Impact Of Nitrogen Deposition On Soil And Plant Nutrients Of Schima Superba And Pinus Massiniana Forest

With the development of economy, the quantity of nitrogen compounds of atmosphere was increasing sharply because of human activities, causing the increasing of the amount of nitrogen deposition in proportion in the near decades. Researches for the nitrogen deposition have been processed in the abroad. The impact on the plant will be more serious if the nitrogen deposition leach the leaves nutrients and lead to drip earlier. Some basic data will be supplied to the study of forest ecosystem for investigating the impact of simulates nitrogen deposition in the background of global nitrogen deposition. As the primary casualty forest ecosystem is also one of the main powers to maintain the earth environment ecology balance. The forest ecosystem has been paid to more attention by the researches about the impact of the nitrogen deposition. China has become the third biggest area of nitrogen deposition just following the Europe and America. And the trend will be more serious in the future. The lacuna will be made up by the study of nitrogen deposition. As an important local kind tree species in southern China, Schima superba distributed in nature and was planted broadly. With the highest overlay rate of forest, Fujian province is also one of the victims of acid rain. A base can be made for our country even for the subtropical area and the theoretical instruction can be provided by the study of impact of nitrogen deposition to the Schima superba and pinus massiniana forest.The field experiment was set to study effects of Nitrogen deposition on soil and plant nutrients of Schima superba and pinus massiniana mixed forest. The experiment was done in the way of field test and experiment in lab which was designed as N0(0kg.hm- 2.a -1), N1(50 kg.hm- 2.a - 1),N2(100 kg.hm- 2.a -1),N3 (150 kg.hm- 2.a- 1)with three replicates in each disposal. CO(NH2)2 was used as the source of nitrogen and its solutions was sprayed the forest field each month.The result obtained showed as follows:1 Effect on the soil nutrient of nitrogen deposition1) The result showed that the change of 0-20cm earth level was most obvious, and the 20-40cm and 40-60cm earth levels were not so obvious relatively. The content of soil nutrient was reduced with the growing on of each level, but the change trend was not obvious for different time. And the content of soil nutrient was restrained by the nitrogen deposition at first and turned to increased at last The conclusion was showed that the change extend of soil nutrient in different earth level was large than that in the same earth level.2) The content of earth valid phosphorus was reduced at first and increased at last. The change extend of earth valid phosphorus in different earth level was large than that in the same earth level. The multiple comparison result showed that the stimulative effect of N3 treatment was most obvious. The order of influence was: N3>N0>N2>N1.3) The available K was restrained all the time, the N3 treatment was most obvious, and has correlation with soil organic matter. 2)The multiple comparison result showed that the stimulative effect of N3 treatment was most obvious. The order of influence was: N3>N0>N2>N1.4) The impact for content of soil organic matter is related with forest age, the effect of N thickness is minus-relation with soil organic matter, the extent of impact is different with ages, the order was 30 years old plantation, 40 years old plantation, 50 years old plantation The content of organic matter for all the soil levels were degressive, the content of organic matter for soil was negatively with the Nitrogen deposition.5) The N of soil was advanced by nitrogen deposition, also was enhanced the content by it. But the leaching of soil N was added with nitrogen deposition. The content of soil Nitrogen was increased with the increase of Nitrogen deposition. The order of influence to content of the soil Nitrogen by the Nitrogen deposition was: N3>N2>N1>N0.6) The soil exchangeable Ca and Mg were reduced with the N increased. The content of Mg was so obvious that the changing trend was so large. They have evident relation with the other ions. The order of influence to the soil changeable Ca and Mg was: N3>N2>N1>N0.2 The effect on plant nutrient of nitrogen deposition1) The content of leaves phosphorus was increasing all the time, which was different from the changing trend of soil valid phosphorus. And they have no relation almost. The relation between leaves phosphorus and forest ages was consanguineous. The difference between 50 years old forest and 30 years old forest was significant. But the difference between 50 years old forest and 40 years old forest was not significant.2) The minus-effect was on the content of leaves K. which was something similar with the soil available K. The content was increased evening but not evident. The relation between leaves phosphorus and forest ages was consanguineous. The difference between 50 years old forest and 30 years old forest was significant. But the difference between 50 years old forest and 40 years old forest was not significant.3) The rule of leaves C was similar with the soil organic matter: the effect on 30 years old plantation was the largest one. The stimulative influence to the 30 years old forest leaves Carbon from Nitrogen deposition was obvious. The content of 40 years old forest leaves Carbon was increasing. The content of 50 years old forest leaves Carbon was also increasing but the range was not large.4) The leaves N were advanced by the nitrogen deposition. The stimulative effects to different age's forest from N1, N2 and N3treatment were different. The order of influence was: N3>N2>N1>N0. The change of 50 years old forest was most obvious, and the change of 30 years old forest and 40 years old forest was not significant.5) The leaves Ca content was advanced at first and reduced at last. The restraining effects to the 30 years old forest from N1, N2 treatment were obvious, N3 treatment showed stimulative effect at last; N1 treatment showed restraining effects to the 40 years old forest and N2, N3 treatment showed stimulative effect; the leaves Ca content of 50 years old forest was degressive at the N3 treatment and the leaves Ca content of 50 years old forest was increased for the N1,N2 treatments.6) The leaves Mg content changing was rapidly, the trend was apparently decline. The leaves Mg content of 30 years old forest was degressive, the degressive extent at N2 treatment was largest and the N3 treatment was least. The restraining effects to the 40 years old forest leaves Mg content was obvious. The restraining effects also showed to the 50 years old forest. The peak value was appeared when the experiment was processed at six and nine months.3 The relation of soil nutrients and forest nutrientsThe interior relation of soil nutrients was more obvious than that of forest nutrients, the interior relation of forest nutrients have little relation between themselves. The impact to the forest nutrients from soil Nitrogen and organic matter was the largest. The impact from soil exchangeable Ca and Mg were least. The response of soil nutrients was larger than forest nutrients.The result of Canonical Correlation Analysis showed that the content of plant nutrients and soil Nitrogen, valid phosphorus, changeable Ca, Mg was consanguineous. And the influence of changeable Ca was largest. The relation of earth nutrients and plant Carbon, Nitrogen, phosphorus, K, Ca, Mg was consanguineous. And the Correlation between soil nutrients and plant Carbon was largest. The influence of soil organic matter was most significant and the relation of other elements was most consanguineous. The influence of soil changeable Ca, Mg was least.