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Northwest University of Science and Technology (2002)

Weibei Arid Platform Ecological Research of Water Factor on Agri-Forestry System

ZhangQingFeng

Titre : Weibei Arid Platform Ecological Research of Water Factor on Agri-Forestry System

Auteur : Zhang Qing Feng

Université : Northwest University of Science and Technology

Grade : Master 2002

Résumé
The model of agri-forestry system runs for thousand years more, only in these years, as a science, does s deep research begin. At present, studies on soil water displacement pursue mostly pure farming land and pure field, and it has less study on agri-forestry system of its soil water movement. If there are some, mostly study the impacts of soil water content on forest growth, crops growth or its productivity, we choose some soil water mechanical methods for a experiment research of change principles in such system of water ecological factors. Two years of on-the-spot surveying and test lead to the following conclusions.1. Zanthoxylum Bungeanum belongs to types of short roots, at 0-120cm layers in vertical distribution of "V " type in great difference, and the difference decreases with the increase of depth ; At 0 250cmhorizontal distribution, the roots stretch in stairs, among which in scope of 0 150cmmost roots are concentrated in distribution, those roots weight taking 70% of total. The root length density and root weight of their spatial distribution present the following features : closer to the forest edge of its water absorb system, tenser the root length, most parts in vertical distribution concentrated in the scope of 0 60cm. At forest edge of 0 60cm layer, the root length density takes 95.9% in layer of 0 120cm, mostly in layer of 20 40cm.2. At agri-forestry system, wheat root distribution features mostly this way : its roots reduces neigyboring the forest ; in vertical direction, the root concentration is mostly at 0 20cm, denser when closer to the forest belt.3. In Weibei arid area, test and analyzes on water movement parameters at non-saturated soil into soil types on agri-forest system is performed. By the data and non-liner parameter adapting method, some math formula are received for the non-saturated soil layers in different ecologies. The models fit good in precision.4. The consumption features of evapotranspiration in such system present the following result. In winter wheat jointing and ripening, its root system absorption of water takes 46.99% of total in forest, 53.01% of total in scrop of 0.5H-1.5H farming field, that is woods absorbs more farming water. Wood root system consumes water from belt and farming field within 0.5H-1.5H, where it is a root mixed region. The conflicts of waterconsumption turn out wheat in advantage. By proportion between wood and winter wheat root systems, wheat water consumption appears most apparent during jointing and ripening. While evapotranspiration of woods turns mainly to be eaporation. The horizontal distribution for farming field evapotranspiraion presents unbalance, that is, in agri-forest system, forest belt is effective and capable of reduction of farming field evaporotranspiration.5. In the consuming movement of soil water in agri-forest system, according to the balance formula of soil water, present the balance formula on different layer of soil

Mots clés : agri-forest system soil water water balance

Présentation (Dissertationtopic)

Page publiée le 21 septembre 2014, mise à jour le 14 septembre 2017