减量施肥对冬小麦休闲期农田杂草物种多样性及生态化学计量特征的影响

【目的】分析减量施肥对冬小麦休闲期农田杂草物种多样性及生态化学计量特征的影响,旨在为化肥农药“双减”政策产生的生态环境效应科学评价提供参考。【方法】以陕西杨凌曹新庄试验地冬小麦肥料试验为基础,设置不施肥（CK）、减量施肥（氮（N）、磷(P₂O₅)用量分别为165和122 kg/hm²）和常规施肥（N、P₂O₅用量分别为220和160 kg/hm²）3个处理,测定不同处理小麦产量及夏季休闲期农田杂草的生物量、株高、盖度、多度、频度、丰富度,以及藜、狗尾草和马唐的有机碳、全氮、全磷含量,计算植物多样性指标及生态化学计量比（C/N、C/P、N/P）,研究减量施肥对农田杂草物种多样性及生态化学计量特征的影响。【结果】与对照相比,减量施肥和常规施肥处理均对冬小麦休闲期农田杂草的生物量、株高、盖度、多度、频度有明显影响,冬小麦籽粒产量和杂草生物量增加;施肥处理藜和地锦草的株高和生物量均显著增加,其他农田杂草的株高和生物量总体降低。与对照相比,施肥处理苋的有机碳含量以及藜、狗尾草、马唐和葎草的全氮含量均显著增加,藜、马唐全磷含量显著降低。相较于常规施肥,减量施肥处理狗尾草全磷含量显著降低。与对照相比,减量施肥和常规施肥处理藜、狗尾草和马唐氮磷比和碳磷比总体显著增加,碳氮比显著降低。相对于常规施肥处理,减量施肥处理缓解了藜和马唐氮磷比的增加幅度。与对照相比,施肥处理的Shannon-Wiener多样性指数、Simpson多样性指数和Margalef丰富度指数均显著降低;与减量施肥处理相比,常规施肥处理Pielou均匀度指数与丰富度显著降低。植物β多样性指数表明,常规施肥对小区植物多样性的影响最大。【结论】减量施肥和常规施肥处理冬小麦休闲期农田杂草的物种多样性均明显降低,但减量施肥处理缓解了常规施肥对农田杂草生物多样性和生态化学计量特征的影响。     

From alley cropping to rotational fallow: Farmers' involvement in the development of fallow management techniques in the humid forest zone of Cameroon

Alley cropping was introduced in the humid forest zone of Cameroon to increase soil fertility in 1987, but until 1992 the adoption rate had remained low. To better understand the reasons behind this, three types of on farm trials were established from fully researcher controlled to fully farmer controlled. During the evaluation of the technology with farmers a number of modifications were registered (1) Pruning height and frequency: Because of the difficulties to consistently cut back at 30 cm, farmers decided to slash at ground level as they normally do while slashing the natural fallow vegetation. This equally allowed for more flexibility in time of pruning. (2) Cropping intensity and pattern: Initially, alleys were cropped each year. This however had several shortcomings. Having observed the positive impact of incidental fallow period in a farmer's field, it was decided to introduce a fallow phase of at least one year. During the fallow period the plot can be used for fodder production, bee farming and production of stakes. (3) Residue management: Fire went incidentally in a farmer's tree plot after slashing, and the trees were not affected. This gave farmers an alternative way to manage the residue, by controlling the fire, before bringing in other crops such as groundnut and cassava. (4) Agroforestry species: Because Leucaena leucocephala, in spite of it soil fertility restoration potential, rapidly became a noxious weed, farmers have asked for a less invasive species. Calliandra calothyrsus was introduced for this purpose and became a good bee forage. With these modifications, the original alley cropping system has evolved into a rotational tree fallow with higher adoption potential. From about 15 farmers who were testing the technology in 1992, the number increased to 52 in 1996, 120 in 1997 and 236 in 1998. This revised version was published online in June 2006 with corrections to the Cover Date.     

对退耕还林工程中种草的探讨

分析种草在退耕还林工程中的重要地位和作用 ,提出退耕种草的草种选择和种植模式 ,并探讨发展草产业的途径和方向     

浅析我国南方冬闲田种植一年生黑麦草的应用研究

针对我国南方地区冬闲田数量多、利用率低的现象,充分利用冬闲田种草养畜,不仅可以解决牲畜季节性青绿粗饲料缺乏问题,还能促进农民增收和农业可持续发展.一年生黑麦草由于适生范围广,鲜草产量高,营养丰富且柔嫩多汁,适口性好,家畜家禽喜欢采食,深受农户青睐,成为一种极具发展前途的越年生优质牧草,近年来在畜牧业生产中得到广泛应用....     

海河平原区棉花饲用黑麦复种方式及水肥利用效率分析

2011年10月-2014年10月连续3年在河北省任县安排了定位试验,通过饲用黑麦不同播期与棉花构建几种棉草复种茬口搭配方式,从产量、经济效益、水分利用效率和养分利用效率以及对土壤肥力影响等方面综合分析棉花饲用黑麦复种的可行性及复种方式。结果表明,棉花可与饲用黑麦复种,为降低饲用黑麦对棉花的影响,饲用黑麦可适当推迟到10月20日播种,次年4月底收获,效益可提高5470.1元·hm^-2。棉花饲用黑麦复种与棉花单作相比,平均水分利用率提高16.49%;水分经济利用效率提高56.54%;并且土壤有机质平均增长幅度提高5.71%,土壤含盐量平均降低幅度达到23.72%,土壤改良效果明显;是适用于该区域的高效复种模式。     

冬季种养结合对稻田土壤微生物量及有效碳氮库的影响

以双季稻冬闲田种植绿肥与养鸡结合的新型种养制度为平台,通过冬季绿肥和鸡粪还田,减少水稻生育期化肥用量,探讨“冬季绿肥-双季稻”轮作种植制度和“冬季种养结合-双季稻”种养制度下对稻田土壤微生物碳、氮和可溶性有机碳、氮的影响。试验包括5个处理,分别为冬闲(F)、冬季种植黑麦草(R)、冬季种植紫云英(M)、冬季种植黑麦草与养鸡结合(RC)以及冬季种植紫云英与养鸡结合(MC)。结果表明,在整个试验的动态过程中,微生物量碳、氮及可溶性有机碳、氮含量高低总体趋势表现为绿肥养鸡>绿肥>冬闲,各处理间差异显著(P<0.05);“冬季种养结合-双季稻”种养制度能显著提高土壤微生物量碳、氮和可溶性有机碳、氮。各处理微生物量碳、氮和可溶性有机氮在3月24日达到最大值,RC、MC、R和M处理微生物量碳最大值分别为492.22,464.91,432.34和435.48 mg/kg;微生物量氮的最大值分别为118.20,101.03,70.13和85.46 mg/kg;可溶性有机氮的最大值分别为1001.47,926.21,832.80和870.75 mg/kg;可溶性有机碳在早稻苗期达到最大值,RC、MC、R和M最大值分别为278.95,266.40,246.13和249.84 mg/kg。微生物量碳含量的高峰在早稻移栽初期、晚稻孕穗期和灌浆期,微生物量氮的高峰出现在早稻分蘖期、齐穗灌浆期和晚稻孕穗期,可溶性有机碳在稻田养鸡及成鸡出栏后较高。与冬闲田种植绿肥和休闲相比,冬闲稻田种植绿肥结合养鸡对增加微生物生物量的贡献更大,并显著提高土壤的可溶性有机碳氮,间接反映了种养制度能提高土壤有机碳、氮的矿化速率和土壤的活性有机碳氮以及满足水稻生长期间自身养分需求。     

乌蒙山冷凉山区饲用燕麦农艺性状与营养品质评价

为高效利用乌蒙山区丰富的冬闲田资源,对17份饲用燕麦(Avena sativa L.)开展了农艺性状与营养成分的比较试验。结果显示,平均生育期为194～226 d,出苗-拔节期时长超过生育期50%;农艺性状变异系数多数高于10%,产量(28.42%)和有效分蘖(30.52%)最高。不同品种粗蛋白(Crude protein, CP)和酸性洗涤纤维(Acid detergent fiber, ADF)含量差异显著(P<0.05),分别为8.33%～10.13%和25.32%～30.15%;中性洗涤纤维(Neurtral detergent fiber, NDF)含量为50.51%～57.58%,品种差异不显著;相对饲喂价值(Relative feed value, RFV)为106.57～133.83,品种间差异显著(P<0.05)。‘永久444’ADF含量显著高于其他品种(P<0.05),爱沃RFV显著高于其他品种(P<0.05);各指标间存在密切相关关系,穗粒数与产量正相关(P<0.05),生育期与CP正相关(P<0.05);铃铛数、NDF、有效分...     

Two perennial legumes (Astragalus adsurgens Pall. and Lespedeza davurica S.) adapted to semiarid environments are not as productive as lucerne (Medicago sativa L.), but use less water

Perennial forage legumes, particularly lucerne (Medicago sativa L.), play a significant role in crop/livestock mixed farming systems in the semiarid region of the Loess Plateau of China as stock feed and a source of nitrogen for subsequent crops. However, there is evidence that lucerne reduces soil water deep in the soil profile, thereby reducing subsequent crop productivity. From 2004 to 2010, this study evaluated the forage productivity and water use of two locally adapted perennial legume species, milk vetch (Astragalus adsurgens Pall.) and bush clover (Lespedeza davurica S.), compared with lucerne. The 7‐year total and average annual forage yield of milk vetch were 56 and 8 t ha^?1 and bush clover was 42 and 6 t ha^?1, respectively, significantly lower than lucerne at 91 and 13 t ha^?1. However, despite lower water‐use efficiencies (16 and 12 kg ha^?1 mm^?1 for milk vetch and bush clover, respectively, compared to 22 kg ha^?1 mm^?1 for lucerne), the total 7‐year water use in milk vetch and bush clover was 3500 mm and 3490 mm, respectively, which was 135–140 mm less than lucerne. After 7 years, lucerne had extracted water from the upper 5 m soil, whereas bush clover used water mainly from the upper 2 m of the soil profile and milk vetch still had some water available below 3 m. We conclude that while the locally adapted forage legumes were not as productive as lucerne as a source of fodder in mixed cropping/livestock system in this region, they use less water, which may be advantageous in drier regions.     

黄淮海平原地下水超采区休耕政策过程绩效评价及改进策略研究

为在耕地休养生息背景下开展地下水休耕政策过程绩效评价,以黄淮海平原为研究对象,通过对黄淮海平原的2 个市、5 个县政府相关部门和农户实地调查,以公共价值理论为基础,构建地下水超采区休耕政策过程绩效评价指标体系,并辅以层次分析法、专家打分法等方法对地下水严重超采区休耕政策过程绩效进行评估。结果表明:1)明晰了黄淮海平原地下水超采区休耕政策公共价值体现并从公平性、参与性、效率性、可持续性等4 个维度构建休耕政策过程绩效评价指标体系;2)黄淮海平原地下水超采区休耕政策过程绩效评估总得分为74.38分,绩效等级处在“较好”的水平;3)休耕政策实施过程的关键环节包括休耕政策面积落实环节、资金管理和使用环节、政府组织环节、政策生态目标认识环节;休耕政策实施过程的薄弱环节,包括休耕政策面积落实环节、资金管理和使用环节、政府组织和论证环节。综上,本研究构建的地下水超采区休耕政策过程绩效评价体系具有系统性、科学性和可操作性,可为休耕政策实施过程定量评价提供了研究思路和支撑。     

浅析北京奥林匹克公园的植物造景艺术

北京奥林匹克公园是2008年北京奥运会留给我们的宝贵财富,是北京人民休闲娱乐的后花园。本文重点对奥林匹克公园龙形水系和休闲花园的植物造景艺术进行了详细分析,包括丰富的植物种类和特点突出的植物配置形式,以引为城市园林的典范。