Nutrient and Water Use Efficiency at Leaf Level of Cucumber Plants under Contrasting Soil Nutrient and Lignosulfonate Level

To reduce the use of commercial conventional inorganic fertilizers the possibility of using pulp and paper industry wastes in agriculture as an alternative source of nutrients is recently under study and discussion. This work aimed to evaluate the effect of sodium lignosulfonate application to soil on photosynthetic leaf nutrient- (N, P, K, Ca, Mg, Fe, and Mn) and water- use efficiency. A pot culture experiment was conducted with cucumber seedlings, using five lignosulfonate concentrations (0, 1, 2.5, 5, and 10 vol. %) in sandy soil under sufficient or low nutrient availability for plants. The impact of nutrient availability on plant physiological traits was stronger than the lignosulfonate impact. Under the condition of sufficient nutrient availability, the lignosulfonate application decreased N-, P-, K-, Ca-, Mg-, and Fe- use efficiency, increased Mn- use efficiency and did not change water- use efficiency. The decrease of nutrient- use efficiency was connected with both photosynthetic rate decrease and leaf nutrient content increase. The decline in soil nutrient availability caused a decrease in nutrient and water use efficiency. Under low nutrient availability, soil lignosulfonate tended to increase nutrient- and water- use efficiency, but it was not successful to eliminate the negative effects of soil nutrient deficiency on plant growth, photosynthetic processes, and efficiency of nutrient use.