Skin temperatures, deep body temperatures and respiratory rates have been measured in Southdown and Merino sheep following feeding, and during infra-red irradiation, rumen infusions of hot and cold water, and cold exposure induced by shearing. The increases in respiratory rate and skin temperatures induced by infra-red heating and the heat increment of feeding were reversed by addition of iced water to the rumen and were suppressed by shearing. These responses could not be systematically related to particular body temperatures in the sheep and appeared to be continuously variable rather than ‘all-or-none’ phenomena. Considerable overlap was observed between respiratory and vasomotor mechanisms of thermoregulation. Measurements of the surface area and weight of ears and legs showed that these regions contribute approximately 23% of the surface area and 8% of the body weight in Merino sheep. Calculations suggested that up to 70% of the additional heat produced in the 2 h after feeding in sheep may be stored in the tissues through increase in mean body temperature. Sheep kept in short wool throughout the winter appeared to establish a new thermoregulatory ‘set-point’ associated with lower rectal temperatures than those in sheep with a full fleece.

Intake, digestibility, nitrogen (N) balance, microbial protein synthesis, weight gain, yields of the main commercial cuts and carcass morphometric measurements were evaluated in lambs fed diets containing different levels of chitosan. Sixty Santa Inês crossbred sheep with an average body weight (BW) of 24 ± 2.2 kg were assigned to three treatments (diets containing 0, 136 or 272 mg chitosan/kg BW) in a completely randomized design. There was no effect of chitosan on dry matter (DM) intake. Ingested and retained N showed a quadratic response, with the highest values estimated at the chitosan levels of 142 and 152 mg/kg BW, respectively. Similar to N balance, microbial protein synthesis showed the same quadratic response, in which the level of 136 mg/kg BW resulted in higher synthesis when compared with the other levels. No effect of chitosan was detected on average daily gain, final weight, or carcass variables (hot carcass weight, cold carcass weight, yield of commercial cuts and morphometric measurements of the carcass). Conformation, visceral fat content and fatness of carcasses were also not altered by the use of chitosan. Chitosan improves the digestibility of DM, crude protein and neutral detergent fibre, and increases N balance and microbial protein synthesis but does not change the production performance of feedlot lambs.

A field experiment was carried out in three wet seasons of 1982, 1983 and 1984 with various combinations of urea and organic nitrogen sources to investigate the nitrogen transformation and productivity of rice crop in a waterlogged situation. The treatments used were: (i) control (No), (ii) FYM + urea, (iii) Sesbania + urea, (iv) urea, the levels of nitrogen being 60 and 90 kg/ha and the proportion being 50:50 between organic and chemical sources where such combination was used. The soil samples were analysed for ammonium, hydrolysable and non-hydrolysable forms of nitrogen at 15, 30 and 45 days after transplanting. The release of hydrolysable and non-hydrolysable nitrogen was superior in the urea-Sesbania combination while the release of NH4·N was slightly better in FYM-urea combination. Yield of rice and apparent nitrogen use efficiency were highest in sole urea treatment and almost similar in FYM-urea and Sesbania + urea combinations. A statistical nitrogen-transformation model outlined the relationship among the various forms of soil nitrogen under submergence. The model suggested a strong correlation among the different forms of nitrogen during the earlier period of submergence.

(1) The edge rows give significantly higher yields than the inside rows, indicating thereby the inadvisability of using edge rows in yield trials.

(2) The variation between rows is very much greater than within rows. Different parts of the same drill row should therefore not be regarded as subject to independent error. The present investigation emphatically confirms Clapham's conclusions on this point.

(3) A slight advantage may be gained by the subdivision of the area to be sampled, without additional labour.

(4) In order to study the effect of the structure of a sampling unit of given size five types of unit have been examined. Of these, method (1), in which the “sampling unit” consists of four parallel half-metre lengths on adjacent rows, appears to be the most precise, and may be recommended on the basis of this trial. The half-metres within such sampling units appear to be negatively rather than positively correlated, and a significantly lower sampling error is obtained in consequence.

The current paper tackles a critical question in climate change literature of whether farmers will be able to fully adapt to monsoonal climate changes owing to technological developments. Making use of the climate, agricultural and social data of Thailand from 1900 to 2015, this paper estimates a technological change instrumental variable by the growth of the normalized rice yield per hectare of land. The estimation shows that 0.98 of the growth in rice yield can be attributed to technological changes while the rest is accounted for by climate, soils and social factors. In the second stage regressions with the technological change indicator, the paper estimates the normalized numbers of the six most important types of live animals in Thailand: goats, chickens, cattle, sheep, pigs and buffaloes. Over the time period studied, the number of each of these live animals has increased vastly, except for buffaloes. The second-stage regressions show that the growth is largely attributable to technological changes, but monsoonal climate variables such as normalized monsoon precipitation ratio and normalized monsoon temperature are not significant factors. The results indicate that the rate of technological changes is overwhelming the rate of climate change on agriculture in Thailand.

Little is known about the quantitative relationships between wheat powdery mildew (Blumeria graminis f.sp. tritici) epidemics and climatic variables at the provincial scale in China, particularly under climate change. The present study assesses the actual disease process and corresponding impact on wheat yield and addresses climatic-driven variables that affect a powdery mildew epidemic. Powdery mildew increased in frequency from 1981 to 2010, and wheat yield decreased in most regions. It was clear that differences in disease and yield loss occurred temporally and spatially. Although particular weather variables were positively or negatively related to the disease, multiple stepwise regression analysis indicated that mostly fewer than three variables affected prevalence and severity of powdery mildew in each province. In most cases, some combination of higher temperature, humidity, rainfall and wind led to higher disease severity. These weather factors had different effects on disease development. The influence of climatic variables on powdery mildew tended to decrease from 1981 to 2010, whereas the effect of non-climatic factors increased and was attributed mainly to the use of fungicides and resistant cultivars. Therefore, the results of the current study suggest that wheat powdery mildew in China will not increase consistently in the future. In addition, the quantitative assessment method used in the current study can generally provide a good way to identify disease epidemics under climate change.

Perennial ryegrass and white clover (WC) have been shown to form compatible mixtures for pasture production under temperate climates. The inclusion of WC has the potential to enhance the performance of grass swards, but the extent of the improvement under contrasting grazing management strategies is unclear. Grazing rotation and fertilizer nitrogen (N) use have been identified as two major factors that can influence the performance of grass–clover swards. The objective of the current study was to examine the effect of differing grazing rotation lengths and the level of N application on the dry matter (DM) yield performance of grass–clover and grass-only swards as well as on WC productivity and persistency under animal grazing. Swards were managed by N application and grazing rotation length: High-N swards were managed on a 21-day grazing rotation (Man 1) and low-N swards were managed on a 30-day grazing rotation (Man 2). The four treatments were: 250 kg N/ha without WC (HN−C), 250 kg N/ha with WC (HN+C), 100 kg N/ha N without WC (LN−C) and 100 kg N/ha with WC (LN+C). There was a significant management × WC interaction over the 3 years for annual DM yield. The LN−C swards produced lower DM yield (−1917 kg DM/ha) than the swards of the other three treatments (11 167 kg DM/ha). Management had a significant effect on annual DM yield with Man 1 swards yielding 801 kg DM/ha more than Man 2 swards (10 288 kg DM/ha). The inclusion of WC yielded significantly more annual DM yield (+1009 kg DM/ha) than grass-only swards. Notably, LN+C produced the same annual total DM yield as swards under High N and a 21-day grazing rotation. Total WC DM yield and proportion across the year was altered significantly by management. Higher N fertilized swards at shorter grazing intervals had a lower WC DM yield (−1544 kg DM/ha) and proportion (−0·13). Dry matter yield of WC with low N application can be similar to that at high N levels if rotation length is used as a mechanism to determine grazing timing. Variations in WC productivity into the final year of the experiment indicate that persistence of significant contributions to DM yield by WC under low N at longer grazing intervals remains unclear after 3 years.

Late sowing causes substantial yield reduction in canola. This yield reduction is principally due to lower emergence and poor crop establishment because of prevailing low temperatures. A field experiment was conducted using five sowing dates over two growing seasons (2014/15 and 2015/16). The effect of two seed-priming strategies (hydropriming and osmopriming with zinc sulphate, ZnSO4) was measured in three canola cultivars (Okapi, Zarfam and Talayeh). Results showed that both seed-priming treatments were effective in improving emergence percentage (EP) of canola cultivars. The highest EP occurred in the earlier sowing in both years. On 5 September, EP for the hydropriming, osmopriming and no-primed treatments were 89, 93 and 73% in Okapi, 83, 89 and 69% in Zarfam, and 81, 89 and 72% in Talayeh, respectively (data averaged across both years). Delay in sowing date compared with 5 September caused a sharp reduction in EP in primed seed and control conditions. Maximum seedling emergence rate and coefficient of uniformity of emergence were seen in early sowing for Okapi cultivar with ZnSO4 osmopriming. Experimental evidence showed that in canola cultivars the activities of superoxide dismutase, peroxidase and catalase were higher in the leaves of plants from seed primed with ZnSO4 compared with seed from hydroprimed plants. Cultivar analysis of total antioxidant content activities indicated, the maximum increase was observed in the Okapi and Talayeh cultivars.

The effect of a slant-legged subsoiler (Trade name, ‘Paraplow’) on the growth of two crops of winter wheat following an intensively grazed grass-clover ley was investigated in 1981–2 and 1982–3. The treatments for the first crop were direct drilling, loosening the soil by shallow cultivation before drilling, loosening by ‘Paraplow’, and a combination of ‘Paraplow’ and shallow cultivation. For the second crop these treatments were repeated and a fifth added, loosening by ‘Paraplow’ after drilling. Seed was sown with a triple disk direct drill and all treatments received the same quantity of fertilizer.

Soil compaction was measured with a cone penetrometer in the autumn of 1982 and spring 1983; root axes were counted and dry-matter weights of shoot, grain yield and components of yield obtained.

Loosening soil by ‘Paraplow’ did not increase significantly the number of roots nor was the uptake of water by the crop in dry periods affected, even though soil strength, measured as cone resistance, was considerably reduced.

Shallow cultivation increased grain yield in the first wheat by 0·34 t/ha (P< 0·05) but had no effect on the second wheat. The ‘Paraplow’ did not increase yield of the first crop but the mean response of 0·65 t/ha in the second crop was significant (P < 0·05). Using the ‘Paraplow’ before or after drilling gave similar yields. Increases in yield were produced by more grains per unit area, not increased 1000-grain weights.

It is concluded that the apparently compacted soil did not restrict the growth of wheat and that the beneficial effect of the ‘Paraplow’ in the second crop was probably due to better drainage in the wet spring.

The productivity and persistence of 91 accessions of grasses, legumes and broad-leaved weeds were evaluated under young rubber at the Rubber Research Institute of Malaysia Experimental Station at Sungai Buloh near Kuala Lumpur. The species were chosen from world collections for their reported shade tolerance. Two small plot experiments were conducted from 1989 to 1990 and regular harvests were used to assess yield and persistence. The soil at the site was acidic (pH 4·7) and infertile, and light transmission declined from 65 to 20% in Expt 1 and from 90 to 50% in Expt 2.

Pattern and cluster analyses were used to allocate accessions to groups with similar yield responses. Grasses which demonstrated both high yield and persistence of yield were Brachiaria decumbens MARDI accession, B. humidicola cv. Tully and Panicum maximum cvs Gatton, Riversdale and Vencedor. High yielding and persistent legumes were Stylosanthes scabra cv. Seca and S. guianensis CIAT 184. Survival of species monitored one year after completion of the experiment indicated the good longer term persistence of grasses Stenotaphrum secundatum, Panicum laxum, Paspalum notatum, Paspalum wettsteinii, Brachiaria humidicola and Panicum maximum cv. Vencedor, and legumes Arachis repens and A. pintoi.

Involvement of plant genotype, stage of development of plant and seed, fertilizer and irrigation in frost tolerance of oil-seed Brassica spp. were examined. The number of apparently frost-killed or undeveloped seeds has been used to assess tolerance. Three B. campestris L. genotypes namely Span, Torch and Bell showed considerable tolerance of frost. Very young and also nearly mature seeds were less affected by freezing than seeds at an intermediate stage of development. The amount of nitrogen fertilizer applied had no effect, but the unirrigated orop was injured by frost more than the irrigated one.

In Volume II. Part 2 of this Journal there appeared a note by W. L. Balls on the above subject, in which he states that “long lint is completely dominant over short.” This dominance, the present writer in India has found to occur in the case of crosses between many very different varieties. The question is not however so simple as it would appear to be from Mr Ball's statement “that the breeding of pure types suitable to the needs of the manufacturer and the cultivator will possibly prove a little difficult”; for though length of staple is on the whole dominant we often get seeds that carry both long and short cotton.

One hundred and seventy-seven female Ayrshire cattle from approximately 6 months to 6 years of age were sampled on one occasion to determine the concentrations in plasma of Cu, P, Ca, Mg, Na, K and glucose. Eighty-nine adults, either lactating or dry, were re-sampled 2 months later to estimate concentrations of ketone bodies and free fatty acids. The data were analysed to estimate the contributions of various factors to variation in the concentrations.

The combination of age and stage of pregnancy or lactation significantly affected variation in all the constituents although some of this variation was accounted for by milk yield. The concentrations of Cu, Mg, glucose and ketones were significantly affected by milk yield. The presence of ketone bodies in milk (recorded in relation to the first occasion of bleeding only) was associated with a significant increase in the plasma concentrations of Na and Mg and a significant decrease of K and Ca.

The herd comprised pairs of genetically related animals. However, the estimates of heritability had large standard errors and only those for P and Ca were significantly positive.

Changes in soil bulk density (BD), soil organic carbon (SOC) content, SOC stocks and soil labile organic C fractions (mineralizable C (Cmin), microbial biomass C (MBC), dissolved organic C (DOC), particulate organic C (POC), light fraction organic C (LFOC) and permanganate oxidizable C (KMnO4-C)) were explored over 3 years in a double-cropping rice system of southern China. Five organic and inorganic nitrogen (N) inputs were used: (1) 100% from chemical fertilizer (M0), (2) 30% from organic manure, 70% from chemical fertilizer (M30), (3) 50% from organic manure, 50% from chemical fertilizer (M50), (4) 100% from organic manure (M100) and (5) without N fertilizer input, as control (CK). All organic manure treatments decreased BD significantly in the 0–20 cm soil layer compared with CK. The SOC content and stocks with organic manure were significantly higher than in M0 or CK; also, the cumulative amount of SOC stocks in M30 and M50 increased at the plough layer, compared with CK. The non-labile C content increased significantly and the percentage of labile C were significantly higher with organic manure application than in M0 or CK. The soil carbon management index (CMI) also increased significantly under the application of organic manure. Therefore, application of organic manure can increase the pool of stable C in surface layers, and increase content and percentage of labile C. Based on soil carbon storage and CMI, the combined application of 30 or 50% N of organic manure with chemical fertilizer improves carbon cycling services and soil quality in southern China paddy soil.

A field experiment was made on rice during the rainy seasons of 1982 and 1983 to study the relative efficiency of prilled urea and urea super granules (USG) applied broadcast or deep placed at different times. USG gave more, longer and heavier panicles with a higher percentage of filled grains than prilled urea. Deep placement of 60 kg N/ha as USG in two applications (half 10 days after transplanting and half at panicle initiation) gave the same grain yield as 120 kg N/ha of prilled urea applied half at final puddling and half at panicle initiation. Urea super granules, therefore, hold considerable promise as a nitrogen fertilizer for rice.

The cobaltinitrite method, in the volumetric form here described in detail, enables known amounts of potassium to be accounted for quantitatively, independently of the presence of alkaline earth sulphates, or phosphates, provided that the amount of potassium is not varied over too great a range. The factor 0·000830 gm. K2O per c.c. N/10 KMnO4 suits the procedure described over a range of about 3 to 50 mg. K2O. Outside this range, or for highly accurate work within it, it may be desirable to calibrate the method.

The method may be applied, in plant-ash analyses, indifferently to the original extracts containing other bases and phosphates, or to the mixed sulphates weighed for sodium and potassium together. It is applicable to small-quantity work upon soils with greater exactness and speed than is the perchlorate method. Citric acid extracts can be handled, with a relatively short manipulation, to give satisfactory results.

Some analyses of ammonium chloride extracts have been unsatisfactory, and attention is called to the desirability of setting exchangeable potassium determinations upon a firmer analytical basis, by investigation of methods of freeing the extracts from ammonium salts.

The extent of mineralization of organic carbon (carbon dioxide production) during incubation at 28° C. of a sandy loam was determined (a) over 6–12 weeks at varying static moisture levels over the range from air-dried to waterlogged, (b) over a second 6-week period after changing soil moisture level, maintained at various moisture levels during the first 6-week period, to 50% saturation or to waterlogging.

Energy budgets and estimates of forage intake requirements were developed for adult camels, cattle, sheep, and goats managed by nomads in the arid Turkana District of north-western Kenya. The estimates were developed by combining our field data on livestock activity patterns, diet quality, weight changes and milk yields with literature based estimates of the associated costs and efficiencies. On an annual basis, the average animal walked 17 km/day and had a total metabolizable energy (ME) allocation of 47% for basal metabolism, 16% for travel, 14% for other activities, and 23% for production. Season and species influenced patterns of energy demand and allocation. Average daily ME requirements ranged from 8·7 MJ (sheep) to 76·7 MJ (camels). ME demand for all species peaked during wet (April-May) or early-to mid-dry periods (June-October), and decreased considerably in the late-dry season (November-March). In the wet season the average sheep or goat allocated 45% of its ME budget to production of milk and gain, followed by cattle (36%) and camels (25%). All species were more similar in ME allocation for production during the late-dry season (7–13%; all to lactation), yet patterns of weight loss during this time indicated that camels experienced the lowest degree of negative energy balance. On an annual basis, camel budgets were the most deviant, as they allocated relatively more ME to activity and relatively less to basal metabolism or weight gain. Estimates of forage dry-matter intakes (per unit live weight per day) ranged from 3·8% (cattle, camels) to 4·6% (sheep, goats) throughout the year, and intakes declined for most species by an average of 50% from the wet to late-dry intervals. This approach has revealed ecological differences among livestock species that help explain the utility of multi-species holdings in this system.

1. In an experiment conducted on an established perennial rye-grass/white clover sward close cutting was carried out over a 3-year period (1956–58), either with a lawn mower to simulate gang mowing or with a reciprocating-knife mower. The sward was cut either six or eight times in each season, and received 0 or 2 cwt. ‘Nitro-Chalk’/acre for each cut.

2. Swards cut with the gang mower yielded from 3·5 to 12·5% more herbage dry matter than swards cut with the reciprocating-knife mower and also gave a greater mean yield of crude protein.

3. The difference in dry-matter yield between swards cut with each of the mowers is attributed to the slightly closer cutting level of the gang mower having a greater inhibiting effect on flower development in the grasses and hence stimulating leaf production and increasing total yields.

4. In the second and third years of the experiment swards cut with the gang mower outyielded those cut with the reciprocating-knife mower by a proportionately greater amount when eight cuts rather than six cuts were taken in the season.

5. When no nitrogenous fertilizer was applied the proportion of broad-leaved weeds in the sward increased more rapidly over the 3-year period where the herbage was cut with the gang mower rather than the reciprocating-knife mower. This disadvantage of gang mowing did not apply where the fertility was maintained at a high level by applications of nitrogenous fertilizer.

6. It is concluded that the gang mower is a more suitable machine than the reciprocating-knife mower for close cutting on a field scale.