Innovative Biofertilizers: An Eco-Friendly Approach for Soil Improvement

Seed potato production often relies on mineral fertilizers. However, biofertilizers offer an eco-friendly, cost-effective means to enhance nutrient uptake, plant growth, yields, and quality while bolstering stress resilience. Two cultivars (‘Spunta’ and ‘Russet’), two in vitro materials as microtubers and plantlets, and four bio-fertilizers were used to produce seed minitubers. These bio-fertilizers included mycorrhiza (T2), microalgae (T3), beneficial bacteria (PGPR) (T4), and vermicompost (T5). Treatment T1, which received 100% mineral nutrients, was used as the control, while the bio-fertilizers were given 40% of the mineral nutrition relative to the control. The study clearly demonstrated the effectiveness of the biofertilizers used in improving plant growth parameters, particularly highlighting the efficacy of vermicompost. The highest seed tuber yield of 173.12 g was obtained from the combination of ‘Spunta’ + microtuber + vermicompost’. In both varieties, in vitro microtubers led to a higher seed yield than in vitro plantlets. In terms of tuber diameter, tuber weight, and tuber number, the performance of the ‘Spunta’ cultivar was significantly higher than that of the ‘Russet’ cultivar. Seed tubers derived from in vitro microtubers had a larger diameter and were heavier than those derived from in vitro plantlets. However, seed tubers produced from in vitro plantlets were of a smaller size but more in number. In in vitro potato seed tuber production, we recommend the use of ‘Spunta’ cultivar and in vitro microtuber, supplementing with vermicompost to enhance yield, size, number curbing costs, and eco-friendliness. Full article

Biofertilizers and biocontrol agents have been improved for several decades as microbiological tools that can provide beneficial outcomes in the growth and health of plants. Two field experiments were performed in the Scientific Farm of the Horticulture Department, Faculty of Agriculture, Minia University, Egypt during the winter of 2022/2023 using clay loam soil. Control plots were treated with the recommended rates of mineral fertilizer of NPK (100%) without inoculation, while other plots were inoculated with Egyptian isolates of effective microorganisms (EMs) (a mixture of Azotobacter chroococcum and Azospirillium brasilense) and strains of Bacillus spp.; the biofertilizers were applied to the soil through mixing with irrigation water. For mycorrhizae, Glomus mosseae and Glamus fasiculatum isolation stock cultures were combined to create the mycorrhizal inoculum. The results showed that biofertilizers with 75% NPK were the best. Biofertilizers changed the properties of soil, increased its content of beneficial microorganisms, increased the total good quality production of onion and potato and decreased the stress of chemical pesticides and mineral fertilizers on crop growth and productivity. Full article

Developing effective regulatory strategies to enhance irrigation water and fertilizer efficiency in the southern Xinjiang region of China, while simultaneously combatting desertification, is of paramount significance. This study focuses on Chinese jujube in Xinjiang and presents findings from a two-year field experiment aimed at investigating the optimal application strategy of microbial organic fertilizer (MOF). The research aims to provide a scientific foundation for achieving high-quality jujube production. The experiment involved a control group (utilizing only freshwater, referred to as CK) and various combinations of MOF treatments. In 2021, these treatments included M1 (0.6 t/ha), M2 (1.2 t/ha), M3 (1.8 t/ha), and M4 (2.4 t/ha), while in 2022, they encompassed M1 (0.6 t/ha), M2 (1.2 t/ha), M4 (2.4 t/ha), and M5 (4.8 t/ha). Over the two-year trial period, we assessed various indices, including the soil’s physical properties, hydraulic characteristics, soil enzyme activities, and relative chlorophyll content. Additionally, we evaluated jujube yield, quality, and economic benefits. The results indicate that MOF application led to significant improvements in soil conditions. Specifically, the average moisture content and profile water storage of the 0–50 cm soil layer increased by 10.98% to 36.42% and 1.8% to 26.8%, respectively. Moreover, in both the 2021 and 2022 experiments, soil saturated water content (SSWC) and water-holding capacity (WHC) increased by 6.25% to 15.98%, while soil hydraulic conductivity (Ks) and bulk density (BD) decreased by 2.91% to 9.88% and 0.63% to 8.08%, respectively. In 2021, MOF application resulted in significant enhancements in soil enzyme activities, with urease activity increasing by approximately 22.5% to 100.5%, peroxidase activity rising by around 24.2% to 148.5%, and invertase activity augmenting by about 5.4% to 32.9%. Notably, the M4 treatment in 2021 demonstrated a substantial jujube yield increase of approximately 19.22%, elevating from 7.65 t/ha to 9.12 t/ha. Based on comprehensive analysis, this study recommends an optimal MOF application rate of approximately 2.4 t/ha. This approach not only provides robust support for the sustainable development of the jujube industry but also serves as a valuable reference for enhancing local soil resilience against desertification. Full article

The present investigation was carried out to study the differential responses to assimilated nutrient management in the cabbage–capsicum–radish cropping system to develop an integrated plant nutrient supply. The experimental trial was laid out in a randomized complete block design (RCBD) with three replicates and included assimilations of 15 various combinations: T₁—recommended dose of fertilizers (RDFs) + farmyard manure (FYM) (Control); T₂—nitrogen and phosphorus (NP) + vermicompost (VC) (75% + 2.5 t/ha); T₃—NP + VC (50% + 2.5 t/ha); T₄—NP + enriched compost (EC) (75% + 2.5 t/ha); T₅—NP + EC (50% + 2.5 t/ha); T₆—NP + plant-growth-promoting rhizobacteria (PGPR) (75% + 5 kg/ha); T₇—NP + PGPR (50% + 5 kg/ha); T₈—NP + VC + PGPR (75% + 2.5 t/ha + 5 kg/ha); T₉—NP + VC + PGPR (50% + 2.5 t/ha + 5 kg/ha); T₁₀—NP + EC + PGPR (50% + 2.5 t/ha + 5 kg/ha); T₁₁—NP + EC + PGPR (50% + 2.5 t/ha + 5 kg/ha); T₁₂—NP + VC and EC (75% + 2.5 t/ha and 2.5 t/ha); T₁₃—NP + VC and EC (50% + 2.5 t/ha and 2.5 t/ha); T₁₄—NP + VC and EC + PGPR (75% + 2.5 t/ha and 2.5 t/ha + 5 kg/ha); T₁₅—NP + VC and EC + PGPR (50% + 2.5 t/ha and 2.5 t/ha + 5 kg/ha) for two consecutive years. Seedlings of the cabbage cultivar were transplanted with a spacing of 45 × 30 cm, whereas the capsicum seedlings were transplanted with a spacing of 60 × 45 cm. The radish cultivar was sown directly in the field with a spacing of 30 × 7.5 cm. The yield and growth attributes of all three crops were notably impacted by the INM modules. The utilization of a combination of 75% of the recommended quantity of NP + VC and EC, along with PGPR, at a rate of 2.5 t/ha, during cabbage cultivation, led to a noteworthy rise in plant height, equatorial diameter, gross head weight, net head weight, and ultimately, the maximum head yield, as per the statistical analysis. In the case of capsicum, the treatment (T₁₄) module demonstrated superior performance in terms of the major yielding components, namely, fruit size, fruit weight, and number of fruits per plant, resulting in the highest yield compared to the other modules, including RDFs. The cabbage exhibited high protein content and inorganic modules in terms of quality traits, whereas ascorbic acid and total soluble solids (TSSs) levels were high due to strong organic support across all three crops. Thus, it can be inferred that the integrated combination of 75% NP, VC, and EC at 2.5 t/ha, and PGPR, along with the basic application of the full recommended potash and farmyard manure (FYM), led to a reduction of 25% in fertilizers (NP), improved growth and yield, and higher annual net returns. Thus, this incorporation can be suggested as an economically efficient strategy for consistently attaining increased productivity with enhanced excellence. Full article

Entomopathogenic fungi Metarhizium species are generally employed to manage the soil-dwelling stage of insect pests, and are known for their rhizocompetency property. Since this fungus is typically recommended for use in soil, it could potentially be investigated as a bioinoculant to reduce abiotic stress, such as salinity, along with improved plant growth promotion. Salt stress tolerance potential of native Metarhizium isolates was evaluated based on mycelial fresh weight, dry weight, and spore yield. All the isolates were found to tolerate NaCl concentrations (50 mM, 100 mM, 150 mM, 200 mM, 250 mM, and 300 mM) supplemented in the culture medium. Metarhizium anisopliae (AAUBC-M15) and Metarhizium pinghaense (AAUBC-M26) were found to be effective at tolerating NaCl stress up to 200 mM NaCl. These two isolates were analyzed in vitro for plant growth-promoting traits at elevated salt concentrations (100 and 200 mM NaCl). No significant effect on IAA production was reported with the isolate M. pinghaense (AAUBC-M26) (39.16 µg/mL) or in combination with isolate M. anisopliae (AAUBC-M15) (40.17 µg/mL) at 100 mM NaCl (38.55 µg/mL). The salinity stress of 100 mM and 200 mM NaCl had a significant influence on the phosphate solubilization activity, except in the co-inoculation treatment at 100 mM NaCl. The isolates were positive for ACC deaminase enzyme activity. An increase in salt concentration was accompanied by a steady and significant increase in chitinase enzyme activity. Total phenolics (149.3 µg/mL) and flavonoids (79.20 µg/mL) were significantly higher in the culture filtrate of Metarhizium isolates at 100 mM NaCl, and gradual decline was documented at 200 mM NaCl. M. pinghaense (AAUBC-M26) proved to be promising in reducing the salt stress in tomato seedlings during the nursery stage. In the pot culture experiment, the treatment comprising soil application + seedling root dip + foliar spray resulted in improved growth parameters of the tomato plant under salt stress. This study shows that Metarhizium, a fungus well known for controlling biotic stress brought on by insect pests, can also help plants cope with abiotic stress, such as salinity. Full article

Fennel fruits (Foeniculum vulgare Mill.) represent one of the plant-based natural spices. This study aims to improve the fruit yield and essential oil (EO) quality by reducing the undesirable component, estragole, under different fertilizer treatments. The fertilizers included chemical nitrogen, phosphorus, and potassium (NPK), and also the organic additive, rabbit manure (RM). For bio-fertilization, plants were inoculated with a mixture of N-fixing bacteria, and P- and K-solubilizing bacteria with/without vesicular-arbuscular mycorrhizal fungi. The results showed that fruit and EO yield parameters, total phenolic content (TPC), total flavonoid content (TFC), and DPPH scavenging activity of fruit extracts were enhanced by fertilizer treatments in both growing seasons. NPK at 150% of the recommended dose (NPK150) and RM at 60 m³/fed (RM60) recorded the highest values of plant height, umbel number/plant, 100-fruit weight, fruit yield, chlorophyll, carbohydrates, N and P content, EO content, and yield. TPC and TFC were enhanced by using biological fertilizers. DPPH scavenging activity was higher in organically and biologically fertilized fennel. The GC-MS analyses of EO revealed higher contents of the desirable trans-anethole in the organically and chemically fertilized fennel. However, the highest proportion of estragole, the undesirable compound, was recorded for NPK150 and unfertilized plants. On the contrary, increases in the EO content and yield of fennel fruits were achieved by RM along with a reduction in estragole, enhancement in trans-anethole, and increments in other favorable compounds such as fenchone and limonene. In addition, the inhibition of estragole formation was recorded with bio-fertilizers, which also increased the trans-anethole content. Furthermore, the trans-anethole/estragole ratio was significantly higher with the application of organic and bio-fertilization. Hence, organic and bio-fertilizer resources can produce high-quality fennel fruit and EO. The reduction in the use of chemical fertilizers can help to reduce environmental pollution. Full article