| In alpine region, water and temperature were the main factors that effected alfalfa planting, and lacking of cold-resistance alfalfa varieties and appropriate cultivation techniques has seriously hindered the development of dryland alfalfa and grassland animal husbandry on the alpine area. In order to provide a theoretical basis for cultivation of high-yielding alfalfa, four planting method treatments included A: Film mulching parallel to the ground, B: film mulching on ridge and furrow, C: film mulching on ridge and furrow + soil cover, and D: ridge and furrow planting patterns were designed on Tianzhu alpine pastoral by testing alfalfa growth characteristics in the planting year and second years, nutrition(CP, NDF, ADF) content, crown and root characteristics in next year when alfalfa green up and in the second years’ autumn, soil temperature, soil moisture and weed control efficacy. The result showed that:1. Changes in soil temperature and moisture under four treatments indicated that the warming effect of treatment A is best, then treatment B, treatment C weakest; warming effect of treatment A, B, and C which were filmed obvious in sunny, cloudy and rainy were weakening. Soil temperature of film treatment increased in the early growth stage and growing stage, the effect on temperature mainly concentrated in the soil from 0 to15 cm. Daily changes of soil temperature under four treatment as follows: treatment A increased temperature faster and higher than others, 8:00 was a minimum time of soil temperature in a day, highest temperature was at 14:00 and 16:00. When in the colder months of cloudy and rainy day, soil temperature had a relationship with soil moisture, it would decreased temperature which under film, and temperature of soil not filmed were increased. Soil moisture of treatment B was the largest, it’s higher than A, C and D for 4.3%-14.5%, 4.2%-13.8% and 14.3%-24.8%. Treatment A had a great contribution on the temperature of alfalfa grown in Tianzhu alpine area, while treatment B on soil moisture.2. In the planting year, under treatment B, natural height of alfalfa can up to 41.2 cm, second branches to 25.1 per plant, fresh and dry matter of alfalfa production was up to 9754.8 kg/hm2 and 2493.9kg/hm2, and significantly higher than that of the treatments of A, C and D(P<0.05). Compared with treatment D, alfalfa fresh production under treatment B increased by 74%, hay production increased by 73.2%. Crude protein(CP)(28.60%) and relative feeding value(RFV)(176.71) of treatment D were highest, while content of neutral detergent fiber(NDF)(36.36%) and acid detergent fiber(ADF)(25.45%) were lowest; CP and RFV of treatment B were lowest, but NDF and ADF were highest. The alfalfa crown buds number of each IV plant in turning green time is 17.0 per plant and crown diameter is 9.87 mm, was 2.63 and 4.94 times of treatment D(buds number is and crown diameter is 2.00 mm). Crown depth of treatment A and B were 3.37 cm and 3.35 cm, significantly lower than that of treatment C(4.71 cm) and D(4.73 cm). Alfalfa plant root volume(9.288 cm3/plant) root surface area(466.287 cm2 per plant), root biomass(7.76 g/plant), root length(85.55 cm), root diameter(8.36 mm) and lateral roots number(26.27) of B were significantly higher than that of treatments A, C and D(P<0.05). Alfalfa crown buds, crown diameter, root volume, root surface area and root biomass between B and C were not significant(P>0.05); but significantly higher than that of treatment D(P<0.05). The top root depth, diameter and root biomass was not significant between B, C and D(P >0.05).3. In September of the second planting year, the height(76.8cm), breaches(11.8), stem base diameter(5.3mm), fresh(23243.2 kg/hm2) and dry yield(8547.0 kg/hm2) of B were higher than the other three treatments, the height of treatment A was 73.8cm, had no significant difference between B(P>0.05), but other indictors of B were significantly higher than other treatments(P<0.05). Then is the treatment A, C, and D is the last; compared with D, treatment B increased height, breaches, stem base diameter, fresh and dry yield for 34.3%, 68.6%, 47.1%, 32% and 49.4%. The crude protein content and RFV content under D is largest for 17.06% and 115.03, crude protein content of other three treatments were not significant different(14.46%-14.87%)(P>0.05); the crude protein content and RFV content under treatment B is lowest; NDF and ADF content of the four treatment is contrary to the crude protein. In the next autumn, crown buds of A is the most for 14.6, and had no significant difference between B(13.9)(P>0.05), both treatment A and B were significantly higher than treatment C(12.5), and treatment D is the lowest(8.1)(P<0.05). There were no significant difference among the three filmed treatment(A, B, C) for crown diameter(9.5mm-9.6mm)(P>0.05), but were significantly higher than D(8.5mm) which wasn’t filmed. Crown depth of treatment C is significantly deepest for 7.0cm(P<0.05), other three treatments were between 4.3cm to 4.6cm, and had no significant difference among them(P>0.05). 0-40 cm alfalfa root volume, root surface area and root biomass in the second year’s fall performanced as: B>A>C>D. Root biomass of treatment A and C in 0-40 cm were no significant difference(P>0.05), other indicators of other treatments were significantly different(P<0.05).4. Weed species, total density and coverage of treatment D(9.3 kinds, 1157.9 plant/cm3, 280.7%) and C(9.3 kinds, 655.0 plant/m3,181%) were significantly higher than A(5.7 kinds, 158.0 plant/m3, 40.3%) and B(6.7 kinds, 161.3 plant/m3, 41.0%)(P<0.05); weed total density and total coverage of treatment D significantly higher than others, weed biomass of C is highest for 1599.7g; under treatment A, weed kinds, number and biomass were lowest, but height was highest for 19.7cm. Compared with treatment D, the stem control effect and fresh weight control effect of A(86.3%&36.5%) and B(86.1%&11.3%) were significantly higher than C(43.4%&-40.8%) and D(P<0.05). |
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