International Journal of Agronomy

Nowadays, the inoculation of plant growth-promoting rhizobia in leguminous and nonleguminous crops is given great emphasis as it improves germination and seedling vigor, resulting in increased yields. In this study, 32 rhizobia isolates were obtained from five different sampling sites in Tigray, Ethiopia. Based on morphological, biochemical, and confirmatory tests, including sugar fermentation, the isolates were identified as belonging to the rhizobia genera. In vitro assessment of plant growth-promoting properties revealed that all isolates produced indole-acetic-acid, ammonia, and solubilized phosphate, except TA8, which did not solubilize phosphate. Only 3 isolates (TA1, TA2, and TA8) produced hydrogen cyanide, so they can be used as biocontrol agents. Nineteen isolates showed a growth reduction activity against Fusarium oxysporum, with a percent inhibition range of 34.2%–65.8%. All isolates tolerated a pH range of 4.0–9.0. The isolates showed growth variations in various temperatures and salt concentrations. A few isolates were tolerant up to 45°C temperature and 6% (w/v) CaCl₂ and NaCl concentrations. Inoculation of the isolates to wheat seeds increased seed germination, seedling shoot/root length, and seedling vigor index compared to the positive and negative controls. Isolates KO3, KO4, ME3, and TA5 increased seed germination by 4%. KO1 (11.60 cm) and TA7 (11.70 cm) showed a significantly enhanced shoot length, and ME3 showed a maximum root length (13.90 cm). SH1, KO2, and the positive control showed a significant () increase in pea seed germination (by 20%) compared to the negative control. The positive control had the longest field pea shoot (5.70 cm), and isolate TA9 had the longest field pea root (5.32 cm) compared to the negative control. Generally, the wheat and field pea seedlings responded differently to the inoculation of different isolates. This study shows that Tigray soils harbor a variety of rhizobia species, which can be used as plant growth-promoting and biocontrol agents.

Smallholder farmers’ access to and use of quality seeds of improved varieties and hybrids is an integral component of sustainable maize production and the reduction of the yield gap in Ethiopia. Formal seed supply systems play a pivotal role in ensuring farmers’ access to good quality seed and increasing the productivity of maize. However, the contribution of the formal seed system to the increase in the average national maize yield in the country is not well documented. This paper specifically analyzes the formal seed supply systems and contributions of improved seed to maize productivity increase in Ethiopia. Secondary sources of information, including published and unpublished data, were used. Analysis of the seed value chain from research to commercial seed producers indicated that public and private maize hybrids dominate the formal seed system. Increased use of improved seed and associated management practices has contributed to the yield increase at the national level. For every 10,000 MT of additional maize-improved seed used by smallholder farmers, the national average maize yield increased by 400 kg per hectare (R sq. = 0.59). Hence, in addition to other yield-increasing technologies and extension support, ensuring the availability of improved seed to farmers can significantly contribute to reducing the maize yield gap between the national average yield and the average yield from on-farm demonstrations already attained by farmers in Ethiopia. Various policy interventions are suggested to improve the maize seed system performance and increase the supply of maize improved seeds.

An initial investigation into the utilization of recycled plant and animal residues as soil amendments (SAs), including compost, biochar, and soil conditioner, was conducted using alfalfa crops. This study evaluated the impact of SAs on alfalfa seed germination, resulting in an 87% germination rate for biochar, 82% for soil conditioner, and 82% for compost. In comparison, untreated seeds displayed a 78% germination rate. After successful germination, the SAs were employed to enhance soil health, with a focus on water conservation and increased forage yield. The study used sandy-textured soil with moderate alkalinity, very slight salinity, slight calcareousness, and high permeability. The germination trial confirmed that SAs usage did not hinder seed germination, even for salt-sensitive crops like alfalfa. Two field experiments were carried out in Al-Wafra, using different application rates of compost, biochar, and soil conditioner at 5, 7.5, and 10 tons per hectare. The results highlighted the positive impact of SAs application on increasing forage production, with varying degrees of enhancement, and confirmed a 40% reduction in water usage compared to treatment without SAs but under 100% irrigation (100% ETc). In conclusion, SAs show promising potential for local forages intensification and water conservation.

In the last two decades, the electromagnetic field of the microwave range has been successfully introduced into various branches of the agribusiness industry as one of the most promising and advanced technologies for drying manufactured products. In this regard, the article proposes a new microwave irradiation technique for drying various objects based on a surface waveguide’s properties. The paper analyses the main links that make up the surface waveguide as a microwave irradiation system and shows the ways of their implementation. The article describes the advantages of applying a vibratory device for exciting a surface wave, using a re-emitting antenna array, and operating a single conductor with a dielectric coating as a surface waveguide. Such advantages make it possible to introduce microwave drying units with the required distribution of electromagnetic field energy along the irradiated material, small dimensions, high drying quality, and low price.

A field study was conducted to evaluate faba bean varieties for yield and yield components and disease reactions in the Lay Gayint district during the 2020 and 2021 cropping seasons. Six faba bean varieties, including local, were arranged in a randomized complete block design with three replications. The crop and disease data were collected, and the disease severity was assessed five times in 7 and 10 days intervals using the disease rating scale for chocolate spot and faba bean gall disease, respectively. The combined analysis variance showed significant differences among faba bean varieties in agronomic traits, disease severity, and area under the disease progress curve. The variety Numan had a higher chocolate spot (46.52%) and faba bean gall (40.46%) disease severity. The area under the disease progress curve (AUDPC) of the chocolate spot was higher on local (1292.85%-days). For faba bean gall, a higher AUDPC value (994.08%-days) was calculated from the Numan variety. The lowest severity of chocolate spot (27.37%) and faba bean gall (21.02%) was assessed from the variety Gora, and this variety also had the lowest chocolate spot AUDPC. The variety Gora and Ashebeka provided the highest grain yield (21988 kg·ha⁻¹) and (20624 kg·ha⁻¹), respectively. The results of the correlation analysis also indicated that the highest yield was associated with lower disease occurrence. In conclusion, varieties Gora and Ashebeka are found to be moderately resistant varieties to chocolate spot and faba bean gall disease than other varieties with higher yields, and these varieties are recommended for production in the study area and other similar ecologies.

Root-knot nematode (Meloidogyne incognita) poses a significant threat to okra production, resulting in substantial yield losses. The objectives of this study were to assess the impact of biological seed protectants on the growth and establishment of okra plants and nematode population reduction in soil. Okra seeds were coated with 40% sesame oil, 50% neem oil, 100% citrus oil, velum at 3.8 ml/7l of water, and a control (sterilized distilled water) at different time intervals of 30 min, 60 min, 90 min, and 120 min to determine the germination percentages and vigor. The experimental setup was laid out in a completely randomized design (CRD), with three replications, utilizing a Jacobson table for the germination test. The laboratory results demonstrated significant differences () in germination percentage and vigor index across the different time intervals. Neem oil, citrus oil, and velum exhibited higher germination percentages and vigor indices at all time intervals. Notably, 30-minute time interval proved to be efficient with 100% citrus oil producing 80.33% germination and 965 vigor index and 50% neem oil producing 75% germination and 994 vigor index. Field evaluations revealed citrus at 100% concentrations as seed coating (T5) and neem at 50% concentrations as seed coating (T3), with the highest nematode reductions (90.1% and 90.4%) and least reproductive factors (RFs) of 0.05 and 0.04, respectively, at the Atomic farms. The study has revealed that treating okra seeds with 100% citrus oil and 50% neem oil has the efficacy of reducing nematode reproduction in soil, while enhancing germination and seedling vigor, together with an improvement in growth and yield. Sesame oil has a negative influence on seed germination and vigor and is therefore not recommended as a preplant protectant.