| Nitrogen (N)、phosphorus (P) and potassium (K) are the three need nutrients of rubber trees, make an important impact on rubber trees’growth and mucus production. The study of N、P、K content and reserves of rubber plantations among different countries and among different age-level plantations in Hainan Island helps to understand the relationships among N、P、K storeroom, nutrient cycle, nutrition movement rules and soil evolvement in different space time for people. And know the zoology restrict gene during rubber trees growth. Guide scientific growth, fertility management and reasonable program. This article aimed to investigate and sampling rubber plantation ecosystems in the main rubber grow areas (twelve countries and cities) in Hainan Island. Rubber plantation ecosystems’reserves are consisted of the reserves of the arborous layers, the understory vegetation layers, litter layers and soil layers. The rubber plantations were divided into six age levels which are respectively5a,10a,15a,20a,25a and30a, and the soil was divided into0～20cm,20～40cm,40～60cm,60～80cm,80～100cm. Analyze N、P、K content indoor. The analysis index of foliage samples are the total N and total P, soils are the total N, total P, available P, total K, slow release K, available K. The results list as follows:(1) N reserves of rubber plantations’ecosystem are7.46t·hm-2, thereinto, the soil layers are6.97t·hm-2, the arborous layers are0.43t·hm-2, the understory vegetation layers are0.045t·hm-2, the litter layers are0.017t·hm-2. They account for93.46%、5.72%、0.60%、0.22%respectively in the ecosystem. The N reserves of rubber plantations’ecosystem of Qionghai is the most (10.50t·hm-2), while the least is Lingao which are5.33t·hm-2. In different age-levels’systems,25a plantation is the most, the range of different age-levels’systems is7.03～8.19t·hm-2, the rank is25a>15a>5a>30a>10a>20a.(2) The total N content of different arborous organizes are21.17g·kg-1、4.72g kg-1、4.53g·kg-1、2.79g·kg-1respectively, shows leaf>root>branch>stem. The average N content of above-ground is21.15g·kg-1, and the average N content of below-ground is12.51g·kg-1.The range of litters’N content in different age-level plantations is13.33～15.09g·kg-1. The total N content of different soil layers decrease with the increase of depth, its range is0.38～0.80g·kg-1. The topsoil (0～20cm) shows significant earth’s surface enrichment.0～20cm differs great markedness from20～40cm, and respectively great markedness from each other layer. The total N content rank of different areas’soil is East>North>South>West=Middle regions, the range is0.46～0.68g·kg-1.(3) P reserves of rubber plantations’ecosystem are3.09t·hm"2, thereinto, the soil layers are2.99t·hm"2, the arborous layers are0.10t·hm-2, the understory vegetation layers are0.002t·hm-2, the litter layers are0.0006t·hm-2. They account for96.55%、3.26%、0.07%、0.02%respectively in the ecosystem. The P reserves of rubber plantations’ecosystem of Dongfang is the most(5.79t·hm"2), while the least is Dingan which are0.92t·hm-2. In different age-levels’systems,5a plantation is the most, the range of different age-levels’systems is2.56-4.08t·hm-2, the rank is5a>15a>20a>30a>25a>l0a.(4) The total P content of different arborous organizes are2.86g·kg-1、1.40g· kg-1、1.32g·kg-1、0.61g·kg-1respectively, shows leaf>root>branch>stem. The P content range of understory vegetation is0.70～0.89g·kg-1, and litters’is0.50-0.66g·kg-1. The range of total P content of different soil layers is0.20～0.28g· kg-1, each of them are closed. They don’t have obvious distribution rule in the section plane. The total P content of different soil layers has no significant diversity. The rank of soil’s total P content of different areas is South> North> West> East> Middle regions, the range is0.17～0.31g·kg-1.The available P content of different soil layers decrease with the increase of depth, its range is1.04～1.47mg·kg-1. The available P content of0-20cm soil layer is higher than else, the available P content of different soil layers also has no significant diversity. The rank of available P content of different areas is East> Middle regions> North> South> West, the range is1.05～1.81mg·kg-1.(5) The soil’s K reserves of rubber plantations’ecosystem are241.14t·hm-2, thereinto, the slow release K are3.87t·hm-2, the available K are1.05t·hm-2. They account for1.61%、0.43%respectively in the soils’ecosystem. The soil’s K reserves of rubber plantations’ecosystem of Tunchang is the most (406.07t·hm-2), while the least is Lingao which are115.79t. hm-2. The rank of soil’s K reserves of different areas is Middle regions>East>South>West>North.(6) The total K content of different soil layers has no obvious distribution law with the increase of depth, its range is16.17～20.42g·kg-1, and its rank is60～80cm>0-20cm>20-40cm>40～60cm>80-100cm. The total K content of different soil layers has no significant diversity. The rank of soil total K content of different areas is Middle regions> East> South> West> North, the range is14.47～23.71g·kg-1. (7) The slow release K content of different soil layers increase with the increase of depth approximately, the range is280.41～382.44mg·kg-1, and the rank is60～80cm>80-100cm>40～60cm>20-40cm>0～20cm. The slow release K content of different soil layers has no significant diversity. The rank of soil slow release K content of different areas is South> East> North> Middle regions> West, the range is255.82-330.76mg·kg-1.(8) The available K content of different soil layers has no obvious distribution law with the increase of depth, the range is75.67～86.00mg·kg-1, and the rank is20-40cm>40-60cm>60-80cm>0-20cm>80-100cm. The rank of soil available K content of different areas is Middle regions>East>South>North> West, the range is69.07～88.77mg·kg-1. |
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