22 variables representing pertinent soil (0–10 cm) and groundwater properties were selected as potential soil‐quality indicators in a coastal salt‐affected farmland of E China. To investigate the role of groundwater in soil‐quality assessment, we designed two sets of minimum data sets (MDSs). Minimum data set 1 (MDS1) had inputs of the 19 soil chemical and physical properties whereas MDS2 was based on the 22 soil and groundwater properties. Using principal‐component analysis, discriminant analysis, and soil‐quality‐index (SQI) model, we demonstrated the procedures of MDS selection, indicator normalization, and integration of MDS into SQI value for soils used for the two cropping systems. Results indicated selection of SOCD, AK, and ρ_b as MDS1 indicators but MDS2 indicators included SOM, SOCD, Cl, Na, WT_g, and EC_g. These were found to be the most effective discriminators between the two cropping systems. Available K (AK) made greatest contribution to SQI using MDS1 indicators, however, WT_g, EC_g, and Cl were the greatest contributors to the SQI for MDS2. Contribution of SOCD to SQI was severely inhibited in cotton–barley rotation system while EC_g and WT_g contributions to SQI were inhibited in rice–rape rotation system. In general, cotton–barley rotation system had a better soil quality over rice–rape rotation system as the former had higher SQI values than the latter for both MDSs. Crop parameters did also exhibit significant relationship with the SQI values using MDS2 but it was not significant for MDS1. Our results suggest that in addition to soil chemical, physical, and biological indicators, groundwater properties particularly the WT_g and EC_g are also important for assessing soil quality in an intensively farmed coastal area.     

伊朗东北部的农业和牧场土壤孔隙大小分布作为土壤物理质量指标

Assessment of soil quality is important for optimum production and natural resources conservation. Agricultural and pasture soil qualities of Deh-Sorkh region located at south of Mashhad, northeastern Iran were assessed using the integrated quality index (IQI) and Nemero quality index (NQI) models in combination with two datasets, i.e., total data set (TDS) and minimum data set (MDS). In this study 6 soil properties considered as MDS were selected out of 18 properties as TDS using principle component analysis. Soil samples were divided into 3 groups based on optimum ranges of 8 soil physical quality indicators. Soil samples with the most indicators at optimum range were selected as group 1 and the samples having fewer indicators at optimum range were located in groups 2 and 3. Optimum ranges of soil pore size distribution functions were also determined as soil physical quality indices based on 8 soil physical quality indicators. Pore size distribution curves of group 1 were considered as the optimum pore size functions. The results showed that relatively high organic carbon contents could improve pore size distribution. Mean comparisons of soil physical quality indicators demonstrated that mean weight diameter of wet aggregates, structural stability index, the slope of moisture retention curve at inflection point, and plant available water content in agricultural land use decreased significantly in relation to pasture land use. In addition, the results demonstrated that the studied MDS could be a suitable representative of TDS. 78% of pasture soils had the optimum pore size distribution functions, while this parameter for agricultural soils was only 13%. In general, the soils of the studied region showed high limitations for plant growth according to the studied indicators.     

长江中游双季稻田不同轮作方式对土壤质量的影响

研究长江中游地区不同种植模式和秸秆还田管理下农田土壤养分、有机碳及其酶活性的变化,评估农业管理措施对土壤质量的影响,可为长江中游双季稻区农业资源高效利用及可持续发展提供理论依据。2012—2017年进行不同轮、连作长期定位试验,设置冬季休耕—双季稻,冬种紫云英—、油菜—、大蒜—和轮作(马铃薯、大蒜、油菜和紫云英年际轮作)—双季稻5个处理,在冬季作物秸秆和水稻秸秆双重还田条件下,通过运用多元方差分析、相关性分析和主成分分析等统计方法,结合南方双季稻田土壤的适宜性,筛选出最小数据集(minimum data set,MDS)中土壤质量指标并测定,最后采用模糊数学方法对双季稻区的土壤质量进行定量评价。结果表明,在长江中游双季稻区,经过6年的冬季种植合适作物并秸秆双重还田,相比冬季休闲处理,除冬季种植大蒜处理外,其他冬种处理均能有效提高稻田土壤质量10.73%～12.91%,不同冬种方式下双季稻田的土壤质量高低依次为不同冬种轮作(0.726)冬季种植油菜(0.723)冬季种植紫云英(0.712)冬季休闲(0.643)冬季种植大蒜(0.638)。由此可见,适宜的轮作方式及秸秆双重还田能显著提高双季稻土壤质量,这为南方稻田健康可持续发展提供了理论支撑。