The main producing area of walnut is the north, which is suitable for temperate continental monsoon climate: most areas have distinct seasons. Winter is cold and snowy, spring is dry, windy and dusty, summer is hot and rainy, autumn is sunny and the temperature is moderate.

1, requirements of walnut on environmental conditions

Walnut with the temperature of (1) is a warm-loving tree species, and the suitable temperature range and frost-free period are: annual average temperature of 9 degrees-16 degrees, extreme minimum temperature of minus 25 degrees-minus 2 degrees, extreme maximum temperature of below 38 degrees, and frost-free period of below 150 days.

(2) Walnuts like light. After entering the fruiting period, it is more necessary to have sufficient lighting conditions. The annual sunshine hours should be more than 2000 hours to ensure the normal growth and development of walnuts. If it is less than 65,438+0,000 hours, the core-shell and nucleolus will be stunted. In cultivation, light must be considered from the aspects of garden selection, planting density, cultivation method, shaping and pruning.

(3) Soil is the foundation for the growth and development of all plants. The huge root system and tree body of walnut need deep soil layer (more than one meter) to ensure its good growth and development.

(4) Moisture Walnut is resistant to dry air, but sensitive to soil moisture. Too dry or too wet soil is not conducive to the growth and fruiting of walnuts. Therefore, soil and water conservation engineering measures should be taken in mountain walnut orchard; On the flat land, the drainage problem should be solved. The groundwater level of walnut orchard should be 2 meters below the surface.

(5) Other walnuts like loose soil and good drainage, and can't grow well in the soil with high groundwater level and heavy viscosity. But it grows best in weak alkaline soil containing calcium. The adaptive range of soil PH value is 6-8, and the soil salt content should be below 0.25%, which has little influence on the growth results. Too much salt will lead to death. Walnuts like fat.

2. Before the construction of walnut orchard, it is of great significance to carefully select the orchard. When choosing and evaluating the location of the garden, climate conditions, soil thickness and groundwater level are generally the key points.

(1) The hilly area should be a type with little difference in soil and climate conditions, which is connected with the flat land. Especially in the gentle slope land with low altitude, the place with light soil erosion, small change of soil type, thick soil layer, good moisture condition, convenient transportation and easy management is taken as the place for walnut orchard construction; In the foothills, the place with gentle slope, convenient transportation, abundant sunshine, smooth air, deep soil layer and high soil fertility should be considered as the place for walnut orchard construction. When planting walnuts in low mountain areas and Zhongshan areas, we should choose sunny slopes, the soil thickness is greater than 1 m, and the garden should be built in gentle slopes with high fertility.

(2) Garden site selection on the flat land.

Different types of flat land have different effects on the growth and development of walnut because of different causes, topography and soil. The establishment of walnut orchard on flat land should be rationally utilized and planned according to the characteristics of different flat land types and the requirements of agricultural zoning. Alluvial plain should pay attention to choose places with high terrain and good drainage to build gardens; Before establishing walnut orchards in desert areas and old rivers, we should first build windbreak and sand-fixing forests, break through the impermeable layer, improve the soil, and solve the problem of irrigation and drainage before opening the orchards for planting. Low-lying saline-alkali land, the salt content should be less than 0.25%, it is suitable to build terraces with a height of about 1.5 meters, and build gardens after sand pressing, but it is not suitable to build gardens on heavy saline-alkali land; Because of the high wind speed in Haiti, walnuts are vulnerable to wind damage, so windbreaks should be built before establishing walnut orchards to create good conditions for young trees to grow faster.

Species distribution is mainly distributed in some mountainous areas of Hebei, Tianjin, Shanxi and Beijing. Walnut has many advantages, such as changing texture, good leather and beautiful shape. Because it has reached a high standard in size, color, shape and texture, and because the yield of wild walnut is scarce, it has always been favored by people. Walnut is the best among ornamental walnuts. In ancient times, it was the favorite thing in the hands of dignitaries and literati. There are many kinds of walnuts. The four most representative and long-standing famous nuclei "lion head, tiger head, chicken heart and pigeon hat" listed in the ancient "Walnut" refer to walnuts, which are basically named according to their shapes. Other fine varieties include official hat, general helmet, monk hat, champion crown and arhat head, all of which belong to the relatively high-grade series of hemp walnuts.