What ecological conditions does the growth and development of walnut require?

  Soil is the main supply site of water and minerals for plants. Through its extensive root system, the walnut absorbs water and organic and inorganic nutrients from the soil. The quality of soil conditions directly affects the growth and fruiting of walnut.

  1. Soil thickness: Walnut is a deep-rooted tree species and requires relatively thick soil, no less than 1 m. If walnut is grown in soil that is too thin, its main roots and lateral roots will find it difficult to penetrate and develop, thus affecting root development, easily forming stunted old trees, and also easily causing "tip dieback" and the inability to bear fruit normally.

Picture: walnut

  2. Soil pH: Walnut can grow in slightly acidic to slightly alkaline soil, but neutral to slightly alkaline soil, that is, pH 6.5~7.5, is suitable. The soil salt content should preferably be below 0.25%; slightly exceeding this limit will affect growth and fruiting. If the salt content is too high, it will cause death, and chlorate is especially more harmful than sulfate.

  3. Soil structure and soil fertility Walnut requires loose structure, strong water retention and good aeration. The relatively suitable soils for walnut are sandy loam and medium loam. If the soil is too clayey, compacted, or the sandy land is too barren, it is unfavorable for growth and fruiting. Walnut likes calcium, so it is suitable to cultivate it in calcium-rich soil or to increase calcium fertilizer when fertilizing.

  Walnut likes fertilizer. According to analysis, for every 100 kg of walnut harvested, 2.7 kg of pure nitrogen is absorbed from the soil. In high-yielding orchards, 90.7 g of nitrogen is absorbed per 100 sq m each year. Nitrogen fertilizer can increase the kernel percentage, and phosphorus and potassium not only increase yield but also improve kernel quality. However, the appropriate fertilizer amount should be determined according to the specific growth and fruiting conditions of the soil and the tree. Slight excess nitrogen fertilizer will prolong the growth period, delay fruit maturity, and be unfavorable for safe overwintering. Increasing soil organic matter is beneficial to the growth and development of walnut.

  4. Terrain: Walnut is not very strict about terrain, but site conditions such as gentle slope, deep soil, and leeward and sunny aspects are more suitable, while shady slopes, steep slopes and windward sides are all unfavorable to the growth and development of walnut. Walnut is suitable for planting in gentle slope areas below 10°.