Eine Vegetationstechnik zur quantitativen Bestimmung der Wasseraufnahme durch Wurzeln aus versalzten Rhizoböden

A vegetation technique to study the water uptake by roots from salinized rhizospheric soils The paper presents a vegetation technique to study the water uptake rate by roots, which are exposed to rhizospheric soils (soil in close vicinity of roots) of different combinations of soil osmotic and soil matrix water potential. The vegetation technique consists of two growth periods, a period of preculture and an experimental period. The aim of the preculture is to obtain series of homogenous plants growing each in a small pot filled with a densely rooted soil. At the end of the preculture all plants are very similar with respect to shoot and root development. The aim of the experimental period is to study the effects of various combinations of soil osmotic and matrix water potential on the water supply of plants. Thus the experimental period starts with supplying all pots with the same amount of water up to field capacity. In order to obtain different osmotic water potentials of the soil solutions, the water is differently salinized. Then the plants are exposed to constant climatical growth conditions. During the following days the water loss of the pots is determined hourly. The development of the matrix, osmotic and total soil water potential, the water uptake rate of the roots, the transpiration rate and growth rate of the shoots can be calculated from the water losses.     

Impact of soil texture on temporal and spatial development of osmotic‐potential gradients between bulk soil and rhizosphere

Solute transport from the bulk soil to the root surface is, apart from changes in soil moisture and plant nutrient uptake, a prerequisite for changes in soil osmotic potential (Ψ_o). According to the convection‐diffusion equation, solute transport depends on a number of parameters (soil moisture–release curve, hydraulic conductivity, tortuosity factor) which are functions of soil texture. It was thus hypothesized that soil texture should have an effect on the formation of Ψ_o gradients between bulk soil and the root surface. The knowledge about such gradients is important to evaluate water availability in the soil‐plant‐atmosphere continuum (SPAC). A linear compartment system with maize grown under controlled conditions in two texture treatments (T1, pure sand; T2, 80% sand, 20% silt) under low and high initial application of salts (S1, S2) was used to measure the development of Ψ_o gradients between bulk soil and the root surface by microscale soil‐solution sampling and TDR sensors. The differences in soil texture had a strong impact on the formation of Ψ_o gradients between bulk soil and the root surface at high and low initial salt application rate. At high initial salt application, a maximum osmotic‐potential gradient (ΔΨ_o) of –340 kPa was observed for the texture treatment T2 compared to ΔΨ_o of –180 in T1. The steeper gradients in osmotic potential in treatment T2 compared to T1 corresponded to higher cumulative water consumption in this treatment which can partly be explained by higher soil hydraulic conductivity in the range of soil matric potentials covered during the duration of the experiments. Differences between texture treatments in Ψ_o at the root surface did not result in differences in plant‐water relations measured as gas‐exchange parameters (transpiration rate, water‐use efficiency) and leaf osmotic potential. If soil osmotic and matric potential are regarded as additive in calculating the driving force for water movement from the soil into the root, the observed differences in water flux between treatments cannot be explained.     

Consequences of sodium exclusion for the osmotic potential in the rhizosphere – Comparison of two maize cultivars differing in Na+ uptake

According to the biphasic model of growth response to salinity, growth is first reduced by a decrease in the soil osmotic potential (Ψ_o), i.e., growth reduction is an effect of salt outside rather than inside the plant, and genotypes differing in salt resistance respond identically in this first phase. However, if genotypes differ in Na⁺ uptake as it has been described for the two maize cultivars Pioneer 3906 and Across 8023, this should result in differences in Na⁺ concentrations in the rhizosphere soil solution and thus in the concentration of salt outside the plant. It was the aim of the present investigation to test this hypothesis and to investigate the effect of such potential differences in soil Ψ_o caused by Na⁺ exclusion on plant water relations. Sodium exclusion at the root surface of intact plants growing in soil was investigated by sampling soil solution from the rhizosphere of two maize cultivars (Across 8023, Pioneer 3906). Plants were grown in a model system, consisting of a root compartment separated from the bulk soil compartment by a nylon net (30 μm mesh size), which enabled independent measurements of the change of soil solution composition and soil water content with increasing distance from the root surface (nylon net). Across 8023 accumulated higher amounts of sodium in the shoot compared to the excluder (Pioneer 3906). The lower Na⁺ uptake in the excluder was partly compensated by higher K⁺ uptake. Pioneer 3906 not only excluded sodium from the shoot but also restricted sodium uptake more efficiently from roots relative to Across 8023. This was reflected by higher Na⁺ concentrations in the rhizosphere soil solution of the excluder 34 days after planting (DAP). The difference in Na⁺ concentration in rhizosphere soil solution between cultivars was neither due to differences in transpiration and thus in mass flow, nor due to differences in actual soil water content. As the lower Na⁺ uptake of the excluder (Pioneer 3906) was only partly compensated by increased uptake of K⁺, soil Ψ_o in the rhizosphere of the excluder was more negative compared to Across 8023. However, no significant negative effect of decreased soil Ψ_o on plant water relations (transpiration rate, leaf Ψ_o, leaf water potential, leaf area) could be detected. This may be explained by the fact that significant differences in soil Ψ_o between the two cultivars occurred only towards the end of the experiment (27 DAP, 34 DAP).     

Der Einfluß der Kaliumkonzentration der ‘Bodenlösung’ auf den Ertrag,den Wasserverbrauch und die K-Aufnahmearten von Zuckerrüben (Beta vulgaris ssp. esculenta var. altissima)

The effect of the potassium concentration of the “soil solution” on the yield, the water consumption and the potassium uptake rates of sugar beets (Beta vulgaris ssp. esculenta var. altissima) . 1. The object of this experiment was to investigate which K concentration of the nutrient solution can be regarded as optimal for the growth of sugar beets. The nutrient medium was a quartz sand with a nutrient solution, of which the nutrient concentration could be controlled and corrected at any time due to a newly developed technique. Compared with a solution culture this technique enables a contact surface between the roots and the soil solution, which equals more field conditions. 2. The experment had three treatments with the following K concentrations: 0.2, 1A and 5.0 me K/1. These K concentrations were controlled and corrected by K additions and were kept approximately constant during the growing period. 3. The yields of beet roots and sugar of the treatment “0.2 me K” were significantly lower than the yields of the other two treatments. Although a K concentration of 5.0 me K means a considerable high concentration, the plants of this treatment did not show any depressive effects. Moreover this treatment (5.0 me K) showed the highest yield in beet roots and sugar, which, however, did not differ significantly from the yields of the treatment “1.0 me K”. It is concluded that this K concentration (1.0 me) of the nutrient solution can be regarded as optimal for sugar beet plants. Also under field conditions the order of magnitude of this K concentration in the soil solution may be optimal. 4. The daily uptake rates for K were the higher the K concentration of the nutrient solution was. This tendency was particularly obvious in the beginning of the growing period. In each treatments the highest K uptake rates were observed during the maximum leaf growth (2nd half of July). 5. High K uptake rates resulted mainly in a considerable increase of the K content of the leaves. But the total cation content (K, Na, Mg, Ca) of the leaves was not affected by these high K uptake rates. In the treatment “0.2 me K” the very low K content of the leaves was compensated quantitatively by higher contents of Ca and Mg. This replacement of K by Ca and Mg, however, could not substitute for the specific functions of K in yield formation. 6. The water consumption of the plants related to the weight unit beet roots was the lower the higher the K concentration of the nutrient solution was. Particularly during August and the 1^st half of September simultaneously with a higher production of organic material the better K supply resulted in an absolutely lower water consumption.     

Combination of micro suction cups and time-domain reflectometry to measure osmotic potential gradients between bulk soil and rhizosphere at high resolution in time and space

A prerequisite to investigate the importance of osmotic potential (Ψ_o) in relation to matric potential (Ψ_m) in the soil for water uptake is the existence of a method that measures the temporal and spatial dynamics of Ψ_o in the vicinity of roots. One method for measuring Ψ_oin situ is the collection of soil solution with micro suction cups, the spatial resolution of which is suitable for rhizosphere studies. A major drawback of soil solution sampling is the disturbance of soil solution equilibrium, which makes frequent measurements impossible, so another method is required to provide information on the temporal dynamics of Ψ_o. The time‐domain reflectometry (TDR) technique might be suitable as the signal attenuation (σ) shows a close linear correlation with the salt concentration for a known soil water content. The temporal resolution of the TDR technique is high and the measurement has no impact on soil solution equilibrium. However, the spatial resolution of the TDR technique is too coarse to be used on its own in rhizosphere studies. We used a combination of TDR (fine temporal resolution) and micro suction cups (fine spatial resolution) to measure Ψ_o in a model system with Zea mays grown in quartz substrates. Osmotic potential changed continuously with time, and a steep gradient between bulk soil and the root compartment developed during the 39‐day growing period. The steepest gradient measured over a distance of 6 mm across the nylon net, separating the bulk soil from the root compartment, was ?365 kPa. The combination of both methods made it possible to extend the time interval between micro suction cup samplings and thus minimize the impact of sampling on soil solution equilibrium. Problems of separate calibration were avoided by calibrating the TDR measurements against the results obtained with the micro suction cups within the same experiment.     

CONTRIBUTION OF PROLINE AND INORGANIC SOLUTES TO OSMOTIC ADJUSTMENT IN COTTON UNDER SALT STRESS

Physiological responses to salt stress were investigated in two cotton (Gossypium hirsutum L.) cultivars (Pora and Guazuncho) grown hydroponically under various concentrations of NaCl. Dry matter partitioning, plant water relations, mineral composition and proline content were studied. Proline and inorganic solutes were measured to determine their relative contribution to osmotic adjustment. Both leaf water potential (Ψ_w) and osmotic potential (Ψ_s)decreased in response to NaCl levels. Although Ψ_wand Ψ_s decreased during salt stress, pressure potential Ψ_p remained between 0.5 to 0.7 MPa in control and all NaCl treatments, even under 200 mol m^?3 NaCl. Increased NaCl levels resulted in a significant decrease in root, shoot and leaf growth biomass. Root / shoot ratio increased in response to salt stress. The responses of both cultivars to NaCl stress were similar. Increasing salinity levels increased plant Na⁺ and Cl^?. Potassium level remained stable in the leaves and decreased in the roots with increasing salinity. Salinity decreased Ca²⁺ and Mg²⁺ concentrations in leaves but did not affect the root levels of these nutrients. The K/Na selectivity ratio was much greater in the saline treated plants than in the control plants. Osmotic adjustment of roots and leaves was predominantly due to Na⁺ and Cl^? accumulation; the contribution of proline to the osmotic adjustment seemed to be less important in these cotton cultivars.     

不同盐分与水分胁迫对灰绿藜种子萌发效应研究

不同盐分与水分胁迫对灰绿藜种子萌发试验研究结果表明,>0 0 5mol/ L(PEG 6 0 0 0溶液渗透势为- 0 .2MPa)浓度盐溶液对灰绿藜种子萌发有明显抑制效应,而较低浓度盐溶液(较低渗透势PEG 6 0 0 0溶液)对种子萌发有促进作用。不同盐溶液对种子萌发抑制程度依次为MgCl2 >Na2 SO4>Na2 CO3 >NaCl>复合盐溶液>MgSO4。PEG 6 0 0 0溶液渗透势≤- 0 .5MPa时对种子萌发抑制作用小于等渗NaCl溶液。未萌发种子复水试验结果表明一定程度盐分与水分胁迫不影响种子萌发潜力,其萌发恢复率随原处理溶液抑制程度的增加而增加;种子萌发潜力未受影响时其忍受的最大渗透胁迫随处理溶液不同而异     

Growth and mineral absorption in maize seedlings as affected by increasing NaCl concentrations

The influence of NaCl solutions of decreasing osmotic potentials (¥π = ‐0.44 and ‐0.88 MPa) on seedling growth and on the concentration of the most important macro‐ and micro‐nutrients in the shoots and roots of maize (Zea mays L., cv. Summer II) grown in Hoagland's solution in a growth chamber was studied. Salt stress was imposed on six‐day‐old seedlings for a three day period. Increasing NaCl concentrations induced a reduction in the leaf water potential and a significant decrease in the length and dry weight of the shoots, whereas these two parameters decreased in the roots only at the lowest osmotic potential.

Although the absorption and accumulation of nutrients upon salt stress differed in the two treatments depending on the plant tissue and nutrient, almost all of the macronutrients decreased in the roots and shoots, showing the lowest values at ¥π = ‐0.88 MPa. Sodium and Cl increased continuously, much more in the roots than in the shoots.

A different response was seen in the shoots and roots in terms of micronutrients. In the roots, almost all of the ions reached their maximum concentrations at ¥π = ‐0.88 MPa; whereas in the shoots, they decreased at ¥π = ‐0.44 MPa without undergoing any further decrease at the lowest osmotic potential.     

Chloride content of onion roots and their adhering soil under irrigation with saline drainage water

Water depletion by plants in saline soils leads to the accumulation of salts in the soil in the close vicinity of the roots (= rhizopheric soil). CI^?/l. After a period of 4 days water depletion the Cl–contents of 2,5 to 4, s me CI^?/ 100 g soil were found in the rhizospheric soil of onions immediately after a water application, when irrigated with water containing 13 to 52 me Cl–content increased in the rhizospheric soil 3-4 fold up to 12 me CI^?/100 g soil corresponding to a CI–concentration in the rhizospheric soil solution of 800 me Cl-L The differences between the irrigation treatments were small. The CI–contents of the roots in this experiment varied from 1,2-1,9 me CT/g DM. When expressing the Cl–contents in terms of the cell sap of the roots, CI–concentrations of 1OC-200 me CI^?/I cell sap were abtained at a root water content of 90 %. Assuming a decrease in the root water contents to 70 % after a water depletion period of 4 days. CT-concentrations of 500-800 me Cl-ll cell sap are obtained, which corresponded to CI-concentrations determined in the rhizospheric soil solution.     

作物相对耐盐性的研究Ⅰ.大麦和小麦不同生育期的耐盐性

本文通过盆栽生物试验和室内培养试验，对大麦和小麦两种作物不同生长发育阶段的耐盐性进行了研究。结果表明，两种作物均在萌芽期、苗期和拔节孕穗期对土壤盐分最敏感。随土壤盐度增加，作物对钠的摄取量剧增，对钾的摄取量明显减少，对钙的摄取量在苗期和拔节孕穗期也有一定程度减少。此外，随土壤盐度增加，作物叶中Ｃａ／Ｎａ比和Ｋ／Ｎａ比均降低，其中尤以Ｋ／Ｎａ比的降低最显著，表明盐分胁迫下作物吸钠对钾吸收的影响最大。     

Mikrobielle Aktivitäten in landwirtschaftlich genutzten Böden Niedersachsens. I. Einfluß der ackerbaulichen Nutzung

Microbial activity of arable soils in Lower Saxony, Germany. I. Influence of agricultural practice A range of microbial functions were measured over four years in field trials on three soil types in Lower Saxony. Generally, glucose-induced short-term respiration and dehydrogenase activity were most susceptible to environmental influences. Higher microbial activity occurred under cereals than under sugar beets. Some microbial functions were affected by soil type and vegetation period. Furthermore, pesticide treatments of sugar beets inhibited some microbial functions.     

Kali-Düngeempfehlung auf der Grundlage von 81 K-Düngungsversuchen zu Getreide und Zuckerrüben auf Lößböden in Südniedersachsen

K-fertilization recommendation on the foundation of 81 experiments with small grains and sugar beets on ‘loes’soils in the southern part of Lower Saxony (West Germany) In no case was it possible to increase the grain yield of winter wheat and winter barley with K-fertilization. However, in the average of 24 experiments with sugar beets, K-fertilization increased significantly the sugar yield. The amount of K-fertilization necessary for sugar beets on the single fields could not be determined by the K soil analysis. Based on these results, which were received mainly on deep rootable and many years intensively fertilized ‘loess’soils, the following K-fertilization for a crop rotation of sugar beets and 2 × small grain is recommended: Independent of the K-content of soils for sugar beets 200 kg K₂O/ha should be applied if the crop residues remain on the field. However, for small grains a mineral K-fertilization is not necessary. If the residues are not returned to the soil the amount of K contained in the residues must be additionally applied.     

A comparison of transpiration rates of young rape plants grown on salinized soils of different texture

During periods of water depletion the water supply of plants from saline soils is reduced due to the simultaneous decrease of the soil osmotic and the soil matric water potential. Common models on the water uptake from saline soils assume a similar depressing effect of osmotic and matric water potentials on the water uptake by plants. As plants differ in their ability to overcome salt stress and soils differ in their water retention curves there is some doubt for the general validity of this assumption. The paper presents results of an experiment with rape grown in a sandy and a silty soil at three salinity levels. The transpiration rate of the plants was determined during a period of 34 hours and related to the total water potential of the two soils. In case of the silty soil, the transpiration was related to the total soil water potential at all salinity levels. In the sandy soil, however, the transpiration was much more affected by decreasing soil matric potential than by equivalent decreases of the soil osmotic potential. The results show that the effect of both potentials on the water supply of plants is not the same and has to be treated separately.     

Carbon mineralization in saline soils as affected by residue composition and water potential

In saline soils under semi-arid climate, low matric and osmotic potential are the main stressors for microbes. But little is known about the impact of water potential (sum of matric and osmotic potential) and substrate composition on microbial activity and biomass in field collected saline soils. Three sandy loam soils with electrical conductivity of the saturated soil extract (EC_e) 3.8, 11 and 21 dS m^?1 (hereafter referred to EC3.8, EC11 and EC21) were kept at optimal water content for 14 days. After this pre-incubation, the soils were either left at optimal water content or dried to achieve water potentials of ?2.33, ?2.82, ?3.04 and ?4.04 MPa. Then, the soils were amended with 20 g?kg^?1 pea or wheat residue to increase nutrient supply. Carbon dioxide emission was measured over 14 days; microbial biomass C was measured at the end of the experiment. Cumulative respiration decreased with decreasing water potential and was significantly (P?<?0.05) lower in soils at water potential ?4 MPa than in soils at optimal water content. The effect of residue type on the response of cumulative respiration was inconsistent; with residue type having no effect in the saline soils (EC11 and EC21) whereas in the non-saline soil (EC3.8), the decrease in respiration with decreasing water potential was less with wheat than with pea residue. At a given water potential, the absolute and relative (in percentage of optimal water content) cumulative respiration was lower in the saline soils than in the non-saline soil. This can be explained by the lower osmotic potential and the smaller microbial biomass in the saline soils. However, even at a similar osmotic potential, cumulative respiration was higher in the non-saline soil. It can be concluded that high salt concentrations in the soil solution strongly reduce microbial activity even if the water content is relatively high. The stronger relative decrease in microbial activity in the saline soils at a given osmotic potential compared to the non-saline soil suggests that the small biomass in saline soils is less able to tolerate low osmotic potential. Hence, drying of soil will have a stronger negative effect on microbial activity in saline than in non-saline soils.     

适宜涂膜预处理提高扇贝柱渗透脱水效率

溶质在渗透脱水过程中过多渗入组织不利于渗透脱水进程,同时对营养、感官特性与外观形态等均会产生不利影响。为了抑制渗透脱水过程中溶质过多渗入扇贝柱,提高渗透脱水效率,研究了壳聚糖、低甲氧基果胶与海藻酸钠等3种不同成膜预处理对扇贝柱渗透脱水过程中传质特性影响。采用Peleg模型拟合扇贝柱渗透脱水过程中传质和动力学参数;采用Fick’s第二扩散定律评估水分扩散系数（Dew）和溶质扩散系数（Des）以及渗透脱水效率（Dew/Des）。扇贝柱渗透脱水过程受到成膜材料种类、渗透溶液温度和氯化钠质量分数影响显著（P<0.05）。成膜预处理扇贝柱的水分损失和氯化钠渗入的初始速率与平衡速率均低于（P<0.05）未经涂膜的对照组。有效扩散系数随着渗透脱水温度的升高而增加,水分和氯化钠有效扩散系数范围分别为1.224×10-9～2.466×10-9 m2/s和1.152×10-9～1.894×10-9 m2/s。成膜预处理可在维持较高失水率的同时有效地控制高温渗透脱水过程中氯化钠的渗入。海藻酸钠与低甲氧基果胶成膜预处理后扇贝柱的脱水效率（Dew/Des）高于（P<0.05）对照组。然而,对于壳聚糖成膜预处理,当氯化钠液质量分数高于30%或者质量分数为20%且温度为25℃时,扇贝柱脱水效率高于（P<0.05）对照组。扇贝柱渗透脱水过程中,为了调控固形物增加和提高渗透脱水效率,成膜预处理是一种行之有效的方法,具有广阔的应用前景。     

土壤有效水分与化肥相互作用机理及其应用研究——Ⅰ.化肥的盐(度)指数

本文应用电导法测定了12种化肥在纯水和三种土壤真溶液中的盐(度)指数。结果表明:①不同化肥的盐指数差别很大,以硝铵为100时,变化在8(ssp)到118(kc);②以实物计量比养分量更能表达不同化肥的盐指数差异;③不同化肥在纯水和土壤真溶液中的盐指数趋势相似。尿素应以土壤真溶液法测定为准;④电导法与渗透压法测得的盐指数值及其排列顺序相似。化肥盐指数是一个重要参数,对土壤持水量和有效水供应有明显影响,是选择种肥、确定复混肥配方、施肥量和施肥技术等的重要依据。     

土壤有效水分与化肥相互作用机理及其应用研究——Ⅰ.化肥的盐(度)指数

本文应用电导法测定了12种化肥在纯水和三种土壤真溶液中的盐(度)指数。结果表明:①不同化肥的盐指数差别很大,以硝铵为100时,变化在8(ssp)到118(kc);②以实物计量比养分量更能表达不同化肥的盐指数差异;③不同化肥在纯水和土壤真溶液中的盐指数趋势相似。尿素应以土壤真溶液法测定为准;④电导法与渗透压法测得的盐指数值及其排列顺序相似。化肥盐指数是一个重要参数,对土壤持水量和有效水供应有明显影响,是选择种肥、确定复混肥配方、施肥量和施肥技术等的重要依据。     

Einsatz der Taupunktmethode zur Charakterisierung von Matrix- und osmotischem Potential in einer Gefäßkultur mit unterschiedlichen Salzgehalten

Use of the dew point method to determine matrix- and osmotic soil water potentials in pot cultures under different salt stress Water consumption of festuca rubra was investigated under different salt stress as measured by the dew point method. Water content of the soil, total tension and water consumption was measured daily. At the end of the growing season the low salt stress plants had used nearly completely all water available and were under water stress. Plants under medium salt stress reduced transpiration in time and showed highest water content in the soil and in the plants after growing season. For the high salt stress plants the total water potential remained low due to the osmotic component. Dew point measurements were compared with other methods (Cl-concentration; electric conductivity). A close correlation was found in all cases, demonstrating the usefulness of the dew point method.     

The composition of the soil solution as influenced by fertilization and nutrient uptake

The composition of the soil solution in unfertilized and well-fertilized plots of three long-term field experiments has been determined at the beginning and at the end of the growing season. All the plots were manured and the K and P fertilizers given in the autumn before the growth of sugar beet. N was applied in the spring, 3–4 weeks before the first soil sampling.The soil solution was removed at a pressure of 5 atm. The composition and the corresponding osmotic pressure were calculated for the moisture contents at field capacity and wilting point.In spring the salt concentrations, cations + anions, at the field capacity were in the range 91–97 mmoles/l in the fertilized plots. In autumn the concentration had dropped to 13.9–20.3, a decrease of 78–85%. At the wilting point, the concentrations in spring were as high as 211–307 mmoles/l and in autumn 31.5–69 mmoles/l. The corresponding osmotic pressures at field capacity in the spring ranged 2.2–2.3 atm. and at wilting point 5.1–7.4 atm.In spring the unfertilized plots showed concentrations of 16–21 mmoles/l and osmotic pressures of 0.38–0.51 atm., the values decreasing 52–65% during the growing season.It was pointed out that the high soil-solution concentration and osmotic pressure at low moisture contents may lead to an unfavourable effect on root metabolism. Further, the obscuring effect of the varying soil-solution concentration on the relationships between root ion exchange and nutrient uptake by plants has been discussed.     

C- und N-Festlegung in Böden Südostniedersachsens nach Krumenvertiefung

Enrichment of C and N in soils of southeastern Niedersachsen after deepening of top soil In a comprehensive study, the effects of deepening of top soil during the last 20 years on C-organic-and N-total-masses of some selected arable land sites have been analyzed. The sampling sites represent soil groups predominating in southeastern Niedersachsen. In 145 plots of 22 agricultural farms with the rotation sugar beets/winter wheat/winter barley, sugar beets/winter wheat/winter wheat respectively, the actual depth of plow horizon varies from 32 to 38 cm in summer. Organic matter has been analyzed in 125 soils. A C-org.- and N-total-balance sheet has been prepared for the time after deepening of the top soils. In luvisols with a top soil deepening of about 10 cm a period of 15 years has been necessary for aquirement of the C-content before deepening. A C-enrichment up to 15 t/ha was recorded with incorporation of plant residues in the last 15 years. During this period up to 1,5t of N/ha accumulated assuming constant C/N-ratios. For chernosems, a similar rate has been determined. In sandy cambisols, the short period of observation of 10 years and less after top soil deepening did not permit a complete reenrichment with organic matter. The ”?potentially”? possible enrichment with organic C amounts to 14–17 t/ha (= 1,4–1,7 t N). Furthermore, luvisols gave a significant correlation between clay- and C-amounts of non deepened soils. A weak interrelation has also been found between clay content and the enrichment potential of organic matter in these soils.