A simple disc instrument for estimating herbage yield

A simple instrument for estimating the yield of herbage from measurements of height has been tested in cutting and grazing experiments. The instrument consists of a verticle graduated shaft and two linked aluminium discs which settle on the herbage. The height of the discs from the ground is recorded. Highly significant relationships were established between the yield and the height of herbage. Linear regressions explained 80–90% of the variation in the cutting experiments, and 39–62% in the grazing experiments. The errors attached to the estimated yields were high, but, because of the simple construction, low cost and rapid operation of the instrument, it is concluded that it has many useful functions in grassland research and management.     

A non-destructive method for estimating lucerne shoot weights

Estimates of leaf and internode weight, leaf appearance rate and shoot number are not appropriate for non-destructive determinations of lucerne ( Medicago sativa ) growth rates as they are too variable. In an experiment involving four cultivars of lucerne harvested on two dates, a good relationship was found between linear measurements and the dry weight of shoots. An equation of the form W^1/3= a.(dl*d2*length)^1/3, where W = dry weight; dl, d2 = two diameters of the basal end of the shoot; length = maximum length of the shoot; and a = constant, gave a good fit to the data. The value of a varied between cultivars and sampling dates, and in the proportion of shoot harvested. The product of estimated shoot weight and shoot number can be used to give an estimate of plot yield.     

A practical equation for pasture growth under grazing

A sigmoid equation that accurately describes pasture growth is presented. The equation has three parameters that can be estimated either statistically from experimental results or algebraically from physiological simulation models. The equation produces satisfactory statistical results and it can account for different environmental conditions, through adjustment of parameter values, making it ideal for incorporation into grazing models when a simple but flexible equation is needed.     

A decision making scheme for potato quality

A decision making scheme is proposed for integrating and evaluating variables important for judging tuber quality in the potato industry. Within the scheme, variables affecting potato quality are grouped into categories according to their mutual association in a decision, and their values are rated according to a common linear scale. Expert opinions, as to which range of variable values ensure “commercially acceptable” and “ideal” potato quality, were superimposed as shaded areas over the numerical ratings. Observations of variables used in a decision can be compared to values delineated by experts to judge whether sampled potatoes would be acceptable for commercial use. The scheme is designed to be utilized at various points in the life cycle of a potato from field to market. It is demonstrated for one variety of sampled tubers that were being stored for chip processing.     

A method of estimating the single flax fibre fineness using data from the LaserScan system

This paper establishes a new method for estimating the single flax fibre diameter using the LaserScan instrument. The method is based on the mathematical modelling of the experimental fibre and fibre bundle width distribution and enables the flax fibre sample composition to be analysed in terms of proportions of single fibre and fibre bundles. The method can also be applied for the analysis of flax fibre fineness distribution produced by the Optical Fibre Diameter Analyser (OFDA) instrument. This method can be used as a tool for classification of flax accessions according to the estimated single fibre diameter, for evaluation of the efficiency of chemical and biochemical treatments aimed at the modification of flax fibre, and for evaluation of the suitability of flax fibre for spinning and manufacture of composites. The method was applied for the characterisation of 83 accessions from the Linum core collection produced by CGN at Wageningen, The Netherlands. The mean and standard deviation of single fibre diameter and proportion of single fibre and fibre bundles in the sample was estimated. Experimental results were in good agreement with theoretically expected relationships between the estimated mean diameter of single fibre and characteristics of fibre width distribution such as the mode and the overall average.     

A method of estimating timeliness costs in forage harvesting illustrated using harvesting systems in Sweden

A method for estimating timeliness costs, depending on dry-matter yield and nutritive value of forage is presented, and used to estimate timeliness costs, to examine different harvesting systems and to present conclusions on machinery selection when harvesting silage for dairy cows in Sweden. Timeliness costs (in € ha⁻¹ d⁻¹) of forage for silage were significantly higher for the first cut compared with the second or third cuts in the season. It is, therefore, important to avoid delaying the first cut. The timeliness costs also varied greatly between years. Harvesting costs decreased with increasing forage area up to a certain threshold area beyond which decreasing machinery costs were outweighed by increasing timeliness costs due to a longer duration of harvest. At increasing transport distances, the difference in cost between different harvesting systems and different sizes of machinery increased. Harvesting of forage by contractors decreased harvesting costs, particularly for small forage areas, since increased annual use of the machinery lowered the machinery costs and enabled larger machines with higher capacity to be used. To avoid high timeliness costs it is important to avoid delays in harvesting.     

A method for estimating harvest indices for use in surveys of potato crops

Summary A simple method was required for estimating the proportion (H) of total dry matter production which is found in the tubers of a potato crop. The ratio (F) of tuber fresh weight to total fresh weight has been found to be a suitable estimator. The relationship is described by the equation: H=0.962 F+14.1. This single equation served to describe the relationship over a range of cultivars, crop maturity and crop water supply.     

A technique for estimating rate of disappearance of dead herbage in pasture

A technique for estimating the rate of disappearance of material from samples of dead herbage protected by simple nylon or wire mesh covers is described. Using this technique on a perennial ryegrass sward in southern England during August-November, relative rates of disappearance close to 0·204 g g^-1 d^-1 (DM) were obtained, but the variability was high. When herbage killed with paraquat was used, the rate of disappearance was higher and the variability lower. There were only small differences in the temperatures recorded in a normal sward and within samples of dead herbage under mesh covers.     

A common regression for estimating dry-matter content of carbohydrate-containing commodities from specific gravity

For nine commodities that consist primarily of carbohydrates and water, corrections for intercellular space permit highly significant correlations between percent dry matter and corrected specific gravity. Drymatter contents for all commodities ranged from about 3 to 36%. Throughout this range the commodity mean values fall approximately on the regression line for specific gravity of sucrose solutions on dry matter percentage of the solutions, and the individual regressions often nearly coincide with the sucrose regression. It is suggested that, when intercellular space is accounted for, the sucrose regression is representative of commodities that consist primarily of water and carbohydrates.     

A method for estimating the decrease in marketable tubers caused by potato late blight

A regression analysis was used to develop a method to estimate the decrease in marketable tubers caused by late blight of potato (Phytophthora infestans), based on estimates of percentage loss in total tuber yield computed from a published method. The economic loss due to late blight in table stocks is the relative percentage marketable yield loss, calculated from the expression: {fx19-01} when total yield losses (in percentage) did not exceed 40%. A graphical method is presented as an alternative. Yield results from seven field experiments conducted in the Maritime Provinces of Canada during the period 1953 to 1971 were used in the study, where marketable tubers were defined as 2 1/4 inch or more in diameter.     

A method for estimating the loss in tuber yield caused by late blight of potato

A method was developed for estimating tuber yield losses caused by late blight of potato (Phytophthora infestans) (Mont.) de Bary. The method is based on yield and disease data collected for the varieties Green Mountain and Katahdin grown in eastern Canada during the period 1953–1970. The percentage yield loss can be calculated for any disease progress curve. The estimated loss was within 5% of the actual loss in nine cases out of ten.     

A semi-selective medium for estimating population densities of pectolyticErwinia spp. in soil and in plant material

Summary Stewart’s medium modified by omitting bile salts and adding 1.15×10⁻³ g/l gentian violet and 20 ppm Agral 90 was better than the original medium and as good as a nonselective medium such as nutrient agar for estimating population numbers ofErwinia carotovora var.carotovora andE. carotovora var.atroseptica. Although growth of unwanted organisms on soil dilution plates of the modified Stewart’s medium was slightly more extensive than on those of the complete Stewart’s medium, viable counts ofErwinia were still feasible.     

Deep neural network algorithm for estimating maize biomass based on simulated Sentinel 2A vegetation indices and leaf area index

Accurate estimation of biomass is necessary for evaluating crop growth and predicting crop yield.Biomass is also a key trait in increasing grain yield by crop breeding.The aims of this study were(i)to identify the best vegetation indices for estimating maize biomass,(ii)to investigate the relationship between biomass and leaf area index(LAI)at several growth stages,and(iii)to evaluate a biomass model using measured vegetation indices or simulated vegetation indices of Sentinel 2A and LAI using a deep neural network(DNN)algorithm.The results showed that biomass was associated with all vegetation indices.The three-band water index(TBWI)was the best vegetation index for estimating biomass and the corresponding R2,RMSE,and RRMSE were 0.76,2.84 t ha−1,and 38.22%respectively.LAI was highly correlated with biomass(R2=0.89,RMSE=2.27 t ha−1,and RRMSE=30.55%).Estimated biomass based on 15 hyperspectral vegetation indices was in a high agreement with measured biomass using the DNN algorithm(R2=0.83,RMSE=1.96 t ha−1,and RRMSE=26.43%).Biomass estimation accuracy was further increased when LAI was combined with the 15 vegetation indices(R2=0.91,RMSE=1.49 t ha−1,and RRMSE=20.05%).Relationships between the hyperspectral vegetation indices and biomass differed from relationships between simulated Sentinel 2A vegetation indices and biomass.Biomass estimation from the hyperspectral vegetation indices was more accurate than that from the simulated Sentinel 2A vegetation indices(R2=0.87,RMSE=1.84 t ha−1,and RRMSE=24.76%).The DNN algorithm was effective in improving the estimation accuracy of biomass.It provides a guideline for estimating biomass of maize using remote sensing technology and the DNN algorithm in this region.     

A novel approach for estimating the relation betweenK/S value and dye uptake in reactive dyeing of cotton fabrics

This paper focuses on the application of a novel mathematical limit approach derived forK/S values in reactive dyeing of cotton fabrics. The relation obtained from Kubelka-Munk equation is used because the Kubelka-Munk equation is the basic relationship among fabric reflectance, fabric dye content and dyestuff characteristics. The limit approach derived in a former paper is applied to the laboratory dyeings and the dyeing behavior of some reactive dyes on cotton knitted fabric has been obtained. The results of the laboratory experiments are discussed using the new mathematical approach. When the actualK/S values obtained from the dyeings and the calculatedK/S values derived by the limit approach are considered independently, it is observed that the limit relation is valid for low dye concentration applications. When theK/S values are calculated taking theK/S value of the initial dyeing concentration (0.1 % owf) as the starting concentration by applying the result of the derived limit approach, the calculatedK/S values fit with the ones obtained in actual dyeings. It is concluded that the novel approach presented in the paper can be used in calculating theK/S values when the initial dyeings at low dye concentrations are carefully carried out.     

Zinc deficiency as a practical problem in plant and human nutrition in Turkey: A NATO-science for stability project

Zinc (Zn) deficiency is a critical nutritional problem for plants and humans in Turkey. About 14 Mha of cropped land in Turkey are known to be Zn deficient, particularly cereal growing areas of Anatolia. In 1993, a joint research project was started in Turkey with the financial support of the NATO-Science for Stability Programme to select and characterize cereal genotypes with high yield and/or high Zn accumulation in grain under deficient supply of Zn.Field, greenhouse and growth chamber experiments were carried to study morphological, physiological and genetic factors determining the bases of genotypical differences in Zn efficiency among cereal species and within cultivars of wheat. Among the cereals, rye had particularly high Zn efficiency (high yield under Zn deficiency). There were large genotypical differences among wheat lines. High Zn efficiency was closely associated with enhanced capacity of some lines to take up Zn from soils, but not with increased Zn accumulation per unit dry weight of shoot or grain. Measurement of Zn-containing superoxide dismutase activity in leaves revealed that an efficient utilization of Zn at the tissue or cellular level is an additional major factor involved in Zn efficiency of cereals.Zinc present in grains from Anatolia seems to be not bioavailable. Phytate : Zn molar ratios in grains, a widely accepted predictor of Zn bioavailability, were extremely high and ranged between 95 and 216 for crops grown severely on Zn-deficient soils of Central Anatolia. In the studies concerning determination of Zn nutritional status of school children in Southeastern Anatolia, most children were found to be of shorter stature and had very low levels of Zn (<100 mg kg⁻¹) in hair.     

A comparison of a rising-plate meter and an electronic capacitance meter for estimating the yield of pastures grazed by dairy cows

The performances of a rising-plate meter and a single-probe electronic capacitance meter were compared for estimating the herbage mass of irrigated pastures both before and after grazing by dairy cows. Mean CV for the rising plate meter and the single-probe meter were 12.7% and 13.3% respectively when herbage mass was measured before grazing, and 21.8% and 15.4% respectively immediately after grazing. These coefficients of variation indicate that while the performance of the two meters was similar when herbage mass was measured before grazing, the single-probe meter was a more precise instrument for estimating herbage mass after grazing.
Trampling of herbage prior to measurement had a major effect on the regressions of both meters; the regression intercept was increased by 2800 kg dry matter (DM) ha⁻¹ for the rising-plate meter and by 2580 kg DM ha⁻¹ for the single-probe meter. The slopes of the graphs, however, remained unchanged.
It was concluded that while the single-probe meter performed better than the rising-plate meter for estimating the mass of post-grazing herbage when trampling was negligible, the large effect that trampling had on the post-grazing calibration regressions precluded both instruments from general use in dairy cattle research. This indicates that another technique is required in circumstances in which pastures are heavily trampled.     

A promising approach for bio-finishing of cotton using immobilized acid-cellulase

In this research, cellulases were immobilized on Eudragit S-100 to minimize the tensile strength loss of cotton fabric caused by the enzymatic hydrolysis. About 76 % of the enzyme activity and 81 % of the amount of protein were recovered after the immobilization process, and the immobilized cellulase exhibited good reuse ability. The immobilized cellulase had the better adsorptive performance on cotton than the free cellulase. In addition, the results revealed that the catalytic efficiency of the immobilized cellulase on cotton was degradation, perhaps because the diffusion of the enlarged cellulase molecules is significantly inhibited in the interior of the cotton fiber. Moreover, the cotton fabric treated with the immobilized cellulase showed less weight and strength losses. SEM pictures further indicated that the cotton fabric treated with the immobilized cellulase suffered less damage.     

A decision support system for agricultural drought management using risk assessment

Since predicted changes in climate will modify temperature and rainfall patterns, there are concerns about the potential impacts of these changes on agricultural drought and agricultural water resources management. An agricultural drought is influenced by several factors such as rainfall, soil characteristics, crops, and reservoir water supply and may be defined as the imbalance of water circulation in paddy and water environments. In particular, soil moisture and water supply for reservoir demand are the most direct and important indicators of agricultural drought events. In the past, conventional drought management approaches based on climatic and meteorological observations have been the primary tools used for measuring drought severity. Because of the spatial and temporal variability and multiple impacts of drought, it is necessary to improve tools to determine the onset, severity, spatial extent, and end of the drought conditions. Improved and available data for mapping and monitoring of this phenomenon are also needed. Effective and efficient drought management can be achieved through drought monitoring based on the ability to assess current conditions and provide improved tools to adapt and mitigate the impacts of future changes. In this article, a methodology is developed to support the risk-based decision-making process involved in agricultural drought management using the following four strategies: drought assessment and monitoring, drought forecast and outlook, drought countermeasures, and drought records management.     

A promising method for screening drought tolerance in potato using apical cuttings

Ten diverse potato genotypes from apical cuttings were screened for drought tolerance in raised beds of 3:1 v/v volcanic soil:burnt rice hull medium. The object was to test whether this method could replace field evaluation. Growth analyses were done periodically on potatoes from apical cuttings grown in beds. Correlations were made with those from seed tubers concurrently grown in the field. Total and tuber dry matter yield of plants grown from apical cuttings in beds and from seed tubers in the field were significantly correlated (r=.80*). Drought stress sensitivity based on % reduction in tuber and total dry matter at maturity in beds was similar to the results found in the field at maturity. Consistency of the method necessitates the standardization of the age, quality and source of apical cuttings and the growing conditions particularly drought stress imposition.