Preliminary Study on Seedling Growth Rhythm and Grey Correlation Analysis of Rubber (Hevea brasiliensis) Seedlings in Danzhou District, Hainan

The rubber tree physiological and ecological process quantitatively described by using mathematical method is an important means to the analysis of rubber tree growth process and mechanism. The study on growth simulation model of rubber tree will lay the foundation for the application of rubber tree cultivation intelligent decision system. A Richards equation was formulated to describe the height and stem diameter growth dynamics of the annual rubber seedlings. An area correlation analysis was done according to the closeness of the observed parameters to the dynamic curve on the gray system composed of the seedling growth increment and the meteorological factors including aerial temperature, precipitation and solar radiation hours that influence upon the seedling growth. The results showed that rubber seedling response fitted the Richards equation quite well. The growth increment displayed a distinct alternation of 'slow—fast—slow— fast—slow' rhythm. The growth course of the seedlings might be partitioned into three periods of time by the sequential clustering analysis, namely pre-growing, fast-growing, late-growing stage. The tray correlation analysis revealed that air temperature had the most significant influence while precipitation had the least impact on height growth of the rubber seedlings. In conclusion, the air temperature had the most significant influence while solar radiation hours had the least impact on stem diameter growth of the rubber seedlings.

Exploration and Practice of Rubber Based Agroforestry Complex Systems in China

Agroforestry ecosystems are constructed by simulating natural ecosystems, applying the principles of symbiosis in nature, and organizing multiple plant populations to coexist, while conducting targeted cultivation and structural control scientifically. Rubber agroforestry complex ecosystems aim for sustainable development in terms of industry, ecology, resource utilization, and the livelihoods of producers. Rubber agroforestry complex ecosystems create a complex production structure system that integrates biology, society, and the economy through species combinations. Rubber trees and associated biological components coordinate with each other, mutually promote growth, and yield a variety of products for producers. Cultivation techniques and patterns of rubber agroforestry are essential components of these ecosystems. This study analyzes the production practices of rubber agroforestry complex cultivation, with a focus on the development and characteristics (complexity, systematicity, intensity, and hierarchy) of rubber agroforestry systems using a literature analysis and a survey approach. It explores the types and scales of complex planting, specifications and forms, and major effects of complex cultivation. This study identifies successful rubber agroforestry cultivation patterns and practical techniques, as well as the potential benefits of developing rubber agroforestry cultivation. It also points out the shortcomings in the development of complex planting, including an emphasis on production practices but insufficient theoretical research, a focus on production but inadequate attention to the market, and an emphasis on yield while overlooking the improvement of standards, brands, and added value. There are various complex patterns for young rubber plantations, but relatively fewer for mature plantations. Based on this analysis, this study suggests that future efforts should focus on in-depth research on interspecies and environmental interactions in rubber agroforestry ecosystems, clearly define key roles, accelerate the innovation of development patterns, and strengthen the foundation for development. It recommends promoting and demonstrating successful rubber agroforestry complex patterns and providing technical training, developing product branding for rubber agroforestry patterns, enhancing product value, expanding the application functions of rubber-forest mixed crop products, and establishing a stable and sustainable industry chain. This study provide practical experience and theoretical insights in rubber agroforestry complex systems from China the potential to enrich the knowledge of rubber agroforestry composite systems, provide practical experience to improve the operating income of smallholders, and even promote the sustainable development of rubber plantations.

Microorganism Characteristics in Decomposition Process of Rubber Tree Leaves Litter in Hainan Island

Microorganism plays an irreplaceable role in litter decomposition,and the dynamics of microbial activity in litter is of ecological significance in understanding the mechanism of litter decomposition. Therefore,the dynamic characteristics of microorganism in rubber litter decomposition were studied during 300 and 240 days by mesh bag method under different control measures in plantations. And the results were as following:(1) Microbial populations were closely related to litter residues and decomposition environments. The microbial population has been rising firstly and then falling on the ground but directly dropping under the ground by time.(2) Microbial populations under different environments as follows:0.07 mm aperture of mesh bag > 1 mm aperture of mesh bag,non-fertile hole > fertile hole,underground group > ground group. During the entire process of decomposition,the quantity of bacteria holed absolute superiority,then actinomycetes,finally fungi.(3) Through the correlation analysis,the total number of bacteria,fungi and microorganism in aboveground group was significantly associated with the decomposition rate,but there was little correlation to actinomycetes. It's suggested that fungi and bacteria are the main participants in litter decomposition on the ground. In underground group,the microbial groups were significantly or extremely significantly related to the dry weight of residues,but was not correlated to decomposition rate significantly,which suggested that litter provided food for underground microbes,and litter decomposition was more dependent on comprehensive effect of microbes,soil animals and soil environments.

A Simplified Cultivation Technology for Disbudding of (<i>Hevea brasiliensis</i>) Stock Seedling

A new simplified cultivation technology which could facilitate rootstock bud of rubber stock seedling was studied. The advantages of the technology were that it could be was simple to operate and used easily. Using telescopic handle and arcuate edge effectively could reduce labor intensity of seedling breeding workers and improve the speed of disbudding. Further, bag budling could be promoted healthy growth and its survival rate could be improved with the technology.

Effects of Storage Temperature on Postharvest Physiology of Amorphophallus cormifer Microbulb

[Objectives]The paper was to explore the optimum storage temperature of Amorphophallus cormifer microbulbs.[Methods]With A.cormifer as the raw material,the effects of different storage temperatures(4,12 and 20℃)on postharvest physiology of A.cormifer during the storage period of 80 d were investigated.[Results]There was no significant difference in starch content among the treatments,and the content of reducing sugar at 4℃was significantly higher than those of other treatments during the storage period.There was no significant difference in total water content among treatments,and the specific gravity of free water at 4℃was significantly lower than those at 12 and 20℃,respectively.At 60 d post storage,the POD activity at 4℃was significantly higher than those at 12 and 20℃,respectively.At the 80th day of storage,the PPO activity at 4℃was significantly lower than those at 12 and 20℃,respectively.[Conclusions]The low temperature of 4℃is more conducive to the storage of A.cormifer microbulbs,and the results also provide the theoretical basis for long-term storage of A.cormifer bulbs.

Removing ammonia from skim by air stripping with rotating packed bed

Based on the effects of skim components on ammonium removal as well as the current processing technology, a new process-intensified technology of removing ammonia from skim by air stripping on rotating packed bed was proposed. The experiments were conducted on a wave-thread packed Rotating Packed Bed(RPB) under atmospheric pressure, suggesting that, in terms of order of importance, the ammonium concentration of feed-stock(x_w), the average ultra-gravity factor(β), feed-stock flux(L), and gas flux(G) had significant impact on ammonium removal rate(η) and the ammonium concentration of products(x_D). In the experiment, mass-transfer coefficient in gas phase(k_ya_e) increases with the increase of β, G/L, and L. The ammonium concentration of products decreases with the increase of β, G/L and the increase of L. The ammonium concentration of products would be as low as ~0.10% and the ammonia removal rate would be 63.21% when skim temperature was 25 °C, x_w0.28%, β 133.2, and G/L 15.0 m^3·L^(-1). Experiment results indicated that the proposed technology for removing ammonium from skim on a rotating packed bed would be a new process-intensified technique compared with traditional aeration process and centrifugal atomization method.

Dynamics of Soil N<span>H</span>⁺<sub style="margin-left:-10px;">4</sub>-N and N<span>O</span>^-<sub style="margin-left:-4px;">3</sub>-N in Rubber Plantation in Wenchang, South China

In this study, the dynamics of soil available nitrogen in rubber plantations was studied to provide a basis for the sustainable management of soil nutrients in rubber plantations. Soil samples were collected from 0 - 20 cm and 21 - 40 cm depth of rubber plantations in Wenchang area of Hainan Province to determine the soil ammonium nitrogen and nitrate nitrogen in March, June, September and December. The results showed that the total available nitrogen in the rubber plantation soil was mainly composed of nitrate nitrogen (>57%), and this nitrate nitrogen was always the absolute composition advantage in the total available nitrogen composition, and this composition advantage did not change with the change of soil depth. Nitrate and ammonium nitrogen in rubber plantation soil showed obvious seasonal variation characteristics in 0 - 20 cm soil layer and 21 - 40 cm soil depth. With the seasonal time change, the contents of soil nitrate and ammonium nitrogen increased first and then decreased. Summer and autumn were the most active periods of soil nitrate and ammonium nitrogen. There was a significant positive correlation between soil nitrate nitrogen content and ammonium nitrogen content (r = 0.6532**). Based on the correlation between soil ammonium nitrogen content and nitrate nitrogen content, the content of ammonium nitrogen in soil can be estimated according to the amount of soil nitrate nitrogen.