2004 Vol. 17, No. s1
The trials on desertification control and technique development of desert industry in accordance with the characters of three kinds of deserts such as the sandy land on middle Yinchuan Plain,Tenggeli Desert,and Maowusu desert were conducted.Great efforts were put on technique development of desert industry,promoting sustainable development of desertification control and ecological construction.Taking increasing the utilization ratio of water resources as the core,taking new techniques with less water use,high investment and high output as the key measures to development desert industry and realize the strategic target of sustainable development in the light of local natural environment.Eight research programs were conducted in 3 demonstration plots.The area of trial demonstration plots established was 1300 hm2,which were extended to 26700 hm2.Four kinds of desert industry were developed which include planting short-rotation fastgrowing and high-yielding pulpwood poplar plantation,producing and processing fresh friuit such as grapes,developing and culturing Xerophyte,and greenhouse cultivation.Three patents were applied,many new techniques were developed and 30 paper and research reports were published.
The soil water characteristic curves and infiltration capability of Maowusu sandy soil were studied in Yanchi County,Ningxia Hui Autonomous Region,so as to provide a scientific basis for vegetation recovery and soil water management.The soil water characteristic curves of Maowusu sandy soil were measured with tensometers and then simulated with the model θ=aψ-b.The highest water supplying capacity and the lowest water holding capacity were found in the soil layer of 0～20 cm and the opposite result in the soil layer of 40～60 cm.The water capacity reached 10-1level at soil suction of 0.06～0.08 MPa,which indicated that soil water was not available for plant uptaking.The infiltration capacity was measured with ring swords in lab,and the original infiltration rate,stable infiltration rate and cumulative infiltration amount were found to be higher in the experimental plots with vegetation cover than that of exposed plots.Thus,drought-resistant tree species,such as Caragana korshinskii,with low planting density,were suggested to be used for vegetation recovery in the local area.
The results of 4-year’s trial showed that when drip irrigation was applied in the establishment of sandy land shelterbelt,the optimal design scheme were as follows:the diameter of drip tube 12 mm,drip flux 3.75 L·h-1,drip space 1.0 m.On the other hand,under drip irrigation,the survival rate of afforestation and increment of tree were both higher than that under normal irrigation condition,and possessed the advantages of water saving,energy saving and labour saving.The design and efficiency of drip irrigation on sandy land shelterbelt were systematically summed up.
Several experiments of after manuring with N,P,K compound fertilizers and urea in different ratio,amount,and application patterns were conducted.The results showed that after manuring had greater effects on the increment of dbh than on height increment.The best application pattern could double the increment.The effects of different fertilizer followed the order of ureafertilizer 3fertilizer 2fertilizer 1.The results of after manuring on 2-year-old poplar plantation showed an increased absolute value of increment,the variation of increment after manuring was smaller than that on current planted plantations.The difference among fertilizer followed the order of fertilizer 2fertilizer 1ureafertilizer 3.As for application pattern,separately application was better than that of one-time applying.The experiment showed that middle June was the best time for fertilizing.
The sandy soil positioning research method was used to study the soil water characteristics and the variation of water potential in SPAC were systematically studied in Maowusu sandy Land. The results were as follows:(1)the empirical equation θ=AS-B could well simulate the water characteristic curves of the soil.The study also showed that the soil had the low moisture capacity and the less supply water and low drought endurance.(2)The main resistance of water distribution in SPAC was from leaf to atmosphere,the distinctly seasonal change of soil moisture was the common result of rainfall,evaporation from the forest floor and transpiration of the trees,the tree tested had a clear daily variation in leaf potential,under the condition of drought stress,the lowest leaf potential appeared in advance,leaf water potential had a correlation with soil and atmosphere water potential to a certain extent.
Based on the environmental condition of sandy land in Ningxia,the key techniques on cultivating grape were summarized.These techniques included:removing soil in digging dike for soil reclamation,water-saving drip irrigation,building vineyard and cultivation technique against cold and frost.A complete set of high-tech and new techniques was developed to produce"green"fruits.These techniques made the grape production in Ningxia reached a high-quality and high-yielding level,and great economic benefits were gained.
The authors studied the adaptability of 8 newly introduced plant species including Rhus typhina,Populus euphratica,Buddleja alternifolia,Caryopteris mongolica,Sabina vlugaris,Atraphaxis bracteata,Morus alba and Calligonum klementzii. The result were as follows:(1)From the viewpoints of survival rate and preserve ratio,all these species,except Populus euphratica,were adaptable to grow in Yanchi.(2)The results of statistical analysis showed that all these species,except Populus euphratica,could grow,pass winter and summer normally without any preservative countermeasures. (3)All these species,except Populus euphratica,showed the characteristics of drought-tolerance and could grow under poor site conditions. Buddleja alternifolia,Atraphaxis bracteata and Calligonum klementzi had also the characteristics of fast-growing and stability.(4)Under the condition without any defrost countermeasures,these species did not suffer from top drying or freezing injury,which showed all these species had strong cold-tolerance. (5) Under the conditions of poor rainfall,high evaporation and strongly windy,all these except Populus euphratica,showed higher drought-tolerance.
From the viewpoints of population quantitative structure and biomass production,the vegetation restoration of Liujiayaotou Watershed at Zhaojiatang under different management measures was analyzed.The results showed that the integrated tree-grass planting had the best effect on vegetation restoration.The vegetation restoration on shrub land was better than that on high tree land.The effect was worse on pure poplar land.Sand-fixing by checkerboard fence could accelerate the fast restoration of vegetation,and spraying chemical sand-fixing agents had obvious effects on vegetation restoration on the slope facing the wind.
Three water-retention agents,namely,American drywater,multifunction nutritional activator,Hanluzhibao,were used to conduct afforestation test on sandy land of Yanchi County.The result showed that all the 3 agents could effectively raise the water content in the soil around the plant root systems so as to promote the growth of seedling and raise the survival rate of afforestation.Among the 3 agent,American drywater performed the best.
The water-retention characters of Maowusu sandy soil were studied in Yanchi County,Ningxia Hui Autonomous Region.The soil water characteristic curves were measured with tensometers and pressure vessel and simulated with the model y=ax-b(y denote water content,x denote soil suction).The water supply character and available water of soil were studied and found to be higher in surface layers than in underlayers.
The transpiration rates of Caragana intermedia and Artemisia ordosica grown on Sandy Land Xerophyte Botanical Garden in Yanchi County of Ningxia,as well as the change regularity of environmental factors, were measured.The results showed the diurnal transpiration rate of C.intermedia followed a single apex curve,while that of A.ordosica followed a double apices curve.Both plants possessed the physiological characteristics adapted to the arid zone.But their approaches to resist the aridity were different.A.ordosica had higher transpiration rate.The air temperature affected the transpiration rates of the two plant species.The water content of soil mainly affected the transpiration rate of A.ordosica.
The industrialized propagation of psammophyte and its advantages were described,and the propagation techniques and its demonstration and extending of psammophyte were summed up taking Buddleja alternifolia and Caryopteris×clandonensis ’Worester Gold’ as testing meterials.
Drip irrigation is a new technique with the character of water saving,and it is applied mainly in economic crops and economic forest with higher economic values.The authors applied drip irrigation in sandy land shelterbelt cultivation for the first time,and discussed the benefits of water saving,energy saving,labour saving and the investment benefits.The application of drip irrigation technique in various tree species showed that compared with channel irrigation,drip irrigation could increase tree increment by 11.54%,save water,energy and labour by 59.1%,40.5%,and 50.9%,respectively.
By quadrat and general investigation methods,94 speciments were collected which belongs to 73 genera of 29 families,including 36 species of medical plant (Glycyrrhiza uralensis,Xanthium sibiricum,etc.), 29 species of forage plant (Caragana intermedia,Stipa capillata,etc.), 17 species of timber plant (Salix psammophila,Populu simonii,etc.) and 16 species of edible plant(Ixeris chinensis,Allium mongolicum,etc.).
The water physiological characters of shrub grown on sandy land and research on them were reviewed.The research on drought-tolerance evaluation index of psammophytes has developed toward physiological and physiological and biochemica1 character from morphological and anatomical characters. The results of research showed that whatever in the morphology and anatomy or in the water physiology and biochemistry such as water potential and transpiration, the shrubs grown on sandy land possessed the characters adapted to drought areas and could reach the destination of avoiding dry conditions by many approaches. The traditional theories and methodology are still being used widely. SPAC theory was the foundation of quantitative study in water transportation and energy transition. The dynamic study and simulation methods on various scales based on the theory have been applied in arid zone.
Tomato R-144 is a fine species with the characters of high adaptability;disease-resistance,high-yielding and easy to storage.Based on several years’practice of introduction and cultivation,the cultivation techniques of tomato R-144 in sandy land of Ningxia were systematically summed up from the aspects of industriallized seedling culture,cultivation techniques,field management,water and fertilizer management,pest control,etc.The prospect of market-development was also described.
The techniques including the determination of seedling culture time and equipment propagation material (seed or cutting) treatment,selection of container,compouding of media,seedling culture,temperature and moisture control,spraying nutrient agents,transplanting of containerized seedling,were reviewed and summed up.Some experiences on afforestation with containerized psammophyte seedlings were introduced.
The research at home and abroad on the simulation of soil water infiltration equation soil water movement parameters and the theory of SPAC were reviewed.The authors indicated that the main standpoint had been moved to energy from morphology,and much effect had been made on the measurement of soil water movement parameters and great achievements had been gained.With the rapid development of computer technique,extensive progress in quantitative simulation had been made.
In order to meet the demand of developing industrial timber plantation on the edge area of Tenggeli Desert,based on the experiences and techniques of long-term poplar afforestation,a whole set of techniques were integrated and an advanced technical combination was formed.The authors summed up systematically the afforestation techniques of short-rotation industrial timber poplar plantation on the edge of Tenggeli Desert from the aspects of afforestation planning and designing,tree increment indexes site and tree species selection,site preparation,seedling standard,afforestation time,density,pattern,tending,pest control,inspection,file extablishment,etc.
The authors put forward the new technologies for establishing energy-saving solar greenhouse,introduced the techniques of seedling growing,culture,water and fertilizer management in protective cultivation,and discussed the significance of protective cultivation.
The results of water-saving irrigation trial on sandy land showed that the change of irrigation pattern could save water greatly.Among furrow irrigation,patch irrigation and flooding irrigation,furrow irrigation could save water by 444～750 m3·hm-2·a-1 and 3 270～4 275 m3·hm-2·a-1 respectively compared with patch irrigation and flooding irrigation.Under the three irrigation patterns,no evident difference was found for the increment of poplar.
Taking 3 kinds of N,P,K compound fertilizers and P fertilizer as basal manure,the experiment was conducted in 3 levels.The results showed that in same level,various fertilizers had no evident different effects.The amount of fertilization could significantly affect the height increment of trees but did not significantly affect the diameter increment.By increase the application of organic fertilizer accompanied with chemical fertilizer,great difference was found in height increment and diameter increment among different treatments.The treatment 6 was the best in promoting branch growth and DBH increase of poplar.
Based on 3-year’s investigatin data of aerial seeding on Maerzhuang plot of Yanchi County,the changes of vegetation and dominant species population after aerial seeding were analyzed.The authors explored the relationship between vegetation change and habitat,and put forward some measures to prolong the growth phase of aerial-seeded plants.The results of the short-term investigation showed after aerial seeding,the species did not change a lot,but the vegetation coverage and biomass increased significantly.
The results of investigation and analysis showed the sandy vegetation on the south edge of Maowusu Sandy Land is a transitive type from grassland to desert,and can be divided into 19 vegetation sub-type belonging to 5 vegetation types.The process of vegetation succession can be divided into 4 phases by spatial analysis,i.e.natural sparse psammophyte stage,artificail shrub forest stage,artificial shrub-natural semi-shrub-natural herbaceous stage and natural herbaceous dominant stage.
By investigation on the damage of longhorned beetles on poplar,it was found that the damage rate decreased with the increase of plant to pest origin.For the trees planted in the current year, 84.9% of notch was distributed in the area 1 meter above the ground,while for 2-year-old trees,the notchs were distributed mainly in the area 2 meters above the ground,which took 75.8% of the total.Two pesticides (Fenitrothion and Luseweilei) were used to control the insect and the results showed that both pesticides could control the insect effectively.When Luseweilei was used,but the notch rate and number seemed to be higher compared with that when Fenitrothion was used,but the former could make higher insect mortality rate than latter.
The results of experiments showed that aerial-seeding seeds wrapped with multifunctional seed-dressing agent could effectively increase the seed preservation rate of seed and the survival rate of seedling,promote the plant growth.The survival and preservation rate of seedling could be improved by 9%～12% and the increment could be improved by 20%.
Four crop species were intercropped in fast-growing and high-yielding poplar plantation.After intercropping with different crops,the increments of poplar increased to different extent.Intercropping with watermelon had the best effects.The height,DBH and amount of new breach increased by 21.6%,44.8% and 100% respectively.The annual net income could be as high as 7 800 yuan·hm2.
By using the conception of soil water potential,the soil water content character and vegetation recovery on 2 sand