The priority of management factors for reducing the yield gap of summer maize in the north of Huang-Huai-Hai region,China

Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity(CK), farmer practice(FP), high yield and high efficiency(HH), and super high yield(SH), to estimate the yield gap. Different factorial experiments(fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha~(–1), respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors(contribution rates) were plant density(13.29%)fertilizer(11.95%)hybrids(8.19%)irrigation(4%) for FP to HH, and hybrids(8.94%)plant density(4.84%)fertilizer(1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.     

南方三省(区)南洋楹气候区划的研究

选择纬度、经度以及16个与水热状况有关的气象因子进行R型主成分分析,用前5个主成分坐标值进行模糊ISODATA聚类分析,将研究区划分为3类;用逐步判别分析建立了各类的判别函数式,回判准确率为91.81%;结合模糊相似优先比的结果,将研究区区划为南洋楹适宜发展区、南洋次适宜发展和南洋楹控制发展区3个气候区.     

南方五省（区）火炬松气候适宜性的研究

本文选取纬度、年平均气温和年均降水量３个与火炬松生长发育密切相关的因子，用模糊相似优先比的方法对研究区火炬松的气候适宜性进行研究，进而将研究区区划为火炬松气候适宜区、火炬松气候次适宜区和火炬松气候不适宜区３个气候生态区．     

第二代杉木林养分动态研究

根据连续定位观测所取得的数据,对4个小集水区第二代10年生杉木人工林生态系统中的养分循环进行了研究.结果表明.集水区由降水输入的N、P、K、Ca、Mg等营养元素总计为59.285kg/hm2a,径流输出为38.938kg/hm2a,净积累量为20.347kg/hm2a.与该林分7年生时相比,净积累量提高了7.2%,说明集水区第二代杉木林生态恢复处于进展的变化过程.     

河北省林业重点工程区后续产业发展的思考

随着河北省林业重点工程的实施,林业重点工程区后续产业发展取得了很大成就,但同时也存在着许多突出的问题。针对这些问题,文章提出了加快河北省林业重点工程区后续产业发展的思路与对策。     

城市交叉口公交优先信号协调模式探讨

对混合交通条件下基本车道饱和流量的各影响因素进行了分析,对比基本车道饱和流量影响因素修正方法,给出了基本车道饱和流量及各类车道通用校正系数常用计算方法。分析了公交车在连线上的运行特性,基于单点定时式公交优先信号配时模型,以人均延误最小为目标,建立了定时式两相邻交叉口公交优先信号协调配时模型;基于以人总延误最小为目标建立了定周期两相邻交叉口公交优先信号协调配时模型。利用实际调查数据,采用仿真分析方法验证本文提出的混合交通条件下定时式两相邻交叉口公交优先信号协调配时模型的正确性。     

The Buyer Cancellation Claim and the Tenant Priority Claim in Auction--Analyzing the Disputes in An Auction Case

Two problems often appear in estate auction.The first is to whom the buyer can claim cancellation of the contract,if he can't get the estate.The second is whether the tenant can still claim his priority to the estate.In auction,we can't use the principle of agency,fiduciary and mediation to explain the relations among client,auctioneer and buyer,because it doesn't accord with the auction practices and the Action Law section 40.The undisclosed agency in Contract Law may be an adapt explanation to the relations.According to the law hermeneutic,we should narrow the scopes of the tenant priority and exclude it from auction.     

新县小流域综合治理开发结硕果

新县小流域综合治理开发结硕果韦彦学（河南省水利厅水土保持处，郑州４５０００３）河南新县连续１０年大搞水土保持小流域综合治理开发，取得了显著的生态、经济和社会效益。１０年间，全县农民人均纯收入、人均存款均增长了９倍，９０％的贫困户摆脱了贫穷开始走向富裕...     

Three new algorithms to calculate the irreplaceability index for presence/absence data

The irreplaceability index is used for determining the priority of sites for conservation. We propose three new and simple algorithms for calculating it from presence/absence data without any statistical assumptions when the representative combination size is the minimum. The rare species algorithm gives accurate results but takes the longest calculation time. The species richness algorithm gives approximated results and takes the shortest calculation time. The combined algorithm is intermediate in accuracy and calculation time. We applied the combined algorithm to real data of butterflies in the Kanto district, central Japan, and derived irreplaceability values.     

牛栏江流域上游保护区“四型”小流域水土流失治理模式

[目的]分析牛栏江流域上游保护区水土流失治理模式,以期为流域水土流失治理提供新的思路。[方法]基于DEM数据在ArcGIS内进行子流域自动提取,结合遥感影像进行人工交互解译、修正以确定子流域;以划分的子流域为基本单元进行定性与定量赋分并计算综合得分,依据综合得分确定流域水土保持分区及其主导功能;根据确定的水土保持分区主导功能进行“四型”小流域治理模式配置。[结果]牛栏江流域上游保护区共划分9个子流域,确定4个水土保持分区;在各水土保持分区分别构建以生态安全型、生态景观型、生态经济型和生态清洁型为主的“四型”小流域治理模式。[结论]子流域可作为牛栏江流域上游保护区“四型”小流域水土流失治理模式配置的基本单元,水土保持主导功能可作为“四型”小流域模式配置的依据,提供因型施策、精准至区的水土流失科学治理模式。