This group, which is concerned with the applications of mathematics to agricultural science, was formed in 1970 and has since met at approximately yearly intervals in London for one-day meetings. The thirty-eighth meeting of the group, chaired by Professor A. Kassam of the University of Reading, was held in the Kohn Centre at the Royal Society, 6 Carlton House Terrace, London on Friday, 31 March 2006 when the following papers were read.

Maize is one of the three staple foods in the world. The white variety represents 60% of the maize importation with a world consumption of 1125 million tons in 2019/2020. Currently, new technologies could contribute to the analysis of this seed, supporting quality control and improvement. This study aims to carry out the morphological and proteomic comparison between the hybrid MR2008 and its parental lines LUG03 and CML491 through mass spectrometry and bioinformatics analysis. Herein, we identified that 34.8% of the hybrid proteome differs from the parental proteome. Also, ontological and morphological analyses determined that the hybrid exhibits more characteristics related to CML491 than LUG03, for example, metabolic pathways and enzymes, such as anthocyanidin 3-O-glucosyltransferase (UniProt P16166). This analysis allowed the identification of dominant characters, metabolic pathways and confirms the utility of this methodology in agricultural practices, mainly in processes of selection and quality control of a crop.

This working group, which is concerned with operational research methods and applications to agricultural science in its broad meaning (i.e. including Forest Management and Fisheries), was formed in 2003 within the European Association of Operational Research Societies (EURO). The first meeting of the group was held at the former Silsoe Research Institute two years ago. The next meeting will be held in 2007 within the XXII EURO Conference in Prague. The group intends to start regular meetings at approximately yearly intervals in association with the EURO Conferences. The second meeting of the working group, chaired by Dr. L. M. Plà of the University of Lleida and organized as a stream within the XXI EURO Conference, was held at the University of Iceland in Reykjavík from 3rd–5th July 2006 where the following papers were read.

This group, which is concerned with the applications of mathematics to agricultural science, was formed in 1970 and has since met at approximately yearly intervals in London for one-day meetings. The fortieth meeting of the group, chaired by Dr John Thornley of Henley-on-Thames, UK and the Centre for Nutrition Modelling, University of Guelph, Canada, was held in the Kohn Centre at the Royal Society, 6 Carlton House Terrace, London on Friday, 11 April 2008 when the following papers were read.

Soil available phosphorus (SAP) and potassium (SAK) are indispensable for crops, and their stocks are important for food production needed for a growing global population. This study analysed 991 soil profiles across a large part of Romania covering forestland, grassland and cropland in almost all ecological regions. This study investigated SAP and SAK stocks for different soil depths and characterized their magnitude and variability within land uses under different environmental ecosystems, soil classes and soil types, for a better soil and land management under a temperate-continental climate. Cropland soils present the highest SAP and SAK stocks. Chernozems, Phaeozems and Vertosols possess the highest SAP and SAK stocks in Romania, representing the largest country's pool. Both SAP stocks and SAK stocks are significantly correlated with basic environmental properties, existing direct correlations between SAP, SAK, soil organic carbon (SOC) and total nitrogen (TN) stocks. For all land uses, SAP and SAK stocks correlated significantly and directly with each other, as well as with annual temperature, clay content, pH and sum of base cations, and inversely with altitude, slope and annual precipitation. The best predictive values using multiple regression models and basic environmental driving factors were found for forestland stocks of SAP and SAK, followed by grassland stocks, while the lowest prediction occurred for cropland stocks, probably due to the long-term additional nutrient input performed by farmers in cropland that changed the natural conditions otherwise present in grassland, and especially in forestland. Based on these results some management measures are discussed.

The net assimilation rates (NAR) of three genotypes of cotton differing in their growth habit were studied under different spacings. The NARs of a very bushy type, G 67, and a comparatively less spreading type, IAN 560, were the same but that of a compact type, IAN 579, was twice as much when the leaf area index (LAI) was one. Though subsequently in G 67 and IAN 560 NAR under varying spacings either decreased less rapidly or remained steady, the decrease was nearly Hnear with increasing LAI. However, for IAN 579 dependence of NAR on LAI was generally positive indicating genotypic improvement. Under different spacings the leaf-density dependance of NAR appeared to have been decreased in IAN 560, but was nearly absent in IAN 579 with more efficiency towards increasing the yield of seed cotton.

Sugar beet has never been grown commercially in Cyprus. Sugarcane was grown in the Middle Ages but its cultivation has since gradually declined, and none has been grown in the last 200 years (Aristidou, 1986). Recently a research programme was undertaken to assess the feasibility of growing sugar beet so that imports of sugar may be reduced. Sugar yields of up to 20 t/ha (165 t fresh roots/ha) were obtained in a coastal area (Akhelia) when the crop was sown in November and harvested in July–September (Hadjichristodoulou, 1984, 1987). Because the period April–October is practically rainless, the crop has to be irrigated, but with November sowing full advantage is also taken of the winter rainfall.

(1) The solubility of the potash in 34 soil samples from 13 soils typical of large areas in the East of Scotland has been determined by the methods of chemical analysis using (a) hot concentrated hydrochloric acid, and (b) 1 per cent, citric acid solution, and the values obtained compared with the quantities of potash existing in the exchangeable form. The total mineral potash has been determined for six samples and Neubauer's method of analysis has been applied to 10 samples and again compared with the exchangeable potash.

(2) The average value of the total mineral potash in the soils examined was 2·04 per cent., which indicates the presence of comparatively large reserves of potash in these soils. No relation was found to exist between the total potash, and the quantities soluble in hot concentrated hydrochloric acid.

(3) The average value of the HCl-soluble potash was 0·50 per cent, and in the profile samples there was generally an increase in solubility with increase in depth of soil.

The results are reported for an experiment in which nitrogen rates from 0 to 672 kg/ ha and potassium rates from 0 to 558 kg/ha were applied annually on an S. 24 perennial ryegrass sward. At each of the five crops cut annually the yields of herbage dry matter and crude protein, and the potassium content of the herbage dry matter were determined. The potassium content of the soil was also measured annually. Models relating each of these variates to the nitrogen and potassium rates were derived, and their validity is demonstrated with reference to the results from earlier experiments. The problems associated with determining the correct rate of potassium fertilizer to apply on swards receiving given rates of nitrogen fertilizer are discussed using the models to predict the effects of different nitrogen-potassium combinations. In order to relate the implications of this discussion more closely to practical grassland management, economic as well as biological criteria are taken into account by incorporating cost factors in the models.

Hanley & Ridgman (1979) reported the results from three cycles of six-course rotations on light land. The report was based on a rotation of sugar beet, barley, barley, potatoes, barley, barley, with treatments involving replacement of one, two or three of the first three crops by 1-, 2- or 3-year leys, the last three crops acting as test crops. One of the problems of drawing general conclusions from rotation experiments is that the test crops are really part of the experimental treatments and may not be the most suitable crops for determining either the direct effects of the ‘treatment’ crops or the longer-term effects of the rotations themselves.

This paper deals with the final phase of the investigations described in the two papers immediately preceding it in the present issue of this Journal. These earlier papers may therefore be consulted for complete details concerning the general design and wider issues of the work as a whole (Woodman & Evans, 1938a, b).

Large-scale field trials in sugar beet were undertaken between 1961 and 1963 to examine the effects of chemical or mechanical weed control followed by machine thinning in terms of labour economy and yield of the crop. The seedling populations were left untrimmed by hand and, where the weed-control measures were completely effective or nearly so, the crops were left unweeded. Yield samples were taken both by hand and by machine so that the potential yield as well as the likely commercial yield might be determined. The chemical and mechanical methods that were studied saved about 75% of the normal labour demand and gave root yields 91.5% of those following hand work.

Thirty-two weaned Kenana bull calves were adequately fed to maximize growth and serially slaughtered at predetermined live weights of 100, 200, 300 and 400 kg. Eight animals were slaughtered at each slaughter point and the left side of each carcass dissected into individual muscles, bone, fat, tendons and fascia. Individual muscles were grouped into nine muscle groups and the distribution of intermuscular fat was studied in four anatomical regions. Huxley's (1932) allometric equation was used to describe the development of carcass tissues.

Relative to overall carcass side growth, fat was the fastest developing tissue, followed by muscle and bone tissues in descending order. The muscles of neck + thorax and abdominal muscles exhibited the fastest rate of growth relative to overall total side muscle growth, and the distal muscles of both limbs exhibited the slowest rate of relative growth. Relative to the rate of side fat deposition throughout the experiment, subcutaneous fat was deposited at a faster rate than intermuscular or kidney + channel fat. Intermuscular fat was deposited at different rates in the anatomical regions of the carcass.

The development of muscle groups was further examined in three arbitrary phases of the test period and revealed significant differences between phases in the rate at which each muscle group developed. Similar changes in the intensity of the rate at which fat was deposited in the subcutaneous region and between the muscles of the carcass or sites were evident.

Kenana cattle compare favourably with foreign dairy and beef breeds of cattle in muscle:bone ratio. Further studies are needed to evaluate the efficiency of meat production from Kenana cattle under different systems of management.

As reported in Part 1 (Gaili & Nour, 1980) a study was conducted to investigate the development of body components in Kenana cattle and to evaluate the potential of the breed for meat production. This paper is an account of the data which were obtained on the development of carcass tissues.

Measurements were made on 104 carcasses of Holstein or Holstein cross-bred calves in a commercial slaughterhouse and retail butchers in Monterrey, NL. Measurements were: chilled carcass weight, circumference of side, maximum depth of forequarter (three measurements), length of leg, length of side, and length of forearm. Carcasses were cut and the sum of the weights of round, rump, short loin and rib (all bone in) defined as ‘high-priced cuts’. Multiple regressions were computed for linear, semi-allometric and allometric equations using a CDC 3300 computer.

The linear form of the equation accounted for more of the total variance than either the semi-allometric or allometric forms. In all equations cold carcass weight accounted for the greater part of total variance (98·9, 97·1 and 98·2% respectively for the three equations in the order as mentioned above). The incorporation of circumference of side slightly improved the goodness of fit in all cases as did the inclusion of length of side and length of leg in the semi-allometric form. The particularly high proportion of the total variation attributable to cold carcass weight in the present study was probably due to the sparse fat cover of the calves.