| Alfalfa(Medicago sativa L) is a perennial legume forage with high quality and plays an important role in the development of agriculture and animal husbandry, improvement of ecological environment and adjustment of economic structure in Northwest China. It is important to study the improvement and utilization of high efficient planting technique of alfalfa in dryland of Loess Plateau, in order to increase farmers’ income and promote animal husbandry industry.In this study, an economic survey was conducted in Lijiabao in Dingxi and Sapu town in Qingyang. we compared the drought resistance of five varieties of Medicago sativa L., which are Jin Huanghou, Longdong, Gannong No.3, MS-LM01, Zhongmu No.1 in different drought conditions through the indoor potted experiment. We studied the effects of plastic film mulching and furrow planting technology on the yield and quality of Medicago in dryland of Loess Plateau in Dingxi, Gansu Province. We used five treatments: no mulching(NM), full film(FF), half full film(HF), mulching ridge(MR), soil ridge(SR). Forage yield and quality, soil fertility, economic benefits were evaluated under different treatment of nitrogen, phosphorus and potassium. The results were as followings:1. Base economic survey was conducted in Lijiabao town, Dingxi city, and Sapu town, Qingyang City in Gansu Province to. The main crops in Lijiabao town, Anding District are corn, potatoes, winter wheat, alfalfa planting area accounts for 2.9% of the total area; the main crops in Sapu town, Qingcheng County are fruit trees, winter wheat, corn, respectively, and the highest economic crops are fruit tree, and alfalfa with planting area covering 4.5% of all crop planting area. Grassland occupies 18.2% and 9.8% of the cultivated land in Li Jijabao town and Sapu town, respectively. The agricultural economic benefit and household income in Sapu town were relatively higher than those in Lijiabao town.2. Five alfalfa varieties were evaluated under three soil moisture treatments, soil moisture content 70%(control group, CK), 55%(mild stress, LS), 30%(severe stress, SS), through the determination of plant height, biomass, root thickness, leaf water content, leaf Proline content, leaf photosynthetic rate and leaf chlorophyll content. The drought resistance ability was ranked as follow: Longdong > MS-LM01> Gannong No.3 > Jin Huanghou > Zhongmu No. 1.3. Five treatments were set up: no mulching(NM), full film(FF), half full film(HF), mulching ridge(MR), soil ridge(SR) to determine alfalfa yield and quality, soil moisture content and the soil temperature. Hay yield reached a maximum of 4999 kg / hm2 with the MR treatment; and crude protein and crude fat content were significantly(p<0.05) increased compared with NM treatment; MR treatment increased the soil moisture content of 0-80 cm in the green period, after first cutting, after second cutting; while MR treatment significantly reduces soil temperature in 5cm, 10 cm, 15 cm.4. Forage yield and quality, soil fertility were evaluated under different treatment of nitrogen, phosphorus and potassium. We adopted ridges covered with common plastic film(MR) cultivation techniques, and a imporved "3414" fertilization application design. The result showed that the highest hay yield was 6366kg/hm2 for P2K2N3 treatment. The highest crude protein and crude fat content were respectively found in P2K1N2 and P2K2N2 treatment. In addition, P2K2N2 treatment significantly increased soil available nitrogen, available potassium, available phosphorus and organic matter content(p<0.05), and was the most effective treatment for improving the soil fertility. |
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