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1.
Summary Three experiments carried out in south-east England tested the proposition that solar radiation falling on the soii (‘wasted’) until the attainment of a complete crop canopy by potato crops, could be utilized by intercropping with cabbages without detriment to the potato yields. The cabbages were established by transplanting and harvested by the time the potato crop had achieved a ground cover between 40–80%. However, almost without exception, intercropping reduced the economic yields of both component crops. The land equivalent ratio (LER) varied between 1.01 and 1.78 and the partial LER of potatoes between 0.56 and 1.11, suggesting only in the latter case was there complete absence of competition between the component crops.  相似文献   

2.
Potato cropping systems in Maine include both continuous potatoes and short-term potato rotations with small grains. Producers recognize the benefits of increased rotations, but the economics of producing a high-valued crop such as potatoes (Solanm tuberosum L.) create incentives for continuous potato production. Research at the USDA-ARS research site in Newport, ME, is evaluating the agronomic and economic impacts of five crops in two-year rotations on potato production and whole-farm profitability. The rotation crops are barley (Hordeum vulgare L.), sweet corn (Zea mays L.) green bean (Phaseolus vulgares L.), soybean (Glycine max L., Mer.), and canola (Brassica napus L.). Enterprise budgets for the five crops were developed. The budgets and historical prices and yields were used as inputs to a Monte Carlo simulation. The simulation was conducted to determine the impact of rotation crops on whole-farm profitability and income risk, as measured by income variability. The net incomes of the five rotation sequences were compared against continuous potatoes. Two rotation crops, sweet corn and green beans, resulted in an increase in net income relative to continuous potatoes. AU of the rotation crops were found to greatly reduce income risk and chance of economic losses. In the case of green beans and sweet corn, the analysis was rerun using data from the research trials on the following potato crop yields. Depending on whether the rotation effect was negative or positive, net income either fell or rose when compared to fist analysis. However, even when the rotation crop led to decreased yields in the following potato crop, income variability and likelihood of economic loss was still superior to the continuous potato rotation. These findings provide support for including rotation crops as a method to improve potato production and sustainability, increase wholefarm profitability, and reduce income risk.  相似文献   

3.
Although there have been several attempts to develop commercial production of high erucic acid (HEA) oil from Crambe since the 1950s, this species has not yet become an established crop. Recent reviews suggest that higher yields are needed to meet the market competition from HEA rapeseed oil and the on-farm competition from other crops. Our remit was to identify the major constraints to high productivity in Crambe crops. We studied Crambe crops under favorable growing conditions and focused on the duration of the developmental stages, leaf area growth, radiation interception and on the relations between assimilate sources and sinks. The radiation use efficiency (RUE) was used as a reference value and a tool to identify constraints to seed formation. The basic crop data collected and the derived relations with temperature and intercepted radiation were integrated in a simple crop model to estimate the attainable yields for a range of years. The major constraint to high productivity in Crambe appeared to be the inefficient use of radiation during seed formation. For the period from emergence to mid-flowering the RUE was 2.2 g MJ−1 against only 0.9 g MJ−1 for the subsequent period to seed ripeness. That inefficient use of radiation was shown to result from the high proportion of radiation intercepted by photosynthetically less active stems and senescing leaves. Seed filling appeared to depend on actual photosynthesis by the pods; however, pod numbers and total pod area were too small to take over crop photosynthesis from the leaves. The simulations suggested that yields were also sensitive to exceptionally low temperatures during early growth because leaf area growth was retarded and a high proportion of radiation was wasted in the period with highest receipts. According to the growth model, an average annual production of 3250 kg ha−1 was feasible for a range of years.  相似文献   

4.
Summary In field trials with potato several methods determining the proportion of intercepted solar radiation by the crop were compared. Non-destructive measurement of the proportion of ground cover with the aid of a grid correlated well with the proportion of intercepted photosynthetically active radiation as measured with a tube solarimeter and with the leaf area index. Measurement of the infrared reflectance of the crop proved to be an efficient and objective method to show differences between treatments. Moreover, it showed a good correlation with ground cover and radiation interception until full closure of the canopy. Percentage ground cover is useful for assessing intercepted solar radiation and leads to fewer errors in calculation of efficiency of conversion into dry matter than the other methods.  相似文献   

5.
Summary In the Netherlands seed potato crops are harvested when still green, the haulm being destroyed before harvest. We compared the effect on the contamination of seed potatoes byErwinia carotovora subsp.atroseptica (Eca) andE. chrysanthemi (Ech) of the common method of haulm destruction by flailing and chemically destroying remaining stems, with the recently developed green crop lifting method. After chenical haulm destruction the levels of contamination with both Eca and Ech surviving cold storage were found not to differ significantly from those after green crop lifting. Losses due to watery wound rot (Pythium ultimum) were considerable in the warm and humid conditions during 1991, especially after green crop lifting.  相似文献   

6.
《Field Crops Research》2001,71(1):17-29
Intercropping may be helpful to solve future food problem in developing countries. The aim of this study was to compare production efficiency in intercropping with sole cropping in terms of radiant energy use. For analysing crop radiation capture and utilisation, three indices are often used: the fraction of radiation intercepted (F), radiation use efficiency (RUE) and harvest index (HI). Using those indices, maize–bean intercropping was evaluated and compared with maize and bean sole cropping systems. The findings were as follows: the intercrop F was higher than the sole crop F, the sole maize RUE was higher than the others, and there was no difference in HI among cropping systems. From those results, the intercropping may be equivalent to maize sole cropping in the overall efficiency of radiation interception and use. Therefore, when it is considered that both maize and beans would be planted in a given area of land, intercropping has more efficient radiation harvests than sole cropping. No effect of row orientation was found on F, RUE and HI.  相似文献   

7.
Maximum yields of potato tubers for growing conditions in the Columbia Basin, Washington, USA were estimated using two methods. The first was based on experimental data from a large number of experiments conducted each year from 1959 through 1973 with Russet Burbank potatoes. The highest yielding plots each year were selected, and boundary analysis was used to determine the relationship between growing season length and maximum yield. Maximum yield was found to be related to growing season length by Y = D - 36 where Y is tuber yield in t/ha and D is days since planting. The second method was based on a model which assumes that dry matter production of a crop is proportional to intercepted radiation. This model has been validated for Scottish growing conditions. The solar radiation conversion efficiency for Russet Burbank potatoes under Columbia Basin conditions was found to be 1.35 g/MJ, using boundary analysis. The model gave better agreement between predicted and measured boundary values than did the simpler model based only on growing season length. Agreement was better, particularly at the end of the growing season when days were shorter and cooler than in the summer. Maximum measured yield was 124 t/ha. The simple model predicted maximum yields around 160 t/ha, while the MW model predicted maximum values around 140 t/ha.  相似文献   

8.
《Field Crops Research》1988,19(3):211-225
Our previous work has shown that early-maturing soybean is suitable for intercropping with vassava at a high latitude (27°S) in south-east Queensland, Australia, as it does not effect the tuber yield. The present study examines whether later-maturing cultivars of soybean with higher yield potential might be more productive. Plant arrangement for cassava was the same in sole crop and in intercrop, while two soybean rows in every six rows were replaced by a row of cassava in intercropping.All soybean cultivars dominated intercropped cassava, and their dry-matter growth and seed yield were not affected by competition with cassava. Growth of cassava was, on the other hand, severely restricted by intercropped soybean, particularly by late-maturing types. After removal of early-maturing soybean, cassava recovered quickly to produce high leaf-area and effectively intercepted solar radiation. Consequential high total dry-matter production, combined with high assimilate allocation to tubers, resulted in tuber yield at the final harvest similar to that in sole cassava. After the removal of late-maturing soybean, however, recovery was poor, and with a short growing season remaining, tuber yields were only 50–60% of that of sole cassava.In addition to their adverse effect on cassave growth, late-maturing cultivars were not suitable as an intercrop because of low harvest indices and low light-conversion efficiency (dry matter produced per unit intercepted radiation), although total light interception during the whole growth of cassava/soybean intercrop was similar to that of sole cassava. The low overall light-conversion efficiency in intercropping with late-maturing cultivars was due to very low dry-matter production of soybean during pod-filling when light interception was still high.  相似文献   

9.
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   

10.
《Field Crops Research》2001,69(3):237-249
Intercropping provides an important means of raising not only productivity and land-use efficiency of smallholder rubber lands, but also income generation during the unproductive immature phase of the rubber tree. To evaluate current recommendations for intercropping rubber in Sri Lanka, we assessed the effects of a range of planting densities of banana, the most common companion crop of rubber on productivity and resource capture. In this paper, we test the hypothesis that rubber/banana intercropping, even at high densities of banana, results in an increase in biomass per unit land area and per crop plant due to an increase in both radiation capture and radiation-use efficiency. Five treatments were imposed: sole crop rubber (R); sole crop banana (B) and three intercrop treatments comprising an additive series of one (BR), two (BBR) and three (BBBR) rows of banana to one row of rubber. Dry matter production in the rubber-based treatments was directly related to planting density, being least in the sole rubber and greatest in BBBR intercrop. A more than four-fold increase in dry matter across treatments derived from an increase not only in light capture (270%) but also radiation-use efficiency (RUE, 230%). Neither R nor BR treatment, which is currently recommended for intercropping in Sri Lanka, achieved full ground cover with fractional interception remaining below 40 and 50%, respectively. Fractional interception was greatest in BBBR treatment and by the end of the measurement period, total intercepted radiation was 23 and 73% greater than that in the BBR and BR intercrops, respectively. Shade did not limit either photosynthesis or growth of component crops in the intercrops, even when planting density of banana was increased three-fold. In fact, intercropping increased growth of both rubber and banana components suggesting that shade associated with the denser intercrop canopies, moderated the microclimate and alleviated plant stress. These results highlight the potential gains that can be made by intercropping and optimising planting density for improved resource capture in immature rubber plantations.  相似文献   

11.
Summary The effects of planting date and row width on canopy development, intercepted radiation and yield were studied in two experiments, with the variety Wilja in 1988 and Cara in 1989. Planting dates were between mid March and early May and were combined with row widths of 0.75 and 1.25 m. Increasing the row width decreased intercepted radiation and yields in both years. Delayed planting reduced the yield of Cara, but not of Wilja. Early planting increased radiation use efficiency of Cara. It is argued that intercropping in spring without potentially reducing tuber yield might be favoured by delaying the planting of a determinate variety such as Wilja but by increasing the row width for an indeterminate variety such as Cara. Trends in mean monthly and soil 10 cm temperatures however suggest that opportunities for intercropping potatoes in the spring in a temperate climate may become more restricted.  相似文献   

12.
Volunteer potatoes were investigated as infection sources for potato leafroll virus (PLRV) and potato virus X (PVX) in a high elevation seed potato growing area of eastern Idaho. Population densities ofMyzus persicae were assessed. Percentage of PLRV and PVX infection of the volunteers and seed potato crops was determined, as well as density of volunteers and certain parameters of volunteer growth and reproduction. Volunteers apparently harbored no more PLRV than the potato crop from which they originated. But they were found to be an important reservoir of PVX with the infection increasing as much as 12.43% in one year. No aphids capable of transmitting PLRV were found although one species that can transmit potato virus Y was recorded. The mean density of volunteers varied from 0 to 84,880 stems/ha. The number of tubers remaining in the field after harvest and winter weather conditions appeared to be the only factors affecting volunteer density. Volunteer plants arising from seed pieces at an average depth of 6.1 cm were found to set an average of 2.1 new tubers per plant at an average depth of 4.0 cm. These results suggest that volunteer potatoes are a significant source of PVX infection in subsequent seed potato crops.  相似文献   

13.
《Field Crops Research》1996,48(1):11-25
There is little detailed information on yield accumulation in sugarcane under high-input conditions, which can be used to quantify the key physiological parameters contributing to yield variation. Sugarcane is grown under plant and ratoon crop conditions. This study analysed canopy development, radiation interception and biomass accumulation of two contrasting cultivars of sugarcane under irrigation during the same season under plant and ratoon crop conditions. Over the 15 month season, 11 crop samplings were conducted. Biomass partitioning to stalk was also measured to determine to what extent differences in partitioning between cultivars under ratoon and plant crop conditions contribute to differential productivity. The key findings were: (1) The ratoon crop accumulated biomass more quickly than the plant crop during the first 100 days of growth due to higher stalk number, faster canopy development and greater radiation interception. For similar reasons, cultivar Q138 had higher early biomass production than cultivar Q117 in the plant crop. (2) Early differences in biomass accumulation due to crop class became negligible at about 220 days because maximum RUE of the plant crop (1.72 ± 0.01 g MJ−1) was 8% higher than in the first ratoon crop (1.59 ± 0.08 g MJ−1). The higher maximum RUE in the plant crop was consistent with a higher crop growth rate (35.1 ± 2.3 versus 31.0 ± 3.4 g m−2 d−1) during the linear phase of biomass accumulation. (3) Biomass accumulation, which ceased about 300 days after planting/ratooning and 140 days before final harvest, attained similar levels of 53–58 t ha−1 in all four crops. (4) The plateau in biomass was associated with loss of live millable stalks, and not a cessation in the growth rate of individual stalks. The crops continued to intercept radiation while on the biomass plateau, so that average RUEs at final harvest were much lower than the maximum values. (5) There was no effect of crop class or cultivar on the fraction of biomass in the leaf and millable stalk components. This study emphasizes that maximising early radiation interception and biomass accumulation will not necessarily lead to higher yield in an environment where biomass production reaches a plateau well before final harvest. Loss of live millable stalks late in the crop cycle results in poor utilisation of intercepted radiation.  相似文献   

14.
《Field Crops Research》1988,18(1):45-56
Growth and tuber yield of perennial cassava crops of up to 4 years' duration were compared with those of annual crops in a subhumid subtropical environment where low winter temperature limits crop growth to 8–9 months per year.Resumption of growth by perennial cassava was rapid; sprouting occurred at many nodes in spring, and its canopy intercepted more solar radiation than did young annual crops. However, total biomass production during a season was generally slightly less than that of annual crops.After four seasons of cropping, four annual crops combined produced 49.4 t ha−1 of tuber dry weight. Corresponding yields for two 2-year crops, one annual plus one 3-year crop, and one 4-year crop, were 44.7, 40.3 and 38.1 t ha−1, respectively. The higher productivity of the annual crops was partly related to irrigation applied in the first three seasons to the annual crops. In the fourth season when no irrigation was applied to any crop, the annual increments of tuber weight in 2- and 4-year crops were similar to the tuer yield of the annual crop. It was concluded that productivity of a 2-year crop is 90–100%, and that of 3- and 4-year crops is 80–90%, that of annual cassava.  相似文献   

15.
Grain legumes, such as peas (Pisum sativum L.), are known to be weak competitors against weeds when grown as the sole crop. In this study, the weed-suppression effect of pea-barley (Hordeum vulgare L.) intercropping compared to the respective sole crops was examined in organic field experiments across Western Europe (i.e., Denmark, the United Kingdom, France, Germany and Italy). Spring pea (P) and barley (B) were sown either as the sole crop, at the recommended plant density (P100 and B100, respectively), or in replacement (P50B50) or additive (P100B50) intercropping designs for three seasons (2003-2005). The weed biomass was three times higher under the pea sole crops than under both the intercrops and barley sole crops at maturity. The inclusion of joint experiments in several countries and various growing conditions showed that intercrops maintain a highly asymmetric competition over weeds, regardless of the particular weed infestation (species and productivity), the crop biomass or the soil nitrogen availability. The intercropping weed suppression was highly resilient, whereas the weed suppression in pea sole crops was lower and more variable. The pea-barley intercrops exhibited high levels of weed suppression, even with a low percentage of barley in the total biomass. Despite a reduced leaf area in the case of a low soil N availability, the barley sole crops and intercrops displayed high weed suppression, probably because of their strong competitive capability to absorb soil N. Higher soil N availabilities entailed increased leaf areas and competitive ability for light, which contributed to the overall competitive ability against weeds for all of the treatments. The contribution of the weeds in the total dry matter and soil N acquisition was higher in the pea sole crop than in the other treatments, in spite of the higher leaf areas in the pea crops.  相似文献   

16.
Summary The growth and duration of crop leaf area determines the amount of solar radiation intercepted by the canopy and therefore influences the extent of photosynthesis, evaporation, transpiration and final dry matter yield. The objective of this study was to develop cultivar specific relationships to estimate the daily leaf area index (LAI) for the potato crop (Solanum tuberosum L.) that included the effects of available soil water. The model is divided into three LAI growth stages, the durations of which are partially related to potato heat units (PHU). The LAI in the first stage is estimated from a cultivar specific leaf area-based radiation use efficiency index with a soil water reduction factor. The second stage involves the maintenance of a constant LAI with the duration related to both PHU and a soil water index that can accelerate senescence. The final stage includes a decrease in the LAI from a maximum to zero in response to a cultivar specific PHU accumulation. Model simulations compared favourably with independent LAI measurements obtained with a LI-COR plant canopy analyzer over two seasons.  相似文献   

17.
河北省一季作区马铃薯主要病虫害有晚疫病、早疫病、黑痣病和二十八星瓢虫,此外,病毒引起的品种退化比较普遍,造成不同程度的损失。本文根据河北省一季作区马铃薯病虫害发生特点总结出一套综合防控技术体系,包括将马铃薯与玉米、大白菜等非茄科作物轮作3年减轻黑痣病危害;采用脱毒薯克服病毒引起的品种退化问题;种薯和(或)土壤消毒控制黑痣病和晚疫病;待马铃薯生长至封垄后,遇到适宜晚疫病发生的天气,喷施1～3次保护性杀菌剂预防晚疫病和早疫病;一旦监测到晚疫病中心病株后即拔除并装入塑料袋带出田外,并交替喷施有治疗效果、能兼治早疫病且作用机制不同的内吸性杀菌剂及混剂;田间出现马铃薯二十八星瓢虫成虫,在杀菌剂中混入高效氯氰菊酯或高效氯氟氰菊酯等高效杀虫剂防虫;马铃薯成熟前1～2周将地上部分割掉并运出田外后收获块茎。  相似文献   

18.
Yield Gaps and Ecological Footprints of Potato Production Systems in Chile   总被引：2，自引：2，他引：0  
  相似文献   

19.
Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed.  相似文献   

20.
The application of nematicides resulted in increased potato yields, and populations ofPratylenchus penetrans were lower for 3 years after application; but longevity of benefits of fumigating potato fields varied with the kind and amount of nematicide, application methods and with growing conditions after fumigation. Fumigation of two fields in the fall of 1965 with Vorlex, Telone, D-D, and mixtures of chloropicrin with Telone or D-D resulted in 70% to 90% control of the meadow nematode,P. penetrans, after two crops in one field, and 50% to 70% control after three crops in another. Yield increases of Kennebec potatoes averaged 42% and 16% in successive crops in the first field and yield increases of Katahdin potatoes averaged 13%, 22% and 16% in three successive crops in the other field. Fumigation resulted in 30 to 70% less vascular browning in tubers in the first two crops but there was no effect in the third crop. There was no effect on black scurf in any crop. Root injury varied proportionally with populations ofP. penetrans in roots in 1967. Populations ofP. penetrans regained injurious levels in three other fields after one crop when abundant root growth in moist 1967 followed spring fumigation with Telone and D-D. Under poor conditions for sealing of the soil following fumigation in the spring of 1968, counts ofP. penetrans collected at different soil depths after fumigation showed excellent kill below 3 inches and poorer kill in the upper 2 inches of soil.  相似文献   

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