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1.
Explorations of the impact of climate change on potential potato yields were obtained by downscaling the projections of six different coupled climate models to high spatial resolution over southern Africa. The simulations of daily maximum and minimum temperatures, precipitation, wind speed, and solar radiation were used as input to run the crop growth model LINTUL-Potato. Pixels representative for potato growing areas were selected for four globally occurring agro-ecosystems: rainy and dry winter and summer crops. The simulated inter-annual variability is much greater for rainfall than for temperature. Reference evapotranspiration and radiation are projected to hardly decline over the 90-year period, whilst temperatures are projected to rise significantly by about 1.9 °C. From literature, it was found that radiation use efficiency of potato increased with elevated CO2 concentrations by almost 0.002 g?MJ?1?ppm?1. This ratio was used to calculate the CO2 effect on yields between 1960 and 2050, when CO2 concentration increases from 315 to 550 ppm. Within this range, evapotranspiration by the potato crop was reduced by about 13% according to literature. Simulated yield increase was strongest in the Mediterranean-type winter crop (+37%) and least under Mediterranean summer (+12%) and relatively warm winter conditions (+14%) closer to the equator. Water use efficiency also increased most in the cool rainy Mediterranean winter (+45%) and least so in the winter crop closer to the equator (+14%). It is concluded from the simulations that for all four agro-ecosystems possible negative effects of rising temperatures and reduced availability of water for potato are more than compensated for by the positive effect of increased CO2 levels on water use efficiency and crop productivity. 相似文献
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Growers' surveys took place in all sixteen potato growing regions of South Africa in 2013 and 2014. The agro-ecological climate of these regions is diverse and potato is produced in rainy or dry seasons, in winter or summer seasons, or year round. Growers were asked how often in ten years crops suffered more than 25% yield losses due to extreme weather events related to precipitation events such as hail, floods and droughts, and to temperature-related events such as frost and heat waves. Simultaneously they were asked their opinion about occurrence and severity of diseases caused by potato viruses, fungi and bacteria and pests such as nematodes, tuber moths, aphids and leaf miners. Weather related hazards resulted in losses over 25% virtually each year in the Gauteng growing region due to hail, frosts and floods; losses occurred less than once every five years, for example due to extremely high temperatures, in the Sandveld area where growers take a risk by producing potatoes in hot summers. Regarding the biotic factors, every pest or pathogen assessed was reported to occur on at least one farm in each growing region. Countrywide the lowest frequency of 50% was recorded for powdery scab whereas the insects tuber moths, leaf miners and aphids were reported most frequently, by between 88% and 98% of the growers. The complex of silver scurf and black dot resulted in the greatest yield losses in all growing regions, followed closely by tuber moth, early blight and the blackleg/soft rot disease complex. Yield losses due to potato virus Y, potato leaf roll virus and aphids were not reported as being very severe. When the growers' perceptions of severity of biotic factors were accumulated, significant differences between the regions appeared, with the Eastern Cape most prone with an accumulated score of 700 due to an array of pests and diseases, and the North–West with a score of only 50 mainly attributed to root knot nematodes. Growers were also asked how frequently biocides were applied to potato to control soil-borne organisms (nematicide and seed treatment), foliar fungi or insects. There were no significant correlations between frequency of biocide applications and severity of the disease as reflected in yield losses, most likely because growers use biocide applications as insurance against pests and diseases. This is common among crop farmers around the world. Although potato production in South Africa appears to carry more risks than production elsewhere, South African commercial potato growers are economically competitive when compared to growers in other areas of the globe, with comparable planting conditions and risks. 相似文献
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J. E. van der Waals K. Krüger A. C. Franke A. J. Haverkort J. M. Steyn 《Potato Research》2013,56(1):67-84
A set of daily weather data simulations for 1961 to 2050 were used to calculate past and future trends in pest and disease pressure in potato cropping systems at three agro-ecologically distinct sites in South Africa: the Sandveld, the Eastern Free State and Limpopo. The diseases and pests modelled were late blight, early blight and brown spot, blackleg and soft rot, root-knot nematodes and the peach-potato aphid Myzus persicae (as indicator of Potato virus Y and Potato leaf roll virus). The effects of climate on trends in relative development rates of these pathogens and pests were modelled for each pathogen and pest using a set of quantitative parameters, which included specific temperature and moisture requirements for population growth, compiled from literature. Results showed that the cumulative relative development rate (cRDR) of soft rot and blackleg, root-knot nematodes and M. persicae will increase over the 90-year period in the areas under consideration. The cRDR of early blight and brown spot is likely to increase in the wet winter and wet summer crops of the Sandveld and Eastern Free State, respectively, but remains unchanged in the dry summer and dry winter crops of the Sandveld and Limpopo, respectively. Climate change will decrease the cRDR of late blight in all of the cropping systems modelled, except in the wet winter crop of the Sandveld. These results help to set priorities in research and breeding, specifically in relation to management strategies for diseases and pests. 相似文献
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辽宁省马铃薯高效复种栽培技术 总被引：1，自引：0，他引：1
经过多年试验示范,针对辽宁省气候特点,总结出马铃薯高效复种栽培模式,筛选出各主产区的适宜品种和相应种植密度,为辽宁省马铃薯科学种植提供依据。马铃薯的三膜覆盖极早熟栽培技术比较适合葫芦岛地区和大连地区应用,下茬复种小西瓜等经济效益较高的作物。马铃薯双膜覆盖栽培技术可克服前期低温的不利影响,缓解晚霜冻害,比常规地膜覆盖提前收获15 d以上,其鲜薯价格高,效益可观,为下茬复种粮食和油料作物高产创造条件,比较适合在辽西和辽南的大部分地区应用。马铃薯单膜覆盖栽培技术适用于辽宁大部分地区,下茬可复种蔬菜、粘(甜)玉米等作物。 相似文献
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Weeds are a major constraint for organic crop production. Previous research has found that cover crops in reduced tillage systems can provide weed interference, subsequently reducing inputs and improving crop yield. However, questions remain about effects of cover crop species identity and cover crop biomass on weed suppression and crop yield. This four-year study investigated how winter cover crops grown alone or in mixture influenced weed presence and crop yield in a reduced tillage organic vegetable system. Treatments were barley (Hordeum vulgare L.), crimson clover (Trifolium incarnatum L.), mixed barley + crimson clover, and a no-cover crop control. Plots were flail-mowed and strip-tilled prior to planting main crops (2011 and 2012: broccoli Brassica oleracea L.; 2013 and 2014: crookneck squash Cucurbita pepo L.). We measured density, diversity, and community composition of weeds and viable weed seeds, changes in weed percent cover within growing seasons, and crop yield. We found that the presence of barley, crimson clover, or barley + crimson clover reduced weed density by 50% relative to the control. Cover crop biomass negatively influenced weed density and weed seed diversity, and positively influenced squash yield. Weed percent cover within growing seasons did not respond differentially to cover crop treatment. Cover crop treatment and cover crop biomass had no influence on weed or weed seed community composition. These results suggest that reduced tillage winter cover crops in mixture or monoculture can similarly suppress weeds and improve yield, primarily due to biomass effects. 相似文献
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Yield losses of soybean and maize by competition with interseeded cover crops and weeds in organic-based cropping systems 总被引：1，自引：0，他引：1
Weed management is a major issue in organic farming systems. Although interseeding cover crops is one alternative to herbicides, cover crops often suppress not only weeds but also main crops. Therefore, using cover crops for weed control without adverse effects on main crop growth is important. To verify the effect of cover crops on competition between main crops, cover crops and weeds in a snowy-cold region, main crops soybean (Glycine max Merr.) in 2005 and maize (Zea mays L.) in 2006 were grown with cover crops winter rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth), respectively. The cover crops were sown on three sowing dates: before main crop planting (Pre-MC), on the same date of main crop planting (Syn-MC) and after main crop planting (Post-MC). A plot without cover crops (Sole-MC) was used as a control. The dry weight (DW), vegetation cover ratio (VCR), vertical community structure and chlorophyll content were measured to estimate the competition between main crops, cover crops and weeds. Weed DW was suppressed significantly by sowing cover crops in both soybean and maize. This weed suppression was associated with the increase of VCR of main crops plus cover crops at the early growth stage of main crops. Soil seed banks of dominant weed also became lower by sowing cover crops, implying the importance of proper weed management for suppressing weeds successively. In addition, the sowing dates of cover crops had large effects on main crops DW especially in maize, i.e., it was significantly lower in Pre-MC and Syn-MC than in Post-MC. Although the cover crop height was markedly shorter than the main crop height, the chlorophyll content of the main crops was significantly lower when cover crops were sown earlier. These results suggest that the growth inhibition of main crops by cover crops was partly caused by competition for nutrients between main crops and cover crops, and this growth inhibition was alleviated when cover crops were sown after the establishment of main crops. Consequently, soybean yield was the highest in Post-MC and decreased by 29%, 18% and 7% in Sole-MC, Pre-MC and Syn-MC, respectively, and maize yield was also the highest in Post-MC and decreased by 68%, 100% and 24% in Sole-MC, Pre-MC and Syn-MC, respectively. It was concluded that weeds could be controlled effectively by sowing cover crops after planting main crops in organic farming systems in a snowy-cold region. 相似文献
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Yield and Nitrogen Use of Irrigated Processing Potato in Response to Placement,Timing and Source of Nitrogen Fertilizer in Manitoba 总被引：1，自引：0，他引：1
Xiaopeng Gao William S. Shaw Mario Tenuta Darin Gibson 《American Journal of Potato Research》2018,95(5):513-525
Optimizing nitrogen (N) fertilizer management in irrigated potato (Solanum tuberosum L.) on coarse-textured soils is challenging. The “4R” nutrient stewardship framework of using N fertilizer at the right rate, right source, right placement and right time provides approaches to improve fertilizer use efficiency while maintaining or improving yield. This 3-years replicated field plot study evaluated effects from a series of N fertilization strategies including 10 combinations of sources, placement and timing, as well as fertigation, on irrigated processing potato (cv. Russet Burbank) grown for a total of five site-years in the Province of Manitoba, Canada. Treatments were designed to provide early to late availability of N to the potato crop. Nitrogen was applied to 80% of Provincial N recommendation to increase the likelihood of observing improved fertilizer use efficiency and effects of treatments on yields. Measurements were tuber yield, size distribution, specific gravity, hollow-heart rate, fertilizer apparent N recovery (ANR) and agronomic nitrogen use efficiency (NUE). Results showed differences in yield, quality, ANR and NUE between fertilizer treatments were generally very small or absent. Average tuber marketable yields for fertilizer treatments were significantly greater than those for the unfertilized control (P?<?0.001). Split application of urea at planting and hilling, and urea at planting with fertigation occasionally increased tuber marketable yields on sites of coarse textured soils (P?<?0.05). Use of polymer-coated urea (ESN) or stabilized urea with inhibitors (SuperU) did not affect yield, quality or N use of potato. Site-year difference (P?<?0.001) were apparent for all measures highlighting the importance of soil and climatic conditions on agronomic and environmental effects of N management practices. The results indicate current grower practice of split urea application at planting and hilling and urea at planting following by in-season fertigation are sound. Results indicate growers could shift to the more convenient practice of ESN at planting without reducing yields. Absence of treatment effects suggests N was generally not a limiting factor for the current study, indicating that the current recommendation for potato production in Manitoba over-estimate site-specific crop N needs. 相似文献
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万载县黑膜覆盖马铃薯高产栽培技术 总被引：1，自引：0，他引：1
近年来,江西省万载县马铃薯种植面积有所增加,马铃薯开始成为当地冬种作物之一。但由于较为落后的耕作方式和栽培技术,其生产效益不理想,以致于影响农户种植马铃薯的积极性,限制了马铃薯产业的发展。黑膜覆盖栽培方式为马铃薯生长发育创造了一个相对稳定的农田生态环境,从而影响其产量和品质的形成。江西省万载县农业局经济作物站在康乐街道里泉村和鹅峰乡涂泉村建立了黑膜覆盖高产示范区,以研究此栽培技术的要点、优点以及应用中存在的问题,并提出了适宜的解决方法,供当地马铃薯种植农户借鉴。 相似文献
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Irish potato production in Zimbabwe can be traced back to the early 1900s. Large-scale commercial farmers dominated production until the early 2000s. Potato is the most important horticultural crop and has been declared a strategic national food security crop in 2012. In 2000, the Fast Track Land Reform Programme completely restructured commercial agriculture and potato farming. A product of the agrarian reforms, the A2 and A1 resettlement growers, started growing potato. The A1 resettlement model has individually owned cropping land and shared grazing, while A2 resettlement comprises of self-contained farm units. A survey was conducted to characterise potato growers, mainly to understand the current potato production systems and to assess the impact of the landmark reform programme on potato farming. Four production systems, large-scale commercial, communal area, A2 resettlement and A1 resettlement, were identified, and two main growing agro-ecological zones, the Highveld and Eastern Nyanga Highlands. In 1961–2013, significant positive trends for annual planted area, average yield and total production were observed. In terms of yield, Zimbabwe is fourth in southern Africa with an average yield of 17 t ha?1 in the 2009–2013 period. Large-scale commercial and A2 resettlement systems were well-mechanised, and growers owned large land holdings ranging from an average of 165–1600 and 31–390 ha across the different areas, respectively, with average potato areas of 11 and 8 ha, respectively. A1 resettlement and communal area growers owned an average of 4 and 3 ha cropping area, respectively, with average potato areas of 0.4 and 1.1 ha, respectively. Input use was significantly different among the production systems. High synthetic fertiliser and biocide use was observed. 相似文献
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《Field Crops Research》2006,99(1):35-47
Both intensification and diversification of cropping systems may allow improving the productivity and sustainability of agricultural production in the Indo-Gangetic Plain (IGP), but the choices to be made require integrated assessment of various cropping systems. A field experiment was conducted from 1999 to 2002 on a sandy clay loam (Inceptisol) to evaluate nine predominant cropping systems in West Bengal, India. Productivity, energy use efficiency, and nutrient uptake generally increased with increasing cropping intensity. Positive residual effects of potato and jute on yield and energy output of subsequently grown crops were observed as well as maintenance or improvement of soil properties such as soil organic matter, available P, and available K. The P balance was positive for most systems, except for jute-containing systems. However, negative K balances occurred due to almost complete removal of crop biomass in all systems, suggesting that recommended rates of applied K fertilizer were to low for sustaining soil K supply over the longer term. Cropping systems containing potato had the highest levels of yield, net return, benefit to cost ratio and energy productivity, but energy use efficiency was reduced due to higher energy consumption in these systems. Jute–wheat and jute–rapeseed–rice systems showed high energy use efficiency along with moderate cost and return. Based on economic considerations alone, jute–potato–rice, rice–potato–rice and rice–potato–sesame can be recommended as cropping systems for resource-rich growers in the eastern part of the IGP. Systems such as jute–wheat, rice–wheat and jute–rapeseed–rice appear to be most suitable for small and marginal farmers that cannot afford the large production costs associated with crops such as potato. 相似文献
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Under semiarid Mediterranean conditions irrigated maize has been associated to diffuse nitrate pollution of surface and groundwater. Cover crops grown during winter combined with reduced N fertilization to maize could reduce N leaching risks while maintaining maize productivity. A field experiment was conducted testing two different cover crop planting methods (direct seeding versus seeding after conventional tillage operations) and four different cover crops species (barley, oilseed rape, winter rape, and common vetch), and a control (bare soil). The experiment started in November 2006 after a maize crop fertilized with 300 kg N ha−1 and included two complete cover crop-maize rotations. Maize was fertilized with 300 kg N ha−1 at the control treatment, and this amount was reduced to 250 kg N ha−1 in maize after a cover crop. Direct seeding of the cover crops allowed earlier planting dates than seeding after conventional tillage, producing greater cover crop biomass and N uptake of all species in the first year. In the following year, direct seeding did not increase cover crop biomass due to a poorer plant establishment. Barley produced more biomass than the other species but its N concentration was much lower than in the other cover crops, resulting in higher C:N ratio (>26). Cover crops reduced the N leaching risks as soil N content in spring and at maize harvest was reduced compared to the control treatment. Maize yield was reduced by 4 Mg ha−1 after barley in 2007 and by 1 Mg ha−1 after barley and oilseed rape in 2008. The maize yield reduction was due to an N deficiency caused by insufficient N mineralization from the cover crops due to a high C:N ratio (barley) or low biomass N content (oilseed rape) and/or lack of synchronization with maize N uptake. Indirect chlorophyll measurements in maize leaves were useful to detect N deficiency in maize after cover crops. The use of vetch, winter rape and oilseed rape cover crops combined with a reduced N fertilization to maize was efficient for reducing N leaching risks while maintaining maize productivity. However, the reduction of maize yield after barley makes difficult its use as cover crop. 相似文献
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中国小麦种植区域的生态特点 总被引：6，自引：0，他引：6
为给进一步研究中国小麦种植区划提供依据,在大量调查和搜集资料的基础上,分析了中国小麦种植区域分布、气候和土壤特点、种植制度以及品种类型.结果表明,中国小麦分布地域辽阔,全国各省区均可完成小麦生活周期,目前除海南省外其余各省(区)均有小麦统计面积.中国小麦种植区域气候因素多样,从寒温带逐步过渡到温带、亚热带和热带地区.小麦种植区域土壤类型复杂,土壤质地多为壤土,次为砂壤土和粉土,少有黏土和砂土.种植制度主要包括一年一熟、一年两熟、两年三熟或一年三熟.中国小麦生产中主要以普通小麦品种种植为主,这些品种根据春化特性可分为春性、冬性和半冬性小麦三大类型. 相似文献
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Soilborne potato diseases are persistent problems in potato production. Use of disease-suppressive rotation crops, such as Brassica spp. (mustards, rapeseed) and sudangrass, has shown potential for management of soilborne diseases and enhanced yield in various crop production systems. However, how to best implement these crops into productive potato cropping systems has not yet been determined. In this research, potential disease-suppressive crops were evaluated under four different types of production management (as a cover crop, green manure, harvested crop-residue incorporated, and harvested crop-residue not incorporated) in potato rotation field trials, and their effects on disease, yield, and economic viability determined. Mustard blend, sudangrass, and rapeseed rotations reduced the tuber disease black scurf (by 16–27 %) and increased yield (by 6–11 %) relative to a barley rotation control, but only mustard blend consistently reduced common scab (by 11 %). All rotation crops managed as green manures produced lower disease (by 15–26 %) and higher yields (by 6–13 %) than other management practices. Overall, the combination of mustard blend managed as a green manure was most effective, reducing scurf by 54 % and increasing yield by 25 % relative to a soybean cover crop. The use of mustard or rapeseed as a harvested crop with incorporation provided the best economic return, increasing net income by more than $860/ha relative to the standard barley rotation, but mustard blend grown as a green manure or non-incorporated harvest crop also substantially increased net income ($600 to $780/ha). 相似文献
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A large percentage of winter and spring potatoes (Solanum tuberosum, L.) grown in the USA is produced in northeast Florida (NEF) on sandy soils with low cation exchange capacity. Maintaining adequate K nutrition is a major concern. A study was conducted on an Elzey fine sand (sandy, siliceous, hyperthermic Typic Humaquept) in NEF to relate yield and leaf K to soil and fertilizer K levels. In 1981, Mehlich-I soil K in the 0–15 cm depth averaged 73 mg/kg. Yields of 35 t/ha were obtained without any K fertilization and no response to K sidedressed at rates up to 70 kg/ha was obtained. In the following three years, soil K prior to fertilization was < 40 mg/kg. In 1982 and 1983, significant differences in yield were obtained as a result of K fertilization at planting at rates up to 186 kg/ha. In 1984, no yield differences were obtained with K fertilizer rates ranging from 94 to 280 kg/ha. Differences in maximum tuber yields from year to year were related to the number of growing-degree days accumulated between planting and harvest. Yield-leaf K relationships for leaf samples taken late in the season showed that the critical leaf K concentration for 35 t/ha yields was no more than about 20 g/kg; that for yields approaching 40 t/ha was no more than about 45 g/kg. The results of this study indicated that current K fertilizer recommendations are higher than necessary for the yields being obtained by most NEF potato growers. 相似文献
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油菜是我国种植面积最大的油料作物,是国产食用植物油的重要来源。油菜生长过程可以优化土壤结构、增加土壤养分、培肥土壤地力,具有用地养地的特征优势。同时,因其具有较强的环境适应能力,可作为先锋作物改良障碍土壤。然而,近年来由于劳动力不足、种植效益低、农民种植积极性不高等因素,导致冬闲田面积逐年增加,冬季光温水土自然资源未能得到有效利用。而油菜作为冬季种植的油料作物,不与粮争地,是开发利用冬闲田最有潜力的作物。利用冬闲田发展油菜生产,不仅可以提升油料产量,还可以充分发挥其养地优势提高后茬作物产量品质、增加种植收益,对维护我国食用油供给安全、助力粮油兼丰及农业绿色可持续发展具有重要意义。本文结合我国油菜生产现状,针对南方稻区冬闲田油菜轮作的生产发展需要,综述了油菜用地养地（油用或肥用）的作物优势,旨在为因地制宜利用南方冬闲田发展油菜生产助力油料产能提升提供科学依据。 相似文献