Leaf Part Characteristics And Nut Quality Response Of Early-fruiting Walnut (Juelans Resia L.) To Varying Nitrogen Fertilizers

Walnut (Juglans regia L.) is one of the most important fruit specieswith high economic, ecological and social benefits among China and world.Early-fruiting walnut cultivar is very popular with farmers because of its’ earlyfruiting, high yield, high economic benefits. In recent years, with the increasingdemands of walnut, the early-fruiting walnut’s planting aera and yield increasedquickly, but it requires critical nutrient demands. Premature senility and diseaseaffliction always appear seriously without appropriate management, which could leadwalnut tree to a short life and low yield. Nitrogen is one of the important nutrientelements, which could improve fruit tree’s growth, yield and fruit’s quality. Differentkinds nitrogen fertilizers always have different influences on plant physiologicalmetabolism, morphogenesis and phasic development. This study was focused on leafpart physiological characteristics and nuts qulity in ‘Zhonglin1’ early-fruiting walnutresponse to different nitrogen fertilizers, proposed to find out a rational fertilizationstrategy and the theoretical basis for improving early-fruiting walnut tree nutritionlevel, nut yield and quality.The main results are as follows:1. Compared with the ammonium and nitrate forms fertilizers, urea was moreconducive to precocious walnut trees on their nitrogen compounds’ accumulation andleaf morphological development, and more advantageous to improve precociouswalnut trees nutrition level in their growth period.2. Ammonium nitrogen fertilizer had the optimal effect on walnut photosynthesis,followed by urea and nitrate nitrogen fertilizer. The precocious walnut photosyntheticrate enhanced significantly with the increase of the amount of nitrogen fertilizerapplied.3. The leaf nitrate reductase activity was highest in the treatments of nitratenitrogen fertilizer, secondly in the ammonium fertilizer treatments.4. Ammonium nitrogen fertilizer had good influence on leaf P content in leaf-expansion stage, while urea in fruit-expansion stage and hard stone stage. To leafK content, urea worked better in leaf-expansion stage but worse in fruit-expansionstage than ammonium and nitrate fertilizer, in hard stone stage nitrate fertilizertreatment had a best effect on leaf K content.5. Nitrate nitrogen fertilizer and urea markedly increased early-fruiting walnut’sproduction; ammonium nitrogen fertilizer and urea improved early-fruiting walnut’skernel rate; the walnut kernel fat ratio was increased with the increasing nitrogenfertilizer application in a certain range,700g N per plant a year was optimal.6. Walnut leaf nitrate content, chlorophyll concent, photosynthetic rate wasnotably increased by trunk smeared with amino acids chelating liquid fertilizer, whichdramatically improved walnut leaf nutrition content and morphological development.Trunk smearing amino acids liquid fertilizer increased the fresh and dry weight ofsingal walnut fruit, improved nut’s kernel ratio and fat content.7.1512g urea per tree with smearing amino acids chelating liquid fertilizer onearly-fruiting walnut’s trunk5times a year in it’s growing period was optimal choicefor early-fruiting walnut field production.