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1.
通过对滇东南石漠化山地不同植被恢复模式下土壤的理化性质进行定点观测和地力变化及水土流失状况的分析,结果表明:封山育林地土壤的肥力较佳,其次是耕地土壤,这是由于封山育林地土壤多年来进行封山育林,耕地土壤进行了平衡施肥;3年后人工林地土壤的理化性质有很大改善,土壤肥力有很大提高,这是退耕还林的结果;从水土流失状况来看,耕地是产流产沙、固体和液体养分流失最严重的类型,人工林地水土流失最低,说明退耕还林和封山育林有利于石漠化山地土壤肥力的改善和水土保持功能的提高。 相似文献
2.
针对试验区的自然经济条件经研究农业持续途径，历经12年，建设了农林果草多元生态经济结构，形成了一套水土资源管理、机械化的农林作物栽培、农区畜牧业发展的技术，提高了农业生态系统抗灾能力，改变了中低产面貌，农民生活走向富裕。 相似文献
3.
Abstract. Crops grown on virgin upland Vertisols of Zambia, are reported to perform rather poorly. However, subsoiling followed by repeated cultivation over two years apparently improves crop growth. Highest yields were recorded under long-term cultivation (12 years). To evaluate the reasons for these differences in crop response to Vertisol management, physical and hydrodynamic characteristics of soil profiles were studied in three soil management systems. The management systems were: uncultivated or virgin land; land cultivated for two years; and land cultivated for 12 years. The mean soil aggregate size decreased with increased time of cultivation, mostly due to the decrease of the largest sized aggregates. The surface horizon dried more slowly on the long-term cultivation plot. A comparison of the hydraulic conductivities indicated that water intake in the deeper layers improved with increased period in cultivation. Oxygen diffusion measurements showed good aeration at field capacity, to a depth of 0.32m on the long-term cultivation plots, but only to 0.17 m and 0.25 m for 2 years cultivation and virgin plots respectively. Repeated cultivation was beneficial in improving surface soil tilth and in improving subsurface drainage, thus removing the problem of a perched water table which occurred close to the soil surface under natural conditions. 相似文献
4.
The grain and sugarcane industries are the dominant cropping enterprises in Australia. Both are facing similar problems in maintaining productivity and profitability, although the management practices employed to achieve these objectives in the two industries differ markedly. The farming systems of both industries have evolved in recent years as our understanding of the physical and chemical benefits of practices like residue retention, reduced tillage and controlled traffic have improved. However the impact of such practices is often evaluated in terms of cost savings, operational efficiencies and efficient capture and use of water. Soil health has not always been an important consideration in system change in either industry, with the exception that crop rotation has always been recognised as important in minimising the impact of soil-borne pathogens. Rotations have been a key feature of grain cropping systems and short duration legume fallows are becoming more prevalent in the sugar industry after more than 25 years of monocultures. However, intensification of cropping in recent years has meant that the pasture leys that were once a dominant component of the grain rotation systems are increasingly being supplanted by short duration cropping breaks with grain legume or other non-cereal crops. Soil organic C has generally been recognised as an important component of soil fertility, but more for the role it plays in soil physical and chemical fertility. Links between organic matter status and soil biological health, and particularly to farming system viability and sustainability, have proven difficult to quantify. This has been partly due to a lack of tools or criteria for monitoring relevant soil properties and also to our limited understanding of the interactions between soil health and other system components. However recent studies are suggesting that the amount and quality of organic matter returned as roots and residues, and the placement of that residue relative to areas of future crop root activity, may be significant factors in the sustainable farming systems of the future. This paper identifies key issues associated with current and developing farming systems in the grain and sugar industries in Australia, and assesses the impact of management practices employed in those systems on soil health. It also identifies some key challenges facing soil biologists and farming systems researchers who are trying to achieve improvements in soil health and sustainability. 相似文献
5.
针对江西赣南果业开发中普遍存在的严重水土流失、土地利用率低下、短期效益少等问题,采取以间、套种草、饲、经济作物为主要手段的水土保持措施,栽种“百喜草”,设置“山边沟”,引入美国籽粒苋发展养殖业,开展立体经营,形成果-苋-猪-沼-果良性循环。实现了果园综合效益的同步增长,达到了增加果园植被覆盖度,提高土地利用率,改善果园生态环境的目的。研究表明:果业开发中出现的严重水土流失现象不容忽视,因地制宜的水土流失治理措施与果园生态环境、经济效益密切相关。其综合经营的多种治理模式促进了各业的发展,取得了明显的生态、经 相似文献
6.
云南小江流域土壤侵蚀十分严重，为揭示其侵蚀机理及探索有效治理方法，对其典型土壤——燥红土不同土地利用类型开展了人工降雨产流产沙试验，并运用水分测定仪（TRASE 6050X1 TDR）对土壤水分变化进行动态监测。结果表明：灌草地蓄水拦沙能力最强，坡耕地（坡式梯地沿等高线开挖垄沟种植花生）次之，裸坡地最弱；同种利用类型土壤不同土层传输水分和吸收水分能力不同；在较大雨强（0．61mm／min）且充足降雨条件下，小江流域燥红土地表产流特征经历了以超渗产流为主、超渗产流和饱和产流同时进行、以饱和产流为主的3个阶段。 相似文献
7.
发展中国家或地区耕地数量和农业用地质量变化是影响农业可持续发展和粮食安全的重要因素之一。分析发展中国家或地区1993-2002年耕地数量变动．结果表明耕地总量波动但人均耕地数量减少．从区域农业自然条件禀赋差异、耕地退化弃耕与可耕地用途改变、人口数量与人口增长等方面分析耕地数量变动的原因；利用1990～2004年的人口变动资料建立二次曲线模型，预测2010年和2025年人口数量并讨论其对耕地的压力。综述发展中国家或地区农业用地质量限制性的现状，分析边地耕作、风蚀与水蚀、化学与物理性因素、有机物投入、信用限制与灌溉面积比重等因素对农业用地质量的限制以及农业用地质量退化对农业的影响。最后讨论发展中国家或地区加强农业用地管理以应对耕地数量和农业用地质量限制问题。 相似文献
8.
吴旗县确立“封山退耕、植树种草、舍饲养羊、林牧主导、强农富民”的开发思路 ,将全县 10 3万hm2 坡耕地全部退耕 ,只保留 2万hm2 耕地发展高效农业 ,农村经济呈现出蓬勃发展的势头。该县在全国率先实施了“封山禁牧、舍饲养羊” ,走出了西部开发的新路子 ,是黄土高原水土保持生态建设的创举。建议总结推广其典型经验 ,加大黄土高原水土保持生态建设力度等 相似文献
9.
以陕西省吴旗县柴沟流域为例研究了退耕还林(草)区不同土地利用类型的土壤水分-物理性质,结果表明:实施退耕还林(草)工程后,土壤水分-物理性质得到了明显改善,土壤自然含水率提高了48.0%,持水量是农田的1.55倍,孔隙度是农田的1.12倍,在不同程度上改善了土壤物理性质,提高了土壤保水、蓄水性能,改善了土壤结构。 相似文献
10.
The separation of agroclimatic areas for optimal crop growing within is suggested within the framework of the natural–agricultural zoning of Russia developed under the supervision of I. Karmanov. Overall, 64 agroclimatic areas have been separated in Russia. They are specified by the particular soil and agroclimatic conditions and by the particular crops recommended for cultivation. The biological potential of these crops should correspond to the soil potential of the given area. A combined scheme of the natural–agricultural zoning of Russia and the separated agroclimatic areas is presented. It is argued that the information contained in this scheme can be used for developing landscape-adaptive farming systems, land cadaster, and land valuation; it is also helpful for terrain and remote sensing monitoring of soil fertility on arable lands and for soilecological monitoring. 相似文献
11.
Concern about soil organic matter losses as a result of cultivation has been voiced consistently since the early part of the 20th century. Scientists working in the US. Great Plains recognized that organic matter losses from an already small pool could have major negative consequences on soil physical properties and N supplying capacity. The advent of reduced- and no-till systems has greatly improved our ability to capture and retain precipitation in the soil during the non-crop periods of the cropping cycle, and has made it possible to reduce fallow frequency and intensify cropping systems. The purpose of this paper is to summarize the effects of reduced tillage and cropping system intensification on C storage in soils using data from experiments in North Dakota, Nebraska, Kansas, Colorado, and Texas. Decades of farming with the wheat ( Triticum aestivum L.)–fallow system, the dominant farming system in the Great Plains, have accentuated soil C losses. More intensive cropping systems, made possible by the greater water conservation associated with no-till practices, have produced more grain, produced more crop residue and allowed more of it to remain on the soil surface. Combined with less soil disturbance in reduced- and no-till systems, intensive cropping has increased C storage in the soil. We also conclude that the effects of cropping system intensification on soil C should not be investigated independent of residue C still on the surface. There are many unknowns regarding how rapidly changes in soil C will occur when tillage and cropping systems are changed, but the data summarized in this paper indicate that in the surface 2.5 cm of soil, changes can be detected within 10 years. It is imperative that we continue long-term experiments to evaluate rates of change over an extended period. It is also apparent that we should include residue C, both on the surface of the soil and within the surface 2.5 cm, in our system C budgets if we are to accurately depict residue–soil C system status. The accounting of soil C must be done on a mass basis rather than on a concentration basis. 相似文献
12.
Communities of arbuscular mycorrhizal fungi (AMF) are strongly affected by land use intensity and soil type. The impact of tillage practices on AMF communities is still poorly understood, especially in organic farming systems. Our objective was to investigate the impact of soil cultivation on AMF communities in organically managed clay soils of a long-term field experiment located in the Sissle valley (Frick, Switzerland) where two different tillage (reduced and conventional mouldboard plough tillage) and two different types of fertilization (farmyard manure & slurry, or slurry only) have been applied since 2002. In addition, a permanent grassland and two conventionally managed croplands situated in the neighborhood of the experiment were analyzed as controls. Four different soil depths were studied including top-soils (0–10 and 10–20 cm) of different cultivation regimes and undisturbed sub-soils (20–30 and 30–40 cm). The fungi were directly isolated from field soil samples, and additionally spores were periodically collected from long-term trap culture (microcosm) systems. In total, >50,000 AMF spores were identified on the species level, and 53 AMF species were found, with 38 species in the permanent grassland, 33 each in the two reduced till organic farming systems, 28–33 in the regularly plowed organic farming systems, and 28–33 in the non-organic conventional farming systems. AMF spore density and species richness increased in the top-soils under reduced tillage as compared to the ploughed plots. In 10–20 cm also the Shannon–Weaver AMF diversity index was higher under reduced tillage than in the ploughed plots. Our study demonstrates that AMF communities in clay soils were affected by land use type, farming system, tillage as well as fertilization strategy and varying with soil depth. Several AMF indicator species especially for different land use types and tillage strategies were identified from the large data set. 相似文献
13.
从育种、耕作与栽培三个方面分析了适应CO2肥效作用的农业技术潜力措施.在育种方面,采用综合运用育种理论和育种技术培育新品种,改善作物生理和生态性状来适应大气中CO2含量升高;在耕作制度上,采用调整作物播期、改变当前多熟制边界、调整水作和旱作作物、C3作物和C4作物的播种面积和区域布局等措施;在栽培措施上,采用调节作物冠层温度、改善灌溉条件、保持土壤肥力和养分以及综合防治病虫草害和极端天气灾害等综合措施.扬长避短,兴利除弊,采取主动适应CO2肥效作用的策略,最大限度发挥作物产量潜力. 相似文献
14.
Abstract There is a large number of hill people in northern Thailand, who practices shifting cultivation. In order to analyze the soil ecological problems involved in the transition from traditional shifting cultivation to more intensive upland farming, the authors carried out comparative studies on the dynamics of organic matter and its related properties in soils both in the traditional shifting cultivation systems adopted by Karen people and more intensive upland farming practiced by Thai and Hmong people in the area. The contents of organic matter and available N in the surface 10 cm layers of soil from the fields continuously cultivated were lower than those in soils under prolonged fallow (more than 10 y) or natural forest. Based on the rate of soil respiration, the amount of organic matter decomposed within 1 y was estimated to reach nearly 10% of that stored in the upper 50 cm layers of the soil profile in the upland crop fields. These results indicate that the organic matter-related resources markedly decreased under continuous cropping. The contents of C, N, and P in the microbial biomass of the surface 10 cm layers of soil ranged from 0.37 to 2.09 mg C g ?l soil, from 22.7 to 188 µg N g ?l soil, and from 6.1 to 65.7 µg P g ?l soil, respectively. Since the contents of microbial C, N, and P in the surface soils were generally higher under prolonged fallow and natural forests than in the fields continuously cultivated, the microbial activity and/or the amounts of C, N, and P available for biological activity seemed to have declined under continuous upland farming. The incubation experiment to assess the N mineralization pattern showed two remarkable characteristics: 1) there was an initial time lag until active mineralization of N occurred in the soils from young fallow forest and 2) the soil burning effect was observed after burning in the fields under prolonged fallow. The active process of nitrification after N mineralization was always associated with a sharp fall in soil pH, suggesting that soil acidification was promoted and basic cations were lost from the soils. In conclusion, rapid deterioration of the soil organic matter-related properties in cropping fields can be considered to be one of the ecological reasons why upland fields must be returned to fallow again a few years after forest reclamation in traditional shifting cultivation systems. Therefore, in alternative farming systems with more intensive land use, it is essential to apply organic materials into soils to decrease the rate of soil degradation, or to improve the soil fertility, in avoiding soil acidification along with nitrification. 相似文献
15.
Efficient mechanisation is a major factor underlying the high productivity and low cost of most Australian crop production systems. Efficiency has generally been associated with greater work rates, achieved by using equipment of greater power and weight. This trend has continued until very recently, despite a reduction in tillage for weed control. Scientists have warned of erosion and soil structural degradation caused by tillage and traffic, but tillage, rather than field traffic was seen as the major problem, and reduction of tillage as the solution. Reduced tillage has provided major benefits, but adoption has occurred slowly and sustained zero tillage is still rare, except in controlled traffic farming systems. The first part of this paper presents research evidence of the direct cost, practical impact and long-term effects of wheel traffic on cropped soil. Direct cost is associated with the energy requirements of disturbing wheeled soil. Practical impact occurs as a result of the lost opportunities and additional operations associated with wheel ruts. Long-term productivity and environmental impact occur because wheel traffic reduces plant available water and increases runoff and erosion. In controlled traffic all equipment wheels are restricted to compacted permanent traffic lanes, so that soil in the crop beds and traffic lanes can be managed respectively for optimum cropping and optimum trafficability. Controlled traffic farming recognizes the symbiosis between controlled traffic and zero tillage in providing opportunities for more productive and sustainable farming of soil uncompromised by wheel effects. The beneficial effects of controlled traffic have been demonstrated in widely different soils and mechanisation systems (e.g. Australia and China), and it has been vigorously advocated in both the USA and Europe, but large-scale adoption has been rare. The second part of this paper discusses cropping system response to controlled traffic farming, and the program which led to large-scale adoption in Australia. This happened first in extensive grain production, but adoption has since occurred in many Australian farming systems, supported by the availability of high-precision field guidance systems and a greater range of compatible equipment. Controlled traffic farming reduces soil degradation and the energy requirements of cropping. It is also more productive, and its practicality and economic viability have been clearly demonstrated in enthusiastic farmer adoption, and the formation of an Australian Controlled Traffic Farming Association. 相似文献
16.
Abstract Soil testing and plant analysis have been used as diagnostic tools for assessing fertilizer needs of crops for more than 50 years. During that time, considerable progress has been made in developing a plethora of improved extraction procedures and analytical techniques, forming a considerable legacy on which to build in the future. However, as laboratories grew and methods became entrenched, a reluctance to change methodologies has caused a certain degree of stagnation and in many cases has resulted in poor prognostic precision. Examples in the realm of soil testing are presented to show what might be gained by implementing improved technology that measures parameters that are the primary yield‐determining factors. In addition, attention is focused on precision agriculture, where an urgent need exists to develop real‐time assays of nutrient levels in the soil and plants so that the appropriate rates and types of fertilizer can be applied to increase yield uniformity within a field. With the increased disposal of organic residues on land, nutrient management plans for farms are now required. Because of the associated regulations, laboratories will have to introduce protocols for analyzing soil, tissue, and water appropriate to the purpose at hand accompanied by stringent quality assurance/quality control (QA/QC) systems to meet the legal requirements. No doubt, within a short time these constraints will be applied to normal crop land being fertilized with inorganic fertilizers as the green lobby grows and applies more pressure for a cleaner environment. The implications of these changes for the future is assessed. 相似文献
17.
以川东北巴中市为例,采用实地采样法和室内测定法,对土壤Se含量及其分布做了研究,以促进其现代农业的发展,合理选择优势作物。结果表明:不同土壤类型Se含量:黄棕壤 > 黄壤 > 紫色土壤。黄壤不同土地利用类型Se含量:其他用地 > 农田 > 蔬菜地;黄棕壤不同土地利用类型Se含量:蔬菜地 > 其他用地 > 林地 > 农田 > 旱地 > 果园地;紫色土壤不同土地利用类型Se含量:农田 > 果园地 > 旱地 > 蔬菜地 > 其他用地。黄壤不同耕作制度类型Se含量:旱作地 > 水耕地;黄棕壤不同耕作制度类型Se含量:水耕地 > 旱作地 > 水旱地;紫色土壤不同耕作制度类型Se含量:水旱地 > 旱作地。不同地域土壤剖面中Se元素含量:通江县 > 南江县 > 巴州区 > 平昌县。巴中市Se含量平均值为0.165 μg/g,低于全国平均值。四个富硒产业带分别为:通江县富硒马铃薯产业带;南江县富硒金银花产业带;南江县富硒蔬菜产业带;南江县富硒茶叶产业带。马铃薯、金银花、茶叶均为巴中的富硒优势作物。 相似文献
18.
宁夏回族自治区南部的固原县位于黄土高原的西部,东邻甘肃省的环县、镇原,南接平凉和本自治区的泾源、隆德,西界西吉、海原,北连同心。地跨东经105°58’—106°57’,北纬35°34’—36°38’,面积6,414平方公里（约962万亩）,是黄土高原地区水土流失重点县之一。 相似文献
19.
干旱区盐渍化土地是我国重要的后备土地资源。研究了在开挖排水沟使地下水位降至临界水位以下的同时,对盐渍化土地进行农、林、牧相结合的改良措施,提出了盐渍化土地综合治理技术一是挖排水沟及造林,控制土下水位低于临界水位;二是选育耐盐良种作物,改良盐碱地;三是发展畜牧业,培肥地力。并应用于甘肃省临泽县小泉子盐渍化土地改良,使土壤含盐量下降,土壤有机质和养分增加,土地利用效率提高,经济效益显著。 相似文献
20.
干旱区盐渍化土地是我国重要的后备土地资源.研究了在开挖排水沟使地下水位降至临界水位以下的同时,对盐渍化土地进行农、林、牧相结合的改良措施,提出了盐渍化土地综合治理技术一是挖排水沟及造林,控制地下水位低于临界水位;二是选育耐盐良种作物,改良盐碱地;三是发展畜牧业,培肥地力.并应用于甘肃省临泽县小泉子盐渍化土地改良,使土壤含盐量下降,土壤有机质和养分增加,土地利用效率提高,经济效益显著. 相似文献
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