What deficiency is indicated by stunted growth, yellowing of lower leaves, and a poor root system?

The symptoms of stunted growth, yellowing of lower leaves, and a poor root system are typically indicative of a nitrogen deficiency. Nitrogen is a crucial nutrient for plants as it is a fundamental component of amino acids, proteins, and chlorophyll, which are essential for growth and photosynthesis. When plants lack nitrogen, they often exhibit stunted growth because they are unable to produce enough biomass and energy for healthy development.

The yellowing of lower leaves, known as chlorosis, occurs as nitrogen is mobilized from older leaves to support new growth, leading to the characteristic yellowing as the plant prioritizes its limited resources. Additionally, a poor root system can result as nitrogen is vital for root development and overall plant vigor.

While potassium, phosphorus, and iron deficiencies can lead to various issues in plants, they do not typically present with the combination of symptoms observed in this case. Potassium is often associated with leaf margin burn and other specific leaf discolorations, phosphorus deficiencies can stifle growth and lead to dark green coloration, and iron deficiencies typically manifest in younger leaves as interveinal chlorosis. Thus, the correct identification of nitrogen deficiency is supported by the specific symptoms described.