Abstract
Nitrogen (N) fertilizers play a crucial role in agriculture, representing a powerful tool for farmers for increasing yields throughout the seasons under both optimal and suboptimal conditions. At the same time, their synthetic/chemical nature could have several influences on ecosystems and human health. For this reason, there is an urgent need to find new and more sustainable means of production to increase plant productivity and optimize nitrogen use. An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop to the foliar application of three plant biostimulants (PBs): Legume-derived protein hydrolysate (LDPH) ‘Trainer®’, tropical plant extract (TPE) ‘Auxym®’ and seaweed extract (SwE) from Ecklonia maxima ‘Kelpak®’ under different N rates of 0, 10, 20 and 30 kg N·ha−1. The responses of baby lettuce plants were assessed in terms of yield, growth parameters and physicochemical composition of the leaves. The fresh yield of baby lettuce in both biostimulant-treated and untreated plants was positively affected by increasing N rates from 0 to 20 kg N·ha−1, reaching a plateau thereafter indicating luxury N conditions at 30 kg N·ha−1. However, high N fertilizer application (20 and especially 30 kg N·ha−1) resulted in undesirable decreases in antioxidant activities and total ascorbic acid (TAA). Under non-fertilized regimens, foliar PBs application boost growth and yield of baby lettuce in comparison to non-treated plants. Foliar spray with LDPH and especially SwE elicited significant increases in marketable fresh yield (averaging 14%, 6% and 7% at 10, 20 and 30 kg N·ha−1, respectively) compared to TPE and untreated plants. Improved agronomical performance of baby lettuce under optimal (10 kg N ha−1) and especially suboptimal N regimens (0 kg N ha−1) was associated with increasing photochemical efficiency and a better activity of photosystem II (higher Soil Plant Analysis Development-SPAD index and chlorophyllous pigments biosynthesis). The application of LDPH enhanced antioxidant capacity and TAA in baby lettuce leaf and did not increased nitrate content as recorded in SwE and TPE treatments. Overall, plant biostimulants may be considered as a sustainable tool of production to increase leafy vegetable productivity in low fertility soils.
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Claims 11
Claim · model-written summary
Fresh yield of baby lettuce was positively affected by increasing N rates from 0 to 20 kg N·ha−1 and reached a plateau at 30 kg N·ha−1.
- Taxon
- baby lettucee0
- Treatment
- increasing N rates from 0 to 20 kg N·ha−1e1
- Outcome
- fresh yielde1
- Direction
- positively affectede1
- Qualifier
- reaching a plateau thereaftere1
- Setting
- plastic tunnele0
Not reportedComparator
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e1“The fresh yield of baby lettuce in both biostimulant-treated and untreated plants was positively affected by increasing N rates from 0 to 20 kg N·ha−1, reaching a plateau thereafter indicating luxury N conditions at 30 kg N·ha−1”
Claim · model-written summary
High N fertilizer application (20 and 30 kg N·ha−1) decreased antioxidant activities and total ascorbic acid (TAA) of baby lettuce.
- Taxon
- baby lettucee0
- Treatment
- high N fertilizer application (20 and especially 30 kg N·ha−1)e2
- Outcome
- antioxidant activities and total ascorbic acid (TAA)e2
- Direction
- decreasese2
Not reportedComparator
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e2“high N fertilizer application (20 and especially 30 kg N·ha−1) resulted in undesirable decreases in antioxidant activities and total ascorbic acid (TAA)”
Claim · model-written summary
Under non-fertilized regimens, foliar plant biostimulants increased growth and yield of baby lettuce compared with non-treated plants.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e3“Under non-fertilized regimens, foliar PBs application boost growth and yield of baby lettuce in comparison to non-treated plants”
Claim · model-written summary
Foliar LDPH and especially SwE significantly increased marketable fresh yield of baby lettuce by 14% at 10 kg N·ha−1 compared with TPE and untreated plants.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e4“Foliar spray with LDPH and especially SwE elicited significant increases in marketable fresh yield (averaging 14%, 6% and 7% at 10, 20 and 30 kg N·ha−1, respectively) compared to TPE and untreated plants”
Claim · model-written summary
Foliar LDPH and especially SwE significantly increased marketable fresh yield of baby lettuce by 6% at 20 kg N·ha−1 compared with TPE and untreated plants.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e4“Foliar spray with LDPH and especially SwE elicited significant increases in marketable fresh yield (averaging 14%, 6% and 7% at 10, 20 and 30 kg N·ha−1, respectively) compared to TPE and untreated plants”
Claim · model-written summary
Foliar LDPH and especially SwE significantly increased marketable fresh yield of baby lettuce by 7% at 30 kg N·ha−1 compared with TPE and untreated plants.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e4“Foliar spray with LDPH and especially SwE elicited significant increases in marketable fresh yield (averaging 14%, 6% and 7% at 10, 20 and 30 kg N·ha−1, respectively) compared to TPE and untreated plants”
Claim · model-written summary
Improved agronomical performance of baby lettuce under optimal and suboptimal N regimens was associated with increasing photochemical efficiency and a better activity of photosystem II.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e5“Improved agronomical performance of baby lettuce under optimal (10 kg N ha−1) and especially suboptimal N regimens (0 kg N ha−1) was associated with increasing photochemical efficiency and a better activity of photosystem II”
Claim · model-written summary
Under optimal and suboptimal N regimens, baby lettuce had higher SPAD index and chlorophyllous pigments biosynthesis associated with improved agronomical performance.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e5“Improved agronomical performance of baby lettuce under optimal (10 kg N ha−1) and especially suboptimal N regimens (0 kg N ha−1) was associated with increasing photochemical efficiency and a better activity of photosystem II”
e6“higher Soil Plant Analysis Development-SPAD index and chlorophyllous pigments biosynthesis”
Claim · model-written summary
The application of LDPH enhanced antioxidant capacity and TAA in baby lettuce leaf.
- Taxon
- baby lettucee0
- Organ / stage
- leafe7
- Treatment
- LDPHe7
- Outcome
- antioxidant capacity and TAAe7
- Direction
- enhancede7
Not reportedComparator
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e7“The application of LDPH enhanced antioxidant capacity and TAA in baby lettuce leaf and did not increased nitrate content as recorded in SwE and TPE treatments”
Claim · model-written summary
The application of LDPH did not increase nitrate content of baby lettuce, unlike SwE and TPE treatments.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e7“The application of LDPH enhanced antioxidant capacity and TAA in baby lettuce leaf and did not increased nitrate content as recorded in SwE and TPE treatments”
Claim · model-written summary
Plant biostimulants may be considered a sustainable tool to increase leafy vegetable productivity in low fertility soils.
Verbatim
e0“An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop”
e7“plant biostimulants may be considered as a sustainable tool of production to increase leafy vegetable productivity in low fertility soils”
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