[Objective] The experiment was conducted to study suitable date of seed- ing and density of spring potato at the stock breeding base in Ebian County at an elevation of 1 200 to 1 500 m. [Methods] Virus-free Potato ＂C...[Objective] The experiment was conducted to study suitable date of seed- ing and density of spring potato at the stock breeding base in Ebian County at an elevation of 1 200 to 1 500 m. [Methods] Virus-free Potato ＂Chuanyu 13＂ was used as material to study the effects of date of seeding and density on growing period, germination rate, yield and water use efficiency of spring potato in the field. [Result] With the postponement of date of seeding, the days from sowing to germination shortened, while the germination rate, the number of tubers per plant, the number of middle and small tubers in a group, yield and water use efficiency all increased. Planting density had no effects on the days from sowing to germination and the ger- mination rate, while the number of tubers per ptant, the number of middle and small tubers in a group, yield and water use efficiency increased significantly along with the increasing planting density. [Conclusion] At an elevation of 1 200 m to 1 250 m in Ebian County, the suitable date of seeding for potato was from February 9 to March 1, and the suitable planting density was 12×10^4 plants per hm^2, however, in the optimum planting density has not been found so that it needs further research,展开更多
Evaluating cloud seeding effects is one of the most critical issues in artificial precipitation enhancement experiments. However, the evaluation is not straightforward because there is natural rainfall variability, wh...Evaluating cloud seeding effects is one of the most critical issues in artificial precipitation enhancement experiments. However, the evaluation is not straightforward because there is natural rainfall variability, which subjects the atmosphere to spatiotemporal instabilities. The aim of this study is to analyze natural rainfall variability using the modern statistical simulation method, "bootstrap", to analyze its influence on the evaluation of seeding activities and to take proper measures to control the influence. The study is based on the 1997?2007 airborne seeding macro records and the daily precipitation data in Jilin Province. The influence of natural rainfall variability can be reduced through three approaches: the increase of the supposed "seeded" sample size N, the rejection of outliers, and the selection of similar control units. A larger N leads to smaller calculated precipitation variability and detectable lower limits of seeding effects. When N is near 470 and the seeding effect is between 20% and 30%, the confidence level reaches 90%. For a single seeding operation, the case deletion model that rejects strong influence points and selects similar control units is established to control the influence of natural precipitation variability, which obviously improves the evaluation of artificial precipitation enhancement. The results demonstrate that the relative seeding effect in Jilin Province is concentrated mainly in the range of 0 to 30%, with an average of 11.95%, and has no significant linear relationship with the actual precipitation amount. However, the fluctuation amplitude of the relative effect decreases as the precipitation amount rises.展开更多
基金Supported by Project of Propagation of Improved Potatoes,Project of CropsLivestock and Poultry Breeding in 12th Five-Year Plan of Sichuan ProvinceTeam Project of Sichuan Potato Innovation under National Modern Industrial and Technological System~~
文摘[Objective] The experiment was conducted to study suitable date of seed- ing and density of spring potato at the stock breeding base in Ebian County at an elevation of 1 200 to 1 500 m. [Methods] Virus-free Potato ＂Chuanyu 13＂ was used as material to study the effects of date of seeding and density on growing period, germination rate, yield and water use efficiency of spring potato in the field. [Result] With the postponement of date of seeding, the days from sowing to germination shortened, while the germination rate, the number of tubers per plant, the number of middle and small tubers in a group, yield and water use efficiency all increased. Planting density had no effects on the days from sowing to germination and the ger- mination rate, while the number of tubers per ptant, the number of middle and small tubers in a group, yield and water use efficiency increased significantly along with the increasing planting density. [Conclusion] At an elevation of 1 200 m to 1 250 m in Ebian County, the suitable date of seeding for potato was from February 9 to March 1, and the suitable planting density was 12×10^4 plants per hm^2, however, in the optimum planting density has not been found so that it needs further research,
基金supported by the National Meteorological Public Benefit Research Foundation(Grant No.GYHY201006031)the China Meteorological Administration Soft Science Project(Grant No.2012-053)+1 种基金the Jiangsu Province Science Department Grant(Grant No.CB10X_295Z)the Jiangsu Province Qinglan Project for Cloud Fog Precipitation and Aerosol Research Group
文摘Evaluating cloud seeding effects is one of the most critical issues in artificial precipitation enhancement experiments. However, the evaluation is not straightforward because there is natural rainfall variability, which subjects the atmosphere to spatiotemporal instabilities. The aim of this study is to analyze natural rainfall variability using the modern statistical simulation method, "bootstrap", to analyze its influence on the evaluation of seeding activities and to take proper measures to control the influence. The study is based on the 1997?2007 airborne seeding macro records and the daily precipitation data in Jilin Province. The influence of natural rainfall variability can be reduced through three approaches: the increase of the supposed "seeded" sample size N, the rejection of outliers, and the selection of similar control units. A larger N leads to smaller calculated precipitation variability and detectable lower limits of seeding effects. When N is near 470 and the seeding effect is between 20% and 30%, the confidence level reaches 90%. For a single seeding operation, the case deletion model that rejects strong influence points and selects similar control units is established to control the influence of natural precipitation variability, which obviously improves the evaluation of artificial precipitation enhancement. The results demonstrate that the relative seeding effect in Jilin Province is concentrated mainly in the range of 0 to 30%, with an average of 11.95%, and has no significant linear relationship with the actual precipitation amount. However, the fluctuation amplitude of the relative effect decreases as the precipitation amount rises.
