Untersuchungen zur Optimierung der N-Aufnahme von Winterweizenbeständen durch ergänzende Düngungmaßnahmen

Investigations on supplemental N-fertilizer application for the optimum course of N-uptake into winter wheat stands
During a period of 5 years 14 N-fertilization field trials with winter wheat have been carried out in which N-uptake and biomass production in 6 growth stages were analysed. By comparison with non-optimal variants of N-supply a critical range for N-uptake has been recognized which centered around an optimum value of 86 kg biomass N/ha at growth stage EC32. In connection with intensified N-uptake during later growth stages, this has allowed full exploitation of the wheat yield potential without substantial decrease of the N-harvest index.
Field trials on two different soil types (Parabraunerde and humose Auenrendzina), different dates of sowing and long year stands in wheat monoculture as well as applications of N-fertilizers containing dicyandiamid for delay of nitrification showed differences in efficiency as related to the fertilizer dosages but no systematic deviation from the optimum course of N-uptake for full exploitation of yield potential.
Provided that excessive fertilizer dosages before EC32 had been avoided, it seems possible to adjust the reuptake of winter wheat stands close to its optimum within an error of not more than 30 kg fertilizer N/ha by growth stage oriented splittings of fertilizer application and adequate account of soil-N supply and weather conditions during early growth stages.
Full exploitation of the wheat yield potential has been possible in all trials without significant losses in N-use efficiency if optimal splittings and dosages of supplemental N-fertilizers were provided.     

Stärke- und Amylosesynthese in Samen von Mark- und Futtererbsen

Changes of clay soils under organic and conventional farming
Chemical, mineralogical and soil-physical measurements were performed on clay soils, which were cultivated under conventional and organical production system for the last 14 years. Soils in the organic system [TNL soils] were loosened from 10–35 cm and organic residues and manure were incorporated into the 0–10 cm layer by a rotowator. Soils in the conventional system [TKL soils] were plowed to a depth of 22 cm. Humus and nitrogen reserve and the amount of mobile phosphate in the top soils of the TNL soils were higher than in those of the TKL soils. The exchangeable potassium in the top soil was higher in TKL soils than in TNL soils, whereas the organic system (TNL) showed a more equal distribution within top and subsoil. This observation was confirmed by measurements of the mobile potassium (ARo-values).
The contents of 2:1 layer silicates with expanded layers was lower in the top soil of TKL soils than in TNL soils. This can be explained by the reduced application of liquid manure (Gülle) and the missing application of potassium fertilizer on TNL soils. The layer charge of the expanded minerals ranged from -0.80 to -0.68 for the vermiculites, and from -0.45 to -0.35 for the smectites, per formula unit respectively.
No influence on the percentage of the fine and mid pores was found. The amount of slow draining large pores (Ø 50-10 μm) was higher in TNL soils than in TKL soils, only in a neighbouring pasture soil the proportion of these pore exceeded those of TNL soils. Measurements of pore continuity did not show such a clear difference between TKL and TNL soils, but was higher for TNL soils.     

Amyloplastenentwicklung und Stärkesynthese in Samen von Futter- und Markerbsen

Development of amyloplasts and starch synthesis in seeds of field and garden peas
Amyloplast development and changes in starch and amylose content in seeds of field and garden peas ( Pisum sativum ssp. sativum and ssp. medullare) was studied from flowering to maturity in view of a possible relationship between amyloplast form and starch composition.
Starch and amylose contents increased at different rates in both subspecies. In field peas starch content had reached the maximum (44 % in DM) 26 days after flowering with 45 % amylose in total starch. In garden peas, 25 days after flowering, starch content had only reached half of its maximum (32 % in DM) with an extremely high amylose proportion (88 %). At that growth stage form and size of amyloplasts were similar in both subspecies. There seems to be no tight relationship between form of amyloplasts and proportion of amylose in total starch.
But then, when amyloplasts abruptly increased in size those of garden peas disrupted suddenly. This disruption is not due to a high amylose content. Because in a cross-breeding of field and garden peas, which was also investigated, the amyloplasts had remained intact irrespective of a high amylose proportion (63 %). The disruption may be due to differences in arrangement of starch molecule and in structure of plastid envelope.     

Strahlungsnutzung durch Bestände ölreicher Körnerfruchtarten — Winterraps, Öllein und Sonnenblume im Vergleich

Radiation use by oil seed crops — a comparison of winter rape, linseed and sunflower For the production of grain crops rich in oil, winter rape, linseed and sunflower are similarly suitable at many arable locations. We wanted to compare the extent to which radiation (PAR) is intercepted and utilized by the individual species for dry matter and yield production. For this purpose, a 2‐year field experiment comprising the factors genotype, N fertilization and soil tillage was conducted. For five phases of crop development, growth rates (CGR, RGR and NAR) and PAR utilization were calculated. At full ripeness, total dry matter, grain, oil and energy yields, the crop‐ and year‐specific PAR supply, its interception and utilization for dry matter production and the resulting energy binding were determined. Due to the different individual vegetation periods, the PAR supply of the crops differed. The crop assimilation areas also differed, with values for winter rape and sunflower higher than those for linseed. The yield productivity of winter rape and sunflower was also higher than that of linseed. N fertilization increased yield to different extents for the different crops. On average, winter rape and sunflower produced the same amounts of dry matter and energy yield. Due to a higher harvest index, sunflower had the highest grain yield, and because the oil concentration in grain was comparatively high sunflower produced the highest oil yield, too. Under cool and wet climate conditions, however, the productivity of sunflower is offset by a relatively high yield risk because of uncertain ripening. The highest PAR utilization by linseed did not compensate for its very short vegetation period in combination with the lowest PAR interception.     

Stärke- und Amylosegehalte in blattreichen und blattarmen Sorten von Mark- und Futtererbsen

Influence of ascending nitrogen supply on the development of Rhizobium symbiotic bacteria on peas ( Pisum sativum L. ssp. sativum ) in nutritive culture solution
The effect of ascending N-supply with 4 different levels from 0.1 to 1.56 mg atom/L culture solution on juncture, quantity and development of Rhizobium bacteria on peas variety Stehgolt was thoroughly investigated. Contemporaneously, all the inoculated plants set on several noduls. The number of nodules formed per plant was negatively and hasty influenced by the ascending N-supply. Higher N-provision lessen the number of Rhizobium nodules per plant, however, these few achieved their active N₂-Fixation phase (Leghämoglobin formation stage) earlier than those formed under insufficient N-supply.     

Einfluß von Bodenbearbeitung, Kulturart und Zwischenfruchtanbau auf den Bodenabtrag und den Oberflachenwasserabfluß

The effects of different soil tillage systems, crop rotations and short time cover crops on soil losses and runoff
Soil and water losses were carried out from 1979 to 1986 on a pseudogley-parabrownearth of the farm Ihinger Hof throughout the growth period of green maize and sugar-beet, both planted by plough and rotary hoe. From 1983 to 1986 the effect of short time soil cover crops (October—Dezember) were also studied.
The soil losses under rotary hoe were significantly lower in comparison to plough, but the differences in runoff between the tillage treatments were not significant. Under sugar-beet the erosion caused by rainfall was less than under maize. From the short time soil cover crops, the legume mixtures were found to have the best influence on soil and water conservation, and on the maize growth as well. There was no relationship between runoff or rainfall amount and soil losses. The soil losses correlated strongly to EI₃₀-indices, and this means that the USLE equation of W ischmeier and S mith (1965) can be applied in our experimental Farm in Ihinger Hof.     

Einfluß der Bestandesdichte auf Ertrags- und Qualitätskriterien sowie über mögliche Ursachen der Konkurrenz in Zuckerrübenbeständen

Influence of Plant Density on Yield and Quality and Possible Causes of Competition in Sugar Beet Crops
In trials conducted over 9 years at 1 location plant densities ranged from 35,000 to 110,000 plants/ha. Root yield, sugar yield and white sugar yield reached maximum values at 92,700, 94,700 and 96,000 plants/ha, respectively. The decrease in yield per 1,000 plants/ha was greater as the plant density fell. The quality criteria (sugar concentration, white sugar concentration and sugar gain) were at their maxima at 107,000, 104,600 and 100,000 plants/ha, respectively, and they decreased at an almost constant rate as plant density declined. The concentrations of potassium, sodium and amino-N, the main factors which determine quality in Germany, as well as the sugar loss were all minimized at about 110,000 plants/ha and they increased at a progressively-greater rate per 1,000 plants/ha as plant density declined. The maximum differences between large and small plant densities were: root yield 13.6%, sugar yield 16.7%, white sugar yield 18.6%, sugar concentration 3.7%, white sugar concentration 5.3%, sugar gain 1.7%, sugar loss 9.3%, potassium concentration 8.4%, sodium concentration 30.5% and amino-N concentration 25.4%. As well as a comparison of the yield and quality criteria, the paper considers competition within the foliage, particularly when different amounts of nitrogen are available, as the main cause for yield differences between sugar beet crops.     

Einfluß von Form und Plazierung der N- und P-Düngung auf Wurzelentwicklung, Phosphat-Aufnahme und Wachstum von Sonnenblumen (Helianthus annuus) und Zuckerhirsen (Sorghum bicolor)

Influence of form and placement of N- and P-fertilisation on the root development, the P-uptake, and the growth of sunflower ( Helianthus annum ) and sweet sorghum ( Sorghum bicolor ).
In pot- and rhizotrone-experiments with Sorghum bicolor and Helianthus annuus , a higher P-uptake was achieved by placement of diammonphosphate (DAP) than by either placement of triplesuperphosphate (TSP) or by broadcasting DAP or TSP, respectively. Dual placement of TSP and ammonia increased the P uptake but it was less effective than placement of DAP for sunflowers, but not for sweet sorghum. Placement of nitrogen resulted in a local root accumulation, where ammonia had a greater effect than nitrate for both of the species. Single placement of TSP had no effect on either P uptake or root development.
Thus, the higher P uptake at DAP placement could be attributed to three main factors: the local root accumulation caused by the placement of nitrogen, a specific physiological ammonia-effect, and the lower binding intensity of the phosphate in the DAP-band compared with placed TSP (W erner and S trasser 1993). The improvement in spatial availability caused by the NH₄⁺ -induced root accumulation was of a greater importance for the P-uptake than was the improvement of chemical availability in the DAP-band. The better response of sunflowers in comparison with sweet sorghum was attributed to better acquisition ability in sweet sorghum.     

Stickstoffausnutzungsvermögen von Lolium perenne und Lolium multiflorum-Sorten

Selection for improved nitrogen-utilization in Lolium
In a 3-year study the responses of 14 Lolium perenne-varieties and 14 of Lolium multiflorum to different nitrogen fertilization (75, 150, 300 kg N/ha) were investigated. The varieties were classificated into four types of nitrogen utilization. "Low input varieties" can be found in type III. The varieties of this type produced always the highest yield at all levels of nitrogen fertilization. The yield of type I was always smaller than the average of all varieties. The varieties of type II gave significant better responses than the trial average up to 150 kg N/ha. Under low and high N-fertilization the type III can be separate of type I and II because it is always the outstanding variety. The dry matter production of the roots did not show varieties differences under the increasing N-fertilization. The soil nitrate contents were with 20 kg nitrate nitrogen per ha very small.     

Untersuchungen zum Einfluß von Standort, Saatstärke, N-Düngung, Sorte und Erntezeitpunkt auf den Ertrag und die Inhaltsstoffe von Zuckerhirse

Investigations into the effect of location, planting density, N-fertilization, variety and harvest date on yield and contents of sweet sorghum
Looking for high yielding plant species as renewable resources, sweet sorghum ( Sorghum bicolor [L.] Moench) seems to be an interesting crop.
In field trials at three locations in the south-west of Germany in 1983 and 1984 should be investigated the effect of N-fertilization, planting density, variety and harvest date on yield, different morphological characteristics and contents of sweet sorghum.
The results indicate that yields of 15-20 t DM/ha are only feasible when the given temperature sum is higher than 2000 °C (> 5°C). The maximum yield of 22.7 t DM/ha resp. 6.5 t/ha "Free Fermentable Sugar" (FFZ) was realized when a sufficient water supply and N-fertilization had been guaranteed.
The different possibilities of utilization of sweet sorghum e.g. as sugar crop, agricultural raw material for combustion or as forage crop urge the plant breeder to intensify the breeding efforts adapting this crop at the climatic conditions of Germany.     

Zum Einfluß von Untersaaten zur Begrünung von Ackerbrachen auf die Vegetationsentwicklung und die Nitratdynamik

The influence of undersown green manure crops for fallows – set-aside land – in view of vegetation-development and the dynamic of nitrate
In view of the establishment of rotational fallows - set-aside land - as well as the bridging of the vegetation-free winter period the suitability of different undersown grasses and legumes m winter cereals was investigated in field trials. Festuca rubra developed well in winter barley and winter wheat. The success of the cultivation of Lolium perenne, Trifolium pratense and Trifolium repens in winter cereals is uncertain because of the risk of light and water deficiences. Dactylis glomerata caused an negative influence on the yield of the cover crop. During the fallow period only low levels of nitrate could be found in the soil. Under fallow tilled repeatedly complete fallow- a nitrate accumulation could be observed during the fallow period. After ploughing up the fallow vegetation, nitrate concentrations - depth 0–150 cm – increased to 60 kg NO₃-N · ha^-1 after the natural fallow without seeding, between 60 and 130 kg NO₃-N · ha^-1 after Trifolium and between 160 and 210 kg NO₃-N · ha^-1 after complete fallow. Lowest nitrate levels were observed from the grass-sites. Undersown Festuca rubra seems to be the best choice in order to compete with weeds, to form a dense sod and to prevent nitrate leaching. In general a seed rate of 8 kg · ha^-1 can be recommended.     

Einfluß von sterilisiertem und nichtsterilisiertem Stallmist und Kompost auf die Effizienz der VA-Mykorrhiza

Effect of sterilized and unsterilized stable manure and compost on the efficiency of VA mycorrhiza
Under greenhouse conditions, it was examined how the three organic manures stable manure, compost out of stable manure and compost out of plant rests in comparison with the corresponding amounts in sterile and homogeneous form, influence the efficiency of VA mycorrhiza cultivated with Capsicum annuum. The manures had been added in 4 stages of concentration: 50, 100, 200 and 300 dt/ha.
In the unsterile treatment the generally positive efficiency of VA mycorrhiza on plant yield decreased with increased amounts of the organic manures. How fast this reduction took place, was dependent on the different kinds of manures. The effect of the inoculation were much better in the unsterile treatment, compared with the sterile one, when the offer of the possible nutrient sources by the manures were low and the relation of the nutrients in the soil solution were unfavorable. The activity of the soil microorganisms always have played a decisive role for this results.     

Vorfruchtwirkungen verschiedener Blattfrüchte auf Winterweizen und Einfluß von Anbaumaßnahmen

Effects of preceding "break crops" on winter wheat and influence of cultural practices
Between 1979—83 there was tested the effect of 5 "break crops" (biennial alfalfa, clover-grass, faba bean, winter-rape, silomaize) on succeeding winter wheat and the interaction with changed cultural practices such as N-fertilization and conventional or reduced primary tillage (plough ↔ rotary tiller).
After the break crops wheat yield decreased within a range of 4 dt/ha as follows: alfalfa → beans → rape/ clover-grass/maize. Raising N-fertilization hardly allowed to improve the value of the break crops; most likely that of maize and with rotavating. Adaption of N-dressings promised greater influence.
The manner of primary tillage exerted stronger influence on the yield than the level of N-fertilization. Concerning long-term yield the rotary tiller equaled the plough after 4 break crops; after faba bean it was superior. Increasing N-fertilization tendentially favoured the rotary tiller after bean, rape and maize. Using the rotary tiller, at beginning of growth there may be calculated on 15 % higher NO₃-values and/or higher N-mineralization or N-transformation.
Eyespot disease could not be prevented sufficiently and purposefully by an other break crop, N-fertilization or primary tillage. Recurrent rotavating suppressed weed less than ploughing.     

Aufnahme und Verwertung von Phosphor und Kalium durch CCM-Mais bei differenzierter PK-Düngung

Uptake and utilization of phosphorus and potassium by CCM-maize in relation to different PK-fertilization
The influence of different PK-fertilizer-application (0/500/1000 mg P pot⁻¹ with 6 kg soil before seeding and as fluid or granuled fertilizer to 15 cm plant height in combination with 0/1500 (3000 mg K - pot⁻¹) on PK-uptake and dry matter production of CCM-maize for six different stages of development was investigated.
For all six times a distinct connection between quantity of P-fertilizer and P-content resp. -uptake is described. For potassium is these not so clear, although the uptake is quicker than phosphorus. In combination of PK-proportions and PK-content resp. -uptake draw a conclusions on the yield, but not in consideration PK-proportions resp. -uptake only. Limitation values are discussed. P-applications to 15 cm plant height is little effective.     

Sorten-Mischungseffekte in Wintergerstenbestanden in Abhängigkeit von Standort und Produktionsintensität

Cultivar mixture effects in winter barley as dependent on location and production intensity
Grain yields of high-yielding six-rowed winter barley cultivar mixtures were compared with those of pure stands under different production intensities in field trials over two years and two locations. Generally, mixing effects tended to be positive with low and negative with high intensities. Significantly negative mixing effects could be observed each year at both locations with highest production intensity. Significantly positive mixing effects could be observed in one year at one location only- Mixing effects could not be explained by the observed levels of diseases and lodging. There were, however, relatively close correlations between mixing effects on grain yields and on grain numbers/m²     

Das Penetrationsvermögen von Wurzeln unterschiedlicher Roggen- und Triticalegenotypen in Abhangigkeit von der Bodenlagerungsdichte

The penetration capability of different rye and triticale varieties in dependence on the soil bulk density By means of a laboratory test the primary roots of 9 rye and 4 triticale varieties were tested for their capability of penetrating overcompactions. The roots served as “natural probes” and as a mark of genotypic differences. The test was carried out in the stages 1.50, 1.65 and 1.80 g/cm³ of soil bulk density. The soil substrate (faint loamy sand) consisted of 5.4 % of clay, 13.8 % of silt, 80.8 % of sand and 0.6 % of total C_t. The tested corn roots respond to compacted soil structures with considerable differences in the rootability. These level differences are not only specific marks for species but also for varieties within the species. Though most of the tested corn varieties respond with restricted root growth in compacted soil, the results cause the expectation that single varieties have a good adaptability to overcompacted soil and can tolerate it better than other ones. At the specific bulk density limit of faint loamy sand (1.50 g/cm³) all tested varieties have an intensive root growth. The rootability of triticale varieties is clearly reduced at the bulk density of 1.65 g/cm³; the roots of rye varieties, however, grow without essential restrictions in this range. Against all expectations the root growth of single rye varieties is similarly intensive as in loose soil at the bulk density of 1.80 g/cm³. Other rye varieties respond very sensitively and with considerable restrictions in root growth in this range. Since a characteristic increase of roots' diameter is to be observed with increasing bulk density, no differences in the root dry matter, caused by bulk density, can be found out. The applied experimental method permits a first selection of plant varieties, which could be interesting in future in view of the mark “Penetration performanc” of primary roots.     

Zum Einfluß von Saatzeiten, Saatstärken und Sorten auf agronomische Merkmale von Winterweizen in einem System mit geringer Betriebsmittelzufuhr von außen

The influence of sowing date, seed rate, and variety on agricultural characteristics of winter wheat in a low external input system
Growth conditions of winter wheat in agricultural low external input systems, e.g. ecological agriculture, are very different compared to conventional agriculture (mineral nutrition, impact of diseases, competition of weeds). In 1986, 1987, and 1988 the influence of sowing date and seed rate on crop development and grain production was studied with two varieties of winter wheat in field experiments in Northern Hessia.
Drilling after the first decade of October decreases grain yield of both varieties significantly. The decrease was due to poor emergence, low plant densities, and low grain weights. Tillering could not compensate low plant densities, presumably because of low mineralization of nutrients in cold soils during respective growth stages.
Variation of seed rate (350, 500, and 650 viable seeds/m²) had little influence on grain yield. Low plant densities and low numbers of ears per nr after sowing in the end of October could not be improved satisfactorily by increased seed rates.
The ability of varieties of winter wheat to compensate unfavourable growth conditions due to "late" sowing varies considerably. Cultivars which are able to develop a high plant density seem to be more suitable for delayed sowing dates, as compared to varieties which own a high grain weight.
Further investigations concerning wheat production are needed to optimize agricultural low external input systems. Especially sandy soils with quick response to increased ambient temperature, and sites with favourable growth conditions in late autumn and early spring should be considered.     

Untersuchungen über die Wirkung von Ammonium- und Nitrat-Ernährung auf die Ertrags- und Proteinbildung bei Hafergenotypen

Investigations about the effect of ammonium- and nitrate nutrition on the formation of yield and protein of oats genotypes
The formation of yield and proteins of three different oats genotypes (cv. Gambo, Flämingskrone, Caesar ) in dependence on ammonium or nitrate nutrition was investigated in pot trials over 2 years (from 1982 to 1983). On oats the NH₄-nutrition showed in comparison to NO₃ nutrition increases in grain yield up to 20 % due to a favourable influence on the number of panicles per pot (s. Fig. 1).
Protein content and protein yield increased particularly by high fertilizing with NH₄-N (N₃- and Invariant); the best effect was ascertained by the N₄-variant increase of 4 % (D.M.). Among the protein fractions (albumins, globulins, prolamins, glutelins) the albumin- and prolamin-proteins increased after NH₄-fertilizing by 1–2 %, whereas at the same time the glutelins decreased by 1–4 %; the globulins showed no differences.     

Auswirkungen differenzierter Bodenbearbeitung auf das Bodengefüge und die Stickstoffdynamik von Lößböden bei viehloser und viehstarker Bewirtschaftung

Effect of different tillage practices on soil structure and nitrogen dynamic in loess soils with and without longterm application of farmyard manure
Field trials were conducted in 1979 and 1980 on two farms with and without longterm application of farmyard manure respectively, to study the effect of different tillage practices (ploughing at low soil moisture in summer and autumn and ploughing at highsoil moisture in autumn) on soil structure and nitrogen dynamic. Soil structure measurements showed great differences between ploughing at low and high soil moisture contents. Ploughing soil at high moisture contents caused a rise in penetrometer resistance as in bulk density and a decrease of macropors as well as in oxygen concentration in top soil and in tillage pan. But little differences were observed between ploughing in summer and autumn at low soil moisture contents.
Ploughing soil at high moisture contents caused a higher soil compaction on the farm without longterm application of farmyard manure compared to the farm with longterm application of farmyard manure.
The differences in soil nitrate content were strongly correlated with soil compaction. Very large differences in soil nitrate content between ploughing at low and high soil moisture contents were always observed in May, when the soil temperature was higher than 15°C These differences in soil nitrate content are due to reduced nitrogen mineralization and an increase of denitrification activity after ploughing at high soil moisture contents.