| Artificial grass is an eco-friendly approach for orchard production,offering multiple benefits such as improving the orchard soil environment,enriching soil nutrients and improving fruit quality.However,in the Nyingchi region of Tibet,there has been a loack of attention and scientific research on artificial grassing during orchard construction.Most farmers and herdsmen still rely on clear-cut tillage,which leads to the loss of soil nutrients and causes problems of declining soil quality in the long term.This study was conducted in the apple orchard of Zanghanqing Agricultural Co.,Ltd.in Jiemai Village,Bujiu Township,Bayi District,Nyingchi City,Xizang Province.Six interplanting grass patterns,including Medicago sativa,Vicia sativa,Avena sativa,Dactylis glomerata,Medicago sativa+Dactylis glomerata and Vicia sativa+Avena sativa,were planted between Black Diamond apple trees,with clear-cut（CK）as control.We investigated the relationship between soil respiration and soil environment,and analyzed the effect of artificial grass on fruit quality to provide a basis for improving soil management measures and promoting grass-growing technology in orchards in Tibet.The research findings indicat that suitable grass planting patterns in apple orchards can improve soil nutrients and fruit quality,and to provide a theoretical basis for improving soil management in orchards in Tibet.The main research results are as follows.（1）During the monitoring period,the soil respiration rate showed its peak in August and the lowest value in December.The interplanted alfalfa plot had the highest soil respiration rate at 4:00 pm,which also coincided with the highest soil temperature period of the day.The planting of grass in orchards retards the rise in soil temperature.The process of soil temperature rise was significantly slowed down in alfalfa unicast and Vicia sativa+oat mixed sowing methods,resulting in a delay of 2h in the maximum soil temperature.The index model showed that a significant positive correlation between soil respiration and 0～5cm soil temperature,indicating that soil respiration was largely influenced by temperature.The quadratic function showed a negative correlation berween soil respiration and 0～5 cm soil water content.The temperature sensitivity coefficient of soil respiration(Q10)ranked from highest to lowest as follows:Medicago sativa>Dactylis glomerata>Avena sativa>Vicia sativa+Avena sativa>Vicia sativa>CK>medicago sativa+Dactylis glomerata.Soil temperature and soil moisture content jointly explained the soil respiration rate by 53.6%～74.5%;This findings suggest that soil temperature and soil water content are the primary factors affecting soil respiration.（2）The soil respiration rate was found to be influenced by different grass patterns.The interplanting Medicago sativa,Vicia sativa+Avena sativa,Vicia sativa,Avena sativa significantly increased increased soil respiration rate as compared to clear-out cultivation.Moreover,unicast lucerne showed a significantly higher soil respiration rate than that of other grass varieties,while mixed sowing showed a significantly increased in Vicia sativa+Avena sativa plots.However,the interplanting of Dactylis glomerata or Medicago sativa+Dactylis glomerata did not have a significant effect on soil respiration rate.（3）Planting grass in orchards is beneficial for improving soil nutrients.Avena sativa mono sowing and mixed sowing of Medicago sativa+Dactylis glomerata have been shown to increase soil organic carbon content.Furthermore,Avena sativa,Medicago sativa,Vicia sativa+Avena sativa incresed soil nitrogen content by 17.02%,10.34%and 4.88%respectively.The available potassium content of soil was also significantly increased with the increase rate of 16.71%.Available phosphorus content increased in all grass treatments except for mixed sowing of Medicago sativa+Dactylis glomerata.Correlation analysis between soil respiration and soil chemical properties showed that soil total nitrogen and soil available phosphorus had a significant effect on grass growth pattern.The correlation analysis between soil respiration and soil chemical properties shows that soil total nitrogen and soil alkali-hydrolyzable nitrogen have certain effects on grass planting mode,and the effect of soil total nitrogen on soil nutrients after grass planting is more obvious than that of soil alkali-hydrolyzable nitrogen.（4）Growing grass in apple orchards can improve the quality of fruit,including increasing vitamin C content of apple（except interplanting Avena sativa）,reducing titrable acid content.Interplanting Medicago sativa can increase the fruit weight,fruit shape index and pulp density of apples,while Vicia sativa+Avena sativa can improve the fruit shape index,pulp density and soluble solids content.To summarize,choosing appropriate grass interplanting pattern in apple orchard can enhance soil nutrient and improving fruit quality.Based on our findings,we recommened promoting the Vicia sativa,Vicia sativa+Avena sativa pattern in Nyingchi,Xizang. |
