Growth, yield and aerenchyma formation of sweet and multipurpose sorghum (Sorghum bicolor L. Moench) as affected by flooding at different growth stages

Abstract The greenhouse experiment was a 4 × 2 factorial in a RCB design with four replications. Three flooding treatments were applied at the early vegetative stage (EV), early reproductive stage (ER) and mid reproductive stage (MR). A non-flooded control group was used. Two proposed bioenergy sorghum types studied were sweet sorghum (Wray) and multipurpose sorghum (SP1). The results showed that plant height, stem diameter, leaf area, leaf dry weight, shoot dry weight, primary root length and root dry weight of both cultivars were significantly reduced by flooding at EV and ER. However, there was no significant difference from the control at MR. Nodal root number were restricted when flooding was applied at EV but increased over the control at ER and MR in both cultivars. Root length and root dry weight, developed in water above soil surface, were significantly higher in Wray flooded at ER. In both cultivars, aerenchyma spaces were formed in the nodal and lateral roots of the flooded plants with the significantly highest number, forming during EV. Aerenchyma was more developed in roots, located above the soil, than in those located in the soil. There were more aerenchyma spaces in the sweet sorghum's roots and stalk bases than in the multipurpose sorghum. At harvest, it was found that flooding applied at EV and ER had significantly reduced the stalk yield of both cultivars. The Wray had been the least affected by flooding at MR. These findings suggest that both sorghum types are susceptible to flooding at EV. Judging from the recovery capacity of stem diameter and height at a later growth stage, sweet sorghum was more tolerant to flooding than multipurpose sorghum. Nodal root development and aerenchyma formation in roots and stalk bases may be important acclimation responses to flooding

Multiple Cropping after the Rice Harvest in Rainfed Rice Cropping Systems in Khon Kaen Province, Northeast Thailand

Cropping intensification in rainfed rice-based farming systems through multiple cropping after the rice harvest by using residual soil moisture and supplemental irrigation offers a way to increase agricultural productivity and boost rural incomes in Northeast Thailand. This study identifies localities, planted areas, types of crops, and number of households growing crops after rainfed rice in Khon Kaen Province; it also analyzes some of the physical and social factors associated with the occurrence of this system. A questionnaire survey was conducted in 2013 of 198 agricultural extension officers in each subdistrict (tambol) in the province to collect data on multiple cropping. An area of 10, 384 ha (2.9% of the total rainfed rice area) was used for multiple cropping by 16, 184 households (10.9% of all rainfed rice farming households). Both field crops (e.g., cassava, crotalaria, field corn) and vegetables (e.g., sweet corn, watermelon, Chinese radish) were grown. These crops generated USD414–49, 072 per hectare per crop for a total revenue of USD32 million, which is three times higher than the value of rice grown in the same field area. However, the area that can be utilized for multiple cropping in different subdistricts may be limited by physical conditions, including availability of irrigation sources and soil texture, as well as social and economic factors such as availability of markets, institutional support, and farmer skills

Households' livelihood strategies facing market uncertainties: How did Thai farmers adapt to a rubber price drop?

International audienc

Wood vinegar seed priming improves yield and suppresses weeds in dryland direct-seeding rice under rainfed production

Rice seed vigor can affect speed of germination, field emergence and crop yield. These agronomic performance characteristics are essential for sustainable production of rainfed, dry direct-seeding rice. Seed priming may enhance rice seed vigor and agronomic performance for rainfed production. The objective of this study was to evaluate the effect of GA3 and wood vinegar seed priming on seed vigor, seedling performance, and grain yield in farmer’s fields. The experimental design was a splitsplit plot with 4 replications and planted in Thailand between April to December, 2013 and 2014. Two rice cultivars (KDML 105 and RD6) were main-plots, 2 planting methods (broadcast and row) were sub-plots and 3 seed priming treatments (GA3, wood vinegar and untreated control) were subsub- plots. Seed priming enhanced speed of germination and final germination percentage under laboratory and field condition. However, field agronomic performance was strongly influenced by year of production. Wood vinegar primed seeds had greater shoot growth and plant population, while GA3 primed seeds had faster speed of seed germination and greater germination percentage. Total weed biomass was different between rice cultivars and planting methods. At 20 and 40 days after sowing (DAS), weed biomass was dependent on planting method and cultivar. Seed priming significantly reduced weed biomass at 140 DAS in 2013, but not in 2014. Yield-related agronomic performance characteristics of tillers plant-1 and yield in ton ha-1 were significantly higher for primed seed in 2013. Seed priming with wood vinegar is a good, sustainable alternative to improve seedling emergence and increase yield of dry direct-seeding rice. However, the response depends on optimal soil moisture availability during flowering and seed formation.This is a manucript of an article published as Simma, Bubpha, Anan Polthanee, A. Susana Goggi, Boonmee Siri, Arunee Promkhambut, and Petrutza C. Caragea. "Wood vinegar seed priming improves yield and suppresses weeds in dryland direct-seeding rice under rainfed production." Agronomy for Sustainable Development (2017) 37: 56. doi: 10.1007/s13593-017-0466-2. Posted with permission.</p

Analysing the water and greenhouse gas effects of soya bean-based biodiesel in five different regions

Bioenergy may have significant lower greenhouse gas (GHG) emission intensities compared to fossil alternatives, but concerns are raised that bioenergy would contribute to additional water scarcity. Therefore, the GHG intensity, water intensity and water-related risks are analysed simultaneously for conventional diesel and soya bean-based biodiesel from Argentina, Brazil, Unites States (U.S.), Thailand and Iran on a life cycle basis. The water-related risks are estimated with a water scarcity—consumption matrix, which was recently developed. Results show that a significant share (9%-38%) of the GHG emissions in all biodiesel cases is caused by soil N2O emissions. In addition, the ranges in water consumption intensity for soya bean-based biodiesel are considerably larger than for fossil fuels. However, whether this leads to high water-related risks depends on the local water scarcity. Soya bean-based biodiesel from Argentina has low water-related risks to all nodes of the supply chain due to low local water stress combined with a low direct water consumption intensity (20 L/GJfuel). In addition, high GHG emission reduction (71%) and a low-specific eutrophication potential (0.04 kg PO4 3−/GJfuel) are achieved. The indirect water consumption intensity is estimated at 120–420 L/GJ for soya bean-based biodiesel, which is significant if the soya beans are rainfed, like in Argentina and Brazil. If irrigation is required, indirect water consumption is dwarfed by irrigation water. Overall, it is concluded that soya bean-based biodiesel can have significant lower GHG emission intensity than fossil diesel, without causing additional water stress in the supply chain if they are produced in water abundant areas and good agricultural practices are used. The used method shows disaggregated water-related risks for the different nodes of the supply chain to acknowledge the regional nature of water scarcity and enables decision makers to identify “hot spots” and take targeted actions