Division Of Forage Grass Grown Areas And The Cultivation Models In The Three Gorges Area

The Three Gorges area, rich in the grass land resources, is a hilly and mountainous region,the total area is 5.76 million hectares. There are now 1.34 million hectares of grass land (23.2% of the total area) in that region and among them, 1.19 million hectares (20.6% of the total area) are available. Animal husbandry is important in rural economy, since the output accounts for 40% of gross agricultural product. And grassland animal husbandry is almost sole economical income of farmers living in remote area in Three Gorges area.The climate is the subtropics moist monsoon in Three Gorges area and Daba mountain is in the north, resulting in the moist and warm natural conditions, i.e. plenty rainfall, warmth in winter and bright sunshine in summer. They provide a fine basic condition for the forage grass planting and grassland animal husbandry. According to the national ecological environment construction plan, the grassland animal husbandry development plan of Three Gorges Area and Chongqing's 15th grass production and the prairie ecology construction plan, it is not only superiority development area of grass-feeding livestock in Chongqing, but also one of important national area of water-soil conservation and key ecology construction. It is necessary to point out that the lowest elevation is 73.1 m and highest one is 2796.8 m above the sea in the area, respectively, 2723.7 m difference between them and resulting in vertical climate variation, In low area, for example, yearly average temperature is 17.5-19.0℃and lowest one is -1.7-9.2℃.In the high area, however, the yearly average temperature is below 14℃and lowest one is bellow - 10℃. Forage grass varieties and cultivation are thus quite different in variable places. Moreover, the growth of forage grasses is greatly influenced by serious soil-water losses, thin soil layers, frequent drought, infertile soils and nutrient deficiency in soils. Wild grass mainly occupied the natural grassland in remote and undeveloped regions, In this case, the grasses are poor in yields and qualities, and short in growth periods, which is very difficult to satisfy the needs of grass feeding animals and limits the development of grassland animal husbandry. It is also unbenefit to improve the local ecological environments and povertyless of farmers there. It is thus necessary to increase the yields of grass and improve the qualities.Grasses vary in varieties and planting areas. The division of forage grasses is the first work needed to carry out according to the natural conditions during grassland construction in developed countries. The suitable grasses could be planted in adaptable places by this way. Therefore, the division of forage grasses could be not only good for full utilization of sunlight, warmth, water and nutrient, but avoid the failure of grass cultivation in new places different from hometown. Also, the division is benefit to the artificial cultivation of grass and the improvements of grassland animal husbandry. It could be said that it is the parity of grass cultivation for the production of economical and ecological effects in accordance the natural conditions, local economical state, scientific plane and so on. In conclusion, the related research is significant for local grass cultivation, i.e. domestication, introduction and breeding, and effective utilization. The research results obtained could provide theoretical and practical supports for the fast economical development of grassland animal husbandry. They could also be applied in the local area and similar ones in the provinces, counties and sub-counties of upper areas of Yangtze River.Elevation changes are the main factors resulting in the variation of climates, soils, geography, society, economy, cultivation, agriculture and animal husbandry. Therefore, we set up the experimental sites in different elevation for the introduction of grass varieties to study their adaptations, including the growth periods, yields, nutrient components, plant height, stress resistance and food likeness of more than 150 varieties demotic and abroad. 24 varieties adaptable for local area were selected from them. Then, we investigate and study natural, social and ecological conditions of Three Gorges reservoir area, and establish rational planting division according to the forage grass division principle and method. In the different area, the fine forage grass varieties selected are used to study their cultivation pattern. At last, we choose three suitable forage grass species which is representative and already planted broadly in the reservoir area-Hemarthria compressa, Medicago sativa and Trifolium pratense, and study changes of yields and quality under different fertilizer treatments. These research results can provide scientific basis for planting forage scientifically, fertilizing rationally, achieving high yields and good quality and developing forage production in the Three Gorges reservoir area. Just so, this paper author mainly studied the adaptability of the main foreign .planting division of suitable forage varieties, cultivation models, planting technique , balanced fertilization technique of three suitable forage grass species and so on. The results show that:(1) Forage species suitable for high altitude spots which is similar to Huazhuping Wushan in ecological conditions: Medicago sativa (Algonguin Defi) Trifolium pratense (Revendel) Lotus corniculatus Pennisetum alopecuroides Sorghum vulgare (Hunnigreen) Festuca arundinacea (Dovey) and Dactylis glomerata (Baridand) ; Forage species suitable for middle elevations spots which ecological conditions is similar to Qiao Ping Banan Area: Festuca arundinacea(Fawn) Dactylis glomerata(Dorson Sparta) and Lolium multiflorum Medicago sativa (Xuke No.2 Sitel Millennium) and Lotus corniculatus (Maku); Forage species suitable for low elevations spots which is similar to Yudong Banan Area in ecological conditions: Hemarthria compressa (cv.Chonggao) Lolium multiflorum (Tetragold Ya97-2) Medicago sativa (Eureka Trifekta Terri Amerileaf721 Total+z MF₂,and so on) . These fine species of forage grass is productive and good quality, their adaptability and palatability is also better.(2)According to the forage grass division principle and method, the Three Gorges reservoir district may be divided into three big planter areas: Mountainous planting area, halfway up the mountainside and half dam planting area and farmland forage grass planting area. Mountainous planting area: elevation varies from 1000 to 1600 meters, yearly average temperature is 17.5-19.0℃,≥0℃accumulated temperature is 4510-5295℃,yearly rainfall is 1353-1575mm and yearly sunshine time is 1432-1785h. The rainfall distributes vertically with elevation. Suitable forage varieties includes Medicago sativa, Lotus corniculatus, Dactylis glomerata, Trifolium pratense, Trifolium repense and so on. Halfway up the mountainside and half dam planting area: elevation varies from 500 to 1000 meters, yearly average temperature is 14.8-16.0℃,≥0℃accumulated temperature is 5296-5818℃,yearly rainfall is 1183- 1352mm and yearly sunshine time is 959-1107h. Suitable forage varieties includes Medicago sativa,Festuca arundinacea, Pennisetum alopecuroides and so on. Farmland forage grass planting area: elevation varies from 250 to 500 meters, yearly average temperature is 17.3-19.6℃,≥0℃accumulated temperature is 5819-6342℃,yearly rainfall is 1055-1182mm and yearly sunshine time is 861-958h. Suitable forage varieties includes Hemarthria compressa,Lolium multiflorum, Sorghum vulgare, Medicago sativa and so on.(3)The best mixed mode of planting high-yield and high-quality artificial grassland under the ecological environment conditions similar to the Three Gorges reservoir area in Wushan huazhuping: I: 40%Dactylis glomerata + 40%Festuca arundinacea + 10%Trifolium repense + 5%Medicago sativa + 5%Lotus corniculatus, Amount of seeding is 30kg/hm²; II: 80% Dactylis glomerata + l0%Lotus corniculatus + 5%Trifolium repense + 5%Medicago sativa, Amount of seeding is 30kg/hm²; The yields of two methods of mixture sowing artificial grassland is up to 81375kg/hm² and 92625kg/hm² , legume : Grass ratio is 0.32 and 0.35 respectively, and their Constitutions are stable relatively. The two mixed sowing models is suitable for high-altitude area;The suitable forage combinations of planting high-yielding and high quality artificial grassland under the ecological environment conditions similar to the Three Gorges reservoir area in Shuangbai Yunyang: 30%Festuca arundinacea + 30%Dactylis glomerata + 20%Trifolium pratense +20% Medicago sativa, amount of seeding is 60kg/hm²,fresh grass yield up to 81655.5 kg/hm², legume : Grass ratio is 0.72, and its constitution is stable. The mixed sowing models is appropriate for middle elevations spots. (4) in the Three Gorges reservoir area, With the unique climate conditions and sloped farmland and high altitude of terraced fields, mainly forage species selected is Medicago sativa (Eureka ) Trifolium pratense (Wuxi), Dactylis glomerata (Baridand) Festuca arundinacea (cv.Dovey) . The optimum mixed sowing model is Medicago sativa (seeding rate 6.0kg/hm²) + Dactylis glomerata (seeding rate 9.0kg/hm²) + Trifolium pratense (seeding rate 6.0kg/hm²) + Festuca arundinacea (seeding rate 9.0kg/hm²), and more economical ways to apply fertilizer is compound fertilizer(N: P₂O₅: K²O=15%: 5%: 5%)225kg/hm²+Sheep Dung 15000kg/hm² By this way , we can get highest fresh yield,ie.43060kg/hm². The results provided an important theoretical basis for soil fertility balance of sloped fields and sustainable utilization of grassland.(5)Balanced fertilization experiments showed that fertilization significantly improved the yield and quality of forage(fertilization treatment means N, P K Mg, Mo, B applied in one hectares grassland,ie kg/ hm²). The yield of fresh forage was highest and higher than that of control groups 185.0% when using N₆₀P₁₂₀K₁₃₅ in the heavy acid soil. The yield of fresh forage was highest and higher than that of control groups 185.0% and 115.0% respectively when using N₉₀P₁₂₀K₉₀ in acid and neutral soil. Fertilization can also greatly increase the protein content of Wuxi red clover. The protein content is highest and higher than that of control groups 113.1%( heavy acid soil )and 46.0%( neutral soil) respectively when using N₆₀P₆₀K₉₀ during the early flower period. However, in acid soil the protein content is highest and higher than that of control groups 43.6%.As to plant Medicago sativa ,its yield is highest and nutrient is best when using N₉₀P₁₂₀K₁₅₀+MgMoB. As to plant Hemarthria compressa, its yield is highest(113950.1kg/hm²) when using N₃₇₅P₁₂₀K₁₅₀,and its protein content is highest ,ie. 12.83% and 11.32% respectively when using N₂₀P₈K₀ in the jointing stage and earing stage. Moreover, the yield of Hemarthria compressa increased with the increase of P applied. 1kgP₂O₂ can increase 88.3kg Hemarthria compressa when using N₉₀P₁₂₀K₁₅₀.But the best P applied should be further studied.