Soil Temperature Around the Crown Node Influences Early Growth, Nutrient Uptake, and Nutrient Translocation of Spring Wheat¹

Abstract

Abstract Farming practices such as stubble mulching are known to influence surface soil temperatures. This study was conducted to determine the effect of temperature variations in the shallow surface zone that normally contains the crown node on early growth, nutrient uptake, and nutrient translocation of spring wheat ( Triticum aestivum L.). Surface soil temperatures below optimum, about 19 C, significantly decreased top growth but not root growth. When surface soil temperature was increased, total nutrients accumulated in the tops increased. Under low surface soil temperature roots appeared to accumulate Cu and Zn. Translocation of 80 Rb from the roots to the tops was significantly greater when the surface soil was warm than when it was cold. Thus, translocation of nutrients from the roots to the tops may be restricted by low soil surface temperatures. Fertilization with N, P, and K appears to modify the detrimental effect of low surface soil temperatures. However, nutrients did not completely alleviate the detrimental effect of low surface soil temperatures. The crown node (transition region) of the plant appears to be the plant component most sensitive to low surface soil temperatures. When the crown node was located above the cold zone , dry weight was nearly equal with cold and warm surface soil temperatures. Unlike the crown node, the shoot growing point (meristematic region) was not affected by low, surface‐soil temperatures.