Effect of Soil Water and Nutrient Supply on Root Characteristics and Nutrient Uptake of Plants

Abstract

ABSTRACT Root growth in soils influenced by soil nutrient supply has widely been investigated. However, limited soil moisture also affects plant growth by reducing soil nutrient supply, as well. The influence of soil conditions on plant growth dynamics and how root growth can be adopted to the different unfavourable soil conditions were studied. Spring barley plants cv. SK 1775 were grown in pot experiments under controlled environment. Different soil moisture and nutrient (NPK) conditions were applied. Whole plants were sampled 9 times from emergence until 30 days of age. In dry soils reduced nutrient supply increased root length in the first ten-day period of the vegetative growth, thereafter these differences disappeared and a positive effect of nutrient supply on root length was found by the 30th day of growth. The increasing rates of soil nutrients compensated for the insufficient water supply to some extent. Under favourable moisture conditions soil nutrient supply had no influence on root length in the first two weeks. The higher amount of available nutrients resulted in higher root elongation afterwards. At medium soil moisture levels an increasing soil nutrient supply increased the root surface to a greater extent than the L values, due to the compensatory growth of finer, longer roots. The rate of elongation was established at different ages in each treatment. The amount of P taken up by plants was markedly influenced by the amount of available soil P. The P uptake rate proved to be highly dependent on soil moisture and nutrient state and was also determined at different ages. On the basis of the data obtained plant growth can be more precisely described and considering other soil properties plant-soil interactions can be further explained. Root surface area as a root parameter and LA:RA as a characteristic of plant growth strategy should be applied.