| In this thesis , soil database, climate resource database , wheat experiment database and wheat-plant statistic database in Hebei are set up. Based on above-mentioned databases , the crop growth simulation model PS 123 is used as a tool to study. The yield gap between winter wheat actual productivity and productive potential , space distributions and crop output goals under different conditions and possible influence factor is studied. Through the experiment in Malan farm, the mount of actual fertilization and the mount of applied fertilization speculated by model under different conditions is compared. By comparing, it can reflect that the mount of applying fertilizer now is abundant or scarce. Though the database is still riot perfect, the following basic conclusion can still be draw:1. The winter wheat production potential rise to 12t.ha-1 from 7t.ha-1 from north to south gradually under PS-1 condition. The east of Hebei is generally 11-12t-ha"', Shijiazhuang , Hengshui , Cangzhou and the southern areas of Langfang are generally 9-11t.ha-1, the southern areas of Tangshan are generally 7-9t.ha-1.2. Under the better controlled factor condition, for example water and fertilization, the main factor that influence regional productive potential under PS-1 condition is the effective accumulated temperature .3. The rain-fed productive potential of all various kinds of soil increase progressively from the north to the south , slightly incline the northwest- the southeast. As far as the productive potential in same place concern, loam is the highest, sandy loam take second place, clay take third place, sand is the lowest. The rain-fed productive potential of loam in the southeast area of Hebei is generally 5-7t.ha-1. The rain-fed productive potential is generally 3-5 t.ha-1 in the mass area from Handan to north reaching Baoding - Xiong County - Dacheng -Jinghai - Wuqing - Yutian line . The rain-fed productive potential of loam is generally 2-3t.ha-1 in some county of Langfang and south of Chengde. After the moisture becomes the main restriction factor, the rain-fed productive potential of winter wheat mainly decided by the amount of valid rainfall in the growth period .4. Though irrigation can increase the winter wheat productive potential of the same place in various degree, it does not basically change the space distributions of rain-fed productive potential in Hebei plain area.5. The yield gap between PS-1 potential and rain-fed productive potential of all various kinds of soil (YP1) in middle and high latitude area is the largest, and it decreased rulelessly to high latitude and low latitude area. Most area of the east in Hebei province is generally 6-St.ha-1, Tangshan , the southern of Chengde is generally 4-6t.ha-1.6. Through the experiment in Ma Lan farm, it is indicate that: If you want to reach the natural productive potential under PS-1 condition, the mount of appliedfertilizer is still far insufficient. The quantity of applied fertilizer seldom exceed appropriate amount in most experiment. But in whole Xinji country ,comparing the mount of applied fertilization speculated by the actual wheat yield using model with the actual mount, the latter is 2.99 times of the former ,it proved that traditional fertilization in countryside is far exceed appropriate mount, now. It can cause the reducing of the fertilizer utilization ratio... |
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