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本文研究了库布齐沙地草场补播改良技术，确定出适宜的补播牧草品种及播前种子处理技术，适宜的补播时间；正确的补播地形和合适的补播机器。改良后的浙江省 地草场生态环境明显改善，土壤养分提高，植被盖度和产草量随着补播年限的增加而增加，补播第三年，植被盖度达到７８％，干草产量５２５０ｋｇ／ｈａ，分别比补播有提高３倍和７倍，流沙移动得到控制．。 相似文献
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为提高库布齐沙地补播改良退化草场的质量和补播的成功率，本文通过引种方式筛选出适宜库布齐沙地补播的牧草品种20个，并且研究了提高补播牧草幼苗抗旱能力和抵御第二年春季风蚀危害的种子处理技术。 相似文献
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选取3个翻耕模式(深翻、浅翻及免耕),以未补播的原生沙质草地为对照(CK),分析不同模式下禾-豆混播草地土壤颗粒组成、植物群落结构特征及数量特征,研究退化沙质草地土壤质地及植物群落对翻耕和补播措施的响应。结果表明:深翻、浅翻、免耕及CK对应的草地群落物种丰富度分别为9、9、5种和8种,机械扰动和补播牧草降低了游击型克隆植物的繁殖与扩展能力,提高了补播牧草在群落中的优势度,深翻处理下多年生禾本科及豆科牧草优势度最为明显,翻耕及补播后草地植物群落物种多样性和均匀度明显增大,生态优势度与物种多样性变化趋势正好相反,其中浅翻处理下补播草地群落物种多样性和均匀度最高,游击型克隆植物提高了原生草地生态优势度;补播草地群落地上生物量大小表现为:深翻(348.39 g·m~(-2))浅翻(285.77 g·m~(-2))免耕(242.08 g·m~(-2))CK(141.83 g·m~(-2)),且与原生草地存在极显著性差异(P0.01);补播草地土壤颗粒组成主要以50~250μm的细沙粒为主,深翻、浅翻及补播牧草显著提高了0~20 cm土层土壤黏粉粒含量和土壤颗粒体积分形维数(P0.01),土壤质地改善效果明显,土壤整体稳定性明显提高。 相似文献
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正南瓜栽培简单,在荒山、荒坡、幼年果园里均可栽培。近年来,自贡栽培面积越来越大,效益较好,农民种植积极性较高,但本地品种多、良种少。荣县农牧业局针对品种单一,广泛引进南瓜新品种,开展品种比较试验,筛选出蜜宝、比蜜甜、蜜月、金船蜜本等优良品种,共农民朋友参考。一、材料和方法试验材料:金船蜜本(汕头市金韩种业有限公 相似文献
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陇中半干旱区集雨补灌小麦玉米复合群体产量及水分效应 总被引：2，自引：0，他引：2
大田条件下研究了陇中半干旱区小麦/玉米复合群体集雨补灌的产量及水分效应。结果表明,复合系统的产量水平和水分利用效率(WUE)因补灌而显著提高,小麦组分也取得明显的边行优势。根据对产量、WUE和灌水利用效率(IWUE)的综合分析,认为在小麦播前补3 mm水,小麦拔节期、孕穗期各补21 mm水,玉米抽雄期补45 mm水是该区最理想的补灌模式。 相似文献
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于2010年4-9月在宁夏云雾山草原自然保护区实验区内对草地进行各种改良措施应用试验,以寻求加快宁南半干旱区草原生态恢复的关键技术.改良后的测定结果表明:草地松耙后的植物群落多样性与对照之间差异不显著(P＜0.05),盖度和生物量明显低于对照,分别低7％、32.4 g·m-2;草地松耙、草地松耙+补播、草地松耙+施肥、草地松耙+补播+施肥、围栏封育处理后的土壤含水量与对照之间差异显著(P＜0.05),容重均小于对照；草地松耙+补播+施肥的土壤养分与对照之间差异显著(P＜0.05). 相似文献
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沙棘为胡颓子科沙棘属,又名酸柳、酸棘、黑棘等.是一种小浆果植物,落叶灌木或亚乔木,主干可达10m,常见2m左右.常与樟子松、落叶松、云杉营造混交林,是干旱、半干旱地区绿化荒山荒坡、营造水土保持林的最佳造林模式.沙棘具有抗干旱、耐寒冷、耐贫瘠的特点,是防风、固沙和保持水土的最佳树种之一,同时义是轻工和食品、医药上业等的重要原料.所以被人们誉为"神奇植物"、"绿色瑰宝"、"整治国土的生物武器". 相似文献
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ABSTRACT The dispersal potential of Xanthomonas oryzae pv. oryzae, causal agent of bacterial blight of rice (Oryzae sativa), was investigated through measurement of primary disease gradients. Plants within individual hills of rice were inoculated, and the number of new lesions in the primary generation of dispersal from these inoculated sources was counted. Two dispersal models that can describe the number of infections at the source (the Kiyosawa and Shiyomi and the modified Gregory) were fit to the lesion counts. Estimated gradient slopes were similar in the 2 years of the study for both gradient models. However, the Kiyosawa and Shiyomi model gave a better fit in both years, as indicated by higher coefficients of determination and significances of slopes and by a more random pattern of residuals. Primary disease gradients were very steep, with half-distances (distances over which lesion numbers are calculated to decrease by half) estimated from the Kiyosawa and Shiyomi model of 0.091 and 0.081 m in 1994 and 1995, respectively. Splash dispersal of X. oryzae pv. oryzae is the most likely explanation for both the steep slopes measured and the superior fit of the Kiyosawa and Shiyomi model over the modified Gregory model. 相似文献
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河北丰宁坝上土地沙漠化现状及其综合整治的研究 总被引：4，自引：1，他引：4
河北丰宁坝上的土地沙漠化主要表现在：①旱作农田的土壤风蚀。②缓起伏沙质草场的退化。③河滩低湿草地的退化。④丘陵山地阳坡的侵蚀沙化。综合整治的总方针是加强天然草原植被的合理管护与人工饲草饲料基地建设，建立综合防护林体系。 相似文献
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在塔克拉玛干沙漠腹地的人工梭梭林,利用咸水滴灌技术,对种植肉苁蓉（Cistanche deserticola）的开挖方式、播种方式、接种深度以及稳产技术等进行了试验研究。结果表明：① 提高肉苁蓉种子和寄主根系接触的几率是提高人工接种肉苁蓉效果的有效途径。不同种植方式的肉苁蓉出土率为：沟种>打洞>穴种,撒种>种植带（种植纸）。② 采用开沟、撒种方式种植肉苁蓉,随播种量增加,出土肉苁蓉数量呈增加趋势,但存在一个上限值。在沙地滴灌种植肉苁蓉适宜的播种量为300粒/m。③ 接种深度应控制在寄主根系主要分布层以内,并结合作业方式及作业成本来综合确定,在沙地滴灌接种深度不宜超过60 cm。④ 人工接种肉苁蓉具有一次接种,多年采收的效果,但肉苁蓉出土率年际间差异较大。接种后第2 a至第4 a为主要收获期。采用沟种、撒种技术春季接种肉苁蓉,接种后连续3 a平均出土率可以保持在1株/m以上,肉苁蓉鲜重产量达1 800 kg/hm2,经济效益显著。 相似文献
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B. D. Sharma H. S. Jassal J. S. Sawhney P. S. Sidhu 《Arid Land Research and Management》2013,27(2):189-200
We investigated the profile distribution of total and diethylenetriamine pentaacetic acid ( DTPA )- extractable micronutrients ( Zn , Mn , Cu , Fe ) in soils developed on six physiographic units of the semiarid Siwalik hills of Punjab in northwest India . The soils showed a gradual fining of texture from shoulder slopes to toe slopes . All soils were alkaline and calcareous . In general , total and DTPA-extractable micro nutrients were higher in surface horizons and decreased in subsurface horizons . However , none of the micronutrients exhibited any consistent pattern of distribution with depth on different geomorphic surfaces . Physiography had a strong influence on the spatial distribution of total and available micronutrients . Contents of all micronutrients and their forms were higher in fine-textured and uneroded soils than in coarse-textured eroded soils . Soil pH , calcium carbonate , organic matter , and size fractions had strong influence on the distribution of total and extractable micronutrients . Based on linear coefficients of correlation , total content of micro nutrients increased with increase in clay content , whereas DTPA - extractable micronutrient content increased with increase in organic carbon and decreased with increase in pH and CaCO3 content . Except for Cu , no other micronutrient showed influence of total reserves on availability of the respective micronutrient . Among the various micronutrients , deficiency of Zn was found to be widespread , followed by Fe and Cu in the cultivated soils on foot slopes , toe slopes , and floodplains . 相似文献
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Early autumn soil disturbance decreases persistence of volunteer summer‐annual oilseed rape (Brassica napus) 
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下载免费PDF全文 Volunteer summer‐annual oilseed rape (sOSR; Brassica napus) is an ongoing concern in Canadian crop production. Large harvest seed losses and secondary dormancy in this species generate a persistent volunteer seedbank. Yield loss in subsequent crops, potential sOSR oil profile contamination and herbicide‐resistance trait introgression create a need for effective sOSR seedbank management. This field study evaluated the effects of timing and type of implement of post‐harvest soil disturbance and seeding a winter cereal on volunteer sOSR population persistence and demographic life‐stage transition rates at five locations in Manitoba, Canada. Following sOSR harvest and supplemental seed rain, seedbank densities ranged from 6770 to 15360 and 50 to 2610 seeds m?2 among sites in autumn and spring respectively. In contrast to European research on winter‐annual oilseed rape, early autumn soil disturbance, shortly after sOSR harvest, was the best strategy to decrease volunteer sOSR persistence (3% population persistence from autumn to spring, compared with 6% in zero tillage). Substantial autumn seedling recruitment (38% of the autumn seedbank) and subsequent winterkill contributed to lower population persistence. Soil disturbance in spring stimulated spring seedling recruitment compared with other disturbance timings (11% and 3% of the spring seedbank, respectively). The implement used for soil disturbance and seeding winter wheat (Triticum aestivum) had minimal effect on population persistence. This research showed that timing of post‐harvest soil disturbance should be utilised as an effective tactic to decrease population persistence of volunteer sOSR via stimulation of autumn seedling recruitment and concomitant winterkill. 相似文献
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坡地是黄土丘陵地区的主要土地类型，并且广泛存在着较严重的水土流夫。关于坡地利用，较多的人认为应退耕还林或梯田化种植。本文认为，在目前的实际社会经济很落后的约束下，这两种利用方式只能作为远期模式，在近中期，还难以普遍推行。比较实际的是生态经济模式，这种模式既不是生态最优，也不是经济最优。而是双方均可满意的利用方式，据此，本文首先讨论了该地区坡地生态经济利用的设计模式，之后，对宁夏黄土丘陵区茹河流域进行了实际案例研究。 相似文献
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Darjeeling and Sikkim hills of India are well known for production of mandarin orange (Citrus reticulata). The recent spread of Citrus tristeza virus (CTV) has threatened the citrus cultivation in this region. During a survey in Darjeeling and Sikkim hills, pomelo trees were recorded as CTV free. Since pomelo trees did not show any disease appearance, a study was undertaken to ascertain whether they are resistant to CTV infection or resistant to aphid feeding or both. Toxoptera citricida, the most efficient aphid vector and which is abundantly present in this region, did not feed on pomelo when other Citrus species such as mandarin, kagzi lime and rough lemon were available. Additionally, CTV isolates of Darjeeling and Sikkim hills were not transmissible to pomelo either by T. citricida or grafting. We report for the first time that pomelo is resistant to isolates of CTV present in this region. 相似文献
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为了防止沙漠化的进一步扩展,于1983～1995年期间,在鄂尔多斯地区飞播了 12万hm2,在这里使用138个飞播区的调查数据,首先对适宜飞播植物种和合理的播种量进 行了探讨,得到如下结论:①在鄂尔多斯地区适宜飞播的植物种有杨柴、籽蒿、沙打旺、草苜蓿。 ②由于种子处理技术的应用,低播种量6.0-7.0kg/ha取得了良好的飞播成效。其次用Ⅰ类 数量化理论对播种时间、沙丘高度、沙丘密度、播前自然植被覆盖率与播后植被覆盖率的关系 进行了探讨,得到如下结论:①适宜的播种时间为5月25日-6月25日。②适宜的播区立地 条件为沙丘平均高度为10m以下,沙丘密度低于75%,播前自然植被覆盖率为12-25%。 相似文献
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Germination is a key process in the dynamics of weed populations. In no‐tillage systems, crop seeding is often found to induce seed germination in the seeding strip. In this research, experiments to investigate options for reducing weed seedling establishment were conducted in no‐till soyabean fields located in two sites in south Brazil. A first experiment revealed that a reduction in emergence of some important weed species can be achieved by lowering seeding speed. Further experiments showed the ability of a modified seeder to contribute to an additional reduction in weed establishment. On the modified seeder, coulter discs were equipped with lateral blades, to diminish soil disturbance and to maintain a uniform soil cover by properly cutting the mulch layer. In a field with a high level of residues, the modified seeder, in contrast to the standard seeder, prevented the increase of soil exposure when seeding at high speed. The predominant weeds were annual species. Averaged over all seeding rates, the new equipment led to a 56% reduction in within‐row weed density, compared with the standard seeder. Regardless of seeder type, overall weed density increased with seeding speed, but with the modified seeder, this increase was only half that of the standard seeder. The modified seeder reduced weed biomass by 30% and increased soyabean grain yield by 42%. The research demonstrated that relatively simple changes, like a minor modification to a seeder and a lower seeding speed, can contribute to more diverse and sustainable alternatives to predominantly chemical‐oriented weed management strategies. 相似文献
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水稻根结线虫病是严重危害水稻生产的主要病害之一,目前尚无成本低且安全有效的防控方法。本研究通过田间小区试验评价了直播、移栽和直播前撒施0.2 kg/667 m 210%噻唑膦颗粒剂(GR)3种种植方式下水稻根结线虫病发生及危害情况。结果表明,与直播相比,移栽田移栽后25 d水稻根结线虫的抑制率达到94.26%,根结指数为1.97,与直播前撒施0.2 kg/667 m 210%噻唑膦GR化学药剂处理组无显著差异;移栽后55 d水稻根结线虫的抑制率为58.56%。同时,移栽田移栽后25 d和55 d根结线虫2龄幼虫虫口减退率分别达到77.63%和72.22%。此外,移栽田水稻株高与根长均高于直播处理组及直播前撒施10%噻唑膦GR处理组;产量比直播处理组增加26.34%,直播处理组产量和直播前撒施10%噻唑膦GR处理组没有显著差异。因此,在水稻根结线虫病发生严重的田块采用移栽方式种植,可显著抑制根结线虫的发生为害,是一种安全、有效的防控措施。 相似文献