Continuing increases in atmospheric carbon dioxide concentration, [CO 2 ], will likely be accompanied by global warming. Thus, it is important to quantify and understand the consequences of elevated [CO 2 ] and temperature on crop growth and yield to develop suitable varieties and agronomic management practices for future climates. The objective of this study was to investigate the growth and development responses of shoots and roots of peanut (Arachis hypogaea L.) grown under different combinations of atmospheric [CO 2 ] and temperature. The study comprised a long-term experiment, in which plants were grown in growth chambers for 112 days, and a short-term experiment, in which growing plants in rhizotrons for 17 days. In the long-term experiment, peanut cultivar Tainan 9 was grown in 20-L containers fitted with minirhizotron observation tubes at 5 cm soil depth and placed in controlled environment chambers under three levels of [CO 2 ] (400, 600, and 800 µmol mol -1 ) and two levels of air temperature (25/15ºC and 35/25ºC day/night temperature). In the short-term experiment, two peanut seedlings were grown in each of 18 acrylic rhizotrons with a 6-mm thick soil layer. Rhizotrons with plants were placed in the same growth chambers as above. At 3-to 4-day intervals, rhizotrons were placed on a flatbed scanner to collect digital images from which root length and number were measured using RMS software. At 25/15ºC, plants grown at 600 and 800 µmol mol -1 CO 2 had main stems that were 24 and 44% longer than those grown at 400 µmol mol -1 , while at 35/25ºC the main stem length was similar in all [CO 2 ] levels. At 25/15ºC, plants showed greater area and dry weight per leaf than at 35/25ºC. At harvest, high temperature significantly reduced total leaf area to 574 cm 2 for 35/ 25ºC compared with 921.2 cm 2 for 25/15ºC. Specific leaf area at low temperature was 22% less than at high temperature. Above ground biomass was increased by elevated CO 2 in both temperature treatments. At high temperature, above ground biomass was 56%, 24%, and 16% higher than at low temperature at [CO 2 ] of 400, 600 and 800 µmol mol -1 , respectively. Pod dry weight increased with increasing [CO 2 ] at 25/15ºC, but was not different among [CO 2 ] levels at 35/25ºC. At 25/15ºC, pod dry weight was 50% higher than at 35/ 25ºC. As the temperature increased from 25/15ºC to 35/25ºC, pod dry weight was reduced by 40% at 400, 53% at 600, and 54% at 800 µmol mol -1 CO 2 . High temperature produced more root length in the containers, whereas low temperature did in the rhizotrons. There were significant interactions between temperature and [CO 2 ] for their effects on main stem length and above ground biomass. High temperature enhanced growth of shoots and roots, but decreased pod dry weight. There was no interaction of elevated [CO 2 ] with higher temperature on the reproductive growth, despite a tendency for beneficial temperature by [CO 2 ] interaction on vegetative growth and total shoot dry weight. The beneficial effects of increased ...
The Satoyama Agricultural Development Tool (SADT) is based on five perspectives identified by the International Partnership for the SatoyamaInitiative (IPSI). To determine itsefficiency in indigenous communities, case studies were undertaken inthree hilltribe com-munities: Mueang Ang, Nhong Lom and Pa Kea Noi, located in the province of Chiang Mai, northern Thailand. Satoyama analysis was conducted in each village by officers attached to the Royal Project Foundation (RPF) and the Highland Research and Development Institute (HRDI) operating out of the stations of Inthanon and Mae Hae. These were compared with similar analysis done by villagers of each village studied. Results showed uniformity amongstvillagers, and amongst officers. No statistical differences were obtained when analysis betweenofficers and villagers were compared, demonstrating that if persons are exposed to the same data and experiences within a given locale, they would produce similar evaluations when using thetool. Further, because villagers are capable of auto-evaluation, it is an indication that the tool should be simplified to facilitate ease of use. We were able to conclude that the SADT allowsevaluation of the extent to which the perspectives of Satoyama are met in any given commu-nity. It is diagnostic in nature and would set the stage for a systematic and scientific approach that should be employed to advance sustainable agricultural development in the community,premised on its local culture and characteristics. The staff attached to the RPF has opted to use the tool as a means of evaluating progress in hilltribe communities affiliated to it.
An increasing large number of cornfield have been cultivated in highland of many Southeast Asian countries. In most cases, this corn plantation is done without proper soil & water conservation such as vetiver system (VS), thus causing land degradation and shallow slide. This study is aimed at investigating the field behaviour of slopes with corn plantation with and without vetiver system in Chiang Mai, Northern Thailand. Tensiometers, soil moisture sensors, in-place inclinometers and tiltmeters were installed at a slope in two locations, with and without vetiver system from surface to 2m depth. The monitoring results show that for the vetiver treatment, the soil moisture tended to be higher and response faster to rainfall than the cornfield without vetiver. However, the pore-water pressure in the root zone (about 0.5m) was higher for the vetiver treatment than the cornfield which only has the root depth of about 0.2m. For cornfield without vetiver, the seasonal variation of the soil moisture and pore-water pressure was also larger. Tiltmeter indicates a larger surface movement in the cornfield without VS. However, the inclinometer readings suggested that for slope with VS there was some cyclic movement toward hillside at the surface. This could be an indication of non-uniform settlement of soil layers or influence of groundwater rising.
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