Einfluß des Standortes, der N-Düngung, der Sorte und des Erntezeitpunktes auf den Ertrag an fermentierbaren Zuckern bei Topinamburkraut und -knollen

Effect of location, N-fertilization, variety and harvest date on the yield of fermentable sugars of Jerusalem artichoke tops and tubers
In the past, the production of fermentable sugar with Jerusalem artichoke ( Helianthus tuberosus L.) resulted nearly exclusively from tubers.
It should be investigated to what extent the tops can be used beside tubers as a source of fermentable sugars, connected with studies about diverse components of yield and morphological characteristics.
In field trials at three locations in the south-west of Germany in 1983 and 1984 yields of "Total Fermentable Sugars" (TFZ) with Jerusalem artichoke tops up to 6.7 t/ha were achieved according to variety, N-fertilization and harvest date. While harvesting Jerusalem artichoke tubers yields of TFZ up to 8.3 t/ha had been feasible.
The presented correlations between components of yield and morphological plant characteristics refer to interesting mechanisms of reaction and dependence on the formation of yield with this crop. The high yield level of Jerusalem artichoke and its adaptability to different locations also present this crop as an interesting renewable biomass crop for the south-west of Germany.     

Effects of cover crops on soil mineral nitrogen and on the yield and nitrogen content of maize

Current agricultural practice favours winter cover crops, which can not only optimize N management in field crop rotation; but also affect subsequent crops. Three field experiments were carried out in Eastern Slovenia to examine the effects of Italian ryegrass (Lolium multiflorum Lam.), winter rape (Brassica napus ssp.oleifera (Metzg.) Sinsk), subclover (Trifolium subterraneum L.), and crimson clover (Trifolium incarnatum L.) as winter cover crops on the mineral N (N_min) content of soil and on the yield and N content of subsequent maize (Zea mays L.), fertilized with 120 kg N ha⁻¹. Italian ryegrass and winter rape decreased soil N_min contents before winter and in spring more than both clovers. In contrast, clovers accumulated significantly higher amounts of N in organic matter and had lower C/N ratios than winter rape and especially Italian ryegrass. In comparison to the control (bare fallow without cover crop), clovers increased the whole above ground maize dry matter yield, maize grain yield and N contents in whole above ground plants and in grain. The yields and N contents of maize following winter rape were on the same level as the control, while yields and N contents of maize following Italian ryegrass were, in two of the experiments, at the same level as the control. The effects of Italian ryegrass on the maize as subsequent crop in the third experiment were markedly negative. Maize in the control treatment exploited N much more efficiently than in treatments with cover crops. Therefore, cover crop N management should be improved, especially with a view to optimizing the timing of net N mineralization in accordance with the N demands of the subsequent crop.     

The influence of crop sequence on fungicide and herbicide use intensities in North German arable farming

The reduction of pesticide use intensity is a societal and political ambition. Crop rotation is one important method to control pests and diseases in arable farming. We investigated the contribution of crop rotation to the variability of herbicide and fungicide use of 60 farms in four regions of Northern Germany. Our study aimed at answering the question: do diverse crop sequences lead to reduced herbicide and fungicide use in arable farming?Ten-year data on chemical plant protection measures and field management were examined for six field crops. We classified crop sequences (triplets of three succeeding crops) according to their susceptibility for weeds and diseases (= ’riskiness’). The Treatment Frequency Index (TFI) of the last crop in the triplet was set in relation to the crop triplet riskiness, additionally also in combination with tillage.In general, herbicide and fungicide use intensities were smaller in more diverse crop sequences. Diversified cereal sequences, involving roots and tubers, maize or spring cereals were less dependent on herbicides. Cultivation of maize in three subsequent years increased herbicide use. Crop sequences including high proportion of winter cereals increased fungicide use in cereals, while roots and tubers, winter oilseed rape and set-aside in the crop sequence decreased it. In winter oilseed rape, sequences with roots and tubers also increased fungicide use. In sugar beets, sequences with maize or a high concentration of sugar beets led to increasing fungicide use. If farmers chose riskier crop sequences tillage by plough decreased the need for herbicide and fungicide use.To reduce herbicide and fungicide use intensities we recommend increasing the diversity of crop rotations, including a higher number of crops per rotation together with ploughing. Simplifying both crop sequence diversity and tillage intensity implies higher use of herbicides and fungicides. Results will be useful for convincing farmers to diversify crop sequences.     

Growth dynamics of winter wheat in the field with daily fertilization and irrigation

In a field experiment with fertilized and irrigated winter wheat the above-ground crop was sampled once a week. Phenological development, plant density and canopy height were recorded and the green surface areas of leaves, stems and ears were measured. Soil mineral nitrogen was sampled and the field climate monitored. There were four treatments. The daily irrigated/fertilized (IF) and daily irrigated (I) treatments were both irrigated by a drip-tube system. Liquid fertilizer was applied to IF following a logistic function according to calculated plant uptake. A total of 200 kg N ha⁻¹ was applied. Treatment I, control (C) and drought (D) were all fertilized once in spring with 200 kg N ha⁻¹. In treatment D transparent screens were used to divert rainwater. Dry matter production ranged between 1400 in D and 2352 g m⁻² in IF. The corresponding amount of nitrogen uptake ranged between 15.8 and 24.6 g m⁻². After harvest, soil mineral nitrogen was lowest in IF.
An increase in the availability of nitrogen and water enhanced total biomass production as well as grain yield and leaf area. The daily supply of nitrogen according to crop demand delayed nitrogen uptake and increased total uptake. The results suggest that when the nitrogen is supplied in accordance with crop demand, the efficiency with which the applied fertilizer is utilized increases and the risk for nitrogen leaching decreases.     

Harvest Dates, Fertilizer and Varietal Effects on Yield, Concentration and Molecular Distribution of Fructan in Jerusalem Artichoke (Helianthus tuberosus L.)

In a pot experiment two varieties of Jerusalem artichoke ( Helianths tuberosus L., cv. Topianka and cv. Violet de Rennes ) were exposed to different supplies of N, P and K. Nitrogen supply increased tuber yield more than the productivity of aerial parts. Violet de Rennes responded better to N than Topianka. Nutrient regimes without P or K addition but including N to some extent depressed the yields of tubers only (by 8–23 %). Carbohydrate concentrations (78–81 % of d.m.) and molecular fructan distributions were neither influenced by fertilizer regimes nor by mineral concentrations in the tubers.
Genotypic differences were significant for yield, for concentrations of N, P, Ca, S and Cu, and for fructan concentration in the tubers. At harvest time the fructose/glucose ratio in tubers of Violet de Rennes was about 10 % higher than in Topianka and remained on a higher level during storage.
Harvest time had the greatest influence on carbohydrate composition. Depolymerization of fructan proceeded at a high rate in November and slowed down during subsequent storage, accompanied by a decline in polydispersity. Simultaneously osmolanty increased, resulting in a freezing point depression of < 0.5 °C.     

Effects of Seeding Rate on Growth Duration and Accumulation and Partitioning of Dry matter in Oats

Crop management influences considerably the three components of grain yield, growth duration, growth rate, and harvest index (HI). Effects of seeding rate on these yield components in oats ( Avena sativa L.) was assessed in field experiments at the Viikki Experimental Farm, University of Helsinki, Finland (60°13'N) in 1991 and 1992. Three Finnish oat genotypes were evaluated; a long-strawed landrace cultivar, a moderately long-strawed modern cultivar, and a semi-dwarf breeding line. The following traits were measured: grain yield, days from sowing to yellow ripeness, number of tillers on main shoot, phytomass, vegetative phytomass, and their growth rates (PGR and VGR, respectively), panicle weight and its filling rate (PFR), HI, leaf area index (LAI), and at intervals, dry-matter accumulation in leaves and straw.
Increases in seeding rate significantly decreased growth duration and PGR of individual plants but increased PGR on a ground area basis. Seeding rate did not, however, affect HI. When seeding rate was increased from 200 seeds m⁻² to 500 seeds m⁻², reductions in vegetative phytomass, panicle weight, VGR, and PFR for individual plants ranged between 20 and 40 %, depending on genotype. At ≥600 seeds m⁻² differences in these components between seeding rates were modest. However, PGR, VGR, and PFR per unit ground area increased with increasing seeding rates up to 600–700 seeds m⁻². Moreover, the higher the seeding rate, the higher the peak LAI (2.7 maximum) and the earlier the canopy closure. Hence, our results showed that a seeding rate of 600–700 seeds m⁻², which resulted in uniculm growth habit, is advantageous in terms of grain yield at high latitudes due to higher biomass accumulation and subsequently greater interception of PAR.     

The Effect of Preceding Crop and Pre-Sprouting on Crop Growth, N Use and Tuber Yield of Maincrop Potatoes for Processing Under Conditions of N Stress

Factorial field trials were carried out on an experimental farm near Kassel, Germany, in two consecutive seasons (2003 and 2004) in order to examine the impact of leguminous and cereal preceding crops (i) on soil N availability under subsequent potatoes and (ii) the effect of preceding crop and pre‐sprouting of seed tubers on crop development, N uptake, N utilization efficiency and total and size‐graded tuber yields relevant for processing into either crisps or French fries. In addition, an approach to analyse complex field experiments using mixed models is discussed. Soil mineralized nitrate‐N at emergence of the potato crop was affected by the preceding crop and was highest when potatoes followed peas, while the short‐term alfalfa/grass/clover ley appeared too sensitive to environmental conditions in the preceding cropping season, and its efficiency in terms of N supply may be hard to predict. Pre‐sprouting advanced crop development and dry matter accumulation of the canopy, translocation of assimilates and N from canopy into tubers and allowed an increased N utilization efficiency. The positive effect of pre‐sprouting on total tuber yield was compensated up to the final harvest, but a higher percentage of marketable tuber yield for French fries (>50 mm) was found independently of the date of harvest. An increasing N supply (after peas and a following catch crop) may be efficient in terms of higher yields of the marketable size‐grades (40–65 mm) for crisps, but increase oversized tuber yields in seasons not affected by Phytophthora infestans. Average tuber fresh weight responded consistently and positively to seed‐tuber preparation (pre‐sprouting), cultivar (cv. Agria) and an increased N supply (after peas).     

华北寒旱区作物轮作的生产效应

To understand mechanisms of crop adaptability to various previous crop croppings, evaluate crop performance on the croppings, and identify suitable crop combinations for rotation of major crops in the cold and arid region of Northern China. A five-year field experiment was conducted using five crops from 2015 to 2019, including potato (Solanum tuberosum), faba bean (Vicia faba), forage maize (Zea mays), oat (Avena sativa), and beet (Beta vulgarwas). Yields of potato, oat, and beet in rotation were 1.30-1.68, 1.28-1.48, and 1.25-1.48 times of those in continuous cropping of single crops, respectively. Yield of faba bean on beet cropping was 10.58% lower than that of continuous faba bean while yield of forage maize on oat or beet stubble was 9.10%-15.42% lower than that of continuous forage maize. The LERr of 10 crop combinations was 1.09-1.68, indicating positive effects of rotation. Combinations of oat → potato, beet → potato, forage maize → potato and faba bean → potato had higher LERr, indicating faba bean and forage maize might be more durable of continuous cropping. In terms of productivity, suitable crop combinations for rotation in the area were oat → potato, beet → potato, forage maize → potato, faba bean → potato and oat → beet.     

Stickstoffaufnahme und Stickstoffrückstände von Hauptfrucht-und Ausfallrapsbeständen

Nitrogen Uptake and Nitrogen Residuals of Winter Oil-Seed Rape and Fallout Rape
The objective of the investigation was a study of the relationship between seed dry-matter production and vegetative dry-matter production in oil-seed rape crops and their dependence on the production conditions. In addition to the relationship between the N-uptake during the vegetation period and the N-residue after harvest was of major interest. Furthermore the potential for N-uptake in fallout rape was measured. Over two vegetation periods factorial field experiments with winter oil-seed rape, cv. Lirabon, different drilling techniques and different nitrogen fertilization levels were tested. Measured traits were: the dry-matter accumulation including root mass and fall-off leaf-material mass, the N-uptake of both the oil-seed crops and the fallout rape stands, and, simultaneously, the soil NO₃-N content. Finally the harvest indices and the N-harvest indices were calculated.
Combined with a N-uptake of up to 330 kg N/ha, oil-seed rape crops produced up to 200 dt dry matter/ ha. At seed yield levels of 33dt/ha (d.m.), harvest indices varied from 0.14—0.23 and N-harvest indices varied from 0.30–0.50. As a result of the residue of vegetative plant material at harvest, leaf losses before harvest and the soil NO₃-N-contents at harvest up to 275 kg N/ha remained in the field. After the harvest of oil-seed rape, the soil NO₃-N-contents were quickly reduced by emerging and growing fallout rape stands. However, following soil-preparation measures in the autumn, a continuous rise in the soil NO₃-N-content was observed.     

不同发育时期菊芋块茎DNA提取效果比较研究

为筛选菊芋块茎DNA提取的适宜生育时期,以“青芋1号”菊芋品种为试材,用改良CTAB法对不同发育时期菊芋块茎DNA进行提取,经琼脂糖凝胶电泳及全波长分光光度计检测总DNA的纯度、浓度及质量,选用4条ISSR引物进行PCR验证.结果表明:不同发育时期提取菊芋块茎DNA效果较好,DNA浓度呈现单峰曲线变化,峰值出现在第9周,与琼脂糖凝胶电泳检测呈现的亮度结果一致,PCR验证结果显示,提取的DNA能够满足后续相关分子生物学的要求.     

The Effects of Ethephon, Chlormequat Chloride and Mixtures of Ethephon and Chlormequat Chloride Applied at the Beginning of Stem Elongation on Spike-Bearing Shoots and other Yield Components of Spring Barley (Hordeum vulgare L.)

Effects of chlormequat chloride (CCC), ethephon and mixtures of CCC and ethephon, applied at Zadoks growth stage (ZGS) 30 (the beginning of stem elongation) on the number of spike-bearing shoots and their contribution to grain yields of four spring barley ( Hordeum vulgare L.) cultivars were studied in 1987 and 1988 at McGill University, Quebec, Canada. The results varied between years and among cultivars. The mixtures of CCC and ethephon or ethephon alone, produced significant increases in the number of spikes m⁻² in cultivars Joly and Laurier , in both years, and in Leger only in 1988. Ethephon and ethephon containing mixtures reduced the yields of Joly and Leger in 1988. In both years CCC had no effect on spikes m⁻² for all cultivars. Increases in spikes m⁻² were accompanied by decreases in 1000-grain weight, and/or grains per spike, which offset or more than offset potential benefits from increased spikes m⁻². These results indicate that under continental climatic conditions such as those prevalent in Quebec, Canada, application of PGRs to spring barley at ZGS 30 does not increase grain yield through an increased number of spikes m⁻².     

Genetic Variability for Mineral Concentration in the Forage of Jerusalem Artichoke Cultivars

Summary One of the potential uses of Jerusalem artichoke (Helianthus tuberosus L.) is as a forage crop. Information on inherent differences in forage nutritional quality is essential if the quality of the forage is to be improved through breeding. The objectives of this study were to determine the genotypic variability among and within forage of Jerusalem artichoke cultivars for the concentration of N, P, Ca, Mg, K and the Ca/P ratio at flowering, to determine if selection among and within cultivars is feasible, to estimate the magnitude of the genotype × environment interaction, and to examine the relationships among mineral concentrations in the forage. Ten cultivated Jerusalem artichoke cultivars grown in an irrigated field nursery at Bushland, TX were evaluated for N, P, Ca, Mg, K, and the Ca/P ratio in the forage at flowering over a 2-yr period. Cultivars, cultivar × year, and error variances were estimated to calculate the phenotypic variance. Estimates of the within-population variances were also determined. The adequacy of Jerusalem artichoke forage at flowering for maintenance of a ruminant animal was classified as follows: N, Ca, Mg, K as adequate, P inadequate, and the Ca/P ratio as excessive. There were genotypic differences among the ten cultivars for N, P, Ca, Mg, K, and the Ca/P ratio for both years and averaged across years. The magnitude of the genotypic variance components indicated that a substantial proportion of the total variation for these elements was due to cultivar, indicating the possibility of improving these elements. However, further studies on heritability and response to selection will be required before conclusions can be reached concerning the likelihood of successfully breeding for these traits.     

黑河绿洲区耕作土壤有机碳及其活性和非活性组分固碳潜力研究

土壤有机碳固碳潜力研究是陆地生态系统碳循环中的前沿领域,可为区域农业碳管理和温室气体减排提供依据。文中选择黑河绿洲区水田为研究对象,采用实地土壤样品采集、室内指标分析和模型模拟方法,研究了表层0-20cm土壤不同粒径与土壤TOC、AOC、NOC之间的关系,在此基础上建立了土壤TOC、AOC和NOC物理化学固碳潜力模型并估算固碳潜力。结果显示：绿洲农田土壤存在较大的固碳空间,TOC、AOC、NOC固碳潜力平均值分别为0.75%、0.14%、0.56%。并以中游绿洲水田为例,计算了土壤TOC、AOC、NOC碳密度、碳储量及其潜力,水田中TOC、AOC、NOC碳密度的潜力为0.18 g/cm2、0.03 g/cm2、0.15 g/cm2,水田中TOC、AOC、NOC碳储量的潜力为7.12 Tg、1.13 Tg、5.79 Tg。分析发现水田中NOC的碳密度和碳储量提升的空间明显高于AOC,说明NOC的提高是TOC固碳的关键。     

滨海盐碱地中垄作模式对菊芋生长及养分吸收的影响

菊芋具有很强的环境适应性,种植菊芋对改良滨海盐碱地并提高土壤固碳量有很大的潜力。为了提高菊芋在滨海盐碱地中的生物量及固碳量,采用垄作模式栽种,探讨菊芋的生长及土壤养分吸收过程,从而为更好地种植菊芋提供依据。结果表明,垄作处理可显著提高菊芋产量、生物量及养分吸收量,菊芋产量可提高约15%,全株干物质量提高47%,生物固碳量提高29%。垄作模式有利于滨海盐碱地中菊芋产量提高与固碳量增加。     

Genotypic variability and genotype by environment interactions for inulin content of Jerusalem artichoke germplasm

Genetic variations in germplasm and genotype × environment interaction (G × E) are important for crop improvement. The objectives were to explore genetic variation in Jerusalem artichoke germplasm and to evaluate G × E interaction for inulin content. Seventy-nine accessions of Jerusalem artichoke were evaluated in a randomized complete block design with two replications for three seasons. Significant variation in inulin content (55.3–74.0% dry weight) was observed and the genotypes with high inulin content could be identified although there was intermediate G × E interaction. Genotypes were also significantly different for days to maturity, fresh tuber yield, biomass and harvest index and G × E interactions for these traits were also significant. The correlation between inulin content and days to maturity was not significant (r = −0.20), whereas inulin content and fresh tuber yield were significantly associated (r = 0.22). JA 37 and CN 52867 are promising for high yield and inulin content.     

Italian ryegrass establishment by self-seeding in integrated crop–livestock systems: Effects of grazing management and crop rotation strategies

We evaluated the re-establishment of an Italian ryegrass pasture by self-seeding on a no-till integrated crop–livestock systems (ICLS) in the southern region of Brazil. This work is part of a long-term experimental protocol initiated in 2003. We tested the effects of various management practices, such as summer crop systems (soybean vs. maize–soybean rotation), stocking methods (continuous vs. rotational) and grazing intensities (low vs. moderate), on Italian ryegrass pasture establishment. In addition, we tested resilience of the system by testing pasture's ability to re-establish following a year without seed head production. The experiment consisted in the rotation, on the same area, of Italian ryegrass pasture grazed by sheep during the winter and up to the end of the grass production cycle, and soybean or soybean–maize grain crops rotation cultivated during the summer. The pasture established itself by self-seeding since 2005. Data were collected in 2011 and 2012 stocking season. The soybean summer crop, continuous stocking and low grazing intensity, all positively affected the production of reproductive tillers in 2011. Grazing intensity in 2011 strongly influenced early vegetative tiller densities (before crop harvest) in 2012. However, none of the grazing intensity or the stocking method treatments affected herbage mass at the end of pasture establishment in 2011 or 2012. On the other hand, the soybean summer crop positively affected pasture establishment, both in term of tiller densities and herbage mass at the end of pasture establishment. The removal of all seed heads in 2011 (preventing seed production) resulted in the total failure of pasture establishment in 2012. Overall, Italian ryegrass establishment by self-seeding relies on the annual replacement of the soil seed bank. This experiment demonstrated that under various stocking methods, moderate grazing intensity and maize or soybean summer crop, Italian ryegrass pasture establishment by self-seeding remains successful even when the stocking periods extended up to the end of the grass production cycle. Self-seeding with moderate grazing intensity ensures successful pasture establishment, reduces labour and costs and allows to increase the stocking period and so animal live weight gain over the grazing season.     

Nitrogen Fixation, Growth and Yield of Intercropped Mungbean (yigna radiata L.) and Groundnut (Aracbis bypogaea L.) as Affected by the Genotype

¹⁵N-aided investigations were conducted to ascertain the Nj fixation and the nitrogen (N) contribution by mungbean ( Vigna radiata L.) and groundnut ( Aracbis hypogaea L.) when intercropped with maize ( Zea mays ). The study involved growing seven genotypes of the above legumes with maize in alternate rows in two separate experiments. A sole crop of maize was used as the reference crop to determine N2 fixation by the ¹⁵N methodology. Significant genotypic differences in pod yield and stover N content were observed in intercropped mungbean and groundnut. The percentage N derived from the atmosphere showed a genotypic variation of 31 to 45 % (7 to 10 kg N₂ fixed ha⁻¹O in mungbean and 47 to 69 % (9 to 18 kg N₂ fixed ha⁻¹) in groundnut. Harvest index for N varied from 58 to 77 % in mungbean and 55 to 75 % in groundnut. In groundnut, the uptake of soil N was significantly affected by the genotype. Assuming that the N contribution to the soil by the helow-ground plant parts was negligible, the removal of seeds at maturity resulted in a negative N balance in the soil in all the genotypes of mungbean. In groundnut, some genotypes produced a positive N balance in the soil. Owing to high N₂ fixation capacity and low harvest index for N, groundnut showed a greater N supplementing ability than mungbean.     

Indentification of strong and weak yield determining components of winter oilseed rape compared with winter wheat

Yield formation of winter oilseed rape was compared with that of winter wheat in terms of absorption of PAR, radiation use efficiency and harvest index by means of crop growth simulation. Cumulative incoming PAR from April 15 until maturity, cumulative absorption of PAR, radiation use efficiency and harvest index were lower for winter oilseed rape compared with winter wheat. To improve potential seed yield of winter oilseed rape, a crop type with increased cumulative absorption of PAR, radiation use efficiency and harvest index is desirable.     

Effects of previous cropping on seed yield and yield components of oil-seed rape (Brassica napus L.)

Information about the effect of the preceding crop or crop combination on the seed yield of oil-seed rape is extremely scarce. Experiments were carried out in northwest Germany to investigate the effect of different preceding crops on the growth, seed yield and yield components of oil-seed rape. The two directly preceding crops, wheat and oil-seed rape, had only a negligible and non-significant effect on the seed yield of the following oil-seed rape crop. Oil-seed rape grown after wheat had more pods per plant, due to an increase in the number of pods on the higher category branches. In contrast, the seed yield and yield components were more affected by the cropping sequence, i.e. the crops 2 years before. Averaged over two experimental years, the greatest yields were observed in oil-seed rape following the sequence peas-wheat (694 g m⁻²), whereas the smallest seed yield occurred after 2 years of oil-seed rape cropping (371 g m⁻²). The differences in the seed yield were again associated with more pods per plant, which compensated for the lower number of plants m⁻², whereas the number of seeds per pod and the mean seed weight were almost unaffected by the previous cropping. It was not possible to relate the described differences to the crop development, since differences in the biomass caused by the previous cropping were only significant at maturity. Oil-seed rape grown after 2 years of oil-seed rape had the highest ratings of stem canker (Leptosphaeria maculans) as well as verticillium wilt (Verticillium dahliae). But the general level of the diseases was low, and therefore other causes for the effects described must be considered.     

Ertragsbildung von getreidereichen Fruchtfolgen und Getreide-monokulturen in einem extensiven und intensiven Anbausystem

Yield formation in cereal-rich crop rotations and monocultures in an extensive and intensive crop-management system
In a long duration trial, conducted from 1979/80 to 1992 at TU-Munich's research station in Roggenstein, the performance of monocultures of winter wheat, winter barley and winter rye, as well as numerous cereal-crop rotations were compared in an extensive and intensive crop-management system. The results obtained can be summarized as follows.
Over the course of 13 years, the influence of the immediately preceding crop on the yield of the main crops was of much greater significance than the rotation as a whole. With winter wheat, no yield differences could be observed between monoculture and cereal crop rotation (if the rotation did not include oats). Oats, rape, field bean, pea, potato and maize as preceding crops, however, in crop management systems, led to, on average, an increase in yield of 13 dt/ha from the following wheat. Winter barley yields were not significantly different in monoculture, cereal crop rotations and crop rotations containing 66% cereals. Furthermore, winter rye yields were the same in monocultures and cereal crop rotations. With all cereals, intensification of fertilizing and chemical plant protection led to a considerable increase in yield, but did not diminish the effects of the preceding crop. Hence, even with the use of modern agronomical techniques it is impossible to compensate for yield losses due to crop rotation.