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1.
Tillage and agricultural sustainability 总被引：1，自引：0，他引：1
R. Lal 《Soil & Tillage Research》1991,20(2-4):133-146
Agricultural sustainability implies an increasing trend in per capita productivity to meet the present needs without jeopardizing the future potential. Soil tillage, soil surface management to alleviate soil-related constraints to crop production, is a basic and an important input with short- and long-term effects on sustainability. An important effect of soil tillage on sustainability is through its impact on the environment e.g. soil degradation, water quality, emission of greenhouse gases from soil-related processes, etc. The need to attain agricultural sustainability is particularly urgent in several tropical eco-regions and soils of low-carrying capacity in the tropics.
Soil tillage influences atricultural sustainability through its effects on soil processes, soil properties, and crop growth. However, there is no one blueprint of a universally applicable sustainable tillage system. Appropriate tillage systems are soil- and crop-specific and their adaptation is governed by both biophysical and socio-economic factors. In addition to increasing crop yields, tillage methods must also facilitate soil and water conservation, improve root system development, maintain a favorable level of soil organic matter content, and reverse degradative in the soil's life-support processes.
Important components or sub-systems of conservation-effective tillage systems include mulch farming, no-till or reduced tillage systems, use of cover crops and planted fallows, agroforestry, raised beds or ridge-tillage, and soil inversion or deep plowing. The ecological limits for the applicability of these components or sub-systems differ widely. The efforts of a multi-disciplinary team (comprising soil scientists, agricultural engineers, agronomists, economists and social scientists) are needed to develop site-specific tillage methods to achieve both short- and long-term goals of agricultural sustainability. 相似文献
2.
Soil degradation due to tillage has been reported Africa-wide. Other main causes of soil degradation are overgrazing, extensive cultivation of marginal lands, widespread clearing of vegetation for agriculture, deforestation, exploitation of unsuitable agricultural technologies, mis-management of arable lands, and frequent drought. Hence, declining soil fertility and increasing population pressure on lands are fragile bases on which to build expectations for improved crop production. This paper recognizes conservation tillage systems as one means for preventing food shortages and natural resources degradation throughout the continent. Conservation tillage has the potential for increasing soil organic matter content and enhancing soil aggregation. Conservation tillage systems can create an aggregated, fertile surface layer that is important from a soil erosion reduction perspective and thus for a sustainable agriculture in Africa. Some indigenous tillage systems in Africa can be adapted to meet objectives of conservation tillage systems. Further, recent technological developments in tillage and seeding machinery will certainly enhance the rate of farmer’s acceptance and adoption of conservation tillage. 相似文献
3.
Soil structural quality, compaction and land management 总被引：3，自引：0，他引：3
B. C. BALL D. J. CAMPBELL J. T. DOUGLAS J. K. HENSHALL M. F. O'SULLIVAN 《European Journal of Soil Science》1997,48(4):593-601
Soil compaction is a concern worldwide, particularly where compactible soils are used for intensive agriculture in a wet climate. We have investigated the impact of compaction and the associated changes in soil structural qualities on crop production and environmental pollution. The overall objective was to develop soil management systems that provide suitable conditions for crop growth and minimize environmental damage. We ran large-scale field experiments studying the preservation of structural quality in arable and permanent grassland, using management systems such as the control or elimination of field traffic and the application of conservation tillage and zero tillage. We measured bulk density, shear strength, cone resistance, macroporosity, relative diffusivity, air permeability and water infiltrability to identify soil qualities that could be used for selecting suitable soil management. Along with crop yield, we measured environmental impacts, such as the emissions of nitrous oxide from the soil, which require the interaction of soil structure and water content near the soil surface. Soil structure influenced wetness, which affected trafficability, compaction and nitrogen retention. Measurement of properties that affect fluid storage and transport, such as macroporosity, provided soil quality indices that helped in recommending suitable soil management systems. Spatial variation of structure associated with wheel-track locations could be estimated rapidly using a cone penetrometer. Variation was particularly important in determining crop yield consistency. Crop productivity and soil structural qualities were preserved best when field traffic was eliminated. A reduced ground-pressure system successfully minimized compaction in grassland but was less effective in an arable rotation. Unless traffic is eliminated, good timing of operations is the most effective way to preserve soil structural quality. 相似文献
4.
The desert oasis is one of the major grain production areas in arid land, and many intensive farming practices have been adopted to improve the land utilization in the agriculture system. However, there remains little consensus on how to improve such farming practices for increasing both productivity and environment benefits in this system. A 4-year experiment was conducted in a typical desert oasis farmland to determine the effects of the farming practices on crop yield, soil carbon (C) and nitrogen (N) accumulation, and carbon footprint (CF). The farming practices included two tillage patterns: conventional (CT) and reduced tillage (RT), two cropping patterns: continuous (Con) and rotation cropping (Rot), and two mulching pattern: film (F) and straw mulching (S) with eight combined treatments. The RT did not significant decrease crop yield but increase soil C and N accumulation rate by 59% and 130%, and thus decrease CF for crop production compared with the CT. S can also improve soil C and N accumulation, and cause low CF for crop production, but leading to 14–41% decrease in maize yield compared with F. Rot result in a 14% increase on maize yield also has extra benefit to decrease CF for crop production, but no significant effect on soil C and N accumulation compared with Con. Our study adds a reasonable perspective on how to improve the conventional farming systems in desert oasis, the information about RT, straw mulching, and maize–soybean rotation have positive effect on improving soil quality and decreasing CF for crop production in this desert soil area is critical to develop the sustainable agriculture system in this desert oasis farmland, which both maintaining crop productivity and minimizing negative environmental impacts. 相似文献
5.
M.L. Jat M.K. Gathala J.K. Ladha Y.S. Saharawat A.S. Jat Vipin Kumar S.K. Sharma V. Kumar Raj Gupta 《Soil & Tillage Research》2009,105(1):112-121
In recent years conventional production technologies in the rice–wheat (RW) system have been leading to deterioration of soil health and declining farm profitability due to high inputs of water and labour. Conservation agriculture (CA)-based resource-conserving technologies (RCTs) vis-à-vis zero-till (ZT), raised-bed planting and direct-seeded rice (DSR) have shown promise as alternatives to conventional production technologies to overcome these problems. The integration of CA-based RCTs with precision agriculture (PA)-based technologies in a systems perspective could provide a better option for sustainable RW production systems. In this study we attempted to evaluate conservation and precision agriculture (CPA)-based RCTs as a double-ZT system integrated with laser-assisted precision land leveling (PLL) in the RW system. A field experiment was conducted in the western IGP for 2 years to evaluate various tillage and crop establishment methods under PLL and traditional land leveling (TLL) practices to improve water productivity, economic profitability and soil physical quality. Irrespective of tillage and crop establishment methods (TCE), PLL improved RW system productivity by 7.4% in year 2 as compared to traditional land leveling. Total irrigation water savings under PLL versus TLL were 12–14% in rice and 10–13% in wheat. PLL improved RW system profitability by US$113 ha−1 (year 1) to $175 ha−1 (year 2). Yields were higher in conventionally transplanted rice followed by direct-drill-seeded rice after ZT. In wheat, yields were higher in ZT when followed by DSR than in the conventional-till (CT) system. RW system productivity under double ZT was equivalent to that of the conventional method. Among different TCE, conventional puddled-transplanted rice-CT wheat required 12–33% more water than other TCE techniques. Compared with CT systems, double ZT consumed 12–20% less water with almost equal system productivity and demonstrated higher water productivity. The CT system had higher bulk density and penetration resistance in 10–15 and 15–20 cm soil layers due to compaction caused by the repeated wet tillage in rice. The steady-state infiltration rate and soil aggregation (>0.25 mm) were higher under permanent beds and double ZT and lower in the CT system. Under CT, soil aggregation was static across seasons, whereas it improved under double no-till and permanent beds. Similarly, mean weight diameter of aggregates was higher under double ZT and permanent beds and increased over time. The study reveals that to sustain the RW system, CPA-based RCTs could be more viable options: however, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies. 相似文献
6.
科学耕作与留茬改良小麦-玉米两熟农田土壤物理性状及增产效果 总被引：2，自引：3，他引：2
为了探讨不同覆盖耕作方式对农田土壤物理性状及作物产量的影响,该试验研究了免耕、常规2种耕作方式和4种留茬高度的玉米秸秆还田处理,对麦-玉两熟农田土壤含水率、容重、孔隙度以及作物产量的影响。结果表明:在0～40cm土层内,秸秆还田的集雨和保水效果显著,免耕留茬0.5m还田处理的含水率比免耕无覆盖处理增加了15.95%。秸秆还田量对0～40cm内土壤贮水量的影响不同。耕作措施显著影响了土壤容重,小麦播种前常规留茬1m还田、常规全量还田处理容重低至1.0g/cm3左右。秸秆还田能增加土壤总孔隙度、降低毛管与非毛管孔隙度的比值。单一免耕处理降低了作物产量,而免耕覆盖能增产,其留茬1m还田处理比无还田处理增产22.44%,比常规留茬0.5m还田处理高3.64%。因此,免耕留茬1m还田处理在改善农田土壤物理性状和增加作物产量方面显著,该研究可为农田管理过程中耕作措施和秸秆还田量的选择提供参考依据。 相似文献
7.
C. Castro Filho J. C. Henklain M. J. Vieira R. Cas o Jr. 《Soil & Tillage Research》1991,20(2-4):271-283
The intensive tillage systems adopted in southern Brazil have accelerated soil erosion, depleted plant-available nutrients and reduced crop productivity. These effects are better perceived in terms of farmer's land use and soil management techniques, i.e. animal- or machine-powered equipment through high and low aptitude land use classification systems. However, these tillage systems coexist together at the level of agricultural watersheds and are not compatible for continuous and sustainable agriculture. This article proposes a methodology for using agricultural watersheds as planning units for integrated soil conservation plans. This methodology is based on considerations of the farmer's socioeconomic conditions, land aptitude and other biophysical factors. The proposed methodology envisages a continuous and intensive land use for sustained production. 相似文献
8.
J. R. Salinas-García J. de J. Velzquez-García M. Gallardo-Valdez P. Díaz-Mederos F. Caballero-Hernndez L. M. Tapia-Vargas E. Rosales-Robles 《Soil & Tillage Research》2002,66(2):177-152
Quantifying how tillage systems affect soil microbial biomass and nutrient cycling by manipulating crop residue placement is important for understanding how production systems can be managed to sustain long-term soil productivity. Our objective was to characterize soil microbial biomass, potential N mineralization and nutrient distribution in soils (Vertisols, Andisols, and Alfisols) under rain-fed corn (Zea mays L.) production from four mid-term (6 years) tillage experiments located in central-western, Mexico. Treatments were three tillage systems: conventional tillage (CT), minimum tillage (MT) and no tillage (NT). Soil was collected at four locations (Casas Blancas, Morelia, Apatzingán and Tepatitlán) before corn planting, at depths of 0–50, 50–100 and 100–150 mm. Conservation tillage treatments (MT and NT) significantly increased crop residue accumulation on the soil surface. Soil organic C, microbial biomass C and N, potential N mineralization, total N, and extractable P were highest in the surface layer of NT and decreased with depth. Soil organic C, microbial biomass C and N, total N and extractable P of plowed soil were generally more evenly distributed throughout the 0–150 mm depth. Potential N mineralization was closely associated with organic C and microbial biomass. Higher levels of soil organic C, microbial biomass C and N, potential N mineralization, total N, and extractable P were directly related to surface accumulation of crop residues promoted by conservation tillage management. Quality and productivity of soils could be maintained or improved with the use of conservation tillage. 相似文献
9.
Bram Govaerts Ken D. Sayre Bart Goudeseune Pieter De Corte Kelly Lichter Luc Dendooven Jozef Deckers 《Soil & Tillage Research》2009,103(2):222
Tropical highlands of the world are densely populated and intensively cropped. Agricultural sustainability problems resulting from soil erosion and fertility decline have arisen all over this agro-ecological zone. Based on selected soil quality indicators, i.e. time-to-pond, aggregate distribution and stability (expressed as the mean weight diameter (MWD) for dry and wet sieving, respectively) and soil moisture, from a representative long-term sustainability trial initiated in 1991 in Central Mexico (2240 masl; 19.31°N, 98.50°W; Cumulic Phaeozem), some insights into the feasibility of conservation agriculture (CA) as part of a sustainable production system in the tropical highlands are given. Zero tillage plots with crop residue removal showed low aggregate distribution (average MWD = 1.34 mm) and stability (average MWD = 0.99 mm) resulting in top layer slaking, increased erosion and low time-to-pond values. Retaining the residue in the field with zero tillage avoided the above-mentioned negative evolution for both aggregate distribution as stability (average MWD = 2.77 and 1.51 mm, respectively) and even improved the physical conditions of the soil as compared to conventional practice. Throughout the growing season the lowest soil moisture content was found in zero tillage without residue (average over the entire growing season = 20.5% volumetric moisture content), the highest in zero tillage with residue retention (average = 29.7%) while conventional tillage had intermediate soil moisture values (average = 27.4%). Zero tillage without residue retention had most days of soil moisture values under permanent wilting point, while zero tillage with residue retention had the least. Taking into account these results, zero tillage with residue retention can clearly be a part of an integrated watershed management scheme towards sustainable agriculture in the tropical highlands. It is clear that to develop new management practices to improve water use, reduce erosion and enhance human labor/animal power focus must be on the use of conservation agriculture both for rainfed as well as irrigated production systems and be fine tuned for each system. 相似文献
10.
Seedbed preparation can involve a wide range of tillage methods from intensive to reduced cultivation systems. The state or quality of the soil to which these tillage methods are applied for cereal crop management is not easily determined and excessive cultivations are often used. Seedbed preparation is crucial for crop establishment, growth and ultimately yield. A key aspect of the soil condition is the soil physical environment under which germination, growth and establishment occur. Crucially this affects factors such as temperature, water content, oxygen availability, soil strength and ultimately the performance of a seedbed. The dynamics of soil physical properties of a range of seedbeds and how they relate to crop establishment are considered in this paper. Significant interactions between cultivation techniques, physical properties of the seedbed in terms of penetration resistance, shear strength, volumetric water content and bulk density and the interaction with crop establishment were identified. A soil quality of establishment (SQE) model was developed for the prediction of crop establishment based upon soil bulk density and cultivation practices. The SQE significantly accounted for ca. 50% of the variation occurring and successfully predicted crop establishment to a standard error of around 20 plants per m−2 across contrasting soil types and environmental conditions. 相似文献
11.
《国际水土保持研究(英文)》2014,2(4):1-12
Conservation agriculture (CA) technologies involve minimum soil disturbance, permanent soil cover through crop residues or cover crops, and crop rotations for achieving higher productivity. In India, efforts to develop, refine and disseminate conservation-based agricultural technologies have been underway for nearly two decades and made significant progress since then even though there are several constraints that affect adoption of CA. Particularly, tremendous efforts have been made on no-till in wheat under a rice-wheat rotation in the Indo-Gangetic plains. There are more payoffs than tradeoffs for adoption of CA but the equilibrium among the two was understood by both adopters and promoters. The technologies of CA provide opportunities to reduce the cost of production, save water and nutrients, increase yields, increase crop diversification, improve efficient use of resources, and benefit the environment. However, there are still constraints for promotion of CA technologies, such as lack of appropriate seeders especially for small and medium scale farmers, competition of crop residues between CA use and livestock feeding, burning of crop residues, availability of skilled and scientific manpower and overcoming the bias or mindset about tillage. The need to develop the policy frame and strategies is urgent to promote CA in the region. This article reviews the emerging concerns due to continuous adoption of conventional agriculture systems, and analyses the constraints, prospects, policy issues and research needs for conservation agriculture in India. 相似文献
12.
A review is made of appropriate tillage methods for West African soils. Soil and ecological constraints to crop production and soil and water conservation measures in West Africa are discussed. Experimental results relating to the effects of different tillage methods on soil productivity and crop responses are described for different eco-regions in relation to the potentials of different tillage methods for soil and water conservation. The review shows that limited experimental data and diverse research methodologies make generalizations from the available information tenuous at best. Serious gaps in our knowledge of the ecological suitability of alternative tillage methods and soil and water conservation technologies are identified. The future course for regionally coordinated research in soil tillage and soil and water conservation is suggested. 相似文献
13.
耕作方式对华北冬小麦.夏玉米周年产量和水分利用的影响 总被引：7，自引：1，他引：7
在冬小麦季设置秸秆不还田翻耕(CT)、秸秆还田翻耕(CTS)、秸秆还田旋耕(RTS)和免耕秸秆覆盖(NTS)4种处理,研究耕作方式对华北小麦-玉米两熟区作物周年产量和水分利用的影响。结果表明:耕作方式对当季冬小麦产量和水分利用影响显著,对夏玉米产量和水分利用影响不大,但秸秆还田提高了夏玉米产量。RTS、CTS、CT 3个处理小麦季产量差异不显著,而NTS由于有效穗数不足,产量显著低于其他处理;与CT相比,NTS周年产量平均减产5.13%,RTS增产2.69%,CTS增产2.33%。耕作方式对当季小麦土壤水分含量影响大,而对后茬夏玉米土壤水分含量的影响较小。NTS提高了小麦季土壤水分含量,增加了土壤储水量,与CT相比,0~60 cm土壤储水量2010年和2011年分别增加39.07 mm和26.65 mm。从耗水构成来看,土壤水在冬小麦耗水中所占比例最大,其次为灌水和降水;而夏玉米耗水以降水为主,且降水中有一部分转化为土壤水储存起来。NTS提高了冬小麦季土壤储水量,降低了土壤水分的消耗,冬小麦季耗水最少。与CT相比,NTS小麦季平均节水22.40 mm,周年耗水量也以NTS最少;但NTS冬小麦产量降低导致其小麦季和周年水分利用效率均最低。从作物周年产量和水分利用的角度来看,如何提高免耕秸秆覆盖小麦季产量,进而提高周年产量,发挥其节水优势,是该耕作模式在华北地区冬小麦?夏玉米两熟区推广应用亟需解决的关键问题。 相似文献
14.
在调查的基础上,评述了六道沟流域影响农业生产的土地、土壤、气候等因素,分析了当前作物生产的结构与布局、耕作制,水肥的管理状况和存在的主要问题。讨论了农业生产发展方向及提高作物生产的措施。 相似文献
15.
Eight conservation tillage methods were evaluated for maize (Zea mays L.) production and were related to water conserved, soil strength, plant stand, plant nutrient status, and methods of managing crop residues on Norfolk loamy sands (Typic Paleudults) in the U.S. southeastern coastal plain. This study summarizes 10 site-years of data collected from 1978 through 1982.
Seasonal soil-water balance and crop residue management largely determined the success of maize production under conservation tillage. Autumn subsoiling increased winter forage and maize production under both conventional and conservation tillage. When early-season rainfall was limited, water extraction by a winter cover crop or winter weeds often reduced early-season growth and yield of maize under conservation tillage. For adequate stands, increased seeding rates and effective weed-, rodent-, bird- and insect-control were all necessary.
Under adequate water regimes, conventional tillage resulted in greater yields at low levels of nitrogen, but maximum yields occurred regardless of tillage system, when 200 kg ha−1 were applied. Conventionally-tilled maize generally resulted in higher yields than conservation tillage production. The only significant increase for conservation tillage occurred under non-irrigated conditions in 1981 during severe drought. The interactive soil and climatic factors which have impact on conservation tillage in this physiographic region were identified. 相似文献
16.
《国际水土保持研究(英文)》2014,2(1):5-13
In response to the dust bowls of the mid-thirties in the USA, soil and water conservation programmes involving reduced tillage were promoted to control land degradation, particularly soil erosion. The farming and land management practices that were considered to adequately address soil and water conservation objectives were based on no-till seeding and maintenance of soil mulch cover. This collection of practices led to what became known as conservation tillage, although no-till systems by definition avoid soil disturbance by no-till direct seeding, and maintain an organic mulch cover on the soil surface.This article is an overview of achievements in soil and water conservation on agricultural lands through the experience derived from the adoption and spread of Conservation Agriculture (CA) world-wide. CA is an agro-ecological approach to sustainable production intensification. It involves the application of three inter-linked principles that underpin agricultural production systems based on locally formulated practices: (i) permanent no or minimum mechanical soil disturbance, which in practice entails direct seeding through mulch into no-till soils; (ii) maintenance of soil cover with crop residues and green manure crops, particularly legumes; and (iii) diversified cropping system involving annuals and perennial in rotations, sequences and associations.In 2011, CA had spread over 125 million hectares (9% of the global cropped land) across all continents and most agro-ecologies, including small and large farms. In addition, there is a significant area of CA orchards in the Mediterranean countries. CA is now considered to be a practical agro-ecological approach to achieving sustainable agriculture intensification. It offers environmental, economic and social advantages that are not fully possible with tillage-based production systems, as well as improved productivity and resilience, and improved ecosystem services while minimizing the excessive use of agrochemicals, energy and heavy machinery. While there are challenges to the adoption of CA, there is also increasing interest from producers, the civil society, donors and private sector institutions to further promote and service the uptake and spread of CA globally. 相似文献
17.
The West African Semi-Arid Tropics (WASAT) is characterized by a monomodal rainfall pattern, and based on the amount of annual rainfall it can be divided into three ecologies: Sahel, Sudan and Northern Guinea savannahs. The major soil groups of the WASAT are Alfisols, Inceptisols and Entisols and Vertisols, with the former three predominating. The major soil constraints to crop growth are: soil compaction, low fertility, high temperature and low soil water retention, available water holding capacity and infiltration rate. Tillage in traditional farming systems is manual. However, mechanization of tillage operations has received emphasis in the recent past. The accelerated soil degradation which is a feature of mechanized-tillage systems under rainfed agriculture can be minimized with no tillage. However, lower yield have been reported to occur with no tillage. Some possible reasons are: the absence or low amounts of residue mulch, high soil compaction, the presence of harmful soil insects in crop residues, the creation of stable pores by tillage in soils of high organic matter, silt and fine sand contents. Unavailability of crop residues in a major impediment to the adoption of no tillage. The use of heavy and intensive mechanical tillage in irrigated agriculture leads to the formation of plow soles. Deep tillage such as subsoiling does not ensure the elimination of plow soles. While no tillage appears to hold promise for use in the irrigated agriculture of the WASAT much research remains to be done. 相似文献
18.
In the U.S. Southeastern Coastal Plains conservation tillage (CT) became useful as a management system with the development of in-row subsoiling systems capable of planting into heavy residues. Research priorities associated with the development of CT included: reducing cover crop water loss, improving stand establishment, assessing nutrient and water management requirements, determining optimal subsoiling strategies, understanding long-term conservation tillage effects on soil properties, evaluating the interaction of crop residue removal with tillage systems, and documenting tillage impact on pests and beneficial organisms. Since the late 1970s the Coastal Plains Soil and Water Conservation Research Center in Florence, SC has made a concerted effort to study these interactions and alleviate them as obstructions to the use of CT management. These studies showed that for Coastal Plain soils such as Norfolk sandy loam (fine-loamy, siliceous thermic, Typic Paleudults) winter cover crops such as rye (Secale cereale L.) desiccated the soil profile by evapotranspiration in the spring. This delayed emergence and early season growth of corn (Zea mays L.) but not full-season soybean (Glycine max (L.) Merr.). Conservation tillage helped manage soil strength by gradually increasing soil organic matter content, restricting traffic patterns and maintaining higher soil water contents. Laboratory studies demonstrated a negative correlation (R2=0.85) between proctor soil strength and organic matter content. Conservation tillage affected nematode, Bradyrhizobium japonicum and Heliothis species populations. Alternate cropping systems using rapeseed (Brassica napus L.) as a winter crop or sunflower (Helianthus annuus L.) either before soybean or after corn provided crop cover against potential soil loss from late autumn through early spring, when bare soil is exposed to intense rainfall. Water quality questions associated with CT have been raised but remain unanswered. Although CT can reduce runoff and erosion, the crop residues can support higher insect populations and pathogen inoculum levels, and thus prompt greater pesticide use. Quantifying relationships between soil strength, macropore formation and persistence, and water infiltration with surface and subsurface water quality is the focus of new long-term evaluations. The findings of these studies, published to date, are summarized in this paper. 相似文献
19.
The application of conservative agricultural practices such as crop rotation, shallow tillage, and organic fertilizer could usefully sustain crop yield and increase soil fertility, thus playing an important role in the sustainable agriculture. This study was conducted to determine the effects of conservative agronomic practices on yield and quality of wheat. The effects of these practices on soil fertility were further investigated in this four-year study (2005–2008). Two cropping systems, durum wheat in continuous cropping, and in two-year rotation with leguminous crops, were investigated at Foggia (Southern Italy) in rain-fed conditions. Within each cropping system, two levels of crop management were compared: i) conventional, characterized by a higher soil tillage management and mineral fertilizers application; ii) conservative, with a lower soil tillage management and organic-mineral fertilizers. The seasonal weather greatly affected the wheat yield and quality, inducing lower production in years that were characterized by unfavorable climatic conditions. This trend was found when the conventional treatment was applied, both in continuous cropping and rotations. The effects of cropping systems and crop management pointed out the positive role played by the leguminous crops (common vetch and chickpea) in crop rotation. This introduction improved wheat yield in rotation (6.47% compared to the continuous cropping), improved grain protein content (5.88%), and reduced the productive gap between conventional and conservative treatments (9.24 and 14.14% of the wheat in rotation and continuous cropping, respectively). Conversely, the effects of cropping systems and crop management on soil fertility were not very high, since the differences found at the end of the study in total nitrogen values were poor. However, total organic carbon (16.04 and 17.58% for cropping system and crop management, respectively) and available phosphorus values (11.30 and 7.43%) depend on root organic matter contribution, plant biomass residues, and fertilizations. The suitable crop rotation and the sustainable crop management appear important agronomical practices to improve yield and quality of wheat, and may reduce the environmental risks resulting from conventional intensive cropping systems. 相似文献
20.
West African soil resources have high potentials for enhancing agricultural productivity, if well-managed and restored. In this context, the importance of tillage systems have not been fully appreciated as an integral part of good farming systems in order to tally with the peculiarities of the soil, crops and the environment. Most improved tillage systems are not widely used, although the relatively small-scale uncontrolled application of mechanical tillage has had untold adverse effects on properties and productivity of soils in the humid and subhumid regions.
In contrast, mechanical soil tillage involving deep plow-till and soil inversion has proven beneficial on compact soils of arid and semi-arid regions. The plow-based systems not only reduce soil bulk density and soil strength but also improve the efficiency of water and nutrient use.
The exposure of structurally unstable Alfisols and Ultisols predominant in the humid and sub-humid regions by mechanical tillage can cause more adverse effects than beneficial effects on soil properties and crop yields, especially on a long-term basis. On the other hand, the no-till system with crop residue mulch can maintain favorable soil properties. The conservation tillage system, however, requires more research to make it applicable to diverse soil types, crops and ecoregions.
Apart from the long-term effects of tillage on the level of soil organic matter and the attendant release of nutrients, the effects of tillage systems on the chemical properties of soil are often contradictory and are confounded by many other factors so that clear-cut cause and effect relationships are not obvious. The interactions between fertilizer application, liming, soil organic matter content and tillage systems, especially on acid soils, are such examples. More detailed studies on nutrient dynamics under different tillage systems are necessary. The interactions between the relatively new technologies of alley cropping and agroforestry which allow a more continuous use of the land should be investigated vis-à-vis tillage systems.
Long-term, well-designed, adequately equipped experiments (which are scanty in West Africa) should be encouraged to elucidate and confirm results of many short-term experiments. 相似文献