核桃林下长柔毛野豌豆腐解动态及养分释放

Decomposition Dynamics and Nutrient Release of Vicia villosa in Walnut Forest

为探究不同生育阶段核桃林下长柔毛野豌豆腐解动态及养分释放特征,本文采用尼龙袋法,研究了3个生育阶段核桃林下长柔毛野豌豆裸露和覆盖处理的腐解差异,分析了其腐解率、养分释放动态和积累规律,并利用对数函数对累积腐解率(y)与腐解时间(t)进行拟合。结果表明:(1)不同处理的长柔毛野豌豆腐解均呈现先快后慢的规律,且同一生育阶段的核桃林下,覆盖处理的累积腐解率均大于裸露处理;(2)不同处理的养分累积释放率均呈现出K元素>P元素>有机碳>N元素的特点,且在相同生育阶段,覆盖处理的P元素、N元素及有机碳累积释放率均高于裸露处理,而覆盖处理的K元素累积释放率小于裸露处理;(3)林龄影响了核桃林郁闭度,进而影响了营养元素的积累。幼龄林有利于有机碳的积累,初果林有利于P元素积累,K元素的积累与林龄无关,而N元素的积累效率首先受覆盖处理影响,其次随着林龄增加或者郁闭度的增加而增大;(4)对数模型y=a+bln(t)很好地拟合了长柔毛野豌豆的累积腐解率(y)与腐解时间(t)的关系。在同一生育阶段,覆盖处理的长柔毛野豌豆在相同时间内的累积腐解率均大于裸露处理,且随着郁闭度的增大而提高。综上,尽管不同生育阶段核桃林下长柔毛野豌豆腐解动态呈现差异,但覆盖处理仍是促进长柔毛野豌豆腐解的重要措施。

In order to explore the decomposition dynamics and nutrient release characteristics of Vicia villosa in the walnut forest under different growth stages,the nylon-bag method was used to study the differences between bare decomposition and covered decomposition of Vicia villosa. The decompositionrate,low of nutrient release dynamics,and accumulation laws were analyzed. Moreover,the cumulative decay rate(y)and decay time(t)were fitted by the logarithmic function. The results showed that:(1)The decomposition of Vicia villosa under different treatments showed the law of first fast and then slow. The cumulative decomposition rate of covered treatment was higher than that of bare treatment at the same growth stage,indicating that the covered treatment was conducive to the decomposition of Vicia villosa.(2)The cumulative release rates of nutrients in different treatments showed the characteristics of K > P > organic carbon > N. At the same growth stage of the walnut forest,the cumulative release rates of P,N,and organic carbon in covered treatments were higher than those in bare treatments,while the cumulative release rates of K in covered treatments were lower than those in bare treatments.(3)The forest age affected the canopy density of the walnut forest,and then affected the accumulation of nutrient elements. The young forests were conducive to the accumulation of organic carbon. And the early-bearing forests were conducive to the accumulation of P. The accumulation of K had nothing to do with the forest age,while the accumulation of N was firstly affected by the covered treatment,and then increased with the forest age or canopy density increasing.(4)The logarithmic model y = a + bln(t)well fitted the relationship between the cumulative decomposition rate(y)and the decomposition time(t)of Vicia villosa. At the same growth stage,the cumulative decomposition rate of covered Vicia villosa was greater than that of the bare treatment,which was increased with the canopy density increasing. In conclusion,although there were differences in the decomposition dynamics of Vicia villosa in the walnut forest at different growth stages,the covered treatment was an important measure to promote the decomposition of Vicia villosa.