基于GIS技术的新疆棉花施肥专家系统

对集成地理信息系统(GIS)技术应用于新疆棉花施肥专家系统(ES)进行了研究和探讨，通过Internet访问该专家系统界面， 用户可以得到农田地块的地理信息，进行棉田施肥推荐；同时可进行农田肥力的综合查询和专题图制作。该专家系统的建立不仅推进了新疆地区平衡施肥信息化的进程，也为精准农业的实践提供决策支持。     

施氮、供水对菠菜(Spinacia oleracea L.)的生长和土壤残留矿质氮的影响

Effects of conventional and optimized water and nitrogen managements on spinach (Spinacia oleracea L.) growth and soil mineral N (N_min) residues were compared in an open field experiment in which water balancemethod and N recommendation with the KNS-system were included. It was shown that the conventionalwater treatment (seasonal irrigated amount: 175 mm) reduced spinach growth compared to the water balancetreatments (seasonal irrigated amount: 80 and 85 mm) at the same N supply level due to N loss through leaching caused by excessive water supply. Although 309 kg N ha^-1 was applied in the conventional N treatment, compared to 82 and 66 kg N ha^-1 in the optimum N treatments, no significant difference in cropyield was investigated between the N treatments with the same irrigation practice. N uptake in spinach andsoil residual Nmin contents were also significantly affected by the irrigation practices. The conventional water supply not only decreased water use efficiency, but also resulted in excessive NO₃^--N being leached below the root zone. In order to meet the same target value of N requirement for the next crop, cauliflower, based on the KNS-system, at least extra 50 kg N ha^-1 was needed in the conventional water treatments in comparison to the water balance treatment.     

Alkaline hydrolyzable nitrogen and properties that dictate its distribution in paddy soil profiles

Nitrogen (N) is a key nutrient for rice production, and its bioavailability in paddy soils is strongly coupled to soil organic matter (SOM) cycling. A better understanding of potentially available N forms in soil, such as alkaline hydrolyzable N (AH-N), and their depth distribution will support the development of best management practices to improve the N use efficiency of rice while minimizing adverse environmental effects. Fifteen rice (Oryza sativa L.) fields from Southern Brazil were selected, and stratified soil samples were taken to a depth of 60 cm before crop establishment. Selected soil physical and chemical properties were analyzed to evaluate their relationships with AH-N contents in the soil profile. The AH-N contents below 20 cm varied extensively (increased, reduced, or constant) compared with that above 20 cm. Although clay and clay + silt contents were highly correlated to AH-N for some soils, the major property dictating AH-N distribution by depth was total N (TN), as the correlation between TN and AH-N was mainly by direct effect. The proportion of TN recovered as AH-N across sites and depths presented high amplitude, and thus AH-N was not a constant N pool across depths, indicating that AH-N can be affected by soil management practices even when TN showed no major changes. The distinct distribution of AH-N across soil sampling sites and depths indicates that depths greater than 20 cm should be considered when calibrating the AH-N index for N fertilizer recommendations for flooded rice in Southern Brazil.     

推荐氮肥适宜施用量的方法论刍议

本文对推荐氮肥施用量的两种技术路线进行了讨论。根据80年代和20032～004年在太湖地区进行的氮肥施用量试验网的水稻和小麦田间试验结果,对区域平均适宜施氮量法的产量效益、经济效益和环境效益进行了初步评价,提出了以区域平均适宜施氮量作为宏观控制的基础,结合田块具体情况进行微调的推荐路线。     

阴山南麓旱作马铃薯的施肥指标

为使内蒙古阴山南麓旱作马铃薯施肥趋于合理,2006~2008年在该地区进行了多点马铃薯"3414"田间试验,分析了不同基础肥力下土壤有效养分含量与马铃薯相对产量的相关性,并依此确定了土壤养分等级和施肥数量。内蒙古阴山南麓旱作马铃薯土壤全氮等级划分为极低(<0.64 g.kg-)1、低(0.64～0.92 g.kg-)1、中(0.93～1.58 g.kg-)1、高(1.59～1.90 g.kg-)1和极高(>1.90 g.kg-)1,对应推荐施氮量每667 m2分别为>9.3、9.3～7.6、7.5～5.0、4.9～4.1、<4.1 kg;速效磷含量划分为极低(<4.9 mg.kg-)1、低(4.9～8.4 mg.kg-)1、中(8.5～19.0 mg.kg-)1、高(19.1～25.0 mg.kg-1)和极高(>25.0 mg.kg-)1,对应推荐施磷量每667 m2分别为>5.1、5.1～4.1、4.0～2.6、2.5～2.1、<2.1 kg;速效钾含量分为极低(<61 mg.kg-)1、低(61～88 mg.kg-)1、中(89～151 mg.kg-)1、高(152～182 mg.kg-1)和极高(>182 mg.kg-)1,对应的推荐施钾量每667 m2分别为>5.0、5.0～4.3、4.2～3.3、3.2～3.0、<3.0 kg。     

浙中红壤油菜田供钾特性和钾肥用量研究

通过多点田间试验研究红壤性水田油菜供肥特性和钾肥施用量 .1 8个田间试验施钾油菜籽增产幅度为 7.5～ 90 .8kg/亩 ,无钾区相对产量变幅为 48.2～ 93.1 % .1mol/LNH4OAc提取的土壤速效钾含量与无钾区相对产量之间达极显著相关 ,相关系数为 0 .6 44 9 (n =1 8) .土壤速效钾的“临界水平”为80mg/kgK ,能满足 95 %相对产量的“足够水平值”为 1 5 0mg/kgK ,系统研究平衡施肥法中各参数的确定 ,并用平衡施肥法和施肥曲线确定油菜钾肥合理用量 ,两种方法具有可比性     

基于土壤氮素平衡的氮肥推荐方法——以水稻为例

基于土壤氮素平衡提出了一种新的氮肥推荐方法——氮素归还指数法,并以水稻为例介绍了其实施过程。经江苏省太湖地区和里下河地区45个水稻田块的举例推荐,用肥料效应函数法推荐的最佳经济施氮量(OENR)、氮素归还指数法推荐的氮素归还施氮量(RNR)和理论施氮量法推荐的理论施氮量(TNR)分别平均为N 246.8±42.5、216.9±27.3和176.9±22.3 kg hm-2。氮素归还指数法可不经过田间试验实现以目标产量为唯一变量的氮肥推荐,但在区域氮素净损失率能否保持相对稳定、长期实施氮素归还施氮量能否使土壤不致产生氮素盈余等方面仍需进一步研究。     

农田土壤养分变异与施肥推荐

采用差分式GPS定位的方法 ,对山东省青州市王母宫乡王七村 5.47hm2的地块进行了50m50m的网格式取样 ,用土壤系统研究法对其大、中、微量元素进行了分析。结果表明 ,土壤中的营养元素均存在着一定的变异。根据土壤养分的抽样分布 ,可将土壤养分分为两种类型 ,一为偏斜型营养元素 ,主要有氮、磷、硫等 ;其它属另一类 ,为非偏斜营养元素。造成土壤营养元素偏斜的主要原因是施用化学肥料。对施肥较多 ,且施肥历史较长的营养元素 ,在进行测土推荐施肥时 ,不仅要考虑大田的平均养分含量 ,还应考虑土壤的养分的空间变异状况 ;对非偏斜元素的施肥推荐以大田平均值即可     

养分平衡法在玉米测土推荐施肥中的应用效果

通过小区试验研究,玉米产量和化肥利用率在不同的施肥技术条件下存在差异。其优化次序为:NPK有机肥>NPK>NP>NK>N>PK>ck;深施NPK有机肥>深施NPK>常规施NPK>薅土浅施NPK>撒施NPK>ck。根据养分平衡法建立了目标产量、空白田产量与土壤养分测定值及相应N、P、K化肥施用量的函数关系,在产前提出N、P、K肥的适宜用量和比例以及相应的施肥技术。     

香山公园古树名木地理信息系统的开发技术研究

为实现古树信息化管理 ,北京香山公园在 1997— 2 0 0 0年 ,组织古树普查 ,建立古树档案及“古树名木信息管理系统” ,内容包括“古树名木管理信息系统 (MIS)”、“古树名木地理信息系统 (GIS)”及“古树名木Web信息查询系统” .作者在网络环境下利用VB作为开发工具 ,利用Oracle管理古树属性数据 ,在保持与MIS及Web信息查询系统数据源一致性的前提下 ,开发出适合本行业的古树名木地理信息系统 ,实现在电脑屏幕上遍历全体古树、查看相关数据、进行空间分析及规划设计等 ,从而实现了对古树的系统化、科学化管理 .