Monitoring seasonal fine root dynamics of Hevea brasiliensis clone RRIM 600 in Southern Thailand using minirhizotron technique

Rubber tree (Hevea brasiliensis) plantations in various environments are affected by climate variability, and the fine root dynamics of rubber trees significantly respond to environmental factors. Therefore, rubber clone RRIM 600 was used to investigate the fine root dynamics in southern Thailand using minirhizotron imaging at 0-60 cm soil depths from February 2014 to January 2015. Dynamics of fine root production and mortality were greater in the rainy season than in the dry season. The fine root distribution peaked around 20-30 cm and decreased over 40-60 cm soil depths. The maximal leaf area index (April 2014) was found 2 months after leaf flushing, while the fine roots showed a slight increase after leaf development for 1 month (May 2014). Both rainfall and soil moisture had significant (p<0.01) positive correlations with fine roots of which there were more in the rainy season than in the dry season

Carbon Sequestration by Fruit Trees - Chinese Apple Orchards as an Example

Apple production systems are an important component in the Chinese agricultural sector with 1.99 million ha plantation. The orchards in China could play an important role in the carbon (C) cycle of terrestrial ecosystems and contribute to C sequestration. The carbon sequestration capability in apple orchards was analyzed through identifying a set of potential assessment factors and their weighting factors determined by a field model study and literature. The dynamics of the net C sink in apple orchards in China was estimated based on the apple orchard inventory data from 1990s and the capability analysis. The field study showed that the trees reached the peak of C sequestration capability when they were 18 years old, and then the capability began to decline with age. Carbon emission derived from management practices would not be compensated through C storage in apple trees before reaching the mature stage. The net C sink in apple orchards in China ranged from 14 to 32 Tg C, and C storage in biomass from 230 to 475 Tg C between 1990 and 2010. The estimated net C sequestration in Chinese apple orchards from 1990 to 2010 was equal to 4.5% of the total net C sink in the terrestrial ecosystems in China. Therefore, apple production systems can be potentially considered as C sinks excluding the energy associated with fruit production in addition to provide fruits

Regulating irrigation during pre-harvest to avoid the incidence of translucent flesh disorder and gamboge disorder of mangosteen fruits

In humid tropical areas, excess water during pre-harvest usually causes the occurrence of translucent flesh disorder (TFD) and gamboge disorder (GD) in mangosteen. To evaluate options for avoiding these incidences, an experiment was conducted with different water management regimes during pre-harvest. Twelve 14-year-old trees were grown under transparent plastic cover with three irrigation regimes: 1) Control (rainfed condition), 2) 7-d interval watering, 3) 4-d interval watering and 4) daily watering. A further four trees were arranged as the control (rainfed) treatment, but these were grown without the plastic roof cover. The treatments were started at 9 weeks after bloom. The results showed that diurnal changes of leaf water potential and stomatal conductance were lowest in the control, because intermittent drying occurred during the study period. The highest fruit diameter, fruit weight, flesh firmness and flesh and rind water contents were found in the daily watering treatment. However, all of these values were lowest in the control trees. The amount of TFD was also lowest in the control (3.7%), and it was significantly different from the treatment where trees were watered at 4-d intervals (18.0%) and where trees were watered daily (28.9%). There was no significant difference of TFD between the control and the 7-d interval watering treatments. In contrast, GD was not significantly different among the treatments. It is suggested that the risk of TFD and GD incidence could be avoided by maintaining mild soil water deficit around -70 kPa during pre-harvest

Climatic considerations which support the choice between natural rubber and oil palm in Nakhon Si Thammarat, southern Thailand

Four climatic variables—rainfall, number of rainy days, relative humidity, and temperature—were studied to observe the characteristics and probable occurrences outside the required bounds for the optimal growth of oil palm and natural rubber. These two economic crops have become increasingly popular among farmers in Nakhon Si Thammarat province, southern Thailand. Monthly and annual data during 1981–2011 were analyzed using appropriate time-series techniques. The out-of-bound probabilities were calculated using the counting method. Only the rainfall showed a significant and increasing trend while the trends in the other variables were not significant. All studied variables showed seasonal fluctuation and cyclical movements. No significant irregularities appeared in the data. The probable occurrences of these climatic variables are crucial in determining the regular and sufficient levels of rainfall required for oil palm and natural rubber. Climate risks were less for growing natural rubber. This study concluded that natural rubber was a more climatically suitable crop for Nakhon Si Thammarat province, if only the four stated climatic variables were considered

How 75 years of rubber monocropping affects soil fauna and nematodes as the bioindicators for soil biodiversity quality index

Natural rubber consumption has led to the expansion of rubber (Hevea brasiliensis) plantations which affects the deforestation and ecosystem. However, no study of the long-term effect of rubber plantations on soil biodiversity has been carried out yet. This study aimed to assess the long-term impact of continuous rubber monocropping on soil biodiversity, focusing on soil macrofauna and nematode diversity. Three successive rubber rotations at young and old ages were compared with the adjacent forest in Suratthani province, Thailand. Soil biodiversity quality index was calculated from a set of indicators which were combined into a single score to present a functional assessment of the gradient of disturbance. The results showed three negative effects on soil biodiversity (i) the biodiversity quality index immediately declined after deforestation (ii) the old age rubber plantations had a lower soil biodiversity as the nematodes were a main driver of diversity in the young plantation, and (iii) similarly, for the soil chemical properties, the long-term effect of rubber chronosequence evidenced deterioration in the third rotation. Therefore, two rotations of rubber plantation (around 50 years) seemed to be the maximum length of rubber monocropping in terms of soil biodiversity recovery

Effect of Feed Supplement Containing Dried Kratom Leaves on Apparent Digestibility, Rumen Fermentation, Serum Antioxidants, Hematology, and Nitrogen Balance in Goats

The objectives of the present study were to examine the influence of supplementation with dried kratom leaf (DKTL) on the performance, hematology, and nitrogen balance in goats. Four 12-month-old male crossbred (Thai Native x Anglo Nubian) goats with an initial body weight (BW) of 24.63 &plusmn; 0.95 kg were allocated randomly to receive four different levels of DKTL using a 4 &times; 4 Latin square design. The DKTL was added to a total mixed ration (TMR) diet with doses of 0, 2.22, 4.44, and 6.66 g/day to investigate the treatment&rsquo;s efficacy. The DKTL was high in secondary metabolites, including mitragynine, total phenolics, total tannins, flavonoids, and saponins. There were quadratic effects on total DMI in terms of kg/day (p = 0.04), %BW (p = 0.05), and g/kg BW.75 (p = 0.02). DKTL increased apparent digestibility with quadratic effects (DM; p = 0.01, OM; p = 0.01, CP; p = 0.04, NDF; p = 0.01, and ADF; p = 0.01). The pH value was within the rumen&rsquo;s normal pH range, whereas NH3-N and BUN concentrations were lower with DKTL supplementation, and also reduced cholesterol (CHOL, p = 0.05) and low-density lipoprotein (LDL, p = 0.01). The protozoa population decreased linearly as DKTL levels increased (p &lt; 0.01), whereas Fibrobacter succinogenes increased quadratically at 0 h (p = 0.02), and mean values increased linearly (p &lt; 0.01). The average value of acetic acid (C2) and methane production (CH4) decreased linearly (p &lt; 0.05) when DKLT was added to the diet, whereas the quantity of propionic acid (C3) increased linearly (p = 0.01). Our results indicate that DKTL could be a great alternative supplement for goat feed. We believe that DKTL could provide opportunities to assist the goat meat industry in fulfilling the demands of health-conscious consumers

Rubber, rubber and rubber: How 75 years of successive rubber plantation rotations affect topsoil quality?

International audienceRubber tree plantations (Hevea brasiliensis) cover large areas in the tropics. In historical producing regions like South Thailand, rubber has been planted by smallholders for three successive rotations lasting a total of 75 years. Despite possible consequences on topsoil, the long-term impacts of repeated rubber plantations on soil quality remain unknown. This study aims to better understand how various factors linked to long-term rubber land use and land use change affect topsoil physico-chemical properties and soil organic carbon (SOC) thermal stability. We focus on the effects of three factors: i. deforestation (change from forest to first rubber plantation); ii. the age of the rubber stand (immature vs. mature); and iii. long-term rubber cultivation (first, second or third successive rotation) over a chronosequence in farmers plots. Our results show that soil was deeply degraded after deforestation to a rubber plantation. Long-term rubber cultivation is also detrimental for the soil and has a more negative impact on soil physico-chemical properties and carbon dynamics, than the age of the rubber stand (e.g., on average, decrease of 50% of SOC content between forest and third rotation). At the third rotation, after 50 years of rubber cultivation, the quality of the 0-10 cm soil layer was very low, with an increase in SOC thermal stability. At this stage, logging practices upset the sustainability of the system. These impacts could be limited by less destructive practices during planting

Rubber, rubber and rubber: How 75 years of successive rubber plantation rotations affect topsoil quality?

International audienceRubber tree plantations (Hevea brasiliensis) cover large areas in the tropics. In historical producing regions like South Thailand, rubber has been planted by smallholders for three successive rotations lasting a total of 75 years. Despite possible consequences on topsoil, the long-term impacts of repeated rubber plantations on soil quality remain unknown. This study aims to better understand how various factors linked to long-term rubber land use and land use change affect topsoil physico-chemical properties and soil organic carbon (SOC) thermal stability. We focus on the effects of three factors: i. deforestation (change from forest to first rubber plantation); ii. the age of the rubber stand (immature vs. mature); and iii. long-term rubber cultivation (first, second or third successive rotation) over a chronosequence in farmers plots. Our results show that soil was deeply degraded after deforestation to a rubber plantation. Long-term rubber cultivation is also detrimental for the soil and has a more negative impact on soil physico-chemical properties and carbon dynamics, than the age of the rubber stand (e.g., on average, decrease of 50% of SOC content between forest and third rotation). At the third rotation, after 50 years of rubber cultivation, the quality of the 0-10 cm soil layer was very low, with an increase in SOC thermal stability. At this stage, logging practices upset the sustainability of the system. These impacts could be limited by less destructive practices during planting

The Livelihood Adjustment of Smallholding Rubber Farming Systems (SRFS) in Southwestern Thailand: Case Study in Ranong, Krabi, Phangnga, and Phuket Provinces

This study aimed to examine the livelihood adjustment, to analyze factors affecting, and to synthesize the relationships between production and livelihood adjustment in model of SRFS for Ranong, Krabi, Phangnga, and Phuket provinces, in Southwestern Thailand. A sample group of 399 rubber farmers was involved in data collection and 60 key informants were selected as a subsample. A structured interview form and a semi-structured interview form were the tools for data collection. In data analysis, descriptive statistics, linear regression and technical- economic simulation were applied, as well as synthesized model of connections between the production system and livelihood under SRFS was analyzed. The results indicate that rubber farming could be classified into four types: smallholding rubber monoculture farming system (S1) (40.9%), smallholding rubber with fruit tree farming system (S2) (35.8%), smallholding rubber with oil-palm farming system (S3) (49.8%), and smallholding rubber with livestock farming system (S4) (5.9%). These were different in livelihood assets and livelihood outcomes. Smallholding rubber with livestock farming system (S4) was better for livelihood outcomes than the other systems. The social capitals were quite high while the economic capitals were quite low. Livelihood strategies give importance to increasing productivity, reducing costs, financial management, and changes in food consumption. All farms relied on government support and received welfare. For the 10-year economic model (2017- 2026), S4 had the highest margin value. This study synthesized the relationships of production and livelihood adjustment model, showing that the model was composed of four sub-models: production system, support system, strategy, and livelihood adjustment system, and the resulting sustainable livelihood system will be useful for analyzing livelihood adjustment