Impact of Soil and Environment on Nutritive Values of Plant Foods

Meaningful Vision:

Plant growth has a significant impact on the composition of fruit and vegetable products.  Vigorous growth rates are associated with higher levels of biomass and a broad spectrum of metabolites.  Soils provide a medium for active root development and assimilation of both macronutrients and micronutrients.  The macronutrients generally include nitrogen, phosphate, and potassium (N, P, K), which are typically associated with leaves, fruit, and root tissues, respectively.  Further, numerous specific soil-borne micronutrients (e.g. zinc- Zn, manganese-Mn, copper-Cu) are important to optimum growth rates.  Each plant will have an optimum level of soil-based minerals that influence plant growth. Most plant foods are affected by a “genetic-by-environment” (G x E) interaction.  Thus, the specific cultivar and the growing conditions dramatically influence the growth rate and inherent nutritional value of plant products.  

The composition of soils directly controls water-holding capacity and the vital movement of minerals within the plant vascular tissue (xylem and phloem).  Soil mineral deficiencies or the presence of alkaline salts will negatively affect plant growth and the nutritional value of the food.  Elements essential to plant growth include C, H, O, P, K, N, S, Ca, and Mg, and soils are important to the bioavailability of these elements for plants to thrive.

Vigorous plant growth impacts overall yield, expressed as total biomass and selected harvestable components (fruits, leaves, stems, roots) used for food.  Mineral content and numerous plant metabolites (vitamins and antioxidants) are highest in well-maintained plants undergoing active growth.  Growth rates are influenced through biotic factors (diseases and pests) and abiotic factors such as (temperature, moisture content, and soil conditions). 

Soil conditions dramatically influence plant growth and the subsequent nutritive value of the food produced.  Mineral uptake and deposition within leaves, stems, and fruit are well demonstrated for leafy greens (spinach), succulent stems (asparagus), roots (carrots), and fruits (apples).  The xylem transports soil minerals to support the photosynthetic processes within the leaves. Active synthesis produces numerous cofactors (vitamins, particularly water-soluble vitamins) and bioactive compounds.   Phloem transports energy and bioactive compounds to various tissues.  It is to be emphasized that active, vigorous plant growth is directly associated with higher levels of nutrients within the plant tissues.  Ascorbic acid, vitamin C, thiamin, riboflavin, and niacin (B-complex) are specifically nutritionally enhanced in plants grown under optimal soil fertility and without generally adverse biotic and abiotic stresses.

The research areas associated with soil interactions with plant growth are important to the agricultural and human nutrition sectors. Plant-based foods' overall productivity and sustainability play a significant role in future development.  Soils (types, condition, and fertility) are increasingly recognized as a vital link for the improved nutritional value of plants used as human food stocks.