The objective of this study was to

The objective of this study was to investigate the effect of biochar application (CA) on soil physical
properties and grain yields of upland rice (Oryza sativa L.) in northern Laos. During the 2007 wet season,
three different experiments were conducted under upland conditions at 10 sites, combining variations in
CA amounts (0–16 t ha1
), fertilizer application rates (N and P) and rice cultivars (improved and
traditional) in northern Laos.
CA improved the saturated hydraulic conductivity of the top soil and the xylem sap flow of the rice
plant. CA resulted in higher grain yields at sites with low P availability and improved the response to N
and NP chemical fertilizer treatments. However, CA reduced leaf SPAD values, possibly through a
reduction of the availability of soil nitrogen, indicating that CA without additional N fertilizer application
could reduce grain yields in soils with a low indigenous N supply. These results suggest that CA has the
potential to improve soil productivity of upland rice production in Laos, but that the effect of CA
application is highly dependent on soil fertility and fertilizer management.

Results (English) 3:

本研究的目的是探讨生物炭的应用效果（CA）对土壤物理性质和
旱稻产量（Oryza sativa L.）在老挝北部。2007在雨季，
三不同的实验进行了旱作条件下在10个地点，结合
钙量变化（0 16 T HA1–
），施肥量（N、P）和水稻品种（改良
传统）在老挝北部。CA改进
表层土壤和水稻
植株木质部汁液流动的饱和导水率。CA导致更高的粮食产量在网站与低磷的有效性和改进的N
和NP化肥处理的响应。然而，钙降低了叶片SPAD值，可能通过
减少土壤氮素的有效性，表明CA没有额外的氮肥，可以在很低的土著
供氮在土壤中的粮食产量减少。这些结果表明，钙对提高老挝陆稻生产土壤生产力
潜力，但钙的影响
应用程序是高度依赖于土壤肥力和肥料管理。