Abstract
An optimized nitrogen (N) fertilization may have a positive effect on leafy vegetables by increasing growth, yield and nutrient content of plants. Nevertheless, crop performance must be coupled with an increase in Nitrogen Use Efficiency (NUE) in order to limit external N inputs and to avoid N surpluses associated with environmental and health problems. The aim of the current study was to assess the effects of a legume-derived plant hydrolysates (LDPH; Trainer®) and N fertilization levels (0, 2.25 and 4.5 g N m−2 for spinach and 0, 2.5 and 5.0 g N m−2 for lamb’s lettuce; N0%, N50%, N100%, respectively) on agronomical, biochemical, qualitative responses and NUE of these two important greenhouse leafy vegetables. Spinach and lamb’s lettuce were sprayed four times during the growing period (at a concentration of 4 mL L−1 of LDPH). In baby spinach, the LDPH application elicited a significant increase at the three levels of N fertilization: +16.8%, +14.2%, and 39.4% at 0, 2.25 and 4.5 g N m−2, respectively. Interestingly, in lamb’s lettuce, the N50% plants treated with LDPH reached similar values of marketable yield in comparison to treated and non-treated plants under N100% conditions. The presumed mechanism involved in the enhancement of yield response in the two leafy greens could be associated to a better activity of the photosystem II (higher SPAD index), biochemical (higher content of chlorophyll a, b and total) and leaf nitrate status. The foliar application of LDPH produced a major fortification in lipophilic and hydrophilic antioxidant activities (+11.6 and 6.3% for spinach and lamb’s lettuce, respectively). The biostimulant application also improved N-use efficiency and N-uptake efficiency compared to untreated plants: +17.8% and +18.8%, and +50% and +73.3%, for spinach and lamb’s lettuce, respectively.
Highlights
Chemical fertilizers, especially nitrogen (N), are basically the main input for boosting yield and concomitantly one of the most expensive inputs in terms of economics and environment
Sustainable agriculture is the greatest challenge of our century, and plant-based biostimulants represent an efficient and concrete possibility to reach this objective by maintaining high production and improving the nitrogen use efficiency (NUE) of leafy greens with several economic, nutritional and environmental benefits
The positive effects of the legume-derived plant hydrolysates (LDPH) biostimulant were manifested in terms of marketable fresh yield in baby spinach, irrespective of N fertilization treatments and at low N rates (N0% and N50%) in lamb’s lettuce
Summary
Especially nitrogen (N), are basically the main input for boosting yield and concomitantly one of the most expensive inputs in terms of economics and environment. It is certainly necessary to adapt the correct management of N fertilization through a balanced application of the elements in order to reach the right dose, by choosing the convenient chemical form and application time. Another possible perspective is to raise the nitrogen use efficiency (NUE) that is linked to the capacity of plants to uptake nutrients, to their systems of transport, storage and mobilization and to the N loss into the environment [10]. NUE is expressed as the harvestable yield per the amount of available N in the soil or per N supply [11,12,13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
