Validation of a food-frequency questionnaire for measurement of nutrient intake in a dietary intervention study

OBJECTIVE: To validate a 171-item semi-quantitative food-frequency questionnaire (FFQ) for measurement of nutrient intake in an intervention trial based on walnut supplementation. DESIGN AND SETTING: Free-living adults from Southern California were randomly assigned to either an intervention (walnut-supplemented) or a control diet. The prescribed 6-month intervention was > or = 28 g of walnuts per day for the walnut-supplemented group and > or = 2 g of walnuts per day for the control group. Participants provided at least six 24-hour dietary recalls and completed a self-administered FFQ. SUBJECTS: Eighty-seven adults aged 30-72 years (48 females, 39 males). RESULTS: Our findings from validation (by correlation with six diet recall measures) of the measurement of 32 nutrients by the FFQ are as follows. We found significant positive correlations (corrected for measurement error) between the FFQ and diet recalls for total energy (r = 0.34), total carbohydrate (r = 0.42), vegetable protein (r = 0.43), total fat (r = 0.51), polyunsaturated fat (r = 0.77), total fibre (r = 0.60), linoleic acid (r = 0.78) and alpha-linolenic acid (r = 0.79) - the last nutrient being an excellent nutrient biomarker of the intervention (walnut supplementation). Significant positive correlations were also found for vitamin C (r = 0.96) and certain minerals (r = 0.46-0.80 for calcium, phosphorus, magnesium, iron and potassium). Uncorrected correlations were also high (r>0.40) for retinol, beta-carotene, folate and alcohol. Both diet recalls and FFQ showed a similar significant difference in alpha-linolenic acid content between the walnut-supplemented and control diets. CONCLUSIONS: The FFQ demonstrated good relative validity in the estimation intake of some of the major nutrients in a dietary intervention trial and was a particularly valid estimate of an important nutrient biomarker of walnut supplementation.     

Soil test reporting a nutrient index system

Abstract

An index system of reporting soil test results is suggested which is not confounded with the requirements of a particular crop but is based on each laboratory's evaluation of the test results in relation to the predicted relative sufficiency of each element in a fertile soil. It is suggested that soil test—fertilizer rate correlation adjustments begin after the fact rather than in a precursory manner to influence the results reported. A 0–100 index is proposed as a self explanatory measure and correlated with general crop response as follows: 0–15, nutrient deficiencies visible; 16–50, nutrient deficiencies obscured but plant response probable; 51–100, adequate nutrients available for most crops; 100+, amounts available in excess of present needs.     

Evaluation of agro-industrial by-products as nutrient source for plant growth

Nutrient leaching from dry (COD) and wet (COW) coffee, sisal (SIS), brewery barley malt (BEB) and sugar cane (FIC) by-products, and linseed (LIC) and niger seed cakes (NIC), and uptake by maize were studied in a pot experiment with tropical Alfisol. After three months, soils were leached to recover labile plant nutrients, and root and shoot biomass was harvested. The leachate from FIC-amended soil had the highest concentration of inorganic P (0.90 μmol L^?1), whereas the highest concentrations of potassium (K) (48,088 μmol L^?1) and calcium (2566 μmol L^?1) were determined in leachates from COD and BEB treatments, respectively. The amendments significantly increased K uptake by maize proportional to the amount of K applied, but the effects for other plant nutrients were small. The results indicated that pre-decomposition of agro-industrial by-products may increase the nutrient release in tropical soils.     

无土栽培营养液循环控制系统

该文介绍了营养液循环控制系统的设计和构成，营养液检测控制过程。采用最小二乘拟合的方法建立离子选择电极的测量模型，从而实现温室无土栽培中营养液的在线检测。采用动态矩阵控制算法控制离子浓度，在一定程度上克服了某些不确定干扰的影响，并解决了超调的问题。     

Carbon and nutrient dynamics under long-term nutrient management in tropical rice-wheat-jute system

Impacts of 43-year nutrient management on carbon (C) and nutrient dynamics were studied in a rice-wheat-jute system in tropical India. Carbon dynamics was investigated on the basis of its distribution of labile (microbial biomass C, permanganate oxidizable C and water soluble C) and slow pools (Walkley Black oxidizable organic C), its indices (C pool index, lability index) and C management index (CMI) at different soil depths. Nutrient dynamics was judged by major nutrients availability, and related soil enzymatic activities. We studied seven treatments including unfertilized control, 100% NPK (N:P₂O₅:K₂O 60:30:60), 50% NPK, 150% NPK, 100% NP, 100% N, 100% NPK + farm yard manure (10 tonnes FYM ha^?1). Nutrients availability and soil enzymatic activities were significantly increased under balanced fertilization (100% NPK + FYM) over other treatments. Labile, slow and total C was also found highest in 100% NPK + FYM. Enhanced C indices under 100% NPK + FYM over 100% NPK and other treatments signified the importance of long term balanced fertilization on soil C stabilization. Lability indexes were lower at sub-soil (30-45cm). In terms of favourable nutrient dynamics and CMI, balanced application of NPK plus organics were recommend for long term sustainability of rice-wheat-jute system in tropics.     

Quantitative evaluation of the microbial nutrient sink in soil in relation to a model system for soil fungistasis

A quantitative approach was devised to evaluate the influence of soil microbial activity as a sink for nutrients exuded by fungal spores as a factor in soil fungistasis. The approach was based on measuring the CO₂ evolved from microbial respiration of ¹⁴C-labelled exudates from conidia of Cochliobolus victoriae incubated on soil. The amount of exudate lost by spores on soil was greater than the amount lost by spores incubated on a bed of sand undergoing leaching at a flow rate of 110 ml h^?1. where restriction of germination was similar to that on soil. Increasing flow rates in the leaching system increased spore exudation and reduced germination. Germination of C. victoriae conidia on membrane filters floated on distilled water decreased as the volume of water increased. The results indicate that the microbial nutrient sink of soil is sufficient to impose soil fungistasis.     

营养液加热消毒机的设计与灭菌性能试验

设计了一种专用于营养液消毒的加热消毒机,可以自动实现排液流量1 m³/h、营养液由室温加热至85℃、保温滞留0～3 min的任务。杀菌试验结果表明本机对番茄萎蔫病病原菌、黄瓜枯萎病病原菌、番茄细菌性青枯病病原菌都有较好的杀灭效果;同时性能稳定、可靠。在杀灭营养液中的这3类病原菌时(起始病原菌浓度为3.9×10⁵～8.3×10⁵ cfu/mL),75℃/90s的杀菌组合,可以达到100％的杀菌效果。     

Techniques of iron addition to a sewage effluent based nutrient film system for growing tomatoes

The use of the nutrient film technique for growth of crops in sewage effluent has demonstrated the need to provide an iron supplement to the plants. Work at Portsmouth Polytechnic has studied several techniques by which iron may be added to the plant root block and also to the plant leaves. The results of the studies show clearly that one technique is particularly successful. Plants grown using this method can produce crop yield comparable with commercial practice.     

Response of potatoes to different nutrient solution management in a closed hydroponic system

Ion control of nutrient solutions to control nitrogen (N), phosphorus (P), and potassium (K) was developed for Superior (medium-to-early maturing) and Atlantic (mid-late) potato cultivars grown in closed hydroponic systems in which solutions were replenished and recirculated. Results were compared with conventional nutrient solution management strategies. In the “solution replacement” treatment, nutrient solutions were completely replaced each week. In the “electrical conductivity (EC) control” treatment, water use by potato plants was compensated by adding ground water to achieve the original volume (water replenishment) and the diluted EC of the solution was adjusted to the target levels using stock solution. In “ion control” treatment, ammonium dihydrogen phosphate (NH₄H₂PO₄) and potassium nitrate (KNO₃) were added to the EC-controlled nutrient solution. The amounts increased with plant age in both cultivars. The concentrations of nitrate (NO₃), P, and K in the ion control nutrient solution could be maintained at target levels. In water replenishment, recycling of nutrient solution resulted in a progressive decrease in EC and an increase in pH. Root activity increased by 93% and 59% in the Superior and Atlantic cultivars, respectively, compared with the nutrient solution replacement. These changes decreased photosynthesis, plant growth, water use, and thus tuber growth in the Superior cultivar. Decreased growth of shoots and tubers occurred without affecting photosynthesis in the Atlantic cultivar. Although there were no significant differences in root activity, photosynthesis, or plant growth between the ion control treatment and the EC control treatment, increased tuber growth was observed in the ion control treatment, possibly as a result of the constant supply of nutrients. High tuber growth and the capability to maintain solution nutrient concentration in the ion control treatment are highly desirable for closed hydroponic systems.     

The influence of eating location on nutrient intakes in Irish adults: implications for developing food-based dietary guidelines

OBJECTIVES: To examine the contribution of the food service sector to the nutrient quality of the Irish diet, and to compare intakes at home, work and outside the home ('out') and within the subgroups of the out location (pub, deli, takeaway). DESIGN AND SETTING: Random sample of adults from the Republic of Ireland. Food intake data were collected using a 7-day food diary. Respondents recorded the location of every eating occasion determined by where the food was prepared rather than consumed. RESULTS: Intakes of energy, protein, fat and carbohydrate were significantly greater at home than at work or out (P<0.05). The intake of alcohol was significantly (P<0.001) greater out than at home or work. The percentage contribution of fat to energy was above the recommendations (33% of total energy and 35% of food energy) for both men and women at all locations, with the exception of the contribution of fat to total energy for men at the out location. Within the subgroups of the out location, the contribution of alcohol to total energy was greatest in pubs and the contribution of fat to both total and food energy was greatest in takeaways. Intakes of fibre and most micronutrients per 10 MJ of food energy were greater (P<0.05) at home than at work or out. CONCLUSION: Foods eaten outside the home contribute a disproportionately high level of fat intake and should be targeted in public health nutrition strategies.     

精准农业中土壤养分分析的适宜取样数量的确定

为研究适合丘陵地区的土壤养分取样数量,减少采样分析成本,本文采用Cochran（1977）公式对丘陵地区土壤特性的取样点数量进行了探讨。结果发现：在1km。研究区域内,利用Cochran公式对土壤养分进行预估,其取样数目比网格取样法明显减少,土壤中的N以15％的相对误差为宜,在置信度分别为90％和95％条件下,分别只采集2个和3个样本就能反映其含量水平;P以15％的均值误差为宜,在置信度分别为90％和95％条件下,分别采集17个和25个样本就足够反映其基本情况;Mg以5％的均值误差为宜,在置信度分别为90％和95％下,取样数量分别为11个和15个。     

Longitudinal changes in dietary intake in Scottish women around the menopause: changes in dietary pattern result in minor changes in nutrient intake

Objective: To examine dietary change that has occurred over 5 to 6 years.Subjects: A cohort of Scottish women (n=898) with a mean age of 47.5 years (range 45-54 years) at baseline.Design: Dietary intake was assessed by validated food-frequency questionnaire (FFQ) and analysed using the UK Composition of Foods database.Results: Since the first dietary assessment, mean daily energy intake had decreased from 8.2+/-2.3 to 7.9+/-2.2 MJ. The degree of low energy reporting (defined as ratio of energy intake to basal metabolic rate <1.1) had increased from 18.7% at baseline to 25.6% at follow-up. Low energy reporters were significantly heavier than 'normal' energy reporters (mean weight at follow-up, 68.9+/-12.6 vs. 66.8+/-11.3 kg) and could be deliberately restricting intake rather than underreporting. Overall there were decreases in intakes of red meat, processed meat and cheese, but increases in poultry and non-oily fish consumption. Consumption of bread, biscuits and cakes had gone down and there was an increase in cereal and rice/pasta consumption. Intake of potatoes had decreased whereas fruit intake had increased. There were small but statistically significant differences in intakes for most nutrients (<8% change). Nutrient intakes at both visits were similar across menopausal status and usage groups of hormone replacement therapy. Modifications to the computer version of the McCance and Widdowson nutrient database, which differed from the published version, were noted. These changes altered the original baseline values for our study.Conclusions: The menopause per se is not a period of marked change in nutrient intake. Caution is advised when using computer databases of food compositions for longitudinal studies.     

Evaluation of nutrient deficiencies in wheat seedlings by chlorophyll fluorescence

Chlorophyll fluorescence of plants is altered by conditions that affect photosynthesis and has proven useful in screening for resistance to environmental stresses. This study evaluated chlorophyll fluorescence for assessing the physiological impact of nutrient deficiencies and for diagnosing deficiencies of specific nutrients. Major nutrient (N,P,K) deficiency‐induced changes in chlorophyll fluorescence were determined in ‘Len’ hard red spring wheat (Triticum aestivum L.). Seedlings were grown in media containing 0, 1, 10, 50, or 100% of N and 0, 1, 10, or 100% of P and K in full‐strength Hoagland solution in a growth chamber for 22 d. Changes in initial (Fo), maximum (Fm), and variable (Fv) chlorophyll fluorescence of leaves and weight, height, and N, P, K, and Mg concentrations of shoots were measured. All chlorophyll fluorescence parameters declined significantly as N, P, and K concentrations declined, but thylakoid membrane efficiency (Fv/Fm and Fm/Fo) was stable at all nutrient levels. Relative units of Fo, Fm, and Fv were usually significantly and positively correlated with growth and. N,P,K, and Mg concentrations of shoots. Chlorophyll fluorescence may be a useful measure of severity of nutrient deficiencies. Use of chlorophyll fluorescence for diagnosing specific deficiencies may not be feasible, however, because of the similar effects of different nutrients.