Plant height (PH) is an important agronomical parameter to assess the growth status in upland rice fields. Recently, field-based phenotyping using unmanned aerial vehicles (UAVs) has received increasing attention as a cost-effective, well-suited sensing technology measure PH. In this study, we evaluated feasibility of low-cost small UAV for estimating PH fields Laos with canopy model (CHM). Images field, including 501 plots (= 167 accessions × 3 replicates), were captured by commercial (DJI...

Canopy hyperspectral (HS) sensing is a promising tool for estimating rice (Oryza sativa L.) yield. However, the timing of HS measurements crucial assessing grain yield prior to harvest because growth stages strongly influence sensitivity different wavelengths and evaluation performance. To clarify optimum stage sensing-based assessments, paddy fields during reproductive phase ripening was evaluated from field data in conjunction with iterative stepwise elimination partial least squares...

Cassava is often grown in low-fertility soils and has a reputation for having modest nutrient requirements. The storage roots that are harvested, however, contain relatively large amounts of potassium (K). We carried out field experiment Laos to determine the growth response K fertiliser examine field’s balance over cropping season. Four different rates (0-40-80-120 kg K2O equivalents ha−1) were applied cassava variety Rayong11. Harvests done at 8 10 months after planting, when crop was...

Abstract In tropical mountainous areas, soil degradation and yield decrease have been anticipated due to conversion from shifting continuous cultivation the introduction of cash crops. our previous report, we quantified in maize under farmers’ fields Laos. this focused on nutritional conditions fields. For purpose, twelve properties were investigated over two years three sample sites each 40 with duration varying 1 30 years. Total carbon (TC), total nitrogen (TN), available phosphorus,...

Flooding and drought are major causes of reductions in crop productivity. Root distribution indicates adaptation to water stress. Therefore, we aimed identify roots response based on root under various soil conditions. The four crops—maize, millet, sorghum, rice—was evaluated continuous waterlogging (CSW), moderate moisture (MSM), gradual drying (GSD) Roots extended largely the shallow layer CSW grew longer deeper GSD maize sorghum. tended promote shoot biomass across status regardless...

Environmental responses of stomatal conductance (gs) as basic information for a photosynthesis-transpiration-coupled model have been increasing under global warming. This study identified the impact gs behavior different soil water statuses and temperatures in rice, maize, millet, sorghum. The experiments consisted various moisture from flooding to drying combination status temperature. There was reduction shoot biomass maize sorghum caused by decreasing gs, photosynthesis (A), transpiration...

It is well known that poor weeding cause of difficulty weed growth reduction and reduce root yield cassava. This study conducted to confirm quantitatively relationship biomass cassava under difference frequency. Field experiment was carried out in Agricultural Research Center, National Agriculture Forestry Institute, Lao PDR from May 2014 March 2015. The laid RCBD with four replications. treatments consisted types manual control; no weeding, 1 time at 2 MAP, times 1.5 3 1, 2, MAP. plot size...

The cultivation period of cassava in Kagoshima, Japan, which belongs to the temperate zone, is limited by low temperature winter. To maximize productivity under this period, investigations were conducted on gas exchange rate and production structure relating light utilization a plant community grown different nitrogen fertilization conditions. Fertilization either at planting or three months after significantly increased stomatal conductance upper canopy root dry weight compared control. In...

Saltpetre (KNO3; potassium nitrate) is one of the major ingredients gunpowder. Simplex saltpetre (total 126 samples) together with gunpowder 93 commodities which are currently prevailing in local markets as used for wildlife hunting and rocket festivals (local name Lao: Boun Ban Fai) were collected from throughout Lao PDR. Dual isotopic composition nitrates (δ15N, δ18O) was analyzed by microbial denitrification method. Binary plotting data conducted to characterize mode formation. In PDR,...

And nutrients removed through maize crop harvest may lead to land degradation.Nutrients are from the soil at harvests.The application of fertilizer supplies support growth and replenish nutrient stocks.Tan et al. ( 2005) estimated global NPK budgets for major production in 2000, suggested that depletion can be attributed insufficient inputs many developing countries all least developed countries.Analyzing balance farmland is useful understanding reveals effects management practices cropping...