政和县星溪里小流域防洪减灾作用的调查

政和县星溪里小流域在开展小流域综合治理前，由于森林过度砍伐，生态环境十分恶劣，十年九灾，堪称当时政和的“小黄河”。1995年被列入省水土流失重点治理小流域项目后，进行“山、田、水、林、路”综合治理，做到因害设防，合理配置各项措施达到群体防护的功能，从而有效地拦蓄了地表径流，削减了洪水流量，大大缓解了洪水的危害。2001年被水利部、财政部联合命名为全国水土保持生态环境建设“十百千”示范小流域。     

沪池沟小流域综合治理成效显著

沪池沟小流域综合治理成效显著韦桂林，张连伟，朱光生（河南省洛宁县水利电力，４７１７００）一、概述沪池沟试点小流域，总面积２３．２９ｋｍ２，其中水土流失面积２２．６ｋｍ２。流域内植被稀少、沟壑纵横、山高坡陡、水土流失极为严重。试点治理前，梁坡是群众耕种...     

浙江省小流域综合治理技术探讨

浙江省 2 0 0 0余条小流域山高坡陡、源短流急 ,水土流失严重 ,水早灾害频繁 ,严重影响着山丘区社会经济的稳定和发展。开展治理后的小流域 ,人均年收入平均增长 45 %,土地利用率平均提高 14个百分点 ,植被覆盖率平均提高13个百分点 ,成效十分显著。详细介绍了浙江省小流域治理技术     

红领巾、怀仁山小流域通过达标验收

2000年10月,江苏省赣榆县红领巾、怀仁山2条小流域顺利通过水利部淮委组织的水土保持生态环境建设“十百千”示范小流域达标验收。红领巾、怀仁山小流域总面积分别为108ｋｍ2和105ｋｍ2,其中水土流失面积分别为62ｋｍ2和78ｋｍ2。自开始治理以来,累计投资149072万元,投入工日23     

永康市生态清洁型小流域建设成效显著

浙江省永康市按照水利部陈雷部长对该市提出的“六个率先”的工作要求和省水利厅的统一部署,根据全市生态清洁型小流域建设规划,以水生态环境为中心,以小流域为单元,“污水、垃圾、厕所、环境、河道”五同步治理,建立“养山保水、进村治水、入川护水”三道防线,形成山、水、田、林、路、村庄的生态清洁综合治理新格局,     

小流域治理对环境人口容量的影响

在对“长治”一期工程42个小流域进行系统分类的基础上,以粮食消费和价值消费为参照标准,分析了小流域治理前后的环境人口容量变化,以及水土保持投资强度与环境人口容量的关系。研究结果表明:小流域综合治理后,研究区42个小流域的环境人口容量均有明显提高,按能反映三峡库区整体水平的第四类小流域推算,经过以大流域为依托、以小流域为单元,实施山、水、田、林、路综合治理后的整个三峡库区可增加人口承载量516.2万人;从提高环境人口容量的角度来看,整个三峡库区合理的投资强度(不包括劳力投入)在20世纪90年代以5.5万元/km2为宜,但目前的投资强度应随社会的发展而做相应调整。     

葛藤坪小流域的综合治理及效益

葛藤坪小流域的综合治理及效益邓正良，王荫菊（湖北省巴东县水土保持办公室４４４３６０）葛藤坪小流域位于三峡库区旅游景点神农溪河畔，总面积１１．８９ｋｍ２，水土流失面积８．１ｋｍ２。该流域涉及２个行政村，共有３１６户，２１４５人。治理前，严重的水土流失不...     

浅谈鸠坑溪小流域水土流失综合治理

南方红壤丘陵区山多地少,坡耕地水土流失非常严重,坡耕地治理是小流域治理和水土保持工作的一项重要任务。结合淳安县几年来小流域治理和鸠坑溪小流域水土流失综合治理的实践经验,对小流域水土流失治理尤其是坡耕地整治作了一些探讨。     

河北省滦平县小流域综合治理初见成效

该概述了河北省滦平县水土流失的状况及危害。回顾了４０多年经过艰苦努力走向小流域综合治理的正确道路。探索出山、水、田林、路综合治理，林、果、粮、草药立体开发，融经济、社会和生态三大效益于一体的治理开发模式。几年来经过综合治理的１３条小流域，已经初步取得可喜的经济、生态和社会等各项效益。     

吉林省水土保持草种选优研究

吉林省水土保持草种选优研究李秋梅（吉林省水土保持科学研究所，辽源市１３８２００）一、试验地概况试验地设在东辽县杏木小流域（北纬４３°０２′，东经１２５°２４′）和辽源市兴国小流域（北纬４２°５１′，东经１２５°０５′）。两小流域均为低山丘陵水土流失区...     

A proposed method to determine adequate amount of fertilizers to be applied to crops

To determine the adequate amounts of fertilizers to be applied to crops is one of the most important problems in the field of soil science.     

Adsorption of Orthophosphate to Humic-Fe-Complexes and to Amorphous Fe-Oxide

The adsorption of orthophosphate to humic surfaces was studied in a model experiment. The adsorption maximum of humic substances greatly increased with higher concentrations of organically complexed Fe (III), indicating that orthophosphate was bound to humic surfaces via metal bridges. The molar ratio P_adsorbed/Fe was nearly 1 for Fe freshly complexed to humic substances, whereas the ratio for amorphous Fe-oxide was a tenfold lower. An increase in pH from 5.2 to 6.2 lead to an increase of P-adsorption of about 30% in the case of humic-Fe-surfaces, which could be explained by an increased accessibility of adsorption sites at pH 6.2. The addition of a 0.01 M CaCl₂-matrix increased orthophosphate adsorption at pH 6.2 but not at pH 5.2. This could be explained by electrostatic interactions caused by the Ca⁺⁺ ion.     

自动分析曲线线型并可绘图的计算机程序

本程序图文并茂,直观性强。而且,引入常数k的曲线模拟模型可提高精确度百倍以上,使其更适合理化特性或理论曲线的模拟分析。     

树盘覆草对果园生态环境的影响

苹果树盘覆草具有灭草、免耕、保墒、蓄水、增肥、防冻的作用，覆草改善了土壤水、肥、气、热状况，从而优化了土壤生态环境，促进土壤营养物质积累、分解、转化、更新，有利果树生长发育，从而显著提高果品的产量和质量。     

Using SAEM to estimate parameters of models of response to applied fertilizer

Many nonlinear functions have been used to predict crop yield response to applied fertilizer. Accurate estimates of the parameter values are required for the formulation of satisfactory fertilizer dose recommendations. In fertilizer trials, several yield measurements for different fertilizer doses are usually made at the same site and in the same year. Model errors are therefore unlikely to be independent for the same site-year. Nonlinear mixed effects models can be used for yield response data. We evaluated the performance of a recently proposed stochastic approximation of the EM algorithm (SAEM) for estimating the parameters of nonlinear mixed effects models. We used the SAEM method to estimate the parameters of four different nonlinear models, using a real dataset including 37 site-years of yield measurements. We then carried out simulations, to determine the bias and the root mean squared errors of the estimators. We compared the results obtained with SAEM with those obtained using a first-order conditional method. SAEM gave better results in most cases. The estimates produced by SAEM were less biased and less affected by initial values.     

A model to simulate response of plant stomata to environmental conditions

In order to simulate plant transpiration under different field climatic conditions we have developed and verified a semi-empirical model for predicting the stomatal response to solar global radiation, leaf temperature, vapour pressure difference between the leaf and ambient air, ambient air CO₂ concentration and soil water potential. The transpiration and the stomatal relative conductance of a Nicotania Tabaccum var “samsun” plant leaves were measured in a laboratory apparatus and compared to those predicted by the model: good agreement was obtained between them for the different investigated cases. The model was incorporated in a numerical greenhouse microclimate model and its effects on the canopy microclimate are discussed here.     

土壤Se的分级与Se的植物有效性的关系

Nine soils with distinct properties and Se levels were selected to test a fractionation procedure of soil Se based on sequential extraction. Soil Se was fractionated into readily available Se (fraction Ⅰ, extracted by 0.5 M NaHCO₃), slowly available Se (fraction Ⅱ, extracted by 0.1 M NaOH-0.1 M Na₄P₂O₇), amorphous oxide-occluded Se (fraction Ⅲ, extracted by acid ammonium oxalate), free oxide-occluded Se (fraction Ⅵ, extracted by dithionite-citrate-bicarbonate buffer solution) and residual Se (fraction Ⅴ, determined by HNO₃-HClO₄ digestion of the final soil residue). The recovery of soil Se (the sum of all fractions over total soil Se determined independently) by this procedure was from 88.1% to 110.9%, mean 99.2%±6.4% for the test soils. The sum of fractions Ⅰ and Ⅱ, provided a good measure of available Se in soils and the percentage of fraction Ⅰ plus Ⅱ over the total soil Se, tentatively defined as Se availability index, could be used to indicate soil Se status and predict Se deficiency.     

Stability of patulin to sulfur dioxide and to yeast fermentation.

The affinity of patulin for sulfur dioxide (SO2) is much less than was previously reported and is of little significance at the SO2 concentrations (below 200 ppm) used in the processing of apple juice and cider. However, at concentrations of 2000 ppm SO2 and 15 ppm patulin, combination was 90% complete in 2 days. Removal of SO2 liberated only part of the patulin, which suggests that 2 mechanisms are involved: one reversible (opening the hemiacetal ring) and one irreversible (SO2 addition at the double bond). Test with 2 yeasts used in English commercial cider making confirmed that patulin is effectively removed during yeast fermentation.     

Chemical response of soil leachate to alternative approaches to experimental acidification

Abstract

One approach to evaluating computer models which predict terrestrial‐aquatic ecosystem response to acid deposition is the experimental acidification of soils with subsequent comparisons among predicted and measured soil solution response. Using a soil microcosm experimental approach, comparisions between simulated acid rain (i.e. dilute H₂SO₄), dry NH₄NO₃, and prilled reduced S were made for suitability for large‐scale field experiments. Soil microcosms consisting of reconstructed soil profiles received a background simulated throughfall dosing over the six month treatment period. Results indicated that simulated throughfall, applied at twice the ambient rate, acidified soil leachates approximately 0.5 pH units over the treatment period. Along with the decline in leachate pH was an apparent release of base cations as well as Fe and Al. Over the length of the treatment period, very little of the prilled S dissolved and the simulated acid rain treatment did not have significant effects on leachate chemistry.