In field conditions the combined application of aqueous extracts from the cyanobacterium Arthrospira platensis (seeds) and the microalga Nannochloropsis oculata (foliar) enhanced the corn (Zea mays L.) yield
摘要
In recent years algae (seaweeds and microalgae) and cyanobacteria have become increasingly important in agriculture as potential sources of biostimulants and biofertilizers that can improve the growth of various crops. As a result, it is of interest to explore this potential in actual field settings. The aim of this study was to evaluate the individual and combined effects of aqueous extracts from microalgae and biofertilizers derived from macroalgae on corn (Zea mays) in field conditions. A 7 × 3 blocked factorial design with 21 treatments, and four replicates was used. The primary factor included seven seed treatments, including a control group, aqueous extracts of microalgae Arthrospira platensis, Nannochloropsis oculata, Tetradesmus obliquus, and Chaetoceros muelleri, as well as commercial biofertilizers based on Kappaphycus alvarezii and Ascophyllum nodosum. The secondary factor comprised three foliar treatments, including a control group, N. oculata aqueous extract, and commercial biofertilizers based on K. alvarezii and A. nodosum. Commercial products were applied at 3 mL kg–1 seeds (equivalent to 75 mL ha–1) for seed treatment, while aqueous microalgae extracts were applied at 170 mg kg–1 seeds (equivalent to 4.3 g ha–1). For foliar treatments, on days 33 and 48 after sowing, the microalgae extract was applied at a rate of 40 g ha–1, while the commercial product was applied at 300 mL ha–1 as recommended by the manufacturer. Foliar application of K. alvarezii/A. nodosum commercial biofertilizer and N. oculata seed treatment resulted in significantly higher (p < 0.05) leaf area indices compared with foliar application of commercial biofertilizer and control seed treatment. The number of grain rows per ear increased significantly (p < 0.05) by 8.16% when using K. alvarezii/A. nodosum commercial biofertilizer seeds treatment compared to the seed control treatment. Compared with the foliar control group, foliar application of K. alvarezii/A. nodosum commercial biofertilizer and N. oculata extract significantly increased the height of the first ear insertion by 5.6% and 4.0%, respectively, and also significantly increased corn plant height by 5.34% and 4.44%, respectively. When C. muelleri seed treatment was used alone, it resulted in an absolute increase of 27.41% in corn yield (2,837 kg ha–1). The combination of T. obliquus seed treatment with foliar treatment using K. alvarezii/A. nodosum commercial biofertilizer resulted in an absolute increase of 29.54% in corn yield (3,057 kg ha–1). The most significant increase (p < 0.05) in corn yield occurred with the combination of A. platensis seed treatment and N. oculata foliar treatment, leading to a 38.24% increase in corn yield (3,957.6 kg ha–1). These results suggest that utilizing biomass from microalgae species like C. muelleri and T. obliquus, as well as a combination of A. platensis and N. oculata, could be advantageous in developing biostimulants for corn crops.
Graphical Abstract