Grain-filling, as the final growth stage of rice, is sensitive to environmental temperature change. Previous studies mainly concerned about the effects of high temperature stress during grain-filling on rice growth, and most experiments were carried out with pot for cultivating rice and greenhouse for warming. This research investigated the response of rice grain-filling of superior spikelets (SS) and inferior spikelets (IS) of two japonica cultivars to elevated temperature during grain-filling stage under open-field warming conditions in lower reaches of Yangtze River Basin using free-air temperature enhancement facility. Results indicated that rice yield was not significantly changed by warming less than 4°C. SS and IS showed different responses to elevated temperature during the grain-filling stage, whereas there were similar trends between two cultivars and years. For SS, although elevated temperature enhanced its filling rate during the early grain-filling period, and caused a shorter grain-filling period and a lighter grain weight; for IS, elevated temperature improved its grain weight by enhancing its filling rate during middle and late grain-filling period due to the increased number of days with suitable temperature. For both SS and IS, key starch biosynthesis enzymes and indole-3-acetic acid content exhibited generally a similar dynamics trend with grain-filling rates, and these sink strength parameters presented higher levels under elevated temperature relative to natural temperature for IS during middle and late grain-filling period. Consequently, warming less than 4°C presented different influences on SS and IS; the improvement of IS filling under warming regime was associated with the intensification of grain sink strength.

In alpine regions of the Qinghai-Tibetan Plateau of China, perennial vetch (Vicia unijuga A. Br.) productivity is often low and variable, constrained by the cold and erratic precipitation environment. The aim of the current study was to identify the soil-environmental modifications needed in harsh alpine environmental conditions for improvement of perennial vetch growth, forage biomass production and seed yield. A 3-year field experiment was conducted in an alpine region of China to evaluate the effects of modified soil temperature and moisture conditions generated by three mulching treatments – plastic film mulching (FM), removal of plastic film mulching at the 30% flowering stage and barley straw mulching – on perennial vetch productivity. Higher mean soil temperature and soil water content were recorded in the FM treatment than in the control and other treatments. This enhanced perennial vetch growth, as indicated by higher photosynthetic rate, higher leaf area index and greater above-ground dry matter, and thus higher seed yield and water productivity. Examination by multiple linear regression showed the relative contribution of mean soil temperature to the variations in photosynthetic rate, above-ground dry matter and seed yield were greater than soil water content, whereas the reverse occurred in seeds/pod. In conclusion, the FM treatment provided adequate soil temperature and water resources to improve photosynthetic rate, above-ground dry matter, seed yield and water productivity, and thus increased the productivity potential for perennial vetch in the alpine region. The current research provides scientific support for large-scale perennial vetch cultivation and management in alpine regions.

A series of experiments investigated mineral supplements for the correction of negative calcium and phosphorus balances in horses fed tropical grass hays containing more than 0·5% total oxalate.

A daily supplement of a soluble calcium source was retained with an efficiency of 60% implying no interference with calcium absorption from supplements by oxalate or other factors in the hays.

The palatability of limestone, rock phosphate, dicalcium phosphate, a limestone and dicalcium phosphate mixture and mono-ammonium phosphate was tested with a view to providing a supplement once weekly. With the exception of the latter, all were consumed readily when mixed with 50–60 % molasses (w/w) and hourly intakes of 200 g calcium and 50 g phosphorus were recorded.

In balance trials using horses fed tropical grass hays, 1 kg of either rock phosphate, or a mixture of limestone and dicalcium phosphate (1:2, w/w), each mixed with 1·5 kg molasses, was fed on the 8th day of a 14-day balance trial. The retention of calcium from the supplements ranged from 19 to 41% and that of phosphorus from 22 to 42%. The passage time for unabsorbed minerals was about 4 days. This amount of supplementation can accommodate calcium and phosphorus losses of at least 20 and 10 mg/kg live weight/day respectively. A supplement of 1 kg limestone overcame a negative calcium balance of 20 mg/kg live weight/day but did not overcome a negative phosphorus balance.

Seventeen supersweet Shrunken-2 (sh-2) maize lines and progenies of their crosses to two sh-2 hybrid testers were investigated for factors responsible for differences in field emergence in Korea in studies carried out in the field, greenhouse and laboratory. The lines and their testcrosses showed significant genetic variation for emergence. Two lines showed significant positive general combining ability (GCA) for emergence while two other lines had significant negative GCA effects. Because none of the specific combining ability effects was significant, emergence was primarily influenced by additive gene action, and could, therefore, be improved by recurrent selection. Seed weight was significantly (P<0·05) correlated with emergence for inbreds (r=0·63) and testcross progeny involving the tester with the lower mean seed weight (r=0·54). Two lines also showed significant positive GCA effects for seed weight. The lines with positive GCA effects for emergence were different from those with positive GCA for seed weight, indicating that factors other than seed weight influence field emergence. The severity of Fusarium infection of seeds of the lines was significantly correlated to germination (r=−0·61, P<0·05) and emergence (r=−0·67, P<0·01), suggesting that practices that prevent pathogenic field infection, such as timely harvest and treatment with fungicides, are crucial for high seed quality. The field emergence of sh-2 inbred parents did not give an indication of emergence in hybrid combinations.

Data are presented from 104 sheep from three separate sources (batches) in which variation in the degree of maternal body protein loss was induced by nutritional means. The change in body protein content during pregnancy was calculated as the difference between body protein content in early pregnancy, predicted from the relationship with body weight in control sheep killed in early pregnancy, and actual content on slaughter at parturition. Serum albumin and globulin concentrations and body weight were measured at intervals during pregnancy and examined for relationships with body protein change.

Highly significant linear relationships were found between the change (%) in albumin concentration during pregnancy or albumin concentration in late pregnancy and the calculated change (%) in maternal body protein content (P < 0·001 in both cases) though fitting separate intercepts for each batoh of sheep led to improvements in fit.

Equations for prediction of loss (%) of body protein from change in body weight or maternal body weight during pregnancy though significant, were also improved by fitting separate intercepts for batches. The relative value of the relationships for predicting body protein loss is discussed.

Serum globulin concentration was not affected by protein status of the animal.

In view of the increase in micronutrient deficiencies in crop plants, ans attempt is made to group 57 Benchmark Indian soils into different micronutrient availability classes (clusters) vis-à-vis some soil characteristics. Since most of the soil characters are expressed in proportions or percentages (a usual practice in soil studies), the data matrix was transformed into log10 values to bring it nearer to normality. The transformed data matrix was used for cluster analysis and subsequently also for discriminant analysis. By following the method of Euclidean cluster analysis, the 57 Benchmark soils could be subdivided into three clusters. The distinctness of clusters was proven by distance-matrix as well as discriminant analysis. All the soils of cluster I and II originated from arid and semi-arid climates and these were alkaline in reaction, low in organic carbon (OC) and high in total lime. On the contrary, cluster III comprised all but a few soils from humid-subhumid regions. These soils were acidic in reaction and relatively high in OC and total lime. The soils of cluster I and II were poorer in diethylene triamine penta-acetic acid (DTPA) extractable micronutrient cations than those of cluster III. This study thus reveals that it is possible to classify diverse soils by statistical means into distinct clusters based upon micronutrient availability and associated soil properties. Furthermore, it suggests that soils of arid and semi-arid climates as a group, because of their low micronutrient availability, are expected to be more prone to deficiencies than those of humid and subhumid zones.

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.

Weeds are a major biotic constraint to the production of crops. Studies on the critical period of weed control (CPWC) consider the yield loss due to the presence of all weeds present in the crop cycle. The CPWC is the time interval between the critical timing of weed removal (CTWR) and the critical weed-free period (CWFP), and the weed presence before and after the extremes of CTWR and CWFP may not significantly reduce crop yield. The crop yield is taken into consideration and weed density or biomass of individual weeds (annual or perennial) is not so important while calculating the CPWC. Only weed density or biomass is considered for calculating weed control efficiency of a particular management practice for which the weed seed bank is also a criterion. However, weed biomass is the outcome after competition experienced by each weed species with the fellow crop and the weeds. Consequently, the weed pressure in the subsequent season will be the cumulative effect of the preceding season too, which is unaccounted for in CPWC. It is argued that in organic farming or low-input farming systems, where herbicides are not used, the concept of CPWC can be misleading and should be avoided. It is concluded that CTWR is more meaningful than the CPWC.

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.

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.

The beneficial effect on the nutritive value of bread and similar cereals of adding small amounts of lysine and other essential amino acids has recently aroused considerable interest both in Great Britain and in America. Tests carried out with rats have shown considerably improved growth rates accompanied by increased efficiency of food conversion.

The rotation responses of unfertilized cotton were investigated using data obtained over a 28-year period from an experiment comparing ten rotations in various combinations of cotton with fallow and an alternating crop of dura (a sorghum millet) and lubia (a legume).

1. The construction and performance are described of a simple climatic chamber for work on poultry in hot climates. In addition, brief reference is made to an improved ventilation system and to refrigeration equipment fitted to chambers of later design.

2. Air temperature and humidity may be controlled over a fairly wide range above that of the external air. Radiant temperature is maintained close to air temperature. The air movement averages about 20 ft./min. in the working space.

3. The apparatus is suitable for accurate tests of heat tolerance lasting for a few hours, or for longterm experiments.

4. It is suggested that the provision of climatic chambers for use with farm animals in underdeveloped agricultural areas is not a formidable problem.

The effects of annual applications of up to 300 lb/acre of N, 100 lb/acre of P2O5 and 200 lb/acre of K2O on cut swards of S. 24 ryegrass, S. 37 cocksfoot and S. 215 meadow fescue were measured in an experiment lasting 3 years.

There were some differences between species in their dry-matter and nutrient yield response to nitrogen and potash applications, but not to phosphate. These differences were inconsistent and over the 3-year period were negligible.

A large response to nitrogen was only fully maintained when phosphate and potash were also applied. There was no response above 50 lb/acre of P2O5 in any year. In the second year, 100 lb/acre of K2O was sufficient, but more than this was necessary in the other years. Symptoms of phosphate and potash deficiency were seen where high rates of nitrogen were applied without phosphate and potash respectively.

Analytical data are recorded which indicate that the application of artificial fertilisers to grass land may result in considerable modifications in the mineral content of the herbage of these pastures. The constituents which appear to show the biggest variations are calcium and potassium and, to a lesser extent, phosphorus. Coupled with any marked increase in the calcium content of the herbage, there is generally to be found an increase in the percentage of nitrogen.

Guinea grass (Andropogon gayanus Kunth cv. Bisquamulatus) and Buffel grass (Cenchrus ciliaris L. cv. Biloela) are grown as temporary fodder crops in the Sahelo-Sudanese region of Africa. Differences in their responses to drought conditions may be important in optimizing cattle feeding programmes in integrated farming systems. An experiment conducted in a wind tunnel equipped with a tank forming a weighable lysimeter compared net photosynthesis (A), stomatal conductance (gs) and leaf water potential (Ψ leaf) of both species in a mixed sward during three simulated environmental conditions: (1) rainy season, (2) drought period within the rainy season and (3) dry season.

With a soil water reserve (SWR in % volume) of 8% during the drought period and the dry season, the Ψ leaf and A parameters were significantly lower (P<0·001) when compared to those recorded with a SWR of 32% in the rainy season. Mean gs values were significantly different during each environmental condition (P<0·001). No significant difference (P>0·05) was found in gs and A between the two species during the rainy and the dry season or during a diurnal cycle, although a significant difference (P<0·05) in Ψ leaf existed between the species during the dry season. During this season, Guinea grass was dormant while Buffel grass was growing slowly.

When the drought period was imposed during the rainy season (SWR declined from 25 to 5%), A was reduced from 19·8 to 7·7 μmol m−2 s−1 for Guinea grass and from 16·8 to 3·7 for Buffel grass. Ψ leaf in both species dropped below −2 MPa while gs declined slowly from 0·70–0·80 to 0·55–0·60 cm s−1. A was significantly higher (P<0·05) in Guinea grass during the last days of the drying cycle, but declined rapidly when drought was extended up to the wilting point. Two days after rewatering, all the parameters of both plants were restored to previous levels.

It is concluded that Guinea grass was as drought-resistant as Buffel grass and that no competition for water existed between the species in the mixed sward. The study also gives relationships between the physiological parameters of both species and the soil water content during a drying cycle.

Acid and neutral invertase activities in the stem of an early (CoJ 64) and a late cultivar (Col 148) of sugarcane were estimated by incubating stem slices in buffered sucrose solution and measuring the production of reducing sugars. High enzyme activity occurred in young tissue but the activity of both enzymes was considerably lower in the mature internodes. Acid and neutral invertase activity was highest in the midinternode position, corresponding to the region of cell expansion.

In a factorial trial comparing liquid digested sludge with equivalent water, and inorganic nitrogen, phosphorus, and potassium fertilizers, almost all the effects observed could be attributed to the uptake of nitrogen or potassium.

Over the 2-year period of treatment application, liquid digested sludge and equivalent inorganic fertilizer nitrogen and potassium gave similar responses of 22.3 and 23.8 lb. dry matter per lb. of nitrogen, and 59 lb./acre K increased the response to inorganic nitrogen alone by 5.4 lb./lb. of nitrogen.

Over the 2-year period of treatment the amount of potassium absorbed by herbage, in excess of that applied, was greater with fertilizer nitrogen than with liquid digested sludge. Added potassium had no direct effect on crude protein production. Liquid digested sludge and inorganic nitrogen fertilizer increased crude protein to a similar extent.

The seasonal rate and extent of dry matter (DM) and neutral detergent fibre (NDF) degradation of the African sourveld grasses Alloteropsis semialata, Andropogon appendiculatus, Cynodon dactylon, Elionurus muticus, Eragrostis plana, Harpochloa falx, Heteropogon contortus, Hyparrhenia hirta, Microchloa caffra, Themeda triandra and Tristachya leucothrix in the rumen were measured using the nylon bag technique at the Döhne Agricultural Development Institute, South Africa, in 1993. The size of the soluble fraction (SF) was markedly different (P < 0·05) between species, being largest in A. semialata (22·6%) and smallest in E. plana (13%). Over all species, the mean SF was highest (P < 0·01) in spring (21·6%) and lowest in winter (11·8%). Species differed (P < 0·05) in the size of the potentially digestible fraction (PDF), with H. contortus and T. leucothrix having the largest (71%) and M. caffra the smallest (53%) PDF. Mean PDF declined (P < 0·01) from spring (77·3%) through to winter (55·8 %). The rate of DM degradation (kd) in the rumen also differed (P < 0·01) between species, with C. dactylon and A. semialata having the fastest (0·054) and E. plana and A. appendiculatus the slowest (0·039) degradation rates. Mean kd values were lower (P < 0·05) in winter (0·039) than in the other seasons (0·048).

Neutral detergent soluble (NDS) content was highest in A. semialata (29%) and lowest in E. plana (21·5%). Species similarly varied in the amount of potentially digestible cell wall (PDCW), with E. plana having the highest (57%) and C. dactylon the lowest (45·1%) PDCW content. Mean PDCW content was highest in spring (59·5 %) and lowest in winter (44·6%). Cell wall degradation (kc) rates were fastest (0·04) in C. dactylon and slowest in M. caffra (0·03). Overall, kc declined from spring (0·039) through to winter (0·029). In general, A. semialata, T. triandra and H. hirta appeared to have the most favourable, and E. plana, A. appendiculatusand M. caffra the least favourable, ruminal degradation characteristics. These differences suggest that species composition is likely to have a major impact on potential animal production on these low quality grasslands.