Effect of Extending the Growing Period on Yield Formation of Sugar Beet

Autumn sown sugar beets (winter beets) are expected to yield markedly higher than spring sown beets. This requires a continuous growth during an extended growing period. So far, bolting‐resistant sugar beet varieties are not available to test winter beets under field conditions in Central Europe. The objective of this study was therefore to analyse yield formation and sugar storage of sugar beet plants during an extended growing period to estimate whether sugar beet has the potential to generate the theoretically expected yield increase. From 2008 to 2012, pot experiments were carried out in the glasshouse with 11 sowing dates spread over the years with sequential harvests. The oldest plants were grown for 859 days (14 242 °Cd). Root fresh matter yield continuously increased till the latest harvest. In contrast, the sugar concentration reached an optimum value between 3400 and 5000 °Cd and then decreased with time. Despite longer growing periods, the number of cambium rings, which are regarded as essential for sugar storage, did not change. This points to an early and genetically fixed determination of the formation of cambium rings. Additionally, the rate of photosynthesis decreased concomitantly with the sugar concentration. In conclusion, there is some evidence that the sugar concentration of the storage root is limited by the sink capacity, which in turn controls the source activity by a feedback regulation of photosynthesis and leaf formation. The dry matter composition of the storage root changed towards lower sugar concentration and concurrent higher concentration of cell wall compounds (marc). The sugar yield still increased beyond a thermal time at which winter beets will probably be harvested in practice. Hence, the theoretical yield increase in autumn sown sugar beets can be realized, provided that the plants show sufficient winter hardiness and bolting resistance.     

Sucrose Accumulation in Sugar Beet Under Drought Stress

Drought stress may affect sucrose accumulation of sugar beet by restricting leaf development and storage root growth. The objective of this study was to identify changes occurring in the storage root of Beta beets in growth characteristics and ions and compatible solutes accumulation under drought with regard to sucrose accumulation. Two pot experiments were conducted: (1) sugar beet well supplied with water (100 % water capacity), under continuous moderate (50 %) and severe drought stress (30 %), (2) sugar beet and fodder beet well supplied with water (100 %) and under continuous severe drought stress (30 %). Under drought stress, the ratio of storage root to leaf dry matter of sugar beet decreased indicating a different partitioning of the assimilates. The sucrose concentration of the storage root was reduced. In the root, the number of cambium rings was only slightly affected, although drought stress was implemented already 6 weeks after sowing. In contrast, the distance between adjacent rings and the cell size was considerably restricted, which points to a reduced expansion of existing sink tissues. The daily rate of sucrose accumulation in the root showed a maximum between 16 and 20 weeks after sowing in well‐watered plants, but it was considerably reduced under drought stress. The concentration of compatible solutes (K, Na, amino acids, glycine betaine, glucose and fructose) decreased during growth, while it was enhanced because of drought. However, when sucrose concentration was added, a constant sum of all examined solutes was found throughout the vegetation period. It was similar in sugar beet and in fodder beet despite different concentrations of single solutes, and the total sum was not affected by water supply. A close negative relationship between the concentration of compatible solutes and sucrose occurred. It is therefore concluded that the accumulation of compatible solutes in the storage root of Beta beets under drought might be a physiological constraint limiting sucrose accumulation.     

Förderung der Jugendentwicklung der Zuckerrübe durch Pflanzung und Anbau unter Folie

Effect of transplanting and plastic mulch on yield and quality of sugar beet
Because of late sowing and the slow growth of seedlings, little of the solar radiation in May and June is used for photosynthesis by sugar beet. Therefore, an acceleration of growth early in the season should increase the yield. In the past, many attempts to accelerate early growth have been made.
The objective of this study was to investigate the effects, on yield and quality, of mulching sugar-beet seedlings with a photodegradable polyethylene film, and of transplanting. Six field trials were carried out at Göttingen (Lower Saxony) from 1981-1986.
Plastic cover increased the temperature of the surface soil by between 2 and 3 °C. This increased the yield of early-sown beet. After late sowing we sometimes found that pests and fungal diseases were more active under the plastic mulch, causing yield reductions.
Transplanted sugar beets produced between 1.4 and 4 t/ha more sugar than directly sown beets. Transplanting stabilized the yield, especially after late planting.
It can be concluded that, at the price level in the Federal Republic of Germany, neither the use of plastic mulch nor transplanting is superior to conventional sowing for sugar beet. However, in Europe, there may be a few special circumstances where transplanting will be beneficial.     

磷酸二铵施用量及方式对甜菜光合性能和产量的影响

光合作用是产量形成的物质基础,为筛选出最适宜甜菜产量形成的施磷方式及施磷量,优化甜菜施肥管理,设置3种不同施磷方式（播种前全部基施;播种前基施2/3,叶丛快速生长期追施1/3;播种前基施2/3,块根糖分增长期追施1/3）,每种施磷方式下设置5个施磷量（60、90、120、150和180kg/hm²）,研究不同施磷方式及施磷量对甜菜光合生理性能及产量的影响。研究结果表明,相同施磷方式下,随施磷量递增,甜菜的叶面积指数（LAI）、相对叶绿素含量（SPAD值）、净光合速率（P_n）、单株干物质积累量及产量均呈先升高后稳定或降低的变化趋势,当施磷量为150kg/hm²时,各光合指标和产量均达到最大值。相同施磷量条件下,基施2/3、叶丛快速生长期追施1/3磷肥的施磷方式对促进甜菜光合性能和产量形成效果最好。故推荐高产甜菜施磷量为150kg/hm²,分2次施入,播前基施2/3,叶丛快速生长期追施1/3。     

Relevance of Osmotic and Frost Protecting Compounds for the Winter Hardiness of Autumn Sown Sugar Beet

The cultivation of autumn sown sugar beet (winter beet) is supposed to result in a marked yield increase compared with spring sown sugar beet. Although the importance of the growth stage reached before winter for the survival of autumn sown sugar beet has already been shown, it is not clear to which extent osmotic and potentially frost protecting compounds may contribute to winter hardiness. The study thus aimed to analyse the acclimatization process of sugar beet to low temperatures and to identify compounds which are important for survival of frost. Field trials with autumn sown sugar beet were conducted at eleven environments in Germany from 2009/10 to 2012/13, which were accompanied by greenhouse experiments with controlled temperature regimes. In the field trials, the survival rates after winter varied from 0 % to 99 %, but only in four environments differences between the five genotypes occurred. During acclimatization, betaine, glutamine, proline and raffinose were markedly accumulated and osmolality was enhanced. In particular betaine, amino acids and osmolality showed a positive correlation to the survival rate and were thus identified as potentially frost protecting substances for sugar beet. In contrast, raffinose and proline seem to act rather as stress indicators as they were negatively related to survival. Possible frost protecting substances were identified which can be used in breeding to improve the winter hardiness of sugar beet.     

The creation of tetraploid beets

Summary In recent years trial fields were laid out with tetraploid families of the sugar beet varieties SX and SY, the fodder sugar beet varieties VA and VB and the fodder beet varieties VC (high content) and VD (low content).It appeared that the tetraploid beets are morphologically distinct from the diploid commercial varieties in leaf form, leaf development, form of the beet, tendency to bolt, size of the clusters and the number of seedlings per cluster.The beets of all the plots are washed, weighed and measured for dry matter, sugar and crude protein content and seed for stecklings is sown on a separate trial field.From the results it appears that there is a variation in the above-mentioned contents so that it seems possible to improve the material by selection. This also holds for the dry matter production which agrees with that of diploid commercial varieties.The investigations are being continued.     

Growth analysis of rhizomania infected and healthy sugar beet

Viral disease of rhizomania is one of the most important diseases of sugar beet all over the world. The disease significantly has reduced the yield and quality of sugar beet, and has imposed high economic loss to farmers. Long-term breeding programs to introduce tolerant cultivars are the only chance of avoiding further yield losses. This study tried to measure and analyze the growth of shoots and roots of rhizomania-tolerant and -susceptible sugar beet with the aim of providing information for modeling of the rhizomania effects on the growth of sugar beet. Growth indices were used for analyzing, quantification, and time-course of sugar beet growth under infested and non-infested soils conditions. A 2-year experiment was conducted using four sugar beet cultivars in 2010 and 2011 in Mashhad, Iran. The results of this study showed that under infested soils, root dry matter and leaf area index of the susceptible cultivars in comparison to tolerant cultivars were lower by 57 and 24%, respectively. In addition, crop growth rate and net assimilation rate of susceptible cultivars were affected by rhizomania and were lower than in tolerant cultivars. On non-infested soil, the difference between dry matter and growth indices of susceptible and tolerant sugar beet cultivars was not significant. Rhizomania decreased green area and photosynthesis capacity and led to lower growth rate and dry matter production. Our study quantified the growth of rhizomania-infested sugar beet plants in comparison with non-infested plants and provided information to be used for modeling of the rhizomania effects on the growth of sugar beet.     

甘蓝型冬油菜(Brassica napus)干物质积累、分配与转移的特性研究

采用不同的模型, 定量地研究了不同播期不同基因型油菜干物质积累、分配与转移规律. 结果表明: 油菜总干物质积累动态可拟合成Logistic模型. 油菜根、茎枝、叶干物质分配呈现出多项式函数的变化规律, 角果干物质分配表现为Logistic曲线的变化特征. 晚播油菜干物质冬前优先分配给叶, 角果发育成熟期优先分配给角果并主要给籽粒     

Effect of Long-term Application of Farmyard Manure on Growth and Quality of Sugar Beet

Field trials were conducted for two years on two farms which differed in long-term application of pig slurry in order to study the effects of long-term organic manuring, timing of slurry application (no slurry, slurry autumn, slurry spring) and additional doses of mineral N-fertilizer (0, 80, 160, 240 kg N/ha) on growth and quality of sugar beet. The results can be summarized as follows: 1. The effect of slurry application on growth of sugar beets varied markedly with the long-term differences in farm management. On the “arable farm” yield of beet roots increased substantially after slurry application and could not be replaced by higher doses of mineral N fertilizer. It is concluded therefore that “special effects” of farmyard manure are involved. On the “livestock farm”, however, highest beet yields were obtained on plots without slurry. Additionally slurry application caused a significant decrease in beet yields. 2. Sugar beets without slurry treatment always developed higher sugar contents and lower concentrations of alpha-amino-N, sodium and potassium as compared to beets from plots with slurry application. 3. Despite the decline in sugar content, sugar yield greatly increased by slurry application on the “arable farm”. The average increase in sugar yield was 10 dt/ha (=8%) with slurry application in autumn and amounted to 16 dt/ha (=14%) with spring application. On the livestock farm however, additional applications of slurry caused a decline in sugar yields in both years because of lower sugar contents and decrease in beet yields. 4. The utilization rate of slurry-N, depending mainly on time of application, annual rainfall and soil N mineralization, varied from 6–41%. On the “livestock farm” the utilization of slurry-N was only half of the rate obtained on the “arable farm”. 5. The application of small doses of slurry may cause a significant yield increase on farms without or only less livestock, while on farms with intensive livestock production continous slurry application needs to be considered as an expensive form of waste disposal. Therefore farms with high livestock density are advised to sell slurry to neighbouring farms without or only low animal production at a fair price for their mutual advantage.     

Effects of weather variables on sugar beet yield development (Beta vulgaris L.)

There is much data on the impact of weather variables on the growth of sugar beet from studies conducted under controlled conditions or single field experiments, but these data are of only limited validity for other sites or larger areas. The aim of the present study was to quantify the influence of weather conditions on the growth of sugar beet for the further development of simulation models, based on data representative of sugar beet cultivation in Germany. For this purpose, 27 field trials were conducted in 2000–2001 in commercial fields with variable climatic and soil conditions. From the end of May until the end of the season, beets were harvested manually every 4 weeks, the dry matter yield of leaves and taproot was determined and their growth rates were calculated. Temperature, solar radiation, rainfall and humidity were recorded daily for each site and the potential evapotranspiration and climatic water balance were estimated. The soil water content to a depth of 0.9 m was determined at every harvest date.Several functions were developed to describe the growth of sugar beet as affected by the given meteorological variables. From sowing to the end of June, the dry matter accumulation of both leaves and taproot was strongly enhanced by increasing temperature and during this period leaf dry matter increased linearly with thermal time. After reaching 700 °C d, the taproot dry matter accumulated exponentially with thermal time. The optimum mean daily air temperature for taproot growth was approximately 18 °C. Higher temperature occurring in July and August decreased final taproot yield, but by the end of the season, growth was independent of temperature. High solar radiation advanced growth during the first 65 days after sowing and again in October.Neither the water input by rainfall and irrigation nor the climatic water balance adequately described the growth of the leaves or taproot, but it was shown that the increase in taproot dry matter during July and August depended on the amount of available water in the soil. The maximum sugar yield that can theoretically be achieved in Germany and comparable agroclimatic regions was calculated as 24 t ha⁻¹. The present data reliable for a large agroclimatic region in Europe are of significant value as input for simulation models.     

Yield of bolting winter beet (Beta vulgaris L.) as affected by plant density,genotype and environment

Winter beet roots and shoots might be a favorable substrate for biogas production in Central Europe. However, detailed information about the attainable yield of this crop is lacking. Thus, the impact of plant density, genotype and environmental conditions on total dry matter yield of winter beet crops that bolt after winter was investigated. A significant increase of the dry matter yield (esp. shoot) was expected by harvesting the 1st shoot after flowering in June followed by a final harvest of the whole plant in July. In 2009/10, 2010/11 and 2011/12, three series of field trials with (i) 3 target plant densities (148, 246, 370 thousand plants ha⁻¹) and (ii) 3 different sugar beet genotypes were conducted at Göttingen (Lower Saxony, GER) and Kiel (Schleswig-Holstein, GER); (iii), additional field trials with 5 different sugar beet genotypes cultivated at 2 target plant densities (148, 246 thousand plants ha⁻¹) were conducted in 2011/12, to investigate the relation between maximum taproot diameter and the shoot and taproot yield of bolting winter beet. The total dry matter yield considerably varied between 4 and 23 t ha⁻¹. It was predominantly affected by the environment and to a substantially lower extent by plant density. Increasing plant densities increased the total dry matter yield, resulting in a significantly higher total dry matter yield at plant densities ≥300,000 plants ha⁻¹ compared with lower plant densities. Genotypic differences in total dry matter yield were negligibly small. Pruning in June substantially increased the total dry matter yield in July by ca. 8 t ha⁻¹ only in one out of three environments.Final yield in June (without pruning) and July (pruning in June) was positively related with cumulated temperature and global radiation, but also with taproot dry matter yield before winter. The taproot, shoot (1st, 2nd) and total plant yield were positively correlated with maximum taproot diameter.In conclusion, high dry matter yields close to yields of established energy crops grown over winter were obtained with winter beet roots and shoots only under very favorable conditions (climate, single plant size). High yields can be achieved after good pre-winter development. However, for sufficient frost tolerance the taproot size of plants must be rather small. Hence, the cultivation of bolting winter beet under Central European climate conditions has to face a severe conflict of goals concerning winter survival and yield formation.     

Estimation of Leaf Area Index of Beta vulgaris L. Based on Optical Remote Sensing Data

Remote sensing and vegetation indices can be used to characterize the canopy of crops with a non‐destructive method on a large scale. Leaf area formation of sugar beet in early summer is the most important variable for crop growth models. This study aimed at estimating whether differences in leaf area development of sugar beet resulting from different agronomic practices can be determined with remote sensing. The relationship between the normalized difference vegetation index (NDVI) and leaf area index (LAI) during the season and yield of the storage root in autumn was studied in six field trials in 2001 and nine field trials in 2002. The vegetation index NDVI gave a good impression of differences in leaf development of sugar beet in early summer. LAI increased with increasing NDVI up to an NDVI of 0.65. Above that the NDVI did not respond as distinctly to treatments as the LAI. An exponential function was developed to calculate sugar beet LAI from NDVI, so that remote sensing data can be used as input variable for crop growth models. The yield of the storage root in autumn did not show any relationship to LAI or NDVI during the season, regardless of whether it was measured in June or September. Therefore, it seems to be necessary to combine NDVI data with crop growth models to forecast a potential sugar beet yield in autumn. For this purpose the formula presented is a valuable tool.     

Molecular and morpho-physiological characterization of sea,ruderal and cultivated beets

Beta vulgaris genetic resources are essential for broadening genetic base of sugar beet and developing cultivars adapted to adverse environmental conditions. Wild beets (sea beets, B. vulgaris spp. maritima and their naturalized introgressions with cultivated beets known as ruderal beets) harbor substantial genetic diversity that could be useful for beet improvement. Here, we compared molecular and morpho-physiological traits of wild beets collected on the Adriatic coast of Italy with sugar beet using eight primer-pairs amplifying 194 polymorphic fragments and four root traits (glucose and fructose content in the root tip, root elongation rate, number of the of root tips, total root length and its distribution among diameters ranges). Genetic diversity was higher in the sea beet accession, which may be due to the highly variable selection pressures that occur in heterogeneous ecological niches, compared with the ruderal and cultivated beets. Sea and sugar beet accessions showed contrasting root patterns in response to sulfate deprivation: sugar beet showed an increase of reducing sugars in the root tips and higher root elongation rate, and the sea beet accession showed an increase in root tip number, total root length and fine root length (average diameter < 0.5 mm). The ruderal beet showed intermediary responses to sea and sugar beet accessions. AFLP and morpho-physiological cluster analyzes showed sea, ruderal and cultivated beets to be genetically distinct groups. The results of this study indicate variability in response to sulfate deprivation is present in undomesticated beets that could be deployed for sugar beet improvement.     

内陆河流域不同播期对春玉米土壤温度及生物量的影响

土壤温度是限制玉米高产的主要环境因子,为了寻求合理的播种时间,使玉米生长发育处于适宜的土壤温度环境中,从而保证干物质的积累和产量的形成。通过在内陆河流域代表区域武威开展不同播期对大田地膜春玉米进行试验,采用全生育期连续定点观测春玉米发育期、产量结构和20 cm、40 cm两个深度的土壤温度变化,分析了不同播期对春玉米生物量和土壤温度的影响。结果表明：营养生长期不同播期处理各层次地温均随生育进程的推进呈逐渐升高的趋势,拔节之后即进入生殖生长期,地温呈降低趋势。第二播期（4月20日）生长状况好,干物质累积量高,尤其是乳熟期和成熟期差异明显(P<0.05)。第二期产量构成优于第三期（4月30日）和第一期（4月10日）。第二播期处理,可以在苗期获得较高的地温,土壤增温明显,而在拔节期以后可保证适当较低的温度,从而保证干物质积累时间和产量结构的形成,是当地最适宜的地膜春玉米播种期。第一播期生物量则表现最差,说明正常情况下作物适当提前播期,延长生长期的做法在玉米的生产上是有一定风险的。     

Relationship Between Cold Severity and Yield Loss in Chickpea (Cicer arietinum L.)*

Seed yield in chickpea (Cicer arietinum L.) is substantially increased by advancing sowing date from the traditional spring to early winter at low to medium elevation areas around the Mediterranean Sea. This shift, however, increases the probability of the exposure to subzero temperatures as low as -10 °C for up to 60 days in a year. These low temperatures often reduce seed yield of cold-susceptible cultivars. Yield losses from cold were estimated in two experiments conducted at Tel Hadya, Syria. In experiment 1, of 96 genotypes sown on nine dates ranging from autumn to spring during the 1981–82 season, those lacking tolerance to cold were killed and produced no yield in autumn sowing, whereas lines with cold tolerance produced nearly 4 t/ha which corresponds to a four-fold increase over spring sowing. Moderately cold-tolerant genotypes sown during early winter produced substantially more seed yield than the normal spring-sown crop. Seedlings were more cold tolerant than the plants in early or late vegetative stages. In experiment 2, in which yield loss due to cold in the field was estimated in 12 yield trials comprising 288 newly bred lines in the 1989–90 season, the regression of cold susceptibility on seed yield in each of the trials was highly significant and negative. On average, winter-sown trials produced 67 % more seed yield than spring-sown trials, but 125 out of 288 genotypes produced yield more than double in winter sowing. Early maturing lines suffered severe cold damage and many lines produced no seed.     

Prediction of Various Effects of Harvest Date in Sugar Beet Growing

One crucial decision in sugar beet growing is determining harvest date. This paper focuses on some aspects associated with harvest date which have to be included in a decision support system for sugar beet growing.
Firstly, a module was created for dirt and crown tare, mainly based on lutum (or clay) and soil moisture contents. An independent test of the module showed poor results, because fine tuning of harvest machinery has an overriding effect. Secondly, the variation in weather conditions during autumn in Wageningen over a period of 38 years was analysed. The ranges of future root and sugar production appeared to be so wide that early predictions of the day on which the sugar quota are exceeded will not be very reliable. Thirdly, risks of severe frost or heavy rainfall in autumn were assessed, based on the same 38 year data set. The risk of frost damage to unharvested beets proved to be negligible when the crop was harvested before November 10, as advised by the sugar industry.
The work described in this study makes the model PIEteR (a field specific bio-economic production model for sugar beet, developed for decision support at field and farm level) more applicable by using its potential to analyse the effects of different years and quota options.     

Development and Yield Formation of Autumn- and Spring-sown Faba Beans in Northern Germany as Affected by Seasons, Sowing Dates and Varieties

Field trials were conducted with autumn- and spring-sown faba beans in Northern Germany during four seasons to examine the expected preceding development of autumn-sown plants, its possible transformation into a higher yield potential and its dependence on sowing dates and varieties. Height, appearance of leaves, inflorescences, mature flowers, potential and actual pot set was rated weekly, and flower initiation and tillering occasionally. Comparison was made for one winter type sown in autumn and spring, and between 6 winter types and 3 spring types, in two seasons each.
Development of autumn-sown plants significantly preceded that of spring-sown in each year, regardless of the plant material used. The mean advance, diminished considerably with time due to prolonged developmental phases in autumn-sown plants which, however, did not improve vegetative, generative or reproductive potentials of main tillers. Potentials formed by the six winter types, interacted strongly with the seasons, at least in part due to changing plant densities. Thus, only a very few traits appeared typical: a short stature with few leaves for Avrissot and the opposite for Bourdon , a high number of ripening pods for Avrissot and a low number for Banner . Early compared to late sowing in autumn increased the number of leaves, and in one year even the number of mature flowers and ripening pods per tiller, but values of early sowing never exceeded those of spring sowing. Enhancement of tiller formation by early compared to late sowing diminished after spring; nevertheless about two reproductive tillers per plant in autumn-sown stands always led to a higher density of tillers than in spring-sown.     

东北旋耕制度下垄作与平作甜菜产质量差异

为研究东北旋耕制度条件下甜菜平作和垄作对于甜菜产量和质量的影响,2017年以‘H004’为试验材料,采用分区设计的实验方法,在哈尔滨呼兰区多年旋耕地测定了在平作和垄作栽培条件下甜菜的块根产量、绿茎叶产量、含糖率、甜菜地下和地上部位的干物质量比例以及不同耕作条件下不同土层的土壤含水量和容重。研究发现转旋耕条件下平作和垄作甜菜含糖量没有显著差异,但是垄作甜菜块根产量要明显优于平作甜菜,垄作甜菜块根单产达到87.8 t/hm2,而平作甜菜块根单产仅为72.9 t/hm2。此外研究发现平作甜菜地上部分干物质积累较多,如平作甜菜根/地上部干物质比值要显著低于垄作甜菜。同时发现垄作栽培土壤含水量及土壤疏松程度均优于平作,如在20-26 cm土层中垄作土壤的容重和含水量分别为1.38 g/cm3和21.96%,而在20~26 cm平作土壤的容重和含水量仅为1.56 g/cm3和19.35%。本研究表明在东北旋耕制度条件下,垄作栽培更适于甜菜生产,也为下一步研发东北高产高糖甜菜栽培模式鉴定重要基础。     

缓释肥对甜菜产质量和土壤中脲酶活性的影响

为了提高氮肥利用率,提高甜菜产质量,推广缓释肥料的使用。采用HI003为试材,研究了缓释肥料和普通肥料对甜菜叶绿素含量、干物质重、蔗糖含量、块根产量和含糖率、土壤脲酶活性的影响。结果表明：缓释肥料处理比普通肥料处理增加了叶片叶绿素含量,8月5日样品中,缓释肥料处理比普通肥料处理叶绿素含量提高12.22%,9月5日样品中,单纯缓释肥料处理比普通肥料处理叶绿素含量提高9.72%。在生育期前期,普通肥料处理的干物质重高于使用缓释肥料的处理；在生育后期,使用缓释肥料的处理的干物质重高于普通肥料处理。缓释肥料和普通肥料对甜菜叶片和块根蔗糖含量影响不显著。缓释肥的施用降低了甜菜生育期土壤脲酶活性。缓释肥料处理比普通肥料处理提高了甜菜块根产量和含糖量,三种处理中,普通肥料：缓释肥料=1：1,产糖量最高,效果最好。初步试验表明,缓释肥料对于甜菜的增产效果明显,有必要进一步对缓释肥料类型进行筛选,减少肥料使用量,减少施肥造成的环境污染。     

甜菜“南苗北植”的生产效应

针对冀西北高原区气候寒冷多风、早春温度极不稳定、甜菜育苗晚、秧苗质量差、移栽甜菜产量和含糖量低等问题,利用冀中平原区丰富的热量资源进行甜菜异地育苗,而后移栽坝上生产的“南苗北植”方式,与当地育苗的甜菜进行比较,探讨南苗北植技术对甜菜生长、养分积累、产量和品质的影响。结果表明,南苗北植甜菜在绿叶叶片数、叶面积指数、根径、产量和产糖量比当地育苗甜菜分别增加了55.6%~75.0%、29.1%~44.2%、9.6%~10.8%、17.1%~19.2%和19.2%~24.0%,效果显著,呈现南苗大于北苗、早栽大于晚栽特征。南苗北植甜菜的氮、磷、钾养分生物学效率高于北苗。“南苗北植”提高了甜菜在冀西北寒旱区的品质与生产力;北苗南育成为甜菜秧苗产业化与规模化生产的首选技术。