| Appropriate management of soil nutrients and reasonable fertilization are the key technological problems related to Chinese agriculture's sustainable development. What features soil nutrients is not only the special viability, but also the temporal viability to some extent. As one of the importance rubber plantation areas of China, the soil nutrients status is not only related to the environments such as non-point source pollution, etc., but also to the yield and quality of rubber latex. Therefore, studying on the soil nutrients'time-space variation characters of Hainan rubber plantation is the precondition and basis for promoting the precision agriculture; it could also control the agricultural non-point source pollution and provide the theoretical basis for the rubber plantations'scientific and balanced fertilization. However, it has been almost a blank for a long time to study the rubber plantations by utilizing GIS and geostatistics. Therefore, the study applies the method coming GIS and geostatistics, adopts two study areas under different scales:Hainan rubber plantations in 1:250000 and Lanyang rubber plantations in 1:50000, analyzes the soil nutrients'time-space variation characters of rubber plantations, and discusses the management analysis models in different scales. The main study results obtained are summarized as follows:1. Soil Nutrients'Time-space Variation of Hainan Rubber PlantationsCompared with those of 1984, the contents of hydrolyzable nitrogen, total nitrogen, total pHospHor, available potassium, PH, and organic in Hainan rubber plantations decreased to different degrees in 2008, the descent range of available potassium was the largest; however, the contents of available pHospHor and total potassium increased compared with those of 1984.After years of different artificial cultivation management, the contents of hydrolyzable nitrogen, total nitrogen, total pHospHor, available potassium, and organic in Hainan rubber plantations'soil gradually presented the uniform trend, and the variation coefficients of these contents above presented the downtrend. The PH's variation coefficient also presented the downtrend, which meant Hainan rubber plantations'soil had the developing trend of uniformity and overall acidification. However, the available pHospHor's variation coefficient increased from 117.81% in 1984 to 200.2%, which belonged to obvious variation.In 2008 the total nitrogen's ratio was 83.12%, spatial correlation was rather weak, which meant artificial factors obviously influenced the total nitrogen's spatial variation; and the hydrolyzable nitrogen, available pHospHor, total pHospHor, available potassium, total potassium, organic and pH all presented medium spatial correlation, which meant the artificial factors such as years of cultivation, fertilization, field management, etc. had reduced the structural factors' influenced on these contents, and consequently weakened their spatial correlation. Hainan soil's time-space distribution grapH and space-time difference grapH further explained the changing status of total nitrogen, available pHospHor, total pHospHor, available potassium, total potassium, organic and PH during more than 20 years. According to the plentiful-lack indexes of rubber trees'nutrients, we divided the nutrient distribution pattern of 2008 Hainan rubber plantations, hydrolyzable nitrogen was divided into two management sub-areas, total nitrogen, total pHospHor, available potassium, available potassium, and organic had been divided into three management sub-areas; then in the future rubber plantation management, we could implement scientific management according to these sub-areas adjusting to the local conditions.2. Nutrients'Spatial Variation of Lanyang Town Rubber PlantationFrom the descriptive statistical results of soil nutrients data it could be seen that the data of Lanyang Town rubber plantations'hydrolyzable nitrogen, total nitrogen and organic conformed to normal distribution, and the data of available pHospHor, total pHospHor, available potassium, and total potassium conformed to lognormal distribution; from the aspect of variation coefficients, the available pHospHor's variation coefficient reached the maximum:231.9%, while that of PH was the minimum,5.97%; the variation coefficients lay between 25.29% and 74.16%, with the order of total potassium>available potassium>total pHospHor> hydrolyzable nitrogen>total nitrogen>organic.The Co/(Co+C) values of available and total pHospHor were less than 25%, and presented strong spatial correlation; structural variation was the main influential factor of spatial correlation, which basically conformed to the study areas'potassium fertilization current status that had been ignored for a long time; and the corresponding potassium variation was closely related to the soil parent materials and patterns. The hydrolyzable nitrogen,,total nitrogen, available pHospHor, total pHospHor, PH, and organic had all presented medium correlation, the spatial variation of these six nutrients was the results of mutual effect between the structural factors and random factors.The correlation distance of every nutrients lay between 2.43km and 12.294km, which were larger than their intervals. The relatively shorter interval belonged to hydrolyzable nitrogen:2.43km, and the larger one belonged to PH,12.294km. From the spatial variation grapH it could been seen that the nutrients distribution of Lanyang Town had all presented certain rules. The spatial variation grapH could intuitionally presented the spatial distribution status, which would provide the theoretical evidence for rubber plantations'management in the future.According to the nutrients plentiful-lack grapH drawn through plentiful-lack indexes, we divided the nutrients distribution patterns of Lanyang Town rubber plantations into sub-areas, total nitrogen, available potassium and organic were divided into two management sub-areas; total potassium, total pHospHor, and available pHospHor were divided into three management sub-areas; then in the future rubber plantation management, we could implement scientific management according to these sub-areas adjusting to the local conditions.3. Nested Analysis on Rubber Plantations'Nutrients Spatial Variation in Different ScalesNested analysis on rubber plantations'nutrients spatial variation in two scales was carried out, the results showed that the variation coefficients of hydrolyzable nitrogen, total nitrogen, total pHospHor, available potassium, pH, organic increased as the studying scale increased; the variation coefficients of available pHospHor and total potassium showed that those of Lanyang Town>Hainan Province, which meant that in the small scale, the randomness of available pHospHor and total potassium were large, which was easily influenced by artificial factors.Hydrolyzable nitrogen, total nitrogen, available pHospHor, total pHospHor, PH and organic showed medium correlation in different scales, available and total potassium showed medium spatial correlation in large scales, but they showed strong correlations in small scales.The total nitrogen's spatial distribution presented obvious geograpHic rules in two scales, and could form a relatively good nested structure. Although hydrolyzable nitrogen, available pHospHor, total pHospHor, available potassium, total potassium and organic presented obvious spatial distribution patterns in two scales, the rules of the two scales are obviously different, which meant good nested structure could not be formed.
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