EFFECT OF CULTIVATIONS ON RAISING SPRING SOIL TEMPERATURES FOR GERMINATION WITH PARTICULAR REFERENCE TO MAIZE

Summary Experiments on south‐facing ridges showed significant increases in soil temperature at 5 cm depth on the south slope of the ridge when compared with the ridge top and horizontal surfaces. The average maximum temperature was 2 °C higher halfway down the south‐facing ridge slope than beneath a horizontal surface and on certain individual days differences of up to 7 °C were recorded in maximum temperatures between the two positions. The ridge top temperature was intermediate between those on the slope and horizontal. Minimum temperatures were similar at all positions. The increased maximum temperature on the ridge slope significantly increased the accumulated temperature hours above 10 °C. The moisture status on the slope of a compact ridge followed closely that of a horizontal surface, being slightly lower during droughts. The ridge top dried out rapidly during droughts. The increase in maximum temperature and accumulated temperature hours above 10 °C, together with the acceptable moisture level found in the side of a compact south‐facing ridge should offer advantages either for earlier germination or for a more rapid rate of emergence of maize.