Reseeding in the Falkland Islands. Herbage production of a range of grass species and cultivars

The productivity of 20 cultivars from a range of 13 grass species was compared by harvesting four times during each of three successive growing seasons. In the experiment, 120 kg N ha⁻¹, 42 kg P₂O₅ ha⁻¹ and 42 kg K₂O ha⁻¹ were applied annually.
Mean annual yield was 3229 kg DM ha⁻¹ and 2147 kg DOM ha⁻¹. Cultivars were arranged in seven groups for comparison. Three of the groups, Lolium, Phleum and 'others' (the latter consisted of Festuca arundinacea cv. Dovey and Poa pratensis cv. Bensun A.34) appeared significantly lower yielding than the Dactylis, Festuca (fine-leaved), Agrostis and Holcus groups.
In the Lolium group, cv. Gremie outyielded cv. Melle every year. No cultivar of Dactylis was significantly better than any other in its group. Phleum CVS Motim and Eskimo were similar and superior to cv. S.50. Festuca ovina cv. Novina and Agrostis canina cv. Kingstown were marginally the best in their respective groups. The two cultivars of Holcus performed virtually identically. Festuca arundinacea cv. Dovey was a good producer of early spring grass. Poa pratensis cv. Bensun A.34 was generally low yielding and subject to fungal rust attack in autumn. The pattern of seasonal DM production was 16% in early spring (cut in October/November), 39% in mid-season (cut in December), 40% in late summer (cut in February/March) and 5% in autumn (cut in April/May). Quality of the herbage was superior to the main indigenous grass Cortaderia pilosa.
It was concluded that although the experiment was conducted under a cutting regime it provided useful guidance for seeds mixture formulation and stock carrying capacity calculations.     

Growth and production of a Cortaderia ptlosa (Gramineae) community in the Falkland Islands

Above ground production of a typical Cortaderia pilosa dominant sward in the Falkland Islands was estimated over one growing season by summing significant positive increments in DM production of various sward components and by sequential cutting to ground level. The standing crop was characterized by a high proportion of standing dead matter at all times of the year. Net herbage production was estimated as 2200 kg ha^-1 and 1440 kg ha^-1 by the 'difference' and "sequential culling" techniques, respectively. The pattern of leaf growth was determined on another site by regular linear measurements of a population of physiologically similar C. pilosa leaves. There was very little early season growth and most of the DM was produced in a short period in the middle part of the growing season. The poor early season growth was attributed to adverse climatic conditions. A significant increase in green matter digestibility in October and November was masked by the low digestibility and high contribution to the overall DM by the standing dead component of the herbage.
The implications of these findings are briefly discussed in relation to the increased utilization of C. pilosa by improved pasture management, including burning and possibly reseeding areas with improved species. Tissue turnover studies combined with more knowledge of sheep nutrition cycles would enable grazing systems to be developed on a sounder basis than previously.     

丸化剂对水稻种子出苗和秧苗生长的影响

以早稻品种金优974、湘早籼31号和晚稻品种新香优80、湘早籼10号为材料,比较研究了自研的丸化剂与进口种衣剂对水稻萌发、出苗、秧苗素质、苗期抗病虫能力的效应.结果表明,用丸化种衣剂包衣有利于种子发芽和出苗,提高秧苗综合素质.其中,成秧率提高6.8%～9.4%,秧苗根系活力提高7.1%～32.4%,病虫害防治效果分别达到95.7%～98.5%和77.5%～90.35%.     

The effect of environmental change on vascular plant and cryptogam communities from the Falkland Islands and the Maritime Antarctic

Background  

Antarctic terrestrial vegetation is subject to one of the most extreme climates on Earth. Currently, parts of Antarctica are one of the fastest warming regions on the planet. During 3 growing seasons, we investigated the effect of experimental warming on the diversity and abundance of coastal plant communities in the Maritime Antarctic region (cryptogams only) and the Falkland Islands (vascular plants only). We compared communities from the Falkland Islands (51°S, mean annual temperature 7.9°C), with those of Signy Island (60°S, -2.1°C) and Anchorage Island (67°S, -2.6°C), and experimental temperature manipulations at each of the three islands using Open Top Chambers (OTCs).     

The influence of seed rate and pesticides on the establishment and growth of white clover slot-seeded into a permanent pasture

The establishment and growth of white clover (cv. Grasslands Huia) was investigated in two experiments with seeds sown in slots cut in old permanent pasture in early May 1982. In the first experiment, fully protected from pests and diseases, either 50 (low), 100 (medium) or 200 (high) seeds were sown evenly per metre length of slot; 100 seeds were also sown in a clumped pattern unevenly. In the second experiment, the effects of various combinations of molluscicide, insecticide and fungicide were investigated.
Nine weeks after sowing there were 27, 37, 34 and 62 seedlings m⁻¹ on the low, medium even, medium uneven and high seed-rate treatments, representing percentage establishments of 54, 37, 34 and 31 respectively. By September, however, there were no significant differences between the dry weights m^−l of any of the treatments. In the second experiment, damage by slugs occurred early in treatments without molluscicide and caused a mean reduction of 70% in seedling establishment. As a result significantly smaller dry weights m⁻¹ of clover were recorded in September in these than in other treatments. Failure to protect against insects resulted in smaller seedlings.
The results indicated that variations in seed rate within the range investigated were not critical but that failure to protect against pests decreased percentage establishment and subsequent growth.     

Seasonal patterns of diet composition, herbage intake and digestibility limit the performance of cattle grazing native pasture in the Falkland Islands

The botanical composition, intake and digestibility of the diet consumed by mature lactating and non‐lactating cows grazing a native white grass (Cortaderia pilosa) plant community in the Falkland Islands was measured in four periods between September 1998 and June 1999. Five lactating and five non‐lactating cows were used in the summer, autumn and winter; five non‐lactating cows were used in the spring. Different cows were used in each period. Plant cuticle patterns in the faeces of cattle were used, in conjunction with the patterns of concentrations of n‐alkanes in the faeces, to estimate the botanical composition of the diet and predicted concentrations of C₃₂‐ and C₃₃‐alkanes in the herbage allowed herbage intake and digestibility to be estimated using the n‐alkane technique. White grass, sedges and rushes comprised 0·78, 0·64 and 0·63 of the diet in autumn, winter and spring respectively. Fine grasses, smooth‐stalked meadow grass (Poa pratensis L.), annual meadow grass (Poa annua L.), bent grass (Agrostis capillaris L.), native fescue (Festuca magellanica Lam.), Yorkshire fog (Holcus lanatus L.), wavy hair grass [Deschampsia flexuosa (L) Trin.] and early hair grass (Aira praecox L.), were consumed at the expense of sedges and rushes in summer and this coincided with the period of greatest estimated metabolizable energy and crude protein intakes by cows. Lactating cows suffered substantial liveweight loss during autumn and winter and this reflected the low quality of the diet consumed. Phosphorus intakes were insufficient and there was an estimated deficiency of vitamin D in the winter and early spring in cattle that were grazed with the experimental cows. The nutrient restrictions imposed on cattle by the low quality of native pasture during autumn and winter are likely to impair the reproductive potential of breeding females and methods should be investigated to improve the diet consumed by cows during these critical periods if cattle systems are to become sustainable in the Falkland Islands.     

Reseeding Mediterranean dryland cereal fallows using Stipa lagascae R. & Sch.: influence of cutting regime during the establishment phase

When grass species are used to reseed depleted drylands, grazing is often prescribed during the establishment phase. Total protection from grazing often leads to the presence of persistent weed species and is hard to accept by land users keen to graze reseeded land as soon as possible. The particular case of reseeding arid Mediterranean cereal fallows with one native grass species, Stipa lagascae (Stipa), in Tunisia was tested. Seedlings, derived from two different seed sources (selected and bulk), and volunteer annual weed species underwent four different cutting treatments to ground level (early cut, late cut, early and late cuts and no cuts). No effect of any of the treatments on seedling survival or dry matter mass of Stipa seedlings was found. It was concluded that Stipa seedlings are indifferent to the presence of annual weed species and can tolerate more than one cut during the year of establishment. In the context of the study, early grazing of reseeded fallows is worth investigating further.     

不同种肥对高油大豆籽粒蛋白质、油分产量的动态影响

以高油品种东农46为试验材料,采用N、P、K、NP、NK、PK、NPK七种种肥处理,每种种肥四个水平,探讨了各种肥料在开花后45～65 d对高油大豆籽粒蛋白质、油分产量的动态影响.结果表明,花后55 d蛋白质产量最高,花后65 d油分产量最高,K对油分产量积累作用明显,K肥高水平蛋白质产量最高,NPK低水平肥力油分产量最高.     

不同施肥种类与数量对大豆产量的影响

在氮磷钾配合施用条件下,大豆产量大幅度增加,大豆产量可达3260kg／hm^2;磷钾配合施用条件下,产量可达3160kg／hm^2。施用氮肥、磷肥的增产效果显著、肥效高。     

Seasonal patterns of diet composition, herbage intake and digestibility identify limitations to performance of weaner sheep grazing native pasture in the Falkland Islands

The botanical composition, intake and digestibility of the diet consumed by 1‐year‐old weaner sheep grazing a native white grass plant community in the Falkland Islands was measured in five periods between June 1998 and March 1999. Five different sheep were used in each period. Two methods were used for estimating the botanical composition of the diet: plant cuticle patterns in the faeces of the sheep and the patterns of concentrations of n‐alkanes in the faeces of sheep. These methods were used to predict the concentrations of C₃₂‐ and C₃₃‐alkanes in the herbage to allow the estimation of herbage intake and digestibility using the n‐alkane technique. It was concluded that the n‐alkane technique gave more accurate estimates of diet composition based on the comparison with estimates of nutrient intake derived from liveweight gains of sheep. The dominant pasture species, Cortaderia pilosa, was the predominant species consumed during the cooler periods of the year. In the summer, when the highest liveweight gains of sheep occur, the proportion of fine grass species, including Poa spp., Festuca magellanica and Agrostis capillaris, and herbs and sedges in the diet was highest. Herbage intake was the highest during the summer periods when digestibility was also at its peak. Estimated nutritional deficiencies of metabolizable energy, crude protein, phosphorus and vitamin D₃ that limit the growth and development of weaner sheep were evident for up to 9 months of the year. Targeted supplementation regimes that counter specific nutrient deficiencies could be developed on the basis of these results to address critical periods in the growth of young sheep.     

复种复筛法在煮炼过程中的应用初探

通过复种复筛法在煮炼过程中的应用与探讨，提出了提高甲种、甲膏纯度，提高糖分收回和产品质量的方法。     

Leaf and seed micronutrient accumulation in soybean cultivars in response to integrated organic and chemical fertilizers application

Plant nutrients can be influenced by organic materials of soils. An experiment was conducted to evaluate the effect of organic amendments on elements uptake by soybean cultivars in a silty loam soil in Mazandaran province, Iran. The experiment was carried out in split plot based on randomized complete block design with three replications in 2006. Main plots were included 8 fertilizer treatments consisted of 20 and 40 Mg ha(-1) Municipal Solid Waste Compost (MSW), Vermicompost (VC) and Sewage Sludge (SS) which enriched with 50% chemical fertilizers needed by soil, only chemical fertilizer treatment and control. Sub plots consisted of three genotypes of soybean (032, 033 and JK). Grain yield was determined and soybean leaves and seeds were digested and analyzed for Mn, Cu, Zn and Fe. Results showed that yield and elements content in soybean leaves and seeds (Mn, Cu, Zn and Fe) were influenced by all treatments. The 40 Mg ha(-1) of sewage sludge enriched with chemical fertilizers produced maximum grain yield. Different soybean cultivars had also significant differences in terms of leaf and seed micronutrients accumulation. Maximum grain yield was observed in JK and 033. Mean comparisons showed that interaction effects of fertilizer and cultivar had significant differences on Mn, Cu and Fe content in soybean leaves, so that the maximum Cu content was observed in 032 cultivars with 40 Mg ha(-1) enriched sewage sludge and municipal waste compost. Also the highest amount of Fe was obtained for JK cultivar when the 40 Mg ha(-1) of municipal compost was used. Among different mentioned traits, Fe and Cu content in leaf and seed and Zn content in leaf had a positive and significant correlation with grain yield.     

直播油菜施肥效应及适宜肥料用量研究

采用“３４１４”肥料效应试验设计方案进行田间试验,探讨直播油菜氮磷钾（ＮＰＫ）肥效应及肥料的适宜用 量。结果表明,ＮＰＫ配合施用显著提高了油菜产量,三因素增产大小顺序为Ｎ ＞Ｋ ＞Ｐ;油菜各器官养分含量和积 累量随相应养分的施用明显提高;试验条件下,Ｎ、Ｐ２Ｏ５和Ｋ２Ｏ用量为１８０、３０和９０ｋｇ／ｈｍ２时,氮磷钾肥表观利用 率最大,分别为３５．１％、２３．１％和７３．９％。用一元二次肥料效应模型对试验结果进行模拟,结果显示,直播油菜Ｎ、 Ｐ２Ｏ５和Ｋ２Ｏ适宜施用量为２１２、２３和１１２ｋｇ／ｈｍ２。     

Effects of soil disturbance, seed rate, nitrogen fertilizer and subsequent cutting treatment on establishment of Bromus inermis seedlings on degraded steppe grassland in China

Establishment of seedlings of Bromus inermis , a native grass species of China, into a degraded steppe grassland was studied in an experiment with a factorial combination of different soil disturbance (control and harrowing), cutting post-sowing (control and cutting), nitrogen (N) fertilizer application (0 and 100 kg KNO₃ hm⁻²) and seed rate (400, 800 and 1200 seeds m⁻²) treatments. Seedling emergence and survival rates, and plant performance, were followed over 2 years. Seedling emergence was increased by soil disturbance (harrowing). Cutting post-sowing and N fertilizer application did not increase seedling emergence. Seedling survival rates at the end of first growing season were strongly influenced by harrowing and the use of higher seed rates. Seedling height was higher in the harrowing and the N fertilizer application treatments and at the higher seed rates. Seedling survival rates in the second growing season were low but much higher with harrowing than the other treatments. Soil disturbance by harrowing may have increased contact between seed and soil, and reduced competition from established plants. It is concluded that, for the restoration of degraded semi-arid grassland in China by re-seeding, soil surface disturbance is necessary for successful seedling establishment, and modest seeding rates should be used to control costs.     

Improvement of seedling establishment under flood condition by seed coating with molybdenum compounds for wheat and barley

Wheat and barley are often cultivated also in paddy fields in winter in Japan. The drainage of paddy fields is often poor. The seedling establishment of wheat and barley is more prone to become poor if it rains heavily after sowing. The flooding damage on seedling establishment is thought to be caused by many factors. The generation of sulfide ions in flooded and reduced soil is thought to be one factor of the flooding damage. In this study, the effect of seed coating with molybdenum compounds, which suppress the generation of sulfide ions, on the flooding damage of wheat and barley seedling establishment. Two poorly soluble molybdenum compounds were coated on wheat or barley seeds at different amounts. Coated seeds were sown in soil and soon flooded for 2 d at 20 °C. When seeds were not coated with molybdenum compounds, rates of seedling establishment were no more than 32%. However, when any molybdenum compounds of .05–.5 mol-Mo kg^?1 were coated, seedling establishment was significantly improved and rates of seedling establishment were no less than 54%. However, when sown seed were not flooded, the establishment rates of the seeds, which were coated with a molybdenum compound of no less than .1 or .2 mol-Mo kg-1, were significantly decreased. Accordingly, coating of molybdenum compounds could improve the seedling establishment of coated seeds under flooded condition, but might impair the seedling establishment of coated seeds under unflooded condition.     

Storage factors control germination and seedling establishment of freshly harvested true potato seed

Freshly harvested true potato(Solanum tuberosum subsp.andigena, Juz. et Buk.) seeds of the ancient Peruvian cultivar Ccompis were dried to 3.4, 4.2,5.1,6.1, and 7.3% moisture content (Dwt basis) and hermetically stored for 6 months at 15, 30, and 45C. Seeds were humidified to uniform moisture (13%) prior to monthly evaluations of germination at 27 and 17C and seedling performance under variable soil temperature. The effects of treatments on percentage of germination after 8 days at 27C were highly correlated with percentage of emergence at 10 days after sowing and foliage dry weight at 17 days. Germination at 27C increased from negligible to <90% with progressive increases in moisture, temperature, and time in storage. However, germination decreased within the first month of storing seeds at 45C with >5.1% moisture, and after 3 months seeds failed to germinate even after 8 days of lowering the temperature in the germination environment to 17C. Otherwise, germination inhibition at 27C was attributed to dormancy since most seeds readily germinated at 17C. Dormancy was sufficiently released and optimum overall performance was obtained after 2 months of storing seeds at 45C and 4.2% moisture.     

Thiram steep seed treatment to control Phoma betae and improve the establishment of the sugar-beet plant stand

For several years there has been increasing pressure to replace diethyl mercuric phosphate (EMP) for control of Phoma betae on sugar-beet seed and a need to achieve quicker emergence and more established plants. Steeping seed in a 0·2% suspension of thiram achieved these objectives. However, in 12 experiments testing factorial combinations of steep duration (0–24 h) and temperature (20–30°C), it was seldom possible to discriminate between the results of treatment for 4–16 h at 30°C, 8–16 h at 25°C, or 16–24 h at 20°C. These thiram treatments resulted in about 5% more plants than an EMP steep for 20 minutes at ambient temperature. Extending the thiram steep to 24 h at 30°C (as previously considered essential) was consistently less beneficial. In 278 simple comparisons, thiram-steeped seed (16 h at 30°C or 16 h at 25°C) gave more plants than EMP in over 80% of the fields; the average improvement was 3%, and this was probably an underestimate. The response to thiram tended to be greatest following early sowings on medium and heavy soils. Thiram-steeped seed resulted in more plants than EMP-treated seed for at least 3 years after the treatments had been applied. The intention is to replace EMP with a thiram-steep treatment in England in 1989.     

Field performance of potato minitubers with different fresh weights and conventional seed tubers: Crop establishment and yield formation

Summary Field performance of five fresh weight classes of minitubers ranging from 0.13–0.25 g to 2.00–3.99 g and conventional seed tubers was studied in a short growing season (79 or 82 days) in two years. The heavier minitubers gave a more regular emergence, faster ground cover soon after emergence, higher dry-matter yields, and higher fresh tuber yields. Radiation conversion coefficient (RCC) did not differ. Higher tuber yields resulted from more radiation intercepted due to a faster ground cover, and a higher harvest index. All minitubers produced plants with one primary stem. In one experiment when heavier minitubers had long sprouts, time to 50% emergence decreased with tuber weight, whereas dry-matter concentration of progeny tubers increased. Conventional tubers appeared superior to minitubers in all characteristics mentioned except RCC, which was similar. Differences in performance between minitubers and conventional tubers were attributed to weight and age of seed tubers, presprouting method and crop husbandry.