国营阳江农场橡胶园土壤有机质与全氮时空变异分析

运用GIS和地统计学相结合的方法研究了1983年和2007年国营阳江农场橡胶园土壤有机质与全氮的时空变异.结果表明.20多年间土壤有机质和全氮含量有所降低.土壤有机质和全氮含量的空间差异缩小,含量水平基本上有朝均衡化发展的趋势,空间变化趋于平均.这些变化主要是由人为生产管理和施肥造成.同时随着生产管理、施肥等人为活动影响的增加与积累,使得土壤有机质和全氮的空间变异减弱,朝均衡化方向发展.     

湖北省秭归县茶园土壤养分概况

对湖北省秭归县具有代表性的茶园的43个土样进行了调查分析,测定了土壤p H、有机质、碱解氮、有效磷、速效钾、全氮及全磷等理化及养分指标,结果表明秭归县茶园土壤各项指标变化范围分别为:p H值为4.10~5.96,有机质为8.01~113.93 g/kg,碱解氮为7.28~236.43 mg/kg,有效磷为0.23~139.79 mg/kg,速效钾为24.56~288.45 mg/kg,全氮为1.04~3.77 g/kg,全磷为0.21~1.48 g/kg。土壤p H水平表明秭归县茶园土壤非常适宜茶树的种植,但是土壤养分含量变异较大,样本中碱解氮及速效钾含量变异系数分别为36.25%与47.13%,有效磷含量的变异系数达92.32%,表明氮磷钾养分管理均存在参差不齐的现象。在今后秭归县茶园的养分管理中,应采取"巧施氮肥,增施磷肥,适量补充钾肥"的土壤养分管理措施。     

滇西南勐永蔗区土壤肥力的综合评价

以滇西南勐永蔗区185份土壤样本为研究对象,采用主成分分析法、隶属度函数和模糊数学法,对蔗区土壤肥力进行综合评价。结果表明:(1)勐永蔗区土壤p H值和有机质、全钾、速效钾、有效磷含量适宜,全氮含量偏高,全磷、碱解氮含量偏低;(2)p H和有机质、全氮、全磷、全钾、碱解氮、速效钾含量的空间变异较小,有效磷含量的空间变异较大;(3)勐永蔗区土壤肥力平均综合指标值0.53,中等水平及以上的占92.3%,说明该蔗区土壤肥力状况总体良好。     

三峡库区土壤养分空间分布状况研究

采用地统计学及GIS技术对三峡库区土壤养分的空间变异性及空间分布状况进行研究,评价研究区土壤养分含量水平。结果表明,试验区土壤养分变异较大,但均为中等变异,其中氮的空间变异主要来自结构性因素,而有机质、磷、钾的空间变异性主要来自于随机因素的影响。另外,研究区各种土壤养分含量水平均不高,其中有机质、磷、钾非常缺乏,钾大部分区域含量中等,部分地区也比较缺乏。     

土壤养分状况对高油酸花生琼花1号品质的影响

高油酸花生是花生品质育种的重要目标之一,本研究以高油酸花生琼花1号为材料,研究了其在13个不同土壤肥力条件下的籽仁品质及其变化。结果表明,琼花1号籽仁可溶性糖、可溶性蛋白质、油酸、亚油酸平均含量分别为6.77%、27.59%、80.04%和3.84%,油酸/亚油酸平均为22.58。籽仁亚油酸含量变异系数最大(32.11%),油酸变异系数最小(2.50%)。花生营养品质之间的相关性分析表明,油酸与亚油酸、棕榈酸和可溶性糖含量间均呈极显著负相关,亚油酸与棕榈酸和可溶性糖含量间呈极显著正相关,棕榈酸与可溶性糖含量间呈极显著正相关,花生四烯酸和山嵛酸含量间呈极显著正相关。不同营养品质的形成受土壤成分影响不相同,可溶性糖含量与土壤有机质和土壤全氮呈显著负相关;可溶性蛋白质含量与土壤有机质、土壤碱解氮和土壤全氮呈显著负相关。研究结果可为高油酸花生大面积推广及施肥策略提供理论支持。     

农场尺度土壤养分时间维变异特征研究——以江苏农垦复兴圩农场为例

根据1980年复兴圩农场全场域第二次土壤普查资料和2000年、2010年GPS定位测土试验数据,研究了复兴圩农场耕作层与剖面土壤有机质、全氮、碱解氮、有效磷、速效钾含量和pH值等的时间维变异特征,以探究农场尺度土壤养分的时间维演变规律,为农场稻麦精确施肥策略的拟订提供理论依据。     

海南儋州耕地土壤有机质空间变异

以海南省儋州市作为研究区域,综合运用地统计学和地理信息技术,对其耕地土壤的有机质空间变异进行分析。结果表明:儋州耕地土壤有机质平均含量为20.64 g/kg,总体水平为中等偏上;变异系数为48.05%,属于中等变异;其空间变异变程约为16.50 km,C0/(C0+C1)值为37.34%,土壤有机质含量属于中等程度的空间相关性;Kriging插值分析结果可反映土壤有机质含量在空间分布上呈大块状分布,有较强的连续性,其分布变异不显著,以3级含量水平分布范围最广;北部最高,其余区域(南部、东部、中部、西部)逐渐降低。这种空间分布可能与当地的地表形态、地质状况及土地经营利用方式等有关。     

云南元阳梯形稻田土壤碳氮空间分布及其影响因素

 采用地统计、方差分析方法,研究了云南元阳土壤有机碳（SOC）、全氮（TN）的空间分布及其影响因素。该区域内水田土壤表层（0~20 cm)有机碳、全氮含量分别为21.38 g/kg和1.65 g/kg,变异系数分别为36.90%和32.95%,属于中等程度变异。土壤有机碳、全氮的半方差模型均为球型,具有中等程度的空间自相关性（块金/基台值分别为0.67和0.71）。土壤有机碳、全氮含量均随海拔上升而增加。土壤有机碳和全氮含量均随着肥料投入水平上升而降低,过量施肥使土壤有机碳、全氮含量略有增加,但会影响肥料利用效率。因此,应根据土壤养分空间分布格局加强农业生产管理措施调控,以提高土地生产力。     

橡胶园土壤肥力指标的小尺度空间变异Ⅰ：0~20 cm土层

在84m2区域内对橡胶园土壤按0.5 m×1 m网格进行取样(n=168),对5种土壤肥力指标进行地统计学分析.结果表明:全氮、有效磷、速效钾、有机质和pH值的半方差函数均可用指数模型描述,其各自变程分别为1.44、1.65、3.36、1.20和1.74m,均表现出强空间自相关关系.从土壤肥力指标的空间分布特征来看,全氮、有效磷、有机质呈现出明显的“肥岛”效应,其中全氮“肥岛”面积最大,影响距离最远;有效磷的“肥岛”面积最小,与周围浓度成倍数递减,成同心圆结构;有机质的空间分布特征介于二者之间;速效钾斑块面积分布比较均匀,与土壤母质类型有关.     

氮肥施用方式对土壤有机质与氮素含量的影响

在秸秆还田条件下,研究了氮肥施用方式对白浆土有机质与氮素时空动态的影响.结果表明:在秸秆还田条件下,白浆土0～20 cm土壤有机质含量随生育进程呈增加的趋势,至收获期达到最大值,20～30 cm土壤于R4期达到最大值;白浆土全氮含量随生育进程呈单峰曲线,于R2～R4期达到最大值;碱解氮含量随生育进程呈单峰曲线,0～20 cm土壤于R5期、20～30 cm土壤于R2期达最大值.种肥施氮增加了0～20 cm土壤有机质含量,追施氮肥使10～30 cm土壤有机质含量增加;种肥施氮增加了R2期以前土壤全氮含量,追施氮肥对土壤全氮含量影响不明显;种肥施氮使20～30 cm土壤碱解氮含量降低,对0～20 cm土壤影响不大,追施氮肥使土壤碱解氮含量增加.白浆土有机质含量与全氮含量、有机质含量与碱解氮含量、碱解氮含量与全氮含量均呈极显著正相关.     

Evaluating Soil Organic Matter Changes Induced by Reclamation

Summary

Evaluating soil conservation and plant production on reclaimed lands requires an understanding of the rate of change in soil organic matter (SOM) under specific land use systems and management practices. By using a geographic information system (GIS), changes in the SOM status were assessed and mapped at an experimental station in subtropical China after eleven years of reclamation. Maps of soil survey, land use and topographic information of the experimental station were entered into the computer after digitalization, and a land unit map was produced by overlaying these maps. The SOM levels in different time periods were entered and combined with their corresponding land units in the land unit map, and their differences (?SOM) in time for each land unit were calculated. SOM changes at the experimental station were then assessed and mapped based on the ?SOM values. The changing status in various land use systems, soil types and relief patterns could be shown in the computer. SOM changes varied with land use systems and the original SOM levels. After 11 years of reclamation, the soils with SOM levels of > 30 and < 10 g Kg^?1 decreased 95.3% and 30.9% in area, respectively, while those with SOM levels of 20-30 and 10-20 g Kg^?1 increased 44.3% and 8.4%, respectively. The SOM content in paddy fields, vegetable fields, pastures, and grasslands increased due to reclamation practices, but decreased in fuel woods, sparse weed land, and bare land.     

海南胡椒优势区土壤pH值与养分肥力指标的相关性分析

对海南省胡椒优势区胡椒园土壤分0～20 cm和20～40 cm两层取样,用以研究海南胡椒种植区土壤pH值与养分含量之间的关系。结果表明,海南胡椒优势区土壤pH值在3.76～5.26之间,极强酸土壤占样品总数的54％,强酸土壤占样品总数的46％;约98％胡椒园土壤有机质含量在较低含量区间;碱解氮含量有85％在适宜值范围内;有效磷含量有54％低于适宜值范围;约54％胡椒园缺乏速效钾;交换性钙、镁含量均低于适宜值范围。线性相关性分析结果表明,土壤pH值与速效钾、交换性钙、镁含量有显著正相关关系,与有机质、碱解氮、有效磷含量相关性不显著;岭回归分析结果表明,土壤pH值与养分因子的相关性由强到弱为：速效钾>交换性钙>有机质>交换性镁>碱解氮>有效磷。因此,应该适当增施草木灰、石灰和有机肥,以提高胡椒园土壤pH值和培肥土壤。     

Long-term effect of no-tillage on soil organic carbon and nitrogen in an irrigated rice-based cropping system

A 10-year field experiment was conducted to determine the effect of no-tillage (NT) on soil organic carbon (SOC) and nitrogen (N) in an irrigated rice-based cropping system. The results showed that concentrations of SOC, soil total N (STN), and soil organic N (SON) were higher at 0–5 cm depth but lower at 5–10 cm depth under NT than conventional tillage (CT), while at 10–20 cm depth the differences were not significant. Consequently, stocks of SOC, STN, and SON under NT were higher at 0–5 cm depth but lower at 5–10 cm depth than those under CT. However, no significant differences were observed in stocks of SOC, STN, and SON at 0–20 cm depth between NT and CT, indicating that the lower st ocks of SOC, STN, and SON at 5–10 cm depth could offset the greater stocks of them at 0–5 cm depth under NT. In addition, there were no significant differences in soil inorganic N concentration and soil C:N ratio between NT and CT at all the three depths. Our study suggests that (1) NT farming does not necessarily store SOC and N more than CT soils for the upper soil layer and (2) converting from CT to NT farming may not cause a significant change in soil N mineralization in the irrigated rice-based cropping systems.     

籼型杂交水稻米质指标测定值的差异分析

以全国多年多点送检的1036份籼型杂交水稻样本为材料,对12项米质指标测定值的变异及稳定性进行了分析。结果表明:1)在遗传、栽培环境、取样测试技术三因素综合影响下,杂交水稻样本的糙米率、精米率、粒长、粒长宽比的多次测定值变异小(变异系数CV<10%),稳定性强;糙米蛋白质含量、直链淀粉含量、糊化温度、整精米率、胶稠度的变异较小(CV为10%~25% ), 稳定性较强;而透明度、垩白米率和垩白度的多次测定值变异较大(CV> 25%), 稳定性较差。2）在排除遗传因素后,12项米质性状测定的变异系数大小排序趋势未见明显变化,但各数值均有不同程度下降。3）在排除遗传及环境因素后,各测定值的变异系数大幅缩小,但仍可借以表明各数值受测定技术影响的程度。对米质指标测定值变异的原因及如何提高米质测定值的稳定性进行了讨论。     

Comparison of ingrowth core and sequential soil core methods for estimating belowground net primary production in grass–clover swards

Estimation of belowground net primary production (BNPP) is crucial for prediction of grassland soil organic carbon sequestration, but there are high coefficients of variation (CV) among methods of estimation. We compared accuracy and precision of two variations of the traditional soil core method and three of the ingrowth core method, over 2 years on grass–white clover swards in Germany. The ingrowth core method (5‐ to 9‐week ingrowth period) provided the most accurate BNPP estimate (471 g m^?2) with the highest precision (CV: 31%), whereas the two soil core approaches resulted in underestimation and high error. Comparing results with other grassland studies, we found that reliability of the ingrowth core method was influenced by ingrowth period and sward rooting pattern related to grass phenological stages, while the precision was determined by ingrowth period and grassland productivity. We therefore recommend using the ingrowth core method for managed grasslands where belowground productivity is relatively high and installation disturbance is likely to be negligible. Using a 6‐ to 8‐week ingrowth period, the method delivers reliable and feasible BNPP estimates for temperate managed grasslands which can be applied to long‐term soil carbon budget simulation. Results from our work and other studies also indicated that standing root biomass masks seasonal pattern of rooting due to synchrony between root birth and death. The soil core method is likely to lead to underestimates and higher errors than the ingrowth core methods and thus should be avoided.     

海南尖峰岭热带山地雨林林窗对土壤呼吸的影响

研究林窗对土壤呼吸的影响及其机制,可为热带森林生态系统土壤呼吸的准确估算和森林土壤有机碳管理提供科学依据。以海南岛尖峰岭热带山地雨林林窗（台风干扰形成）样地为研究对象,通过开展林窗内和林窗外（林内）土壤呼吸的原位观测试验,并设置去除/保留凋落物处理来分析凋落物对土壤呼吸的影响;结合林窗内外土壤的理化性质及气象要素,研究土壤呼吸的排放与环境因子的关系。结果表明：林窗的空气相对湿度、土壤温度和土壤含水量与林内均存在极显著差异（P<0.01）;林窗的空气温度与林内的差异不显著（P>0.05）;林窗内外的平均土壤呼吸分别为(3.29±0.54)μmol/(m²·s)和(2.38±0.51)μmol/(m²·s)。在月尺度上,林窗内外的土壤呼吸的排放速率呈现多峰型曲线变化规律,排放趋势大致相同,整体呈现出雨季大于旱季的变化规律。林窗和林内的土壤呼吸速率存在显著差异（P<0.05）。影响林内和林窗土壤呼吸的最主要因素分别是有机碳和地下5 cm温度。     

Scaling up of a mechanistic dynamic model in a GIS environment to model temperate grassland production at the regional scale

Regional‐scale ecological processes are mediated by processes occurring at local scales. Spatially explicit models are needed to understand the broad‐scale consequences of a large number of local processes, driven by factors which are heterogeneous at a broad scale. A Geographic Information System (GIS)‐based mechanistic model, which can be used as a flexible tool to investigate the regional‐scale effects of changes in environmental factors on herbage production from a Lolium perenne sward, was developed and used to investigate the consequences of aggregating driving variables at different resolutions. The model allows rigorous scaling up of previously existing field‐based modelling approaches within a GIS context. The model's mechanistic approach allows flexibility in the simulation of the separate effects of environmental driving variables and of cutting regimes. The driving variables (temperature, solar radiation, available soil moisture and soil nitrogen status) are scaled up using geostatistical techniques. The model is used to evaluate weekly changes in herbage production under environmental conditions, variable both in space and time, under different cutting regimes. It is shown that, in this model, aggregation at 1 km² is a good compromise between accuracy and practical feasibility, and that, while ignoring heterogeneity over many square kilometres can induce large errors, their magnitude and direction also depend on the model response curve to an input variable. The results obtained were consistent with the known trends in influential environmental factors. The programming within a GIS makes the model flexible in its application and, therefore, makes it easy to apply at a variety of scales.     

南方红壤丘陵区土壤细菌对土壤水分和温度的响应差异

红壤丘陵区稻田不同时期进行的水分管理导致土壤水分和温度同时变化,继而影响土壤微生物群落结构,二者对土壤微生物的影响机制目前还不清楚。本研究以中国科学院桃源农业生态实验站长期定位试验的稻田作为研究对象,同时以旱地农田作为对照,利用末端限制性酶切片段长度多态性分析（T-RFLP）和荧光定量PCR（qPCR）方法,研究不同水分管理时期细菌群落结构与丰度的变化特征,进而分析其变化的影响因素,阐明水分和温度的相对贡献。结果表明,稻田土壤细菌受土壤水分状况的显著影响,淹水期土壤细菌群落结构明显区别于其他时期,且淹水期土壤细菌丰度和多样性指数均显著低于晒田期。稻田土壤细菌群落结构和多样性指数均受到土壤含水量和土壤温度的显著影响,但土壤含水量的相关性大于土壤温度。而作为对照的旱地农田土壤含水量在不同时期没有差异,土壤细菌群落结构也没有差异,仅土壤细菌丰度和多样性指数发生一定变化,但这种变化并不与土壤温度呈现相关性。因此,本研究认为,南方丘陵区农田土壤细菌对土壤水分的响应比对土壤温度更敏感。     

Meta‐analysis of grass ley response to phosphorus fertilization in Finland

Studies have shown that yield responses of grass leys to phosphorus (P) fertilization vary considerably and initial soil test P (STP) does not always predict such variation. To identify the sources of variation in dry‐matter (DM) yield responses to P, we used a meta‐analysis to review quantitatively 38 Finnish field experiments on various soil types and growth conditions and to develop yield‐response models. The major sources of variation in the yield responses to annually applied P were soil type, soil acidity (for organic soils), initial STP and control yields fertilized with nitrogen (N) and potassium (K). According to Mitscherlich‐type exponential models, the maximum yield increases due to P fertilization in the low‐STP class were 18% over the control on mineral soils and 28% on organic soils. However, only about 40% of the variation in yield could be attributed to annual fertilizer P applications. Control yields explained about 25% of variation in yield responses to P fertilization, and P addition became less efficient with increasing control yields, which were associated with rising N rates. While applied P leads to infrequent or small yield responses on mineral soils, other practices to increase grass yields should be prioritized, including optimal N fertilization. On moderately acidic organic soils that show clearly lower P responses than do similar but less acidic soils, liming should be the first step to increase yields. Moreover, the models derived in this work indicate that revising P fertilizer recommendations in Finland would avoid unnecessary application at non‐responsive STP levels.