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Sanborn试验地建立于1888年,是密西西比河西部建立最早的一个农业试验地.它为长期作物轮作和土壤管理,包括每年的施肥对土壤侵蚀以及这些技术措施的持续性的影响提供了可靠的依据.对各试验小区中连作玉米的、连作梯牧草的和6年一轮玉米、燕麦、小麦、三叶草及2年梯牧草轮作的连续耕作100年后的表土保留情况进行了分析.结果表明,种植100年后的连作玉米小区比6年一轮梯牧草小区保留的表土有明显减少.连作玉米小区保留的表土只相当于梯牧草小区的44%.而轮作小区则相当于梯牧草小区的70%.连作玉米小区耕层的粘土含量比轮作和梯牧草小区有显著增高,而且玉米小区还出现耕层与底层粘土混合的现象.据测产表明,在有侵蚀的小区即使施用大量肥料,其玉米产量仍比无侵蚀小区减产60%.因此,如果要持续长期生产就必须改进条播耕作管理工作. 相似文献
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不同种植方式对北疆绿洲土壤养分和生物学性状的影响 总被引：4，自引：0，他引：4
长期种植不同作物对土壤的理化性质与生物学性状有很大影响。本研究针对北疆绿洲灰漠土几种典型作物种植方式,研究了不同作物长期种植对土壤养分、酶活性、微生物量碳氮以及土壤呼吸的影响。结果表明:长期种植不同作物使土壤表层(0～20cm)与亚表层(20～40cm)的土壤肥力性质产生明显分异,表层土壤的肥力水平明显高于亚表层;土壤pH则表层低于亚表层,而不同种植方式对灰漠土pH无显著影响。长期种植不同作物对土壤主要生物过程关键酶活性、土壤呼吸等土壤生物性状有明显影响,磷酸酶、脲酶、β-葡萄糖苷酶、多酚氧化酶、纤维素酶在不同种植方式下差异显著,小麦/油葵轮作10年(WSR)方式下上述5种酶活性均较高。土壤微生物量碳氮随棉花连作年限的延长而显著下降,且玉米连作10年(CrM)、小麦连作10年后棉花连作10年(WCtR)、棉花连作15年(CtM)和小麦/油葵轮作10年的土壤微生物量碳氮比分别为6.31、6.02、5.83和3.53。不同种植方式下土壤呼吸在120h内的变化均为先下降后趋于平稳,不同种植方式下的土壤呼吸商之间呈显著性差异,WSR呼吸商最高,平均20.54μg(CO2-C)·mg-1(Bc)·h-1,WCtR最低,平均14.01μg(CO2-C)·mg-1(Bc)·h-1。作物长期连作后与绿肥作物轮作,有利于提高土壤生物活性,是一种较好的种植方式。 相似文献
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作物茬口对连作棉田土壤环境及棉花产量的影响 总被引：13，自引：0，他引：13
于2007－2008年在连作8 a的棉田上进行不同作物轮作倒茬田间试验,以研究不同茬口对连作棉田土壤养分、土壤微生物区系以及棉花产量的影响,从而筛选出适宜棉田轮作倒茬的最佳作物茬口。研究结果表明：不同作物茬口的土壤有机质、速效养分含量及棉花产量均高于连作棉田,其中加工番茄茬口对土壤的速效磷含量增加最为显著,小麦、玉米茬口对土壤速效钾含量增加显著;各作物茬口土壤微生物总量均比连作棉田有明显的增加,表现为细菌和放线菌数量增加真菌减少;草木樨、番茄茬口土壤氨化细菌、硝化细菌生理群也明显增加。不同作物茬口的棉花产量表现为加工番茄→棉花＞草木樨→棉花＞小麦→棉花＞玉米→棉花＞棉花→棉花;加工番茄、玉米、小麦可作为连作棉田的良好前茬。 相似文献
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我国不同地区土壤肥力监测报告（1998—1997）——东北区土壤肥力变化趋势及原 总被引：3，自引：2，他引：1
通过１０年土壤监测数据分析表明,在常规施肥和管理水平下,东北区三种主要种植制度中,施肥区玉米、水稻连作作物产量较高并呈上升趋势,玉米与大豆轮作产量较低但下降趋势不明显。玉米、水稻连作土壤有机质和全氮基本稳定,有效磷呈上升趋势,碱解氮和速效钾下降趋势明显。玉米,大豆轮作,土壤养分均呈下降趋势。主要原因是施肥量的影响。表现出的农田养分平衡状况是磷有余而钾不足。 相似文献
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长期轮作与施肥对农田土壤磷素形态和吸持特性的影响 总被引：10，自引：0，他引：10
通过对黄土旱塬地区长期定位施肥(26a)条件下的不同轮作系统的土壤磷素形态和吸持参数的测定,研究了轮作和施肥对土壤磷素吸持特性和磷素形态的影响,以及土壤磷素吸持参数与磷素形态之间的关系。结果表明,长期轮作与施肥都可以减低土壤磷素的最大吸附量（Qm）,相对于其它轮作和连作,在氮磷（NP）施肥下,小麦-玉米-豌豆轮作可以减低土壤的Qm,在氮磷有机肥（NPM）施肥下,小麦-玉米轮作可以减低土壤的Qm。在施肥相同的条件下,小麦-玉米轮作和小麦-豌豆轮作可以显著增加土壤中各形态无机磷的含量,长期轮作比连作可以增加土壤中的有效磷养分,尤其对Ca2-P的提高效果更为显著。相关分析表明,Qm和磷吸持指数（PSI）与全磷（T-P）、Olsen-P、CaCl2-P、Ca2-P、Ca8-P、Fe-P、Ca10-P和有机磷呈极显著负相关（p＜0.01）,与闭蓄态磷（O-P）呈显著负相关（p＜0.05）,与Al-P关系不显著。土壤有机质（SOM）与Qm、PSI和磷最大缓冲能力（MBC）之间存在极显著负相关关系,与磷吸持饱和度（DPSS）存在显著正相关。通径系数和逐步回归分析表明,在石灰性黑垆土土壤的无机磷形态中,Ca2-P对Olsen-P的贡献最大。 相似文献
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玉米?水稻轮作和水稻连作土壤根际和非根际氮含量及酶活性 总被引：2，自引：0，他引：2
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[目的] 为探究坡耕地等高反坡台阶整地对玉米连作和玉米—芸豆轮作系统根土微生态特征的影响。[方法] 以玉米—芸豆轮作为研究对象,玉米连作为对照,采用野外原位监测采样和室内试验分析相结合的方法,通过GC-MS和高通量测序技术分析作物根系分泌物和土壤微生物群落组成、结构特征,揭示坡耕地等高反坡台阶整地对玉米连作和玉米-芸豆轮作根系分泌物种类、含量和土壤微生物群落组成及多样性的影响。[结果] (1)根系分泌物相对含量变化在CRT措施上更为突出,在轮作模式中更为显著。(2) CRT2处理提高土壤微生物群落数量、丰富度和多样性效果更显著。(3)在根系分泌物与土壤微生物互作下,根系分泌物、土壤微生物、土壤环境因子的两两相关性在CRT2处理下更显著。[结论] 坡耕地等高反坡台阶整地通过改变玉米连作和玉米—芸豆轮作的根系分泌物含量,使作物根土微生态环境发生变化,提高土壤微生物数量、多样性及丰富度,且该措施与玉米—芸豆轮作结合的提升效果更佳,对根土微生态的改善作用更显著。研究结果为坡耕地作物种植、耕作方式选择及改善土壤微环境和水土流失综合治理提供理论基础。 相似文献
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[目的]以不同轮作模式为研究对象,研究不同轮作模式对土壤容重、土壤含水量及作物产量的影响,优化兰州市旱地区作物种植制度。[方法]以马铃薯(P)、玉米(M)、蚕豆(B)为供试作物,开展9种年际间轮作模式试验,分别为:(P-P-P),(M-M-M),(B-B-B),(P-M-P),(P-B-P),(M-P-M),(M-B-P),(B-B-P),(M-M-B)。测定不同轮作模式下,土壤容重、土壤水分及作物产量,并进行经济效益分析。[结果]马铃薯轮作模式(P-M-P,P-B-P,M-P-M,M-B-P及B-B-P)能显著减少0—40cm土层的土壤容重,对40—60cm土层的土壤容重没有显著影响;不同作物轮作下土壤含水量、耗水量影响大小相似:玉米>马铃薯>蚕豆,水分利用效率受作物种类影响大小为:马铃薯>玉米>蚕豆,其中轮作模式以M-M-M下土壤含水量最低、耗水量最大,B-B-P下水分利用效率最高;同种作物轮作产量均高于连作产量,如2016年P-M-P,P-B-P,M-B-P,B-B-P较连作P-P-P产量分别提高了40.37%~79.28%,M-M-B蚕豆轮作较B-B-B连作增产23.56%,M-P-M轮作较M-M-M连作玉米产量提高10.51%;不同轮作模式经济收益大小与连作相比,轮作更利于产量与经济收益的提高。[结论]综合土壤容重、水分利用效率、产量及经济效益,P-B-P与P-M-P轮作模式,能改善土壤环境、提高产量与经济效益可作为主推轮作模式。M-B-P轮作模式经济效益次之,但水分利用效益较高,能作为协调水分利用的种植模式。 相似文献
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用生物耗竭试验法研究了在不同供钾潜力土壤上,植物对钾肥的反应,植物对土壤钾和肥料钾的利用。不同供钾潜力土壤的钾素有效性是不同的,通过植物吸收,速效钾和缓效钾均有不同程度的降低,植物吸钾量中部分来自矿物钾,但矿物钾释放量只占矿物钾总量的0.04—1.58%。矿物钾的释放很慢,不能满足植物迅速生长的需要。用阳离子树脂袋法和其它化学方法与生物法进行了比较。用树脂袋法和生物法测得的矿物钾释放量,二者接近。树脂袋法的提取量同水稻和大米草吸钾量也很接近,而且二者的相关性均达到0.916**树脂袋法较生物法简便。 相似文献
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THE EFFECT OF SOIL COMPOSITION AND ENVIRONMENTAL FACTORS ON THE SHRINKAGE OF SOME CLAYEY BRITISH SOILS 总被引：4，自引：0，他引：4
The shrinkage potential of natural clods from a variety of clayey soils was measured and related to their physical, chemical and mineralogical properties. It is shown that the most important factors affecting shrinkage are initial bulk density, clay content, organic carbon content and cation exchange capacity of the peroxidised clay, and mica-smectite content on a whole soil basis. Multiple regression equations involving the initial bulk density, clay content, organic carbon and cation exchange capacity accounted for 87 and 82 per cent of the variation in total shrinkage of topsoils and subsoils respectively. Because of restrictions on shrinkage imposed by factors such as climate, crops, ground-water and moisture release characteristics of soils, soils with a high shrinkage potential may not behave very differently to soils with a much lower potential. On these grounds it is concluded that the shrinkage criteria used in US Taxonomy are not applicable in Britain. 相似文献
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Xiaohua Ren Wenjing Zou Juying Jiao Ryan Stewart Jinshi Jian 《European Journal of Soil Science》2023,74(5):e13413
Conservation agriculture (CA) has the potential to sustain soil productivity and benefit agroecosystems, yet it is not fully understood how yield responses of different cropping systems are affected by inherent soil characteristics, for example, texture and dynamic soil properties, such as aggregation, nutrients and erosion. In this study, we conducted a systematic review to compare crop yield from cropland with conventional management versus different CA practices, specifically reduced- or no-tillage, agroforestry, organic farming and cover crops. The data were first analysed for different climatic regions, soil textures and cash crop types. We then quantified how yield responses correlated with soil properties change under different CA practices. The results showed that CA practices were associated with an overall mean crop yield increase of 12%. This response was primarily driven by corn, which had a mean yield increase of almost 41% after CA implementation, whereas other cash crops did not have significant yield responses or showed slight decreases, as rotation with mixtures of multiple cash crops had a mean decrease of 6% when using CA. The increase in corn yield after CA may be related to the enhanced ability of that crop to absorb nutrient elements (e.g. nitrogen) and reduce nutrient leaching. Agroforestry increased crop yield by 66% and cover cropping increased yield by 11%, likely due to increases in soil water content and nutrient availability and decreases in erosion and surface runoff. However, other agricultural systems showed no significant increase after CA compared with conventional row cropping practices. Using CA practices had the greatest yield benefit in tropical climates and when farming in coarse-textured soils. In addition, legumes and grass-legume mixtures resulted in significant cash crop yield increases, possibly because legumes promoted the increase of soil nitrogen and depleted soil moisture less compared with other cover crops. The results provide new insight into how interactions between soil properties and CA practices affect crop yield and at the same time can help guide the development of practical, evidence-based guidelines for using conservation practices to improve yield in corn and other cash crops. 相似文献
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Shiveshwar Pratap Singh Room Singh Mukesh Prasad Singh Vijay Prasad Singh 《Journal of plant nutrition》2014,37(4):618-632
A field experiment was conducted at farmer's field in Mollisols of Tarai soils in Uttarakhand (India), to assess the direct and residual effect of sulfur fertilization in wheat-soybean cropping sequence. Four levels of sulfur (S; 0, 15, 30, and 45 kg ha?1) were applied to main crop (wheat) along with recommended dose of nitrogen (N), phosphorous (P), and potassium (K). The direct and residual effect of sulfur at highest level showed 27 and 6 percent increase in grain yield of wheat and soybean over control, respectively. The increase in grain yield of wheat was significant at each sulfur level. The direct as well as residual effect of sulfur showed significant increase in sulfur concentration and its uptake by grain and straw except increase in sulfur concentration and uptake by soybean straw. In wheat-soybean cropping sequence, the agronomic efficiency and apparent sulfur recovery decreased with increase in levels of sulfur, but the percent response increased with increasing sulfur application. Different forms of sulfur such as total sulfur, organic sulfur, calcium chloride extractable sulfur, potassium dihydrogen phosphate extractable sulfur, and non-sulfate sulfur in post-harvest soil increased according to sulfur level applied but it decreased under control and also after residual crops. The buildup of sulfur in surface soils was greater than in the deeper soils. Application of sulfur showed the positive sulfur balance and it increased with increase in sulfur level, while it was negative under control. A major portion (46–62%) of applied sulfur contributed to increase in sulfur content of root zone soil followed by unaccounted component (25–40%) and small portion (11–18%) was absorbed by wheat plant as uptake. 相似文献
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半干旱农牧交错带栗钙土的发生与演变 总被引：12，自引：2，他引：10
半干旱农牧产错带玄武岩和沙质沉积物上发育的典型草原土壤－栗钙土形成了距今６０００～８０００年以前。随着时间的进程,它经历了有机质积累与分解,碳酸盐淀积与淋溶,元素氧化物迁移与富集,以及风沙堆积等作用,近二百余年,栗钙土在人为强度活动,开垦种植和过度放牧经营管理下,土壤理化性质逐渐趋恶化,从而反映出演变过程中的土壤退化现象。 相似文献
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通过田间调查和土壤肥力指标分析，探讨了松辽平原玉米带黑土肥力退化的原因和机理。结果发现，现行的以小四轮拖拉机为主要动力的耕作制度下，土壤剖面中耕层与犁底层的界面为“波浪型”，而年年进行秋翻的玉米田，其耕层与梨底层的界面为“平面型”。而且两者耕层土壤的养分含量和理化性质等指标也有明显差异。研究还发现，现行的以无机氮磷肥为主的施肥制度和玉米连作种植制度对土壤养分平衡有很大影响。因此认为，现行的不合理的耕作、施肥及玉米连作制度是导致松辽平原玉米带黑土肥力退化主要原因。 相似文献
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连作植烟土壤酚酸类物质变化特征及其与主要环境因子的Mantel Test分析 总被引：1，自引：0，他引：1
为明确酚酸类物质在连作植烟土壤中的变化特征,探讨土壤主要环境因子对酚酸类物质的影响,以不同连作年限（4 a,6 a,8 a,14 a和16 a）植烟土壤为对象,研究了不同连作年限植烟土壤酚酸类物质、理化性状、酶活性和细菌多样性的变化特征,并利用Mantel Test分析了酚酸类物质与土壤主要环境因子的相关性。结果表明,随连作年限增加,土壤酚酸类物质和速效钾含量升高,pH、有机质含量、细菌菌群丰度和多样性降低,水解性氮和有效磷含量呈先降低后升高趋势,酶活性呈先升高后降低趋势。Mantel Test分析表明,土壤酚酸类物质含量与理化性状、酶活性和细菌丰度显著相关,且与理化性状相关性最高;不同酚酸类物质含量与土壤主要环境因子相关性存在差异,其中,对羟基苯甲酸和阔马酸与植烟土壤理化性状、酶活性以及细菌丰度的相关性最高。因此,在本试验条件下,连作植烟土壤酚酸类物质具有明显积累特征,植烟土壤环境恶化;酚酸类物质积累受理化性状、酶活性和细菌多样性影响,且理化性状影响最大;不同酚酸类物质受主要土壤环境因子的影响存在差异,其中对羟基苯甲酸和阔马酸积累所受影响最大。 相似文献
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Oxisols comprise large soil group in tropical America. These soils are acidic and have low fertility. Use of tropical legume cover crops in cropping systems is an important strategy to improve fertility of these soils for sustainable crop production. Data are limited on nutrient uptake and use efficiency of tropical cover crops under different acidity levels. The objective of our study was to evaluate growth and nutrient uptake parameters of sixteen tropical legume cover crops under three soil pH (5.1, 6.5, and 7.0) of an Oxisol. Shoot dry weight was influenced significantly by pH and cover crop treatments and their interactions, indicating that cover crops used had differential responses to changing soil pH levels. Overall, shoot dry weight decreased when soil pH was raised from 5.1 to 7.0, indicating acidity tolerance of cover crops. Nutrient concentration (content per unit of dry weight), uptake (concentration X dry weight), and nutrient use efficiency (dry weight of shoot per unit of nutrient uptake) varied significantly among cover crops. The variation in nutrient uptake and use efficiency among cover crop species was associated with variation in shoot dry matter production. Significant variation among crop species in dry matter production and low C/N ratios (average value of 14.25) suggest that cover crops which produced higher dry matter yield like white jack bean, gray mucuna bean, black mucuna bean, mucuna bean ana, and lablab are important choices for planting in tropical soils to recover large amount of macro and micronutrients, and to prevent such nutrient leaching in soil plant systems. 相似文献