THE INFLUENCE OF ROLLED EROSION CONTROL-SYSTEMS ON SOIL-TEMPERATURE AND SURFACE ALBEDO - PART I - A GREENHOUSE EXPERIMENT

A greenhouse study examined the influences of various surface covers ( a bare control soil and seven rolled erosion control systems - RECS) o n surface radiative properties, and soil temperature. In our companion paper we examine relationships with soil moisture, biomass production , and nutrient assimilation. Randomization and replication were key co mponents to our study of microclimate under tropical radiation conditi ons. The bare Oxisol control soil exhibited the most extreme microclim atic conditions with the lowest albedo (not significantly different fr om that of P300(R) North American Green, a dark green polypropylene sy stem), and the highest mean and maximum hourly temperatures recorded a t depths of 5 and 8 cm. This hostile climatic environment was not cond ucive to biomass production or moisture storage and it is likely that the observed soil surface crusts impeded plant emergence. Rolled erosi on control systems, on the other hand, generally moderated soil temper atures by reflecting more shortwave radiation, implying less heat ener gy at the surface for conduction to the soil. The result was that RECS exhibited lower mean soil temperatures, higher minimum temperatures a nd lower maximum soil temperatures. An aspen excelsior system (Curlex I(R) Excelsior) had the highest albedo and the soil beneath this syste m exhibited the greatest temperature modulation. Open-weave systems co mposed of jute (Geojute(R) Price & Pictures) and coconut fibers (BioD- Mat 70(R) RoLanka) were the RECS most similar in temperature response to the bare control soil. Other systems examined were intermediate in their temperature response and surface albedo (i.e., SC150BN(R) North American Green, C125(R) North American Green and Futerra(R) Conwed Fib ers). (C) 1998 John Wiley & Sons, Ltd.