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1.
Effect of Timing and Nitrogen Fertilizer Application on Winter Oilseed Rape (Brassica napus L.). I. Growth Dynamics and Seed Yield 总被引：1，自引：0，他引：1
The field experiments conducted on the grey‐brown podzolic soil in the four growing seasons (1998–2001) at Krzeslice Farm, central‐western Poland comprised seven fertilization variants: 80NF + 80CAN; 80CAN + 80CAN; 80AN + 80AN; 80NF + 50CAN + 30CN; 80CAN + 50CAN +30CN; 80AN + 50AN + 30CN (where NF – nitrofos NPK; CAN – calcium‐ammonium nitrate; AN – ammonium nitrate; CN – calcium nitrate) and control (without N) applied in split rates at the beginning of spring regrowth (80 kg N ha?1), stem elongation (80 or 50) and flower buds visible stages (30). The yielding effect of tested fertilization variants was significant in comparison with the control (2.24 t ha?1). The highest mean seed yield (3.64 t ha?1) was collected from 80AN + 80AN and 80CAN + 80CAN variants. Mean values of 4 years indicate that the second N rate division (80 + 50 + 30) decreased yield, although not significantly in comparison with these two N treatments. Plants grown on these treatments have developed different patterns of growth to yield the seeds. These patterns were characterized by very high crop growth rate during flowering (above 21 g m?2 day?1) and negative at maturation (down to ?2.5 g m?2 day?1). Plants fertilized with ammonium nitrate (80AN + 80AN) reached maximum growth rate earlier (65 days), which lasted longer (20 days) than plants fertilized with calcium‐ammonium nitrate (71 days lasting 17.5 days). Plants grown on the control treatment reached the highest crop growth rate within 79 days (14.8 g m?2 day?1), which lasted 15 days. 相似文献
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杂交狼尾草生育特性研究 总被引：14，自引：2，他引：12
研究了杭州生态条件下移栽杂交狼尾草的生育特性,试验表明,杂交狼尾草平均每叶展开需积温前３叶为７５．９℃、９叶至２０叶为６２．３℃;４叶１心开始分蘖;单株干物质积累高峰期出现地拔节后,茎叶粗蛋白含量随生育期而下降;重施拔节肥是高产优质的关键,根茎安全越冬应保持地温在１０℃以上。 相似文献
4.
Soluble solids comprise most of onion bulb dry mass, and dehydrator onion cultivars are developed from breeding populations
that have high dry mass content. Realized and narrow-sense heritability estimates were obtained for the soluble solids content
(SSC) trait in two open-pollinated dehydrator onion breeding populations (BP) using response to selection and half-sib family
analysis. Parental populations, designated as BP9335-U and BP9243-U, were derived from two-way crosses of lines advanced as
open- pollinated (OP) populations to the F7 or F_6 generation, respectively. BP9335-U had one previous selection cycle for
increased SSC and BP9243-U had three SSC selection cycles. In these experiments, parental populations were screened again
for high SSC, and selected bulbs were intermated to form half-sib progeny groups, designated as BP9335-S and BP9243-S. Mean
SSC was increased by 6.6% and a realized heritability estimate of 0.64 was obtained for BP9335-S. Mean SSC was increased by
6.3% and a realized heritability estimate of 0.36 was obtained for BP9243-S. Narrow-sense heritability estimates of 0.58 ±0.05
and 0.30 ±0.03 were obtained for parental populations BP9335-U and BP9243-U, respectively. Narrow-sense heritability estimates
of 0.40 ± 0.03 and 0.63 ± 0.23 were obtained for progeny populations derived from selected high-SSC bulbs of these lines (BP9335-S
and BP9243-S), respectively, indicating that there is significant additive genetic control of the SSC trait in these populations.
Significant differences in half-sib family performance in the advanced groups BP9335-S and BP9243-S demonstrate that progeny
testing was effective for evaluating phenotypic selections.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
甘薯生长发育模拟模型的初步研究 Ⅰ.光合作用和干物质生产与分配 总被引：3，自引：0，他引：3
光合作用和干物质的生产与分配模型是作物生长模型模型中最基础的部分，在试验的基础上，以徐薯１８为例建立模型。光合作用模型以门司一佐伯的模型为基本蓝图，增加了温度因子对光合强度影响的研究，干物质分配模型打破了传统的采用分配系数的方法，引入潜在生长和实际生长的概念，根据不同的时期、不同的优先等级分配光合产物，使光合产物的分配也建立在一个动态的过程之中。模型验证结果表明，块根和拐子的模拟精度较高，茎、叶片、叶柄次之，纤维根的模拟误差较大。 相似文献
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Anne Kjersti Bakken 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):62-68
Abstract In two experiments timothy plants (Phleum pratense L., cultivars ‘Bodin’ and ‘Grindstad’, well established and vernalized in the first experiment and 7 weeks old in the second) were given daylength treatments with 12 h of photosynthetically active radiation (PAR) and day-lengthening light of low irradiance for from 2 to 13 weeks. Significant daylength effects on dry-matter, total nitrogen, nitrate and soluble protein content in the leaves of plants were demonstrated after only two weeks of treatment. The nitrogen and protein content decreased with increasing daylength, irrespective of the developmental stage of the plants. The dry-matter content increased with daylength when long days had induced generative development and decreased when all treatments at the same harvest were vegetative. The total nitrogen and protein per plant did not decrease from short to long days. The lower nitrogen and protein content in long days can therefore be regarded as a dilution caused by the increased dry-matter production found in these treatments. The observed effects of daylength on the ratio of assimilated nitrogen to assimilated carbon might be direct or indirect, since long days induce both enhanced dry-matter production and generative development in Bodin and Grindstad. 相似文献
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The grazing behaviour by sheep, after the loss of the temporary incisors and before their replacement with the permanent incisors, was compared with that after the first pair of permanent incisors had completely developed in grazing experiments, conducted from June to September 2001, with three Suffolk castrated male sheep, born in late‐March 2000. A new method was developed to investigate bite mass and bite force, using hand‐constructed swards, which were composed of groups of four (4L), eight (8L), twelve (12L), sixteen (16L) and twenty (20L) leaves of cocksfoot (Dactylis glomerata) arranged 15 cm apart. Each group of leaves was attached to a separate three‐directional load cell. The period of time between loss of temporary incisors and the complete eruption of permanent incisors was c. 1 month. The number of bites per group of leaves increased with increasing leaf density. The number of bites per group of leaves was higher after the loss of temporary incisors than with the permanent incisors. The number of leaves per bite and dry‐matter (DM) intake per bite were almost twice as great with permanent incisors than after the loss of temporary incisors; DM intakes per bite force were 3·9–4·9 mg N?1 and 1·7–2·6 mg N?1 respectively. After the loss of temporary incisors, the proportion of forward‐direction forces accounted for 0·805 of the forces in the 4L treatment and 0·155–0·317 of the forces in the 8L–20L treatments. In contrast, the proportion of forward‐direction forces accounted for only 0·292 in the 4L treatment and 0·026–0·163 in the 8L–20L treatments with permanent incisors. The angles of bite forces were almost the same (54·7–56·3°) when sheep used a forward direction, and were 51·3–57·3° when sheep used a backward direction. 相似文献
8.
Productivity and nutritive value of some cultivated perennial grasses and mixtures in the alpine region of the Tibetan Plateau 总被引：1，自引：0，他引：1
The productivity and nutritive value of some cultivated perennial grasses, Bromus inermis (B), Elymus sibricus (S), E. nutans (N), Agropyron cristatum (A), Poa crymophila (P) and mixtures B + N, S + A, B + S + A, S + B + N, N + S + A, B + S + N + A, B + N + A + P, B + S +A + P and S + N + A + P, in the alpine region of the Tibetan Plateau were investigated. Elymus nutans and E. sibricus and the mixtures, B + S + N + A, B + S +A + P and S + N + A + P, were most productive with yields of dry matter (DM) of between 11 000 and 14 000 kg?1 of biomass annually in the second harvest year. Acid‐detergent fibre (ADF) concentrations increased (P < 0·05), and crude protein (CP) concentrations and in sacco DM degradability values decreased (P < 0·05) with the maturity of the cultivated grasses. Swards, based on these species and mixtures, have the potential to be the main choices for cultivation in the Tibetan Plateau because they produce more nutrients than other grass species and mixtures. Late August (flowering stage of dominant grasses) is the optimum time for harvesting as the yield of rumen‐degradable CP is highest that of DM relatively high and the DM degradability is satisfactory. 相似文献
9.
Su Zhifeng Yang Wenping Yang Zhenping Du Tianqing Hao Jiaomin Sun Min Gao Zhiqiang 《棉花学报》2015,27(5):435-444
为探求生土地当年最佳施肥方式,快速提高棉花地上部生产力并改良根干物质质量垂直分布,试验连续2年以黄土母质生土为供试土壤,采用根管土柱法,研究不同肥料(N,P,NPK,有机肥,不施肥对照(CK))、不同施肥深度(0~20 cm,40~60 cm,80~100 cm土层)对棉花(Gossypium hirsutum)茎叶干物质质量、棉铃干物质质量及根干物质质量垂直分布的影响。结果表明,所有处理中,以有机肥深施40~60 cm处理的茎叶和棉铃的干物质质量最大,其次为NPK肥深施40~60 cm处理,二者差异显著(P0.05);以含P肥深施40~60 cm处理的根干物质质量较大,且40 cm以下根层的分布比例较大;所有处理均以0~20 cm层的根分布比例最大,约占0~100 cm总根干物质质量的40%~80%。总的来看,当年生土地棉花冠￣根系统的最佳肥料运筹是有机肥深施40~60 cm。 相似文献
10.
Forage evaluation indices are available to assist farmer decision-making on the most appropriate ryegrass cultivars to grow. However, these indices currently take no account of any feeding value trait that reflects the interaction between the animal and the structural and morphological characteristics of the pasture. Information on the feeding value of ryegrass cultivars can be confounded by nutritive value, arising from the relationship between nutritive value and heading date. The objective of this study was to determine the milk production response of dairy cows grazing four perennial ryegrass diploid cultivars: two morphologies within two different heading dates and on three occasions during lactation across two years: late spring, summer and autumn. No consistent phenotypic effect occurred on milk production across the two years. Milk production responses were more closely aligned to energy intake. The sward structure changed physiologically from year 1 to year 2, with a reduction in the ratio of leaf to stem and subsequent increase in stem mass in year 2. Despite this, the relative difference in leaf to stem between mid-season and late-season heading dates remained consistent between years and had no effect on milk production. In one year, the apparent dry-matter intake was higher but it was not possible to determine which sward structure traits or group of traits contributed to this response. We conclude that, at this time, the evidence is insufficient to support inclusion of a phenotypic trait as represented by “feeding value” in forage evaluation indices. 相似文献