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.     

Abstracts of nippon Dozyohiryogaku Zasshi

The present study was carried out to analyze the factors that affected the growth of sugar beet in four different soil types by using concrete-framed plots as follows: soil acidity (soil pH, exchange acidity y ₁) and nitrification of fertilizer introduced by row application. Comparison of the value of the exchange acidity y ₁ of the four soil types with the pH value adjusted to the same level (pH 5.1) revealed that the Humic Gray Upland soil displayed the highest y ₁ value (y ₁: 18.0), followed by the Humic Volcanogenous Regosol (y ₁: 6.9), Haplic Brown Lowland soil (y ₁: 5.3), and Low-humic Andosol (y ₁: 2.2). Al release to the soil solution was considered to occur at soil pH values of 4.8 and lower except in the Low-humic Andosol. Al concentration in the soil solution of the Low-humic Andosol was substantially lower than that of the other soils. On the other hand, the soil pH value decreased temporarily by nitrification of the fertilizer introduced by row application, especially in the Humic Gray Upland soil. In this case, the soil pH value became lower than 4.8 for a time. At this pH level, Al release to the soil solution was assumed to occur. As described above, the soils displayed different properties in terms of soil acidity. In the four soils, although the growth of sugar beet was significantly related to both soil pH and exchange acidity y ₁ values before sowing, these relations were not strictly valid. On the other hand, the linear correlation coefficients of the relationships between the growth of sugar beet (leaf length) and NO₃-N content in rows were higher than those of the soil pH and exchange acidity y ₁. No appreciable variation associated with the differences in the soil types was observed in this relation. Furthermore, the values of both soil pH and exchange acidity y ₁ were closely related to the NO₃-N content in rows and the relationship between the NO₃-N content and y ₁ value appeared to be somewhat closer than that with the soil pH. These closer relations had two important implications. Firstly, NO₃-N content reflected the nitrogen nutrient conditions. NO₃-N promoted the growth of sugar beet directly. Secondly, the NO₃-N content was affected by the soil acidity, which is expressed by the value of the exchange acidity y ₁. Low NO₃-N content indicated indirectly the toxicity of soil acidity to sugar beet growth. It was thus suggested that in the present study, nitrification of the fertilizer expressed by the NO₃-N content was a beneficial factor for the growth of sugar beet regardless of the soil types. Finally, to promote the nitrification of fertilizer and to minimize the Al toxicity enhanced by the decrease of the soil pH associated with nitrification, it is important to avoid low values for the soil pH.     

Micronutrient Levels in Sugar Beet in Soils of Greece

A survey was conducted in order to estimate micronutrient levels in plants and soils of 215 farms in Greece cultivated with sugar beet. Soils were analyzed for particle-size distribution, pH, organic carbon (C), CaCO₃, and DTPA-extractable copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn). Sugar beet leaves were analyzed for the same metals. Also, aboveground biomass (top), root, and raw sugar yields were recorded. DTPA-extractable Fe and Mn were above critical levels in all cases, whereas Cu and Zn were above critical levels in 49% and 24% of the soil samples, respectively. Concentrations of the four metals in plant tissue were similar or higher than the sufficiency range. Concentrations of DTPA-extractable Fe and Mn, and plant Zn and Mn, were significantly and negatively correlated with soil pH. Soil pH and DTPA-extractable Fe seemed to have a significant positive impact on root, top, and raw sugar yields. However, in all cases, less than 14% of the variance of the sugar beet parameters was explained by soil characteristics.     

Effects of Tea Plant Compost and Mineral Nitrogen Levels on Yield and Quality of Sugar Beet Crop

A field experiment was carried out during two successive seasons of 2009–2010 and 2010–2011 at Sakha Agriculture Reseach Station, Egypt, to study the effects of different applications of compost tea (C) under three mineral nitrogen (N) levels and their interaction effects on sugar yield and juice quality characteristics of sugar beet (Beta vulgaris L.), and soil available nutrients. Results indicated that the sugar yield and juice quality characteristics of sugar beet were significantly increased with compost tea treatments, especially in the plots treated with compost tea foliar application in three batches. A quality percentage of sugar beet was increased about 8.0% in the plots treated with compost tea or interaction between N mineral N and compost tea treatments above the control treatment. The interaction between mineral N and compost tea treatments had a significant effect on sugar yield, sugar percentage, purity, and quality of sugar beet and soil fertility.     

Water stability of soil aggregates and their ability to sequester carbon in soils of vineyards in Slovakia

Soil water-stable aggregation is an important process for carbon sequestration and is a key factor controlling soil sustainability and resilience; therefore, the objectives of the present study were to (1) evaluate the differences in soil organic matter state, its specific and labile fractions and their importance in the formation of water-stable aggregates in vineyard soils differing in their genesis and texture under different soil management (vineyard rows – tilled and grassed in-between strips), and (2) estimate the ability of the vineyard soils to sequester soil organic carbon (SOC) into water-stable macro-aggregates (WSA_ma). The results showed that the WSA_ma content of the soils ranged from 47% to 97%. Soils with grasses had a higher SOC and labile carbon (C_L) contents than the bulk soil and, as a result, the higher total WSA_ma content. Soils ranged in a decreasing order in their ability to sequester SOC and C_L from bulk soil to WSA_ma: Haplic and Stagni-Haplic Luvisols > Calcaric Fluvisol = Rendzic Leptosol > Haplic and Luvi-Haplic Chernozem > Dystric and Eutric Cambisols. Our results showed that the maximum ratio of SOC content in WSA_ma to that in bulk soil was 1.0 at the maximum WSA_ma content regardless of the soil type. An increase in the ratio above this threshold value (1.0) resulted in a decrease in WSA_ma content.     

Der Einfluß von P-Ernährung und pH auf die Phosphataseaktivität von Zuckerrübenwurzeln

The influence of phosphorus nutrition and pH on phosphatase activity of sugar beet roots For the determination of acid phosphatase activity (P_ase) of sugar beet roots (cultivar: Reka), plants were cultivated in nutrient solution with 1 or 100 μM P in a growth chamber for 12, 18, 24, 30, 36 and 42 days. The phosphatase activity of intact roots was measured in buffer solutions with pH 4 to 7.2 and 14 mM p-Nitrophenylphosphate (NPP) after 10 min of incubation at 20°C. The influence of P nutrition on P_ase activity was significant at all intervals. At P deficiency the activity was increased by a factor of 4 to 20. During the experimental period the pH optimum was 6. At pH 5 and 7.2 the P_ase activity reached only 63 and 64% respectively of the optimum value. At P deficiency (1 μmol P L^—1) the absolute rate of NPP-hydrolysis at pH 6 was 144 nmol min¹ m¹ root length (day 12 to 36). The plants which received optimum P supply showed only 10% of this value. Sugar beet roots with P deficiency have a high potential of P_ase activity from the acid to the neutral pH-range. Therefore, under this condition they may effectively use dissolved organic phosphorus compounds.     

Sugarcane yield and plant nutrient response to sulfur-amended Everglades histosols

High soil pH causes leaf nutrient deficiencies and reduces sugarcane yield. Soil pH in Florida histosols has been increasing as these soils subside and depth to limestone is decreased. A factorial experiment of four sulfur (S) rates and three added calcium carbonate (CaCO₃) levels in soil was designed to determine S-amendment effectiveness in reducing pH and increasing nutrient availability in sugarcane as calcium (Ca) carbonate levels were increased. Sulfur-amendment and increased CaCO₃ level had limited effects on yield and leaf nutrient concentrations during the growing season. Most leaf nutrients were within optimum range except nitrogen (N), phosphorus (P), iron (Fe), and manganese (Mn). Unexpected increases in Mn concentrations with added CaCO₃ were associated with reducing conditions due to increased soil bulk density. High soil pH caused Mn deficiencies in the plants. Soil pH, P and Mn concentrations were important factors in predicting sugarcane yield.     

Potassium‐fertilizer management in winter oilseed‐rape production in China

Optimal potassium (K) fertilization is beneficial for oilseed‐rape (Brassica napus L.) yield and quality. However, the discrepancy between the high K demand of winter oilseed rape and low soil fertility and insufficient potassium input has limited the sustainable development of oilseed‐rape production. A series of on‐farm experiments in the key winter oilseed‐rape domains of China was conducted from 2004 to 2010 to evaluate K‐fertilizer management for winter oilseed rape. Currently, the average NH₄OAc‐extractable K content in the 0–20 cm soil layer is 89.1 mg kg^–1 indicative of “slight deficiency”. In addition, farmers in China usually fail to use sufficient K fertilizer in oilseed‐rape production, the average mineral‐potassium‐fertilizer input in 2010 being only 35 kg K ha^–1, far lower than the recommended rate of potassium for winter oilseed rape. Adequate potassium fertilization significantly raises seed yield. The average yield‐increase rate for the major production regions due to K‐fertilizer application was 18.5%, and the average K fertilizer–use efficiency 36.1%. Based on the negative correlation between yield response to potassium fertilization and available soil K content, a soil‐K‐test index was established for winter oilseed rape with a threshold value for NH₄OAc‐extractable soil K of 135 mg kg^–1. When available soil K‐content is below this threshold value, more K fertilizer should be applied to achieve high seed yield and to increase soil fertility. The major challenge for K‐fertilizer management in winter oilseed‐rape production in China will be to guide farmers in the different regions in making reasonable use of K fertilizer through soil K‐testing technology in order to maintain both seed yield and soil fertility.     

Effects of land use and mineral characteristics on the organic carbon content,and the amount and composition of Na‐pyrophosphate‐soluble organic matter,in subsurface soils

Land use and mineral characteristics affect the ability of surface as well as subsurface soils to sequester organic carbon and their contribution to mitigation of the greenhouse effect. There is less information about the effects of land use and soil properties on the amount and composition of organic matter (OM) for subsurface soils as compared with surface soils. Here we aimed to analyse the long‐term (≥ 100 years) impact of arable and forest land use and soil mineral characteristics on subsurface soil organic carbon (SOC) contents, as well as on amount and composition of OM sequentially separated by Na pyrophosphate solution (OM(PY)) from subsurface soil samples. Seven soils with different mineral characteristics (Albic and Haplic Luvisol, Colluvic and Haplic Regosol, Haplic and Vertic Cambisol, Haplic Stagnosol) were selected from within Germany. Soil samples were taken from subsurface horizons of forest and adjacent arable sites continuously used for >100 years. The OM(PY) fractions were analysed for their OC content (OC_PY) and characterized by Fourier transform infrared spectroscopy. Multiple regression analyses for the arable subsurface soils indicated significant positive relationships between the SOC contents and combined effects of the (i) exchangeable Ca (Ca_ex) and oxalate‐soluble Fe (Fe_ox) and (ii) the Ca_ex and Al_ox contents. For these soils the increase in OC (OC_PY multiplied by the relative C=O content of OM(PY)) and increasing contents of Ca_ex indicated that OM(PY) mainly interacts with Ca²⁺. For the forest subsurface soils (pH < 5), the OC_PY contents were related to the contents of Na‐pyrophosphate‐soluble Fe and Al. The long‐term arable and forest land use seems to result in different OM(PY)‐mineral interactions in subsurface soils. On the basis of this, we hypothesize that a long‐term land‐use change from arable to forest may lead to a shift from mainly OM(PY)‐Ca²⁺ to mainly OM(PY)‐Fe³⁺ and ‐Al³⁺ interactions if the pH of subsurface soils significantly decreases to <5.     

Einfluß 85jähriger differenzierter organischer und mineralischer Düngung auf Bodeneigenschaften im Statischen Versuch Bad Lauchstädt

Influence from a 85-year differentiated organic manuring and mineral fertilization on soil fertility in the static experiment at Bad Lauchstädt The results of the static experiment started on chernozem from loess at Bad Lauchstädt in 1902 are used to demonstrate the influence of differentiated organic manuring (no manuring, 20 t and 30 t ha^?1 of farmyard manure) and mineral fertilization (NPK, NP, NK, N, PK, no fertilization) on the organic matter and nutrient contents in soil. After 85 years the content of organic C (C) in the topsoil was higher by 0, 5% after organic and mineral fertilization than after mineral fertilization. Exclusive mineral fertilization (NPK) increased the C-contents in soil by 0, 2% than without fertilization. Farmyard manure considerably reduced nutrient deficiency, which is due to plots without mineral fertilization. This holds especially true for potassium and phosphorus deficiencies. With rising pH value the Mn content in the soil diminished.     

Ratios of Nutrients in Lowland Rice Grown on Two Iron Toxic Soils in Nigeria

ABSTRACT

Iron (Fe) toxicity is a widespread nutritional soil constraint affecting rice production in the wetland soils of West Africa. Critical levels of total iron in plant causing toxicity is difficult to determine as different rice cultivars respond to excessive Fe^{2 +} in various ways in what is called “bronzing” or “yellowing” symptoms (VBS). An investigation was conducted to evaluate the relationship between plant growth and nutrient ratios at four iron levels (1000, 3000, 4000 μ g L^?1) and control. This involved two rice cultivars (‘ITA 212’ and ‘Suakoko 8’), and two soil types (Aeric Fluvaquent and Aeric Tropaquept). The experimental design was a 2 × 2 × 4 factorial in a completely randomized fashion with four replications. The results showed that nutrient ratios [phosphorus (P)/Fe, potassium (K)/Fe, calcium (Ca)/Fe, magnesium (Mg)/Fe, and manganese (Mn)/Fe), Fe content, and Fe uptake vary widely with the iron levels as well as with the age of the cultivars. The iron toxicity scores expressed as VBS increased with increasing Fe^{2 +} in the soils, resulting in simultaneous reduction of the following variables: plant height, tiller numbers/pot, relationships grain yield (GY) and dry matter yield (DMY). There were no significant difference between nutrient ratios, Fe contents, Fe uptake, the GY and DMY of both rice cultivars on both soil types. Multiple stepwise regression analysis showed that Fe uptake and Fe contents contributed 42% and 17% respectively to the variation in the grain yield of ‘ITA 212’ on Aeric Tropaquept. On both soil types and cultivars, Fe uptake and Fe content contributed between 26 and 68% to the variation in the DMY, while the nutrient ratios (P/Fe, K/Fe, Ca/Fe, and Mn/Fe) contributed between 3% and 13% DMY. Thus, it could be concluded that iron toxicity in rice is more a function of a single nutrient (Fe) rather than nutrient ratios.     

黔西南土壤养分与烤烟糖含量的关系

  【目的】  黔西南烤烟还原糖(RS)和总糖(TS)含量过高是影响其品质的两个重要原因。我们研究了该地区土壤养分对烟叶总糖和还原糖的贡献,为通过施肥提高黔西南烟区的烤烟质量提供理论依据。  【方法】  选取黔西南州晴隆、普安、兴仁、兴义、贞丰和安龙6个县(市)烟草种植集中连片区,确定典型烟田,采集土壤样品和对应的烤后烟叶样品,测定土壤大、中、微量养分含量以及烟叶总糖和还原糖含量,并对两者之间的关系进行相关分析、逐步回归分析和通径分析。  【结果】  黔西南州烟叶的总糖和还原糖含量总体偏高;植烟区土壤酸碱性处于中性至弱碱性,土壤有机质、碱解氮、交换性钙、交换性镁、有效铁和有效锰含量丰富,速效钾、有效磷、有效铜、有效锌、有效硼和有效钼含量适宜,但存在空间分布不均问题。烟叶总糖和还原糖与土壤养分显著相关,其中,烟叶总糖与土壤速效钾(AK)、有效锌(Zn)和有效硼(B)呈极显著负相关,与土壤有效钼(Mo)呈极显著正相关;烟叶还原糖与土壤速效钾(AK)呈极显著负相关,与土壤有效锌(Zn)和有效硼(B)呈显著负相关,与有效铜(Cu)呈极显著正相关,与有效锰(Mn)呈显著正相关。烟叶总糖和还原糖与土壤养分的回归方程分别为TS=31.69?1.78Zn+17.05Mo+1.09Cu+0.003Mg?0.01AK和RS=25.12?0.01AK+1.39Cu+6.91Mo。土壤速效钾、有效铜、有效锌、有效钼和交换性镁为影响烟叶总糖含量的重要指标,土壤速效钾、有效铜和有效钼是影响烟叶还原糖含量的重要指标。通径分析表明,土壤养分含量对烟叶糖含量既有正面(促进)也有负面(制约)作用。  【结论】  对黔西南州烟叶糖含量贡献较大的土壤养分是速效钾、有效镁、有效铜、有效锌和有效钼。在速效钾和有效锌相对丰富的情况下,土壤速效钾含量和有效锌含量会抑制烤后烟叶总糖、还原糖含量的积累,而有效镁、有效铜和有效钼会增加烤后烟叶的总糖和还原糖含量。     

盐土改良肥对草甸盐土的改良效果和对甜菜经济效益的影响

[目的]研究甘肃省河西走廊盐土改良肥对草甸盐土改良效果和甜菜经济效益的影响,为该区甜菜产业可持续发展提供技术支撑。[方法]选择甘肃省酒泉市肃州区铧尖乡草甸盐土,采用田间试验方法开展研究。[结果]影响甜菜产量的原料依次是:盐土调控剂甜菜专用肥有机碳肥。盐土改良肥配方组合为:甜菜专用肥0.0586:盐土调控剂0.0623:有机碳肥0.8791。盐土改良肥施用量与草甸盐土孔隙度、团聚体、持水量、有机质、速效氮磷钾、甜菜农艺性状、经济性状和产量之间呈显著的正相关关系,与容重、pH值、全盐含量之间呈显著的负相关关系。经回归统计分析,盐土改良肥经济效益最佳施用量为39.64t/hm2,甜菜块根理论产量为96.68t/hm2。施用盐土改良肥与传统的抗盐丰盐碱土改良剂和沃丰隆盐碱土改良剂比较,施肥利润分别增加414.48,946.10%元/hm2。[结论]施用盐土改良肥,可以改善草甸盐土理化性质,提高酶活性和甜菜产量。     

Wirkung differenzierter K-Düngung auf bodenphysikalische Eigenschaften,Bodenwassergehalt und Ertrag von Zuckerrüben und Sommergerste auf einem Tschernosem im Mitteldeutschen Trockengebiet

The water balance in the soil profile and soil moisture dynamic (available water content [%]) under sugar beet 2009 and spring barley 2010 were investigated in selected treatments of a long-term K-fertilization trial on a chernozem developed from loess in Bernburg, Germany (21% clay, 73% silt, 1.5% C_org), which received an annual K-fertilization of 0/0 and 249/124.5 kg ha^?1, respectively, to sugar beet/spring barley within the last 14 years. Intensive K-fertilization increased the K content of topsoil and subsoil as well as available water capacity up to 60 cm soil depth. Under water stress conditions in August 2009, the treatment with high K-fertilization achieved the highest sugar beet yield, sugar content (°S) and white-sugar-yield at final harvest. Combined with the higher beet yield, the water use efficiency was also increased and the water pool of the subsoil was used more efficiently. In the following year (2010), weather conditions were relatively wet. Under these conditions, no differences in yield parameters and water consumption of sugar beet and spring barley between both K-levels were observed.     

Kemink subsoiling before and after planting

The Kemink exact soil management system is a non-inversion soil management system based on subsoiling, ridges and controlled traffic. Previous studies have documented benefits of the Kemink system used in its entirety, but the isolated effect of Kemink subsoiling has not been investigated before. To determine the isolated effect of Kemink subsoiling before and after planting two field experiments in sugar beet and barley were conducted in 1999 and 2000 under low nutrient input conditions in a conventional soil management system without recognized compaction problems. Kemink subsoiling after planting generally showed a negative effect on the growth and yield of both crops, whereas subsoiling before planting increased sugar beet yield from 8.4 to 9.5 t ha⁻¹ and sugar beet nitrogen uptake from 48.5 to 57.4 kg ha⁻¹. There was no effect of subsoiling before planting on the grain yield of barley. The negative effect of subsoiling after planting was more pronounced in 1999 than in 2000, and more pronounced in spring barley. The study shows that Kemink subsoiling after planting involves a significant risk of crop damage and cannot be expected to improve crop performance in conventional soil management systems in its current form, whereas Kemink subsoiling before planting may have potential as a measure to increase yield of sugar beet and possibly other row crops too, under low nutrient input conditions.     

Effects of wastewater irrigation on soil and cabbage‐plant (brassica olerecea var. capitate cv. yalova‐1) chemical properties

The use of wastewater for irrigation is increasingly being considered as a technical solution to minimize soil degradation and to restore nutrient contents of soils. The aim of this study is to increase fertility and minimize degradation of soils irrigated with wastewater exposed to different purification treatments. A field experiment was conducted to investigate the effects of control and irrigation with wastewater, which had undergone different purification treatments, on macro‐ and micronutrient distribution within the soil profile and nutrient contents of cabbage (Brassica olerecea var. Capitate cv. Yalova‐1) in Erzurum, Turkey. Wastewater irrigation and preliminary treatment–wastewater irrigation significantly affected soil chemical properties especially at 0–30 cm soil depth and plant nutrient contents after one year. Application of wastewater increased soil salinity, organic matter, exchangeable Na, K, Ca, Mg, plant‐available P, and micro‐elements and decreased soil pH. Wastewater increased also yield and N, P, K, Fe, Mn, Zn, Cu, B, and Mo contents of cabbage plants. Undesirable side effects were not observed in plant heavy‐metal contents, due to salinity and toxic concentrations of metals from the application of wastewater to soil.     

Nutritional Status,Yield, and Fruit Quality of “Encore” Mandarin Trees Grown in Two Sites of an Orchard with Different Soil Properties

Abstract

The nutrient status [annual fluctuation of leaf nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn)], yield and fruit quality [soluble solids concentration (SSC), titratable acids (TA), SSS/TA and juice content] of “Encore” mandarin trees cultivated in two sites of the same orchard were studied. The trees were grafted on Carrizo citrange rootstock and grown under identical conditions, apart from some soil properties. Soil B (site B of orchard) contained more K, Ca, Mg, and organic matter than soil A (site A of orchard). The patterns of annual variation of leaf nutrient concentrations were similar in both soils, although leaf concentrations of Ca, Mg, Mn, and Fe in soil A were significantly higher than those of soil boron (B), while leaf K concentrations were significantly lower. The mineral analyses of the leaves revealed some interesting antagonisms between K–Mg, K–Ca, and K–Mn. Manganese deficiency was especially limited in the trees grown in soil B. The average fruit yield per tree in soil A, on two-year basis, was significantly higher than this in soil B. The significantly higher water infiltration rate in soil B, in contrast to soil A, seemed to be the dominant factor responsible for the differences among the two sites in yielding and leaf mineral composition.     

贵州省开阳茶园土壤养分状况与肥力质量评价

为明确贵州省开阳县茶园土壤养分状况,为优质茶叶生产提供参考,对贵州省开阳县茶园土壤进行了调查,分析了158个土壤样品的养分含量及养分间的相关性,并采用主成分分析法和模糊数学隶属度函数模型,通过计算土壤肥力综合指标值(IFI)对土壤养分状况进行综合评价。结果表明:贵州省开阳茶园土壤p H偏酸,有机质、全氮和碱解氮含量较为丰富;但全磷、速效磷、全钾和速效钾含量缺乏所占比例较大,分别仅有16.46%、14.56%、20.89%和12.66%的土壤样品达到优质高产茶园标准。开阳茶园土壤IFI值平均为0.59,属于中等以上土壤肥力茶园所占的比例为61.40%,茶园土壤肥力质量总体水平属于良好,但土壤偏酸,速效磷和速效钾的含量相对偏低,应重点改酸和增施磷钾肥。     

Beziehungen zwischen Klimafaktoren und C-, N-Pools in Partikelgrößen-Fraktionen zonaler Steppenböden Rußlands

Relationships between climatic factors and C, N pools in particle-size fractions of steppe soils, Russia Many soils of the Russian steppe are characterized by high soil organic matter contents and similar parent material. Thus, they are suitable for investigations of a climatic impact on C and N pools. We sampled 10 topsoils of the zonal Russian steppe at 0–10 and about 50–60 cm depth intervals. After particle-size fractionation into clay (<2 μm), silt (2–20 μm), fine sand (20–250 μm) organic C and N concentrations were determined in bulk soils and fractions. The results suggest that especially the older organic matter of the subsoil (in the silt fraction) is correlated with climatic factors. Topsoils show less evidence for climatic influences on C and N pools. As the ratio of mean annual precipitation to potential evaporation (=N/V) increases, C/N ratios decrease in all fractions and, thus, in the bulk subsoil. Obviously the degree of soil organic matter alteration was more pronounced in the order Greyzem (N/V = 1.0) > Chernozem, Phaeozem (N/V = 0.89) > Haplic Kastanozem (N/V = 0.6) > Calcic (N/V = 0.34), and Gypsic Kastanozem (N/V = 0.32). The organic carbon contents of the bulk subsoil are highest in the subsoil of the Chernozem and Phaeozem, and decrease with increasing N/V ratio (i.e., increasing heat input and dryness) to the Calcic Kastanozem. This is accompanied by an increasing enrichment of organic carbon in the silt fractions (r = ?0.99 for the correlation of the C enrichment in silt with N/V).     

Soil Factors Affecting Yield,Quality, and Response to Nitrogen of Sugar Beets Grown on Light-Textured Soils in Northern Greece

For 7 years (1997–2003), five nitrogen (N) rates (0, 60, 120, 180, and 240 kg N ha^?1) were applied to sugar beets arranged in randomized complete block (RCB) design experiments with six replications and grown on light soils (sand content >50 g kg^?1) in northern Greece. The aim of this work was to identify soil characteristics that affect yield, quality, and sugar beet response to N fertilization. Before sowing, soil analyses were conducted in control plots (0 kg N ha^?1) at two depths (0–30 and 30–60 cm). Soils differed in their physical and chemical properties and especially in sand content, which ranged from 500 to 732 g kg^?1. Quantitative (root number, RN; root yield, RY; and sugar yield, SY) and qualitative (percentage sucrose content in fresh root weight, SC; potassium, K; sodium, Na; and α-amino N) traits of control plots were used as soil fertility index. The RN was positively affected by clay content, and RY and SY were positively related with sand and negatively with silt content. The SC was negatively affected by soil (NO₃)-N and sodium (Na) concentrations. Also, soil (NO₃)-N concentration was positively related with root impurities (K, Na, α-amino N). In combined data over years, N rates had a negative effect on the RN. The RY was the only trait affected by years, N rates, and their interaction. The SC and SY differed significantly between years, and N rates affected significantly the former but not the latter. In combined data over years, N rates were curvilinearly related with Na concentration in roots, whereas a strong, linear relationship was found between α-amino N concentration and N rates. To study the significant years × N rates interaction evidenced for the RY, the relative response (RR) of the RY to N was introduced. Actually, the RR expresses the increase or decrease of the RY for a 150 kg N ha^?1 rate compared to the control (0 kg N ha^?1). The RR was strongly related with soil K concentration at the 0- to 30-cm depth (y = –0.00002x² + 0.0082x + 0.5085, r² = 0.92, P < 0.01, n = 7) and with total N concentration at the deeper layer (y = 1.8335x² – 3.5312x + 2.6614, r² = 0.88, P < 0.05, n = 6). Thus, the RY response to a rate of 150 kg N ha^?1, which is the commonly applied to the sugar beet crop in Greece, can be predicted reliably by soil characteristics (K and total N concentration) determined before sowing. The strong relationship between soil K concentration and sugar beet response to N merits further research.