Nitrogen

Abstract

A computer model, comprised largely of equations that did not vary with the species, gave good estimates of the growth and N‐uptake of a range of crops grown with different levels of fertilizer‐N on several sites and also of the nitrate in fallow and cropped soils. Much of the apparent inter‐species variation in N‐fertilizer requirement appeared to result from gross differences such as those of total plant mass at harvest. The inputs to the model are readily available. The model, which may provide more reliable fertilizer advice, takes into account more of the important factors influencing N response than hitherto.

Key words:

• Nitrate
• N‐uptake
• simulation
• vegetables
• yield