Comparisons of methods of scheduling irrigations of potatoes

Irrigation of Netted Gem potatoes was scheduled during three growing seasons by three methods: (a) when plants displayed first visual symptoms of moisture stress, (b) when indicated by a soil moisture budget involving estimated evapotranspiration, and (c) on the basis of tensiometer readings of soil moisture suction. When the tensiometer method of scheduling was used, the mean yields of tubers were 55.0 and 25.8 cwt/acre (6160 and 2890 kg/ha) higher than those obtained with the other two scheduling methods. Methods did not affect the specific gravity of potatoes. Method (a) scheduled irrigations least frequently. Scheduling by the budget method was not always adequate because it was based on the assumption that the crop extracted water from a constant 4 ft (1.2 m) profile from planting to full vegetative growth. In one year the budget method scheduled the first irrigation earlier than necessary and delayed the second irrigation during a critical period of crop growth. From full vegetative cover to harvest the irrigation schedules were alike for both the budget and tensiometer methods.     

Determination of the potential for development of bacterial soft rot of potatoes

A method has been devised for assessing the potential hazard of soft rot development in potatoes. Tubers are placed in a mist chamber at 20 C (68F), a film of water is maintained on the tuber, and the extent of decay is assessed after 5 days. The soft rot potential determined in this way is intended as apractical indication of potential storage hazard, reflecting the overall effect of the various factors leading to bacterial decay. Tubers that had passed through a flume system and a rinsing spray in a commercial packing plant had a greater decay potential, even after passage through a hot-air dryer, than unwashed tubers. Differences in decay potential could be demonstrated between tubers that had been mechanically harvested and loaded into storage bins and those that had been harvested manually. In addition to the effect of mechanical damage and of passage through flumes, the decay potential was probably affected by the inoculum level ofErwinia carotovora. Pectolytic clostidia were also usually present in tubers rotting in mist chambers, and are probably involved in the decay.     

Comparison of two methods of PCNB application for control of Rhizoctonia infection of potatoes

A broadcast application of PCNB (Terraclor) resulted in a reasonably uniform distribution of the chemical in the soil with the concentration decreasing in a linear fashion with increasing depth in the soil profile. A banded application resuluted in a considerably higher chemical concentration at the 4–6 inch depth than at the 0–2 or the 2–4 inch depths. The problem of the lack of uniformity of chemical distribution could probably be solved by altering nozzle placement and size and allow use of the band method of application to minimize grower cost. More complete disking in the case of the broadcast treatment would probably result in a relatively uniform distribution of the chemical but at higher cost to the grower. PCNB application rates of 10, 15 and 25 lbs per acre broadcast and 71/2, 10 and 121/2 lbs per acre in a band significantly reduced the severity ofRhizoctonia infection of Russet Burbank potatoes but did not increase potato yields significantly.     

Effect of kneading and baking on the degradation of the lipid fraction of biscuits

An experimental investigation was carried out with the aim of evaluating the effect of kneading and baking on the degradation of the lipid fraction of biscuits. For this purpose, the raw materials, the dough, and the end-products sampled during processing at a biscuit-making industrial plant were analysed. The results showed that the kneading stage caused a significant decrease in content of polyunsaturated fatty acids and a concomitant significant increase of triacylglycerol oligopolymers and oxidised triacylglycerols that are indexes of oxidative degradation. The subsequent baking step caused the degradation of part of the oxidised compounds to volatile substances, as confirmed by the determination of the p-anisidine value. On the whole, the biscuit-making process, although determining a significant increase of triacylglycerol oligopolymers, has only a small impact on the oxidation level of raw materials.     

由国际饮茶日设定,谈茶的社会效应

国际饮茶日设定说明了全世界人更重视茶,标志着茶文化发展到新高度.茶不仅有大家熟知的保健功效,茶也具有社会效应.提倡饮茶,是中国人们生活将要进入小康社会的标志;是人类科学技术发展到一定高度的标志,是人们更重视相互交流重要性的体现,同时也促进人类命运共同体的构建.     

The mode of operation of a regulating reservoir for effective use of river flow

In the absence of a reservoir on the downstream side, a river flow that increases temporarily by rainfall cannot be stored and discharged apart from requirements in a command area. This unused water (excess water) occurs to some extent even in a drought year and making effective use of this supply is considered as one of the countermeasures for water shortage. Setting up a regulating reservoir on the upstream side of head works is regarded as one of the methods for making effective use of excess water. The inflow to the river and water delivery loss occurred from rainfall are stored in the regulating reservoir and supplied to the command area on the downstream side as agricultural water. An operational method for the regulating reservoir to effectively utilize the excess water was examined for a canal system by simulation. In an investigated area, there was excess water even in drought years, and making use of it through the regulating reservoir whose capacity is smaller compared to that of a dam can become one of the countermeasures for the drought period. The simulation in this study could estimate quantitatively the effect of the regulating reservoir to make the excess water effective.     

波罗蜜叶片突变体叶绿素含量测定和超微结构观察

波罗蜜（Artocarpus heterophyllus）是一种热带果树,至今对其突变体的研究少有报道。本研究以波罗蜜叶片为试验材料,探究其叶片出现白化和返绿现象的可能原因。（1）用分光光度计法、比色法测定波罗蜜叶片突变体和正常绿叶的叶绿素及叶绿素前体物质含量;（2）用叶绿素酶Elisa试剂盒测定叶绿素酶活性;（3）用透射电子显微镜对叶绿体的超微形态结构进行观察。研究结果表明：（1）不同叶色所产生的叶绿素a含量、叶绿素b含量、叶绿素总含量、类胡萝卜素含量均存在显著差异;（2）波罗蜜叶片突变体和正常绿叶的叶绿素合成前体物质含量之间并没有出现显著性差异;（3）对波罗蜜叶片的叶绿素酶活性进行测定时,发现其活性出现显著差异,但对其叶绿素含量的差异性并没有产生较大影响;（4）观察波罗蜜叶片内叶绿体超微形态结构时,发现正常绿叶的叶绿体形态完好且数量较多,白化叶和返绿叶的叶绿体内部结构存在缺陷,其原因是叶绿体基粒构建阶段受阻;基于测定波罗蜜叶片中的叶绿素、叶绿素前体物质含量和叶绿素酶活性,并观察波罗蜜叶片内叶绿体的超微形态结构,对得到的数据结果进行比较分析。本研究推测是在叶绿素合成阶段,原脱植基叶绿素合成叶绿素时受阻及叶绿体发不良导致波罗蜜出现白化和返绿现象,为今后进一步综合研究波罗蜜突变体提供理论依据。     

Measurement of black spot susceptibility of potatoes

The black spot reaction was initiated by dropping plugs of varying weights from different heights onto the stem end of potatoes with known temperatures. The degree of discoloration was assessed in a scale from 0 to 5, the results were added and the sum was divided by the number of tubers. Relationships between black spot incidence, temperature and impact were very close in samples containing 100 or more tubers. This was not always the case, however, if samples were of a more manageable size of 20 to 25 tubers. Results indicated the desirability of testing under a standard set of conditions—such as 100 g falling 30 cm onto the stem end of tubers with a temperature of 10 C. The results of visual assessment of the black spots were closely related to the results of a more objective, but also more laborious, method in which the amount of discolored tissue was weighed.     

Models of the interconnection of pumps to supply water to branched networks

The basic concepts from a hydraulic and mathematical point of view were introduced to describe the operation of a hydraulic branched network of water distribution. Moreover, each one of the elements (simples and complex) of the system was identified. Classic hydraulic equations were inputted to apply them to branched networks and obtain a standard solution. A set of linear and non-linear equations, through the Newton–Raphson method with the jacobian matrix were required to solve the branched network that interconnects two kinds of very different pumps: a volute type centrifugal pump and another one is submersible pump, both of them installed in a deep well. The system is a branched network with two nodes and five pipe lines, to adequately supply two pressure irrigation systems: a central pivot and a semi-portable sprinkler, where the pumps are located in different places and heights. The solution was obtained by solving a system of two linear equations and three non-linear, simultaneously.     

The effects of degree of chopping grass for silage and method of concentrate allocation on the performance of dairy cows

Three silages were produced from the same swards by harvesting grass using either a double-chop harvester (DC) or a precision-chop harvester adjusted to produce a long staple length (PL) or a short staple length (PS). The mean particle lengths were 47, 52 and 14 mm respectively.
Of each material 250 t was ensiled unwilted and with formic acid additive at the mean rate of 2-4 litres t^-1 of grass. All three silages were well preserved and degree of chopping had no effect on fermentation as indicated by either pH, ammonia N or organic acid concentration.
The silages were offered ad libitum to seventy-two British Friesian cows with a mean calving date of 28 January which were in their second or later lactation, in a randomized-block experiment from day 8 of lactation until 12 April. In addition twelve animals on each silage received a uniform daily concentrate allowance of 7·2 kg while twelve were offered concentrates according to their individual milk yields but with a mean concentrate allowance over the twelve cows of 7·2 kg d^-1. Degree of chopping had no significant effect on either silage dry matter intake or milk yield with mean intakes during the final 21 d of the experimental period of 9·2, 9·2 and 9·2 kg d^-1 and mean milk yields of 25·2, 25·2 and 25·2 kg d^-1 for the DC, PL and PS silages respectively. Method of concentrate allocation did not affect either the total yield of milk during the experimental period, 1717 and 1697 kg, or the total lactation yield, 5635 and 5711 kg, for the uniform and yield-related allocation methods respectively. The butterfat and protein concentrations of the milk were not significantly affected by either the degree of silage chopping or the method of concentrate allocation.     

Measurement of Gliadin and Glutenin Content of Flour by NIR Spectroscopy

Traditional NIR calibration methods rely on assembling a calibration set of samples and using procedures such as multiple linear regression or partial least squares to develop the calibration. The problem with this methodology is to assemble a calibration set which maximises the diversity of samples represented whilst minimising the intercorrelations between constituents, particularly total protein content and moisture content. The application of NIR measurements of grain has moved beyond simply measuring protein and moisture content. There is now considerable interest in using NIR to measure a range of quality parameters such as Extensograph extensibility and maximum resistance. These parameters are not themselves represented in the NIR spectrum, but are a direct result of the protein composition of the sample. Consequently, a method for predicting the protein composition would be useful. In this paper, we present the results of a comparison of a curve fitting methodology and the more usual partial least squares curve fitting of the component protein spectra, using samples obtained from a wheat breeders» trial. Gliadin and glutenin contents were measured by SE-HPLC and used to develop a partial least squares calibration and the results compared with a curve-fitting methodology. For the situation examined here, the curve fitting methodology did not perform as well as partial least squares calibration. For glutenin, SEP=0·65 for the curve fitting compared to SECV=0·38 for a traditional PLS calibration. However, the results from the curve-fitting are independent of the total protein content and show sufficient discrimination for potential use in sample protein ranking.     

Effects of Chemical Functionalization of MWCNTs on the Structural and Physical Properties of Elastomeric Copolyetherester-based Composite Fibers

Elastomeric copolyetherester (CPEE)-based composite fibers incorporating various neat and functionalized multiwalled carbon nanotubes (MWCNTs) were prepared through a conventional wet-spinning and coagulation process. The influence of functionalized MWCNTs on the morphological features, and the thermal, mechanical properties and electrical conductivity of CPEE/MWCNT (80/20, w/w) composite fibers were investigated. FE-SEM images show that a composite fiber containing poly(ethylene glycol)-functionalized MWCNTs (MWCNT-PEG) has a relatively smooth surface owing to the good dispersion of MWCNT-PEGs within the fiber, whereas composite fibers including pristine MWCNTs (p-MWCNT), acid-functionalized MWCNTs (a-MWCNT), and ethylene glycol-modified MWCNTs (MWCNT-EG) have quite a rough surface morphology owing to the presence of MWCNT aggregates. As a result, the CPEE/MWCNT-PEG composite fiber exhibits noticeably increased thermal and tensile mechanical properties as well as a faster crystallization behavior, which stems from an enhanced interfacial interaction between the CPEE matrix and MWCNT-PEGs.     

Effects of oxathiapiprolin on Phytophthora nicotianae,the causal agent of black shank of tobacco

Oxathiapiprolin is a new fungicide active against oomycetes. In vitro assays and field studies were conducted to examine the effect of oxathiapiprolin on Phytophthora nicotianae (Pn), the causal agent of black shank. The efficacy of oxathiapiprolin on mycelial growth, sporangia production, zoospore motility, and zoospore germination was assessed with four Pn isolates. EC₅₀ values were low ranging from 0.0039 to 0.0049 μg a.i./mL for mycelial growth, 0.00052–0.00081 μg a.i./mL for sporangia production, 0.0035–0.0051 μg a.i./mL for encysted zoospore germination, and 0.0055–0.0166 μg a.i./mL for zoospore motility. Sixty six Pn isolates, 60 from tobacco and six from ornamental plants were examined for sensitivity to oxathiapiprolin at 1 μg a.i./mL. Mycelial growth at 1 μg a.i./mL was observed in only one isolate from tobacco whereas the six Pn isolates from ornamental plants five of which were resistant to mefenoxam at 100 μg a.i./mL, were found to be sensitive to oxathiapiprolin. The efficacy of oxathiapiprolin against black shank was assessed in three field studies in North Carolina. Treatments of oxathiapiprolin were equal or superior to mefenoxam against black shank in each field study. Our results suggest that oxathiapiprolin is a highly efficacious fungicide against P. nicotianae, and will be a useful tool in controlling black shank of tobacco.     

微量元素缺乏与过量对脱毒马铃薯苗生长的影响

采用不完全营养液法研究了微量元素的缺乏与过量对脱毒马铃薯苗生长的影响。采用营养液栽培时,脱毒马铃薯苗对微量元素吸收很少,但营养液中缺乏Fe和Mn会表现出明显的缺素症状,缺乏Cu、Zn、B、Mo无明显的表现;Cu、Mn、Zn、B、Mo等元素过量植株会出现明显的中毒症状,MS营养液中Mn元素需适当降低才能适应脱毒马铃薯苗的液体培养。     

The effects of foliar application of cytokinins on potato yields in southeastern Idaho

The “Cytex” product, a commercial seaweed extract containing natural cytokinins, was tested as a foliar spray for seven years, using several potato clones and several rates and dates of application. Throughout seven years, the Russet Burbank cultivar showed no measurable response to the “Cytex” product. Application of kinetin in a single season also produced no response. Throughout five years of testing, the Lemhi Russet showed a substantial yield response in one year, a moderate response in a second year, and a possible small response to 1 of 6 treatments in a third year. The best time for application is during the 2-week period directly following tuber initiation.     

Comparison of two strategies for use of translaminar and contact fungicide in the control of potato late blight in the highland tropics of Ecuador

Strategies based on using the translaminar fungicide cymoxanil for control of potato late blight, caused by Phytophthora infestans, were compared in the highland tropics of Ecuador in three separate field experiments. In one strategy, a commercial formulation of cymoxanil mixed with mancozeb was sprayed sequentially three times early in the season; this was then followed by three sequential sprays of a commercial product containing mancozeb alone. For the other strategy, the same commercial products were alternated. For each strategy, a spray interval of 14 d was used after the contact/translaminar mixture and 10 d after sprays containing mancozeb alone. Both strategies were evaluated with a manually operated knapsack sprayer but with two levels of application quality. High quality was achieved with a constant pressure valve and a new nozzle, while for low quality, fungicide was applied without a valve and using a damaged nozzle. All treatment combinations gave adequate disease control and no consistent effect of application strategy or application quality could be measured on disease severity or yield. However, approximately twice the volume of fungicide was applied using poor quality equipment, regardless of the application strategy. Advantages and disadvantages of the strategies and their potential effects on fungicide resistance are discussed.     

阿司匹林在茶树上的应用前景

本文通过对茶树叶面喷阿司匹林后能增强抗旱性、促进生长发育、提高茶叶产量和品质等方面的研究,以及大面积推广应用所具的长效性和经济效益的显著性,论证了阿司匹林是一种有应用前途的茶树生长调节物质和保护剂。     

栽培稻分类方法的比较

 为了比较Glaszmann和程侃声等对亚洲栽培稻的分类体系,将Glaszmann氏提供的197个水稻品种的同功酶位点原始记录和程氏对它们就6个形态性状的评分作了主成分分析和聚类分析。结果显示二人的分类基本一致,数值分类也表明栽培稻可以只分籼粳两个亚种,处于中间的少数品种可称为偏籼或偏粳。程氏采用的“性状指数法”似更为便利而有效,特别适于田间及育种工作,虽然带有一定的经验成分,但加以生化或数值分类的检验,即可弥补该法的不足,有助于澄清个别不够明确和错划的事例。因此,我们建议为求得最佳的分类系统,最好运用二种以上的方法,相互补充校正。     

水合氧化铁提前施用对持续淹水条件下水稻甲烷的减排效应

水合氧化铁是一种弱晶质三价铁氧化物,可用来减少稻田甲烷（CH4）的排放。采用水稻盆栽试验,研究水合氧化铁的提前施用对持续淹水条件下水稻CH4排放的影响。结果表明:水合氧化铁在水稻移栽前47 d施用,加Fe处理的全生育期CH4总排放通量比对照减少17.52%,其CH4减排效应仅出现于水稻生长后期。在移栽后第70天,加Fe处理的根孔隙度、根表铁膜含量和单株根表铁膜数量均显著高于对照,而稻根产CH4速率则显著低于对照。因此,提前施用水合氧化铁能够通过促进植株介导的根表铁膜的形成抑制稻根的产CH4潜力,进而实现持续淹水条件下水稻CH4的减排。     

Effect of altering the grazing interval on growth and utilization of grass herbage and performance of dairy cows under rotational grazing

The effects of short grazing intervals in the early part of the grazing season on the growth and utilization of grass herbage, and the performance of grazing dairy cows, in a rotational grazing system were examined. Seventy-six cows were allocated to two grazing treatments: a normal rotation treatment (20-d rotations for the first 60 d) and a short rotation treatment (12-, 8-, 8-, 8-, 12- and 12-day rotations). Thereafter, both treatments had the same grazing interval and over the season as a whole both treatments received the same amount of nitrogen fertilizer and were stocked at the same rate. The short rotation treatment significantly reduced pre- and post-grazing sward heights and pre-grazing herbage mass in May and June. Total herbage production was significantly lower on the short than the normal rotation treatment as a result of a significant reduction in the growth rate of herbage in May and June. The short rotation treatment had a significantly lower milk output per cow. Grazing shorter swards, as a result of shorter rotations, significantly reduced herbage intake, reflecting reductions in intake per bite, grazing time and total bites per day. Treatment had no significant effect on herbage quality or pre- and post-grazing sward height in August and September, despite the increased grazing severity in May and June with the short rotations. The severity of rotation length in this instance had a detrimental impact on animal performance, whereas a more modest reduction in grazing interval may control herbage production, without reducing animal performance.