休闲期耕作方式和施用保水剂对旱地小麦产量及水分利用率的影响

为探讨提高旱地麦田休闲期土壤蓄水保水能力、保证旱地小麦稳产高产的有效途径,本研究采用双因素裂区试验,主区为耕作方式(深松、深翻和旋耕),副区为保水剂施用量(0、45、90 kg·hm^-2),研究了耕作方式和施用保水剂对土壤含水量、土壤养分、旱地小麦产量和水分利用率的影响,并分析了土壤含水量、生育期耗水量与旱地小麦产量及其构成因素和水分利用率之间的相关关系。结果表明,与休闲期旋耕相比,休闲期深松提高了播前20~160 cm土层的土壤含水量,休闲期深翻提高了播前0~20 cm和60~140 cm土层的土壤含水量,加速了收获期20~200 cm土层的水分利用;并通过增加穗数和穗粒数使旱地小麦产量分别提高了12.63%和6.88%,显著提高了水分利用率和降水利用率,20~40 cm土层有机质、碱解氮、速效磷含量总体提高。休闲期耕作,配施保水剂45 kg·hm^-2显著提高了旱地小麦休闲期蓄水保水能力、水分利用率和产量。休闲期深松增产效果和提高水分利用率效果优于休闲期深翻。旱地小麦产量和降水利用率与播前60~120 cm土层含水量呈正相关。本研究结果为晋南旱地小麦优化耕作方式和保水剂施用量提高产量和水分利用率提供了理论依据,对旱地小麦稳产高产、减小年际间产量波动具有重要意义。     

旱地冬小麦覆盖黑色液膜对土壤微生境及产量的影响

采用田间小区试验研究了黑色液膜覆盖旱地冬小麦对土壤微生境及产量的影响。在枯水年型条件下，在5，10cm土层中，黑色液膜处理抽穗期的日平均温度分别较对照高2．9℃，0．4℃；黑色液膜处理在10～20cm的土壤容重和0～20cm的平均总孔隙度分别较对照降低3．1％和增加1．90％；黑色液膜处理在小麦拔节～成熟期0～100cm土层的耗水量占全生育期0～200cm土层总耗水量的47．9％，水分利用效率达到0．78kg／m^3，较对照提高22．26％；黑色液膜处理较好地协调了旱地小麦穗数、穗粒数和千粒重，使产量达2188．5kg／hm^2，较对照增产17．95％。该项研究为旱地小麦覆盖材料开辟了新的领域。     

黄土台塬旱地小麦土壤水分特征及水分利用效率研究

对黄土台塬乾县试区旱地小麦不同降水年型的土壤水分特征及水分利用效率长期研究结果表明,该区按降水量多少分为丰水、平水和干旱3种降水年型,干旱少雨是这一研究时段的主要特点;夏闲期是该区旱地小麦土壤水分的恢复阶段,降水多少与下渗深浅密切相关;小麦生育期是旱地小麦土壤水分的损耗阶段,时至收获2m土层内土壤水分降到全年最低值;小麦产量与耗水系数呈负相关,与田间耗水量和水分利用效率呈正相关。     

旱地小麦保护性耕作增加播前地表处理的研究

针对临汾旱地小麦保护性耕作试验中存在的播种质量不高、缺苗断垄、苗数不足等问题进行了研究。主要采用覆盖深松加地表处理的方法，研究了不同地表处理对土壤墒情、覆盖率、小麦产量和经济效益的影响。结果是：在覆盖量相同的情况下，动土量越小，土壤保墒效果越好；与保护性耕作原工艺相比，增加地表处理后播种质量改善、出苗率提高；增加地表处理可提高0～50 cm土层水分利用率；增加地表处理使小麦单产在保护性耕作基本处理的基础上显著提高，经济效益明显。试验证明，覆盖深松加地表处理是一项旱地小麦增产的有效措施。     

晒旱地施肥技术及增产效果研究

对豫西旱区晒旱地小麦氮磷肥施用技术及增产效果进行三年研究的结果表明：晒旱地小麦氮肥由常规播前施改伏前翻耕晒垡时施，使０－３０ｃｍ土层碱解氮含量较高且分布均衡，有利小麦不同时期对氮的利用，小麦增产１１．４％－２６．８％。磷肥适当浅施（１０－１５ｃｍ）有利于小麦在磷敏感期对磷的吸收，增产效果较好。     

耕作方式对旱地麦田土壤蓄水变化特征及小麦产量的影响

为探讨不同耕作方式对山西晋南旱地土壤蓄水变化特征及小麦产量的影响,以“晋麦92号”为试验材料,连续2年研究休闲期免耕+常规条播、休闲期免耕+探墒沟播、休闲期深松+常规条播和休闲期深翻+常规条播4种耕作模式对麦田土壤蓄水量及变化特征、小麦产量和水分利用效率的影响。结果表明:休闲期免耕条件下,沟播较常规条播更有利于提高100-200 cm土层蓄水量。沟播对旱地小麦产量的增加效果不明显或略有降低,2个年份水分利用效率分别降低3.6%和9.3%。休闲期深松和深翻比免耕均能提高旱地小麦播前和返青期0-200 cm土壤蓄水量,以深翻效果最佳,这种增加作用主要集中在0-100 cm土层。小麦产量在2个年度均表现为休闲期深翻+常规条播处理最高(较休闲期免耕+常规条播处理增产44.6%和147.2%)。产量增加与地上部干物重和穗粒数呈显著正相关。深松和深翻使2个年度水分利用效率分别增加12.7%和46.74%,53.70%和94.91%,且在较干旱年份(2018—2019年)增加效果越明显。可见,休闲期连续2年深松和深翻均能提高土壤蓄水量,提高旱地小麦产量和水分利用效率。免耕条件下,沟播对小麦产量影响因年份不同而异,仍需进一步探讨。     

旱地冬小麦茬口、种植模式对土壤贮水、耗水及水分利用效率的影响

为高效利用天然降水资源,缓解干旱逆境因子对旱地小麦的不利影响,提高土地复种指数,在山西洪洞采用大田对比方法,开展了旱地冬小麦茬口、种植模式对土壤贮水、耗水及水分利用效率的影响研究。结果表明,在丰雨年型条件下,在小麦播种期0-200cm土壤贮水量玉米茬口高于小麦茬口;在播种至收获阶段,3个覆膜种植模式在0-200cm土层耗水量大于露地条播种植模式,3个覆膜种植模式、露地条播种植模式100-200cm土层耗水量占0-200cm土层耗水量分别为45.33%,22.67%,覆膜种植模式可有效利用土壤深层水;3个覆膜种植模式均较露地条播种植模式增产,其中以玉米茬口1膜4行种植模式增产幅度最大;玉米茬口1膜4行种植模式可较玉米茬口露地条播种植模式水分利用效率提高15.08%。该项研究可为以旱地小麦为主要轮作作物的种植制度提供理论依据和良好的技术支撑。     

旱地小麦产量与栽培、施肥及主要土壤肥力因素的关系探讨

小麦种植是我国农业种植的主要分支,在我国农业种植资源中占有基础性地位。随着我国农业种植技术的逐步开发,国内旱地小麦种植要素分析,在当前小麦种植技术研发中发挥着牵引性作用。基于此,结合国内旱地小麦产量的差异,对旱地小麦栽培、施肥以及主要土壤肥力的影响因素进行探究,以达到进一步提高国内小麦产量,实现国内农业绿色化发展的目的。     

不同降水年型下播期对晋南旱地小麦产量和水分利用率的影响

根据近54年来山西省临汾市逐日降水量,将7个试验年份分为丰水年型、平水年型和枯水年型,研究了不同年型不同播期对旱地小麦关键生育期持续时间、降水、积温、日照时数、小麦产量及籽粒水分利用效率的影响,并进行相关、多元回归和通径分析,为旱地小麦稳产高产提供理论依据和技术支撑。结果表明,播期对小麦生育期持续时间的影响主要表现在苗期、分蘖期和起身拔节期,而对抽穗期和成熟期影响最多仅相差1 d。旱地小麦全生育期持续时间与积温显著正相关。降水年型显著影响旱地小麦产量及其构成因素,相同降水年型下降水分布不同小麦产量也有较大差异,丰水年型旱地小麦产量较平水年型和枯水年型分别提高100.0%和135.9%。籽粒水分利用率为丰水年型枯水年型平水年型,丰水年型和枯水年型下,籽粒水分利用率随播期推迟而升高,平水年型下,籽粒水分利用率随播期推迟先升高后降低。在拔节—抽穗期,小麦产量与积温显著负相关,与日照时数极显著负相关,与降水量极显著正相关;在抽穗—成熟期,产量与积温、日照时数均呈极显著正相关。年降水量及其分布是影响旱地小麦稳产高产的关键,丰水年型适播期在10月4日左右,产量构成因素协调,可获得高产,同时生育期耗水量最少,水分利用率较高;平水年型和枯水年型适播期应在9月28日左右,产量最高,水分利用率也较高。随播期推迟,应适当加大播量。     

不同补灌次数对旱地高产小麦氮素运转及产量的影响

试验研究了不同补灌处理对旱地高产田小麦氮素运转和产量的影响.结果表明: 增加补灌次数和灌水量, 导致小麦籽粒蛋白质含量降低, 旱地CK处理籽粒蛋白质含量最高, 其成熟期积累量虽然比灌1水和2水的处理低, 但显著高于灌3水以上处理.适量补灌, 可提高籽粒产量, 提高氮素利用率.补灌次数和补灌量过多, 小麦贪青晚熟, 氮素转移量小, 氮素转移率亦大幅度降低, 对产量提高的贡献并不大, 且产量和产量构成因素中千粒重、穗粒数反而下降, 低于灌2水和3水处理.综合考虑产量和水分利用效率、蛋白质积累等因素, 在本旱地高产试验田, 拔节期、灌浆期2水补灌120 mm的W2处理是最经济高效的补灌方案.     

THE IDENTIFICATION AND DETERMINATION OF GLUCURONIC AND GALACTURONIC ACIDS IN SCOTTISH SOILS AND SOIL FRACTIONS USING ION-EXCHANGE AND GAS-LIQUID CHROMATOGRAPHY

Two methods have been used for the identification and determination of uronic acids in soils and soil fractions. The uronic acids were released by hydrolysis with sulphuric acid. After partial purification by ion-exchange chromatography they were separated either by further ion-exchange or by gas-liquid chromatography of derivatives. The latter method is preferable for determination of the specific activities of uronic acids in soil tracer work. Both galacturonic and glucuronic acids were detected in the four Scottish soils examined, the galacturonic acid being present in slightly greater amounts in each soil. Mannuronic acid was not detected. The total amount of uronic acids found ranged from about 4 mg to 6 mg/g soil.     

坡面汇流汇沙与侵蚀—搬运—沉积过程

侵蚀、搬运和沉积过程是土壤侵蚀过程中相互影响又相互制约的三个子过程。自从 2 0世纪 40年代Ellison[1～ 4] 将水蚀过程分为四个子过程 ,即雨滴侵蚀过程、径流侵蚀过程、雨滴搬运过程和径流搬运过程以来 ,许多学者从不同角度对其进行了研究。Meyer和Wischeier[5] 及Meyer和Fo     

甲酸甲烷杆菌和甲烷八叠球菌的分离和特征

本文介绍从德国哥廷根污水处理厂腐化塔污泥中分离出的两株甲烷细菌，其中一株为甲酸甲烷杆菌（Ｍｅｔｈａｎｏｂａｃｔｅｒｉｕｍｆｏｒｍｉｃｉｃｕｍ），其细胞杆状，可利用甲酸或Ｈ２／ＣＯ２作为碳源和能源，另一株为甲烷八叠球菌属（Ｍｅｔｈａｎｏｓａｒｃｉｎａ），其细胞球状，成堆排列，可利用甲醇或Ｈ２／ＣＯ２作为碳源和能源。     

有机无机肥配施对小麦吸收氮磷及土壤肥力的影响

￣（１５）Ｎ示踪试验表明，有机无机肥配施促进了有机叉的矿化和小麦对有机氮的吸收利用，基施氮肥主要用于营养器官的形成，返青追肥主要用于生殖器官的形成。有机无机氮肥配施提高了总氮生产效率。配施处理小麦对磷素的吸收总量稍高于单施无机氮肥处理，磷素在籽粒中的分配率稍低于单施无机氮肥处理是导致磷素生产效率下降的重要因素。有机无机肥配施提高小麦产量的同时也培肥了地力，是小麦高产稳产的重主措施之一     

MAKING SOIL AND WATER CONSERVATION SUSTAINABLE: FROM COERCION AND CONTROL TO PARTNERSHIPS AND PARTICIPATION

For close to a century, rural development policies and practice have taken the view that farmers are mismanagers of soil and water. This paper reviews the history of farmers being advised, paid and forced to adopt new soil and water conservation measures and practices. Many have done so, and environments and economies have benefited in the short term, but ill-conceived policies and badly designed programmes and projects have undermined these efforts in the name of conservation. Most efforts have been remarkably unsuccessful, often resulting in more erosion. They have undermined the credibility of conservation and wasted huge sums of money. For a new era of soil and water conservation, new initiatives are showing how to make conservation sustainable. Farmers are now considered the potential solution rather than the problem, and so the value of local knowledge and skills is being put at the core of new programmes. This involves a major focus on building farmers' capacity to innovate and develop technologies appropriate to their own conditions. Local organizations are strengthened through participatory processes, this participation being interactive and empowering. Recent evidence is indicating that these new interactions between professionals and farmers are producing considerable productive and sustainable benefits. For widespread impact, enabling policy frameworks are still needed to encourage the spread of more sustainable practices for agriculture. © 1997 John Wiley & Sons, Ltd.     

水肥耦合对小麦玉米带田产量效应及土壤水分动态研究

采用3414最优回归设计方案,研究了水肥耦合对小麦玉米带田产量效应及土壤水分动态规律。结果表明：不同水肥耦合模式对带田作物的产量差异达极显著水平。在灌水量4800m3/hm^2,施氮肥420kg/hm^2,磷肥120kg/hm^2的处理（W2N2P2）中,带田产量和水分利用效率达最高值,决定带田总体产量性状主要因子为氮...     

黄土与古土壤中重金属的存在形态及风化成土作用对其影响

本文采用了七步连续萃取方法，研究了洛川黄土剖面黄土与古土壤中Ｆｅ，Ｃｕ，Ｚｎ，Ｃｏ和Ｎｉ五种重金属的存在形态。结果表明：黄土与古土壤中上述元素主要存在于残余态和晶形，无定形氧化铁的结合态中，而且线性回归分析表明Ｃｕ，Ｚｎ，Ｎｉ与晶形氧化铁之间存在关；ｃＵ，ｃＯ，Ｎｉ与无定形氧化铁之间存在相关；黄土风化为古土壤后，碳酸盐结合态的重金属含量增加是古土壤相对于黄土重金属增加的主要原因。     

稻草和尿素配施时水稻对肥料氮和土壤氮的吸收利用

利用＾１５Ｎ同位素示踪技术,研究了稻草和尿素配施时水稻对肥料和土壤氮的吸收。结果表明,稻草单施导致土壤速效氮的生物固定,氮素供应不足是影响水稻分蘖成穗的限制因子,稻草配合尿素施用,明显改善肥料氮和土壤氮的供应,既有利于当季水稻增产,也有利于培养土壤肥力,还有利于后茬物作产量的提高 。     

MIGRATION AND AGGREGATION OF Na AND Ca CLAYS BY THE FREEZING OF DISPERSED AND FLOCCULATED SUSPENSIONS

The ability of clay to move ahead of an ice-liquid interface depends on the rate of freezing, the particle size, the release of dissolved air from the water through its probable effect on local freezing rates, and on the electrolyte and its concentration through their effects on interparticle forces and particle mobility. A freezing-rate of 1 cm per hour did not move flocculated clay in most cases, but moved dispersed clay up to 0.7 cm before being trapped in the ice with released air. Aggregates of clay (0.1 to 1 mm) were produced by freezing. After thawing they swelled and dispersed depending on the electrolyte and its concentration in a similar manner to aggregates formed by drying.     

GROWTH AND POTASSIUM TRANSPORT IN COMMON AND DURUM WHEAT AS AFFECTED BY ALUMINUM AND NITRITE STRESS

Aluminum (Al) toxicity has been identified as one of the most important factors limiting plant growth in acid soil. Besides Al, nitrite (NO₂ ^?) may also be a significant stress factor in an acid environment. The objective of this study was to examine the effects of Al and NO₂ ^? stress on the growth and potassium (K⁺) uptake of roots and their transport toward the shoots of an Al-resistant common wheat (Triticum aestivum L. cv. Jubilejnaja 50) and an Al-sensitive durum wheat (T. durum Desf. cv. GK Betadur) grown in 0.5 mM CaSO₄ solution at pH 4.1 or 6.5. Root elongation of durum wheat was inhibited with 30% at 10 μM AlCl₃ treatment, while this low Al-concentration did not show a significant effect on root growth of common wheat. In all cases shoot growth was not influenced under low-salt conditions by 10 μ M AlCl₃, but exposure to 100 μM KNO₂ (alone or in combination with Al) had a definite stimulatory effect on growth. Aluminum was found to stimulate the K⁺(⁸⁶Rb) influx in short-term (6 h) experiments, but to inhibit it in long-term (3 days) experiments. This treatment was thought to damage the plasma membrane. When 10 μM 2,4-dinitrophenol was present in the uptake solution the Al-stimulated K⁺ uptake stopped even in short-term experiments. In the case of nitrite and nitrite + Al treatment combinations, however, a striking inhibition was observed in the K⁺(⁸⁶Rb) influx and the K⁺ concentration of the roots and shoots of both species.