Effects of irrigation water qualities on biomass and sugar contents of sugar beet and sweet sorghum cultivars

An experiment involving four qualities of irrigation water two sugar beet and three sweet sorghum cultivars was conducted in a split plot design with four replications at Rudasht Drainage and Reclamation Experiment Station in 1999. The results showed salinity of water has an adverse effect on sugar beet and sweet sorghum biomass. Sweet sorghum cultivar SSV108 had the lowest biomass under all qualities of irrigation water Sweet sorghum cultivar Rio had the maximum biomass with water qualities of 2, 5, and 8 dS m(-1). Sugar beet cultivar 7233 had the maximum biomass with 11 dS m(-1). The effect of irrigation water quality was not significant for sugar characteristics such as brix, pol and purity. However, responses of cultivars on the above parameters were significant and sugar beet cultivars had higher brix, pol and purity and lower invert sugar and starch than sweet sorghum cultivars. In conclusion, sweet sorghum cultivars are not recommended to be irrigated with saline water of more than 8 dS m(-1) for sugar production. Under such condition, they may be suitable to be grown for forage purposes.     

燕麦对盐碱胁迫的反应和适应性

研究了自然盐碱胁迫对燕麦植株生长、水势、渗透调节物质质量分数以及对K 、Na 选择性吸收的影响,结果表明,随着土壤盐碱胁迫的增强燕麦植株生长受抑,叶片和根系的水势较对照均有所降低,其中裸燕麦较皮燕麦水势下降幅度大,表明裸燕麦比皮燕麦对盐碱胁迫更敏感。燕麦叶片内脯氨酸和可溶性糖累积。随着土壤盐碱胁迫的增强植株对Na 的吸收增加,对K 的吸收受到抑制,从而使w(Na )/w(K )和SNa K 值升高。在盐碱胁迫下,燕麦是以合成和积累有机溶质(脯氨酸和可溶性糖)以及吸收和积累无机离子(Na )来进行渗透调节,以适应盐碱胁迫。     

Inter-relationship between growth analysis and carbohydrate contents of sweet sorghum cultivars and lines

The carbohydrate contents of sweet sorghum (Sorghum bicolor L. Moench) is an important industrial factor for crystal sugar or bioethanol production. In this study the relationship between growth analysis and carbohydrate contents were studied to recognize the best growth stages for sweet sorghum harvesting. Five sweet sorghum cultivars and four sweet sorghum lines were evaluated for leaf area index (LAI), net assimilation rate (NAR), relative growth rate (RGR) and stem crop growth rate (CGR) in relation to sucrose content, invert sugars and total sugar at booting, soft-dough, hard dough and post grain maturity Except at post grain maturitystage, the correlations among LAI, NAR and RGR forsucrose content and total sugar were positive and forinvert sugars were negative. The relationship between invert sugars including glucose, fructose, maltose and xylose athard dough stage regarding LAI, NAR and GRG were negative. As plant grows LAI, NAR and RGR increases which consequently increases sucroses content and decrease invert sugar.     

生态肥料 NutriSmartTM在甜椒生产中应用的生态效应

过量施用肥料导致产品质量下降,引发水体和土壤的严重污染;减少施用农田化肥或施用对环境影响较小的肥料将有利于减少农田N、P损失。因此,世界各国尝试研究和开发既能提高作物产量和质量又可降低环境风险的新型肥料。生态肥料Nutrismart在甘蔗、野菜种植上均取得较好的成效,但在蔬菜上的应用研究及其施用后的N、P损失研究鲜见。本研究以甜椒(Capsicum annuum var.grossum)为例,进行温室培养试验,共设8个处理,采用不施肥、纯施常规化肥和混施不同比例的生态肥料NutriSmartTM和常规化肥的技术,比较生态肥料NutriSmartTM和常规化肥混施与单独使用常规化肥对甜椒产量及品质的影响,并进一步通过土柱淋溶试验模拟研究生态肥料对土壤氮磷损失的影响,评价其生态风险。结果表明,生态肥料NutriSmartTM的施用,不仅大幅度降低化肥的用量,还保持了甜椒的产量和质量,且施用量的提高未增加土壤中氮、磷的淋溶,造成水体富营养化的风险降低,在蔬菜中有良好的应用前景。     

Development and test of a crop growth model for application within a Global Change decision support system

When examining potential impacts of Global Change on water resources on the regional scale, spatial and temporal changes in crop water and nitrogen demand are of fundamental significance. State-of-the-art crop growth models are powerful tools to assess the response of crops to altered environmental conditions and cultivation practices. In this paper, the process-based, object-oriented and generic DANUBIA crop growth model is presented. To evaluate the performance of the model, a validation analysis is carried out by comparing modelled data with various field measurements of sugar beet, spring barley, maize, winter wheat and potato crops. Model performance statistics show that crop growth is efficiently simulated. The closest agreement between measured and modelled biomass and leaf area index is achieved for sugar beet and winter wheat. Additionally, the response of the model to changed nitrogen availability caused by cultivation practices is analysed and reveals good results. The results suggest that the model is a suitable tool for numerically assessing the consequences of Global Change on biomass production, water and nitrogen demand, taking into account the complex interplay of water, carbon and nitrogen fluxes in agro-ecosystems.     

土霉素废水农灌的可行性研究

探讨了将经过一定处理后的土霉素废水与清洁水混合 ,作为农业生产灌溉用水的可能性。试验表明 ,经处理后的污水不仅不会增加农业环境负担 ,而且能起到改良土壤和增加农作物产量的作用     

Effects of planting date and time of nitrogen application on yield and sugar content of sweet sorghum

This experiment was conducted at Azad University experiment station to evaluate the effects of planting date and time of nitrogen application on yield and sugar content of sweet sorghum in 2003. Four planting dates (May 4, March 19, June 3 and June 18) and three stages of nitrogen application (3-5/8 leaf stage, boot stage and soft dough stage) were assigned to the main and subplots, respectively. Plant height and diameter, fresh stalk yield, total dry weight, brix value (soluble solids), sugar content and grain yield were affected by planting date. For all the characteristics, the maximum value was obtained by the first planting date. Only stem height, diameter and total plant dry weights were affected by time of nitrogen application. In these cases, nitrogen application at (3-5/8) leaf stage was superior to others. According to the results, sweet sorghum should be planted on the beginning of May and nitrogen be applied at (3-5/8) leaf stage.     

The value of information on the response function of crops to soil salinity

The expected profitability to farmers from acquiring additional information on the biological response function of crop yield to soil salinity is investigated. First, a switching regression approach to estimate piecewise linear response function with critical threshold level is presented. Then, an optimization irrigation model is developed, aimed at determining the optimal use of irrigation water for soil leaching. Finally, a loss function is defined, the expected value of sample information is calculated and the optimal number of additional needed observations is determined. At each stage, an empirical analysis, using data from potato field experiments in Israel, is presented.     

Irrigation suitability of White River in Indiana,Midwestern USA

Climate change models consistently project future precipitation reduction and temperature increase during the crop growing season in the US Midwest, which may exacerbate surface water scarcity issues confronting regional agriculture. To maintain consistent crop yields under the risk of increased droughts, farmers may shift from rain-fed agriculture to irrigation agriculture, particularly during drought periods. There is an urgent need to understand whether surface water in the Midwest is suitable for irrigation. In this study, irrigation water quality was comprehensively analyzed for commonly used parameters regarding salt content including sodium adsorption ratio (SAR), adjusted sodium adsorption ratio (SAR_adj), soluble sodium percentage (SSP), electrical conductivity (EC), total dissolved solids (TDS), residual sodium bicarbonate (RSBC), magnesium adsorption ratio (MAR), permeability index (PI), Kelley’s ratio (KR), synthetic harmful coefficient (SHC), and salinity. Results indicate that water in the White River at Muncie was rated mostly in excellent to good condition with regard to irrigation quality. However, the irrigation suitability level exhibited two distinct patterns between May–July and August–October. Specifically, an average of 7.8% of the samples from May to July were unsuitable for irrigation, and an average of 24.5% of samples from August to October were unsuitable for irrigation considering all parameters. Flow rate change over time and the release of pollutants from wastewater treatment plants and combine sewage outflows to the White River impacted on the irrigation water quality variations of the river. This study showed that there are higher risks during the fall season for farmers to use surface water as an irrigation source, and this risk might be greater if extended or more frequent drought events occur in the future. To our best knowledge, this is the first peer-reviewed study on irrigation water quality assessment in the Midwest and provides useful information for farmers and decision makers to consider while formulating applications for irrigation.

     

Effects of nitrogen treatments and harvesting stages on the aconitic acid, invert sugar and fiber in sweet sorghum cultivars

Sweet sorghum is adapted to the hot and dry climatic conditions and its tolerance to slat is moderately. It can be used for different products such as food, feed, fiber and fuel. This study was carried out to evaluate the effects, three nitrogen treatments, and three harvesting stages on the aconitic acid, fiber and invert sugar of three sweet sorghum cultivars in the experimental station and the results showed that the effects were significant. Among nitrogen treatments, application of 100 kg ha(-1) urea at planting and 200 kg ha(-1) urea at 4 leaf stage had the highest aconitic acid (0.26%) and invert sugar (3.44%). Among sweet sorghum cultivars, IS2325 and Vespa had the highest aconitic acid (0.26%) and invert sugar (3.86%), respectively Plant harvested at 4 leaf stage had the highest aconitic acid (0.26%) and the highest invert sugar (3.85%). Rio had higher fiber content than Vespa and IS2325 and all cultivars had the highest fiber content before chilling harvesting stage. In general, since high invert sugar and high aconitic acid interfere crystallization of sugar so, it is suggested that to plant Vespa, apply urea 100 kg ha(-1) urea at planting, 100 kg ha' urea at 4 leaf stage and 100 kg ha(-1) urea at booting and harvested before chilling that had lowest aconitic acid and invert sugar. Thereby, it is recommended to plant Vespa, apply urea 100 kg ha(-1) urea at planting, 100 kg ha(-1) urea at 4 leaf stage and 100 kg ha(-1) urea at booting and harvested at 4 leaf stage that had the highest aconitic acid.     

微咸水膜下滴灌对白僵土盐碱地水盐特性及油葵生长的影响

为了解滴灌条件下不同微咸水矿化度及覆膜与否对盐碱地土壤水盐特性及油葵生长的影响,在宁夏平罗西大滩盐碱地进行不同灌水矿化度(0.2、1、2、3 g/L)膜下滴灌田间试验.结果表明,地膜覆盖比不覆盖处理土壤含水量高约2%,盐分表聚减缓,油葵株高、产量及其构成均高于不覆膜处理,产量最高增幅达82.5%;不同矿化度微咸水之间比较发现,利用矿化度为1 g/L的微咸水进行灌溉时,下层土壤含水量较高,微咸水滴灌不但没有为上层土壤带去过多盐分,反而由于土壤有一定的渗透性能,灌水将土壤上层盐分逐渐淋洗至下层.膜下滴灌微咸水矿化度为1 g/L时,油葵产量最大.因此在适宜条件、合理措施下,微咸水覆膜滴灌技术可以促进作物生长,确保作物产量,在淡水缺乏而微咸水较为丰富的盐碱地地区应积极推广利用.     

Identifying key life-traits for the dynamics and gene flow in a weedy crop relative: Sensitivity analysis of the GeneSys simulation model for weed beet (Beta vulgaris ssp. vulgaris)

The benefits of genetically modified herbicide-tolerant (GMHT) sugar beet (Beta vulgaris) varieties stem from their presumed ability to improve weed control and reduce its cost, particularly targeting weed beet, a harmful annual weedy form of the genus Beta (i.e. B. vulgaris ssp. vulgaris) frequent in sugar beet fields. As weed beet is totally interfertile with sugar beet, it is thus likely to inherit the herbicide-tolerance transgene through pollen-mediated gene flow. Hence, the foreseeable advent of HT weed beet populations is a serious threat to the sustainability of GM sugar beet cropping systems. For studying and quantifying the long-term effects of cropping system components (crop succession and cultivation techniques) on weed beet population dynamics and gene flow, we developed a biophysical process-based model called GeneSys-Beet in a previous study. In the present paper, the model was employed to identify and rank the weed life-traits as function of their effect on weed beet densities and genotypes, using a global sensitivity analysis to model parameters. Monte Carlo simulations with simultaneous randomization of all life-trait parameters were carried out in three cropping systems contrasting for their risk for infestation by HT weed beets. Simulated weed plants and bolters (i.e. beet plants with flowering and seed-producing stems) were then analysed with regression models as a function of model parameters to rank processes and life-traits and quantify their effects. Key parameters were those determining the timing and success of growth, development, seed maturation and the physiological end of seed production. Timing parameters were usually more important than success parameters, showing for instance that optimal timing of weed management operations is more important than its exact efficacy. The ranking of life-traits though depended on the cropping system and, to a lesser extent, on the target variable (i.e. GM weeds vs. total weed population). For instance, post-emergence parameters were crucial in rotations with frequent sugar beet crops whereas pre-emergence parameters were most important when sugar beet was rare. In the rotations with frequent sugar beet and insufficient weed control, interactions between traits were small, indicating diverse populations with contrasted traits could prosper. Conversely, when sugar beet was rare and weed control optimal, traits had little impact individually, indicating that a small number of optimal combinations of traits would be successful. Based on the analysis of sugar beet parameters and genetic traits, advice for the future selection of sugar beet varieties was also given. In climatic conditions similar to those used here, the priority should be given to limiting the presence of hybrid seeds in seed lots rather than decreasing varietal sensitivity to vernalization.     

NaCl胁迫对甜高粱发芽期生理生化特性的影响

为筛选耐盐甜高粱材料,探讨NaCl胁迫对甜高粱发芽期生理生化特性的影响,研究了0、70、140、210 mmol.L-1NaCl胁迫对吉甜3、BJK156、甜132、凯勒、威利、考利、吉甜2、戴尔等8个甜高粱材料发芽率、发芽势、发芽指数、活力指数、芽长、根长、芽鲜质量、根鲜质量等8个指标盐害系数的影响,利用系统聚类分类法对甜高粱耐盐性进行聚类可分为3类：耐盐性最强的是甜132,耐盐性中等的是BJK156,耐盐性较敏感的是考利、吉甜3、吉甜2、戴尔、凯勒、威利。进一步研究了盐胁迫对甜高粱芽苗中丙二醛、可溶性蛋白含量及过氧化物酶（POD）、过氧化氢酶（CAT）、超氧化物歧化酶（SOD）活性的影响。结果得出：随着盐胁迫的加重丙二醛含量逐渐增加,可溶性蛋白含量逐渐减少。NaCl胁迫不同程度地提高了8个甜高粱材料POD、CAT、SOD活性,受3种NaCl质量浓度胁迫后8个甜高粱材料POD、CAT、SOD活性的变化趋势不同,这可能是它们耐盐差异的生理原因之一。另外,在3种NaCl浓度胁迫后甜132中的丙二醛增加量在8个材料中都是最低的,这与系统聚类分析得出甜132耐盐性最强的结论相吻合。研究认为丙二醛含量的变化可以作为筛选发芽期耐盐甜高粱品种的一个指标。     

Dynamic simulation of water depletion in the root zone

The joint effect of the distribution of the soil water potential and of the root mass in the crop root zone upon the water uptake by the crop is represented by a simple equation. This expression is used to join a layered crop canopy model for finding the evapotranspiration, as controlled by stomatal action and the weather, with a hydraulic flow model for the root zone and the underlying soil. The complete model is used for the calculation of the water extraction pattern and the changes, with time, of other plant and soil processes. A simulation of a 20-day drying period is performed, using S/360 CSMP, for a constant diurnal weather pattern, and for a fully developed sorghum crop. The results show that, after a few days of essentially constant water use by the crop, a monotonic decline sets in, that is principally attributable to the decrease in transpiration. For the entire drying period a substantial amount of water - about 30% of the total used - is contributed by upward flow into the root zone from the soil below. The results demonstrate the difficulty of quantitative definition of concepts such as “field capacity”, “wilting percentage”, and “available” or “extractable” water.     

Assessing the effect of long-term crop cultivation on distribution of Cd in the root zone

Trace elements such as cadmium (Cd) may be inadvertently added to cropland soils through application of fertilizers, irrigation water, and other amendments. These toxic trace elements pose a potentially threat to soil quality and, through the food chain transfer, to human health. A generalized soil trace element mass balance model that accounts for the interactive processes governing the reactions of trace elements in soils, and consequently removed with crop harvest and leaching out of the soil profile with irrigation water was developed in this research. The model conceptually approximates the mechanisms and kinetics of a real field cropland system. The model was used to evaluate the long-term cultivation on distribution of Cd in California croplands. Under typical California cropping practices, Cd added into the soils accumulated primarily in the plow layer while the Cd content below the plow layer was barely affected. After 100 years of continuous cultivation, the soil Cd content of the plow layer increases from the background level 0.22 mg kg⁻¹ to 0.40 mg kg⁻¹. The accumulation of Cd in the plow layer is in proportion to the external inputs and is affected by the soil and plant characteristics, and management practices. The model can be used to evaluate the environmental fates of other toxic element in soils with case specific parameters.     

Response of plant species to coal-mine soil materials

A two-year experiment was conducted on the Black Mesa Coal Mine near Kayenta, Arizona to investigate the growth and establishment of seven plant species in unmined soil (undisturbed soil) and coal-mine soil (spoils). Natural rainfall (20 cm/yr) and natural rainfull plus sprinkler irrigation (50 cm/yr) were the irrigation treatments applied to each soil material. Plant species grew better in unmined soil than in coal-mine soil. Supplemental irrigation water resulted in more plant growth than did natural rainfall alone in both soil materials; however, there were highly significant differences among species. Alfalfa (Medicago sativa L.) and all of the annual perennial grasses used, excluding Indian ricegrass (Oryzopsis hymenoides Ricker), produced effective ground cover on both soil materials when they received supplemental irrigation water. Fourwing saltbush (Atriplex canescens Pursh.) had low germination (emergence), seedling establishment, and stem production during the first year of growth; however, in the second year of growth, this species produced a dense ground cover on coal-mine soil with natural rainfall plus irrigation. In revegetating the Black Mesa Coal Mine, Harlan II barley (Hordeum vulgare L.) and Super X wheat (Triticum aestivum L.) provided initial protective cover until adapted perennial species could be established for permanent stabilisation. The Black Mesa Research Study indicated that irrigation water during seedling establishment was essential for the effective stabilisation of coal-mine soils in a semiarid environment.     

Influence of the sewage irrigation on the agricultural soil properties in Tongliao City, China

Increasing shortages of fresh water has led to greater use of treated wastewater for irrigation of crops. This study evaluates the spatial variability of soil properties after irrigation with wastewater and freshwater. Geostatistical techniques were used to identify the variability of soil properties at the different sites. A set of physical and chemical soil properties were measured including total nitrogen (TN), total phosphorus (TP), organic matter (OM) and soil moisture. The TN concentration levels varied from 567 to 700 mg·kg^-1, while OC levels ranged from 7.3 to 16.3 mg·kg^-1 in wastewater-irrigated zones. The concentration levels of TP were between 371.53 and 402.88 mg·kg^-1 for the wastewater-irrigated sites. Wastewater irrigation resulted in higher TN, TP and OM concentrations by 18.4%, 8% and 25%, respectively. The highest TN and OM occurred along the wastewater trunk. It was also observed that nitrogen concentrations correlate with the soil's organic matter. The increase of salinity may be associated with the increase of pH, which might suggest that a reduction of pH will be beneficial for plant growth due to the decrease of salinity. The average concentrations of nitrogen in topsoil were higher than those in subsurface soils in irrigated areas. Such differences of the N profile might be due to variations in organic matter content and microbial populations. Consistent with TN and OM, soil C:N decreased significantly with an increase of depth. This phenomenon possibly reflects a greater degree of breakdown and the older age of humus stored in the deeper soil layers. The analysis of pH levels at different depths for the three sites showed that pH values for wastewater irrigation were slightly lower than the controlled sites at the same depths.     

The MONICA model: Testing predictability for crop growth, soil moisture and nitrogen dynamics

A fundamentally revised version of the HERMES agro-ecosystem model, released under the name of MONICA, was calibrated and tested to predict crop growth, soil moisture and nitrogen dynamics for various experimental crop rotations across Germany, including major cereals, sugar beet and maize. The calibration procedure also included crops grown experimentally under elevated atmospheric CO₂ concentration. The calibrated MONICA simulations yielded a median normalised mean absolute error (nMAE) of 0.20 across all observed target variables (n = 42) and a median Willmott's Index of Agreement (d) of 0.91 (median modelling efficiency (ME): 0.75). Although the crop biomass, habitus and soil moisture variables were all within an acceptable range, the model often underperformed for variables related to nitrogen. Uncalibrated MONICA simulations yielded a median nMAE of 0.27 across all observed target variables (n = 85) and a median d of 0.76 (median ME: 0.30), also showing predominantly acceptable results for the crop biomass, habitus and soil moisture variables. Based on the convincing performance of the model under uncalibrated conditions, MONICA can be regarded as a suitable simulation model for use in regional applications. Furthermore, its ability to reproduce the observed crop growth results in free-air carbon enrichment experiments makes it suited to predict agro-ecosystem behaviour under expected future climate conditions.     

影响甜菜黑腐丝囊霉的几种生态学和生物学因子

通过对河西灌区甜菜(Beta vulgaris L.)黑腐病(Sugar Beet Black Rot)为期3a的研究，探讨了甜菜栽培品种与病害发病率及病原菌黑腐丝囊霉（Aphanomyces cochlioides)分离频率的关系以及3种环境因子即温度、pH值、不同天然培养基与甜菜黑腐丝囊霉的关系。结果表明：各栽培品种在田间的发病率与室内病原分离频率不同，其中工农2号田间发病率为1．3％，室内分离频率为93％，工农5号分别为1％和7．2％，宁甜301分别为2％和6．1％，工农2号具有更大的耐病性；甜菜黑腐丝囊霉的生长温度范围为5—30℃，最适温度为25—27℃，对高温敏感，33℃为其致死温度；甜菜黑腐丝囊霉可在pH3．5—11范围内生长，最适pH为5—9．9；甜菜黑腐丝囊霉在PDA、玉米粉琼脂、甜菜汁、麦芽糖—胨、麦芽糖酵母汁及燕麦琼脂培养基上均可生长，其中在甜菜汁培养基上生长最好．图4表3参11     

Trace elements in wild grasses: a phytoavailability study on a remediated field

There have been significant efforts to establish a widely usable method for the prediction of trace element bioavailability in soil. In this work, we used extraction with 0.01 M CaCl₂ and 0.05 M ethylenediaminetetraacetic acid (EDTA) to estimate bioavailable concentrations of As, Cd, Cu, Pb, and Zn in a soil moderately contaminated with trace elements 1 and 2 years after the application of three amendments. The experiment took place in a field plot of a soil affected by the toxic spill of the Aznalcóllar mine. Four treatments were established: three with amendments (biosolid compost, sugar beet lime, and a combination of leonardite plus sugar beet lime) and a control without amendment. Trace element concentrations of two representative species in each year (Lamarckia aurea and Poa annua in 2004 and Lamarckia aurea and Bromus rubens in 2005) were analyzed. The results showed a positive effect of the amendments both on soil and vegetation. Trace element concentrations in plants growing in the amended subplots were lower than those in plants from nonamended subplots. As a rule, concentrations of CaCl₂-soluble Cd, Cu, and Zn in soil were positively correlated with trace elements in plants, whereas EDTA extraction was scarcely correlated with plant concentration. For species of grasses, especially L. aurea, CaCl₂ seems to be a more suitable extractant to predict trace element bioavailability in this contaminated soil.