1. Different planting densities and different planting forms will lead to different tree, aboveground and underground management measures, thus forming different cultivation management systems.

2. The optimal cultivation management system should be that the leaf area coefficient increases rapidly in the young tree period, and it can maintain a high effective area of photosynthesis after entering the high-yield period, and it should be easy to manage. Sparse pear orchards bear fruit late and take effect slowly. Variable density design is to plant permanent plants and temporary plants at the same time, and it is better to plant 333 plants or11plant at 666.6m m.

3. The distance between the permanent rows and the plants is 2m, and the row spacing is 5m: two temporary rows are planted in the middle of the permanent row 1m, and 333 plants can be planted at the row spacing of1m. After three years of planting, the fruit can easily exceed 1500 kg in four years. 111/small row spacing of 2 m, large row spacing of 4m, plant spacing of 2m and 666.6m can be used for planting plants.

Environmental requirements:

① temperature. Pear trees like temperature, which requires higher temperature for growth and lower temperature for dormancy. The suitable annual average temperature of pear trees is 4- 12℃ for Qiuzi pear, 7- 15℃ for Pak Lei and Xiyang pear, and 13-2 1℃ for Shali pear. When the soil temperature reaches above 0.5℃, the roots begin to move, and new roots grow at 6-7℃; When the temperature is above 30℃ or below 0℃, the growth will stop. When the temperature is above 5℃, pear buds begin to germinate, when the temperature is above 14℃, they can blossom, and when the temperature is above 14℃, the flowering is accelerated. Pears have different cold tolerance. Qiuzi pear, which originated in northeast China, is extremely cold-resistant, and its wild species can tolerate -52℃ and its cultivated species can tolerate -30-35℃. Pak Lei class can withstand-23-25℃; Sand pear and sand pear can tolerate about -20℃. The critical freezing temperatures of pear organs in Laiyang, Shandong Province are -5℃ in bud stage, -3.5℃ in inflorescence separation stage,-1.5-2℃ in flowering stage and-1.5℃ in flowering stage.

② illumination. Pear is a fruit tree that likes light. The annual sunshine demand is between 1600- 1700 hours. The light compensation point of pear leaves is about 1 100 lux (lx), and the light saturation point is about 54,000 lux (LX).

3 moisture. Pear trees need more water to grow. The transpiration coefficient is 284-40 1, and the transpiration water per square meter of leaf area is about 40g. If it is lower than 10g, it will cause harm. Qiuzi pear, Pak Lei pear and Xiyang pear have poor moisture tolerance, while Shali pear has strong moisture tolerance. In sandy loam, when the soil water content is 15-20%, it is suitable for root growth, and when it is reduced to 12%, the root growth is inhibited.

④ Soil. Pear trees have strong adaptability to soil, and sandy loam with deep soil layer, loose soil, good air permeability and water retention and low groundwater level is the most suitable. Pear trees have wide adaptability to soil acidity and alkalinity, and can grow normally in the range of pH 5-8.5, and pH5.8-7 is the most suitable. Pear trees also have strong salt and alkali tolerance. When the soil salt content is below 0.2%, it grows normally. When it reaches more than 0.3%, the root system grows poorly and its growth is obviously poor. Generally speaking, Du pear requires partial alkali, while Sha pear and Dou pear require partial acid.