Mitiku Haile

Improving crop productivity largely depends on understanding soil fertility constraints and the effects of nutrient management on yield performance. Accurate determination of existing soil nutrient status and targeted application of limiting nutrients are essential for enhancing wheat (Triticum spp.) productivity. However, the specific effects of omitting one of the macronutrients such as nitrogen (N), phosphorus (P), or potassium (K) on wheat yield have not been investigated in the target area. This study employed the Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model to estimate the N, P, and K fertilizer requirements needed to achieve a predefined wheat yield target. The objectives were to: (i) evaluate yield responses to complete versus nutrient omission (N, P, or K) fertilization treatments, and (ii) analyze corresponding nutrient uptake and use efficiency dynamics. The experimental treatments included: (1) full NPK fertilization, (2) NP only (K omitted), (3) NK only (P omitted), (4) PK only (N omitted), and (5) an unfertilized control. Topsoil samples were analyzed and used as inputs for the QUEFTS model. Yield and agronomic data, as well as nutrient uptake and use efficiency, were measured. Model performance was validated using standard statistical metrics. Results showed that full NPK application significantly (p < 0.05) improved yield, yield components, and nutrient uptake compared to omission treatments and the control. The strong agreement between QUEFTS-predicted and observed yields highlights the model’s potential as a reliable, cost-effective decision-support tool for optimizing site-specific fertilizer recommendations. These findings demonstrate that balanced NPK fertilization markedly boosts wheat yield and nutrient uptake, while the QUEFTS model provides a powerful, reliable tool for tailoring fertilizer management to local soil conditions.

This study quantified how soil and water conservation (SWC) practices, slope position, and soil depth influence labile and recalcitrant carbon (LC, RC) and nitrogen (LN, RN) fractions in the Tigray highlands of northern Ethiopia. Ninety‐six composite soil samples were collected from four SWC‐treated subwatersheds, Mechahile (20.54 ha), Hararu (9.45 ha), Abdi‐Ruba (10.37 ha), and Rva (11.30 ha), and four untreated ones—Endacherkos (12.06 ha), Lihay (8.95 ha), Bringede (14.40 ha), and Zban‐Dera (19.25 ha). Two factorial experiments (management × slope × depth; distance × slope × depth) were established, each with 12 treatments across 48 plots. Data were analyzed in R (v4.2.3) using ANOVA and Tukey’s HSD at p < 0.05. SWC practices and slope position significantly increased LN and RN ( p < 0.001), with LN rising from 0.00115 to 0.00155 mg g ⁻¹ and RN from 1.29 to 1.71 mg g ⁻¹ on treated lower slopes. Similarly, LC increased from 0.0269 to 0.0451 mg g ⁻¹ and RC from 33.6 to 56.3 mg g ⁻¹ , indicating strong enrichment of both labile and stable pools. All fractions were higher at 4 m than at 8 m from SWC structures, showing nutrient accumulation near conservation features. Overall, SWC structures enhanced soil organic carbon and total nitrogen, particularly on lower slopes, by improving both fast‐cycling and stable fractions. The findings highlight slope‐specific management and optimized SWC spacing as critical strategies for maximizing soil C and N sequestration, fertility restoration, and sustainable land management in erosion‐prone drylands.

The Tigray war in northern Ethiopia (2020–2022) had substantial environmental impacts due to fighting, blockade, and power outages. This study contrasts post-war observations at 56 sites with 26 years of legacy data on land degradation, a rare before-and-after analysis by the same research team, in Dogu’a Tembien, a district of Tigray that did not experience large influxes of internally displaced people. The qualitative repeat study used transect walks alongside group observations and discussions. Unlike the war and environmental catastrophe of the 1980s in Tigray, basic soil conservation interventions including stone bunds, check dams and forest conservation have served as buffers against the conflict's repercussions. However, notable geomorphic changes occurred in battlefield areas and downriver banks. Still, restoration efforts over the last 30 years have largely withstood degradation. Under challenging conditions, farmers have maintained most soil conservation systems. Many gullies remained stable, although some formed due to enhanced water channeling in the upper area. The conflict caused a decline in woody vegetation, but, away from the main roads, many forests remained in good condition. Farmer-led irrigation expanded, supported by good spring discharges, improved marketing conditions for local produce due to isolation, and the lack of off-farm work opportunities. We attribute this land system resilience not only to long-term conservation investments, but also to the co-production of resilience through social and ecological systems. The intrinsic properties of the land (clayey, stony soils, stress-adapted vegetation, and reduced hydrological connectivity) helped buffer degradation. Meanwhile, communal land ethics, informal institutions, and local stewardship practices persisted despite the collapse of state support, echoing long-standing tenure traditions. In some areas, however, these systems frayed, revealing the spatial and social contingency of resilience. Our findings contribute to land resilience theory by showing how ecological durability and socio-political agency interact to shape land outcomes under crisis.

Wheat is a vital staple crop addressing significant nutritional needs. However, it faces micronutrient deficiencies in Ethiopia, prompting the use of balanced nutrient fertilizers to obtain better yields, nutrient concentration, and nutritional quality. This study investigated the effect of different P and Zn fertilizer combinations on wheat yield and nutrient use efficiency across three locations in Tigray, Ethiopia. A randomized complete block design (RCBD) was used with four P levels (0, 10, 20, and 30 kg P ha⁻¹), and three Zn levels (0, 5, and 10 kg Zn ha⁻¹) in three replications. A balanced application of P and Zn fertilizers significantly increased wheat grain and biomass yields, while applying higher rates of both nutrients (i.e., 30 kg P ha⁻¹ and 10 kg Zn ha⁻¹) reduced yields. The combined application of 20 kg P ha⁻¹ and 5 kg Zn ha⁻¹ achieved the best yield, which also improved Zn use efficiency. Increasing Zn application (from 5 to 10 kg Zn ha⁻¹) while reducing P (from 20 to 10 kg P ha⁻¹) enhanced Zn concentration in wheat grain. These findings highlight the importance of carefully managing P and Zn fertilization to optimize grain yield and Zn bioavailability, contributing to improved food security in diverse agro-climatic conditions.

Wheat is a vital staple crop globally, addressing significant nutritional needs. In Ethiopia, the excessive application of nitrogen (N) and phosphorus (P) fertilizers can reduce crop production, including wheat. Additionally, excessive phosphorus application can limit zinc (Zn) uptake, making it essential to balance these nutrients to enhance yield and nutrient availability. Agricultural soils often face micronutrient deficiencies, prompting the promotion of blended multi-nutrient fertilizers. This study examined how different combinations of Zn and P fertilizers affect wheat yield and nutrient efficiency in Tigray, Northern Ethiopia, across three locations during the 2019 and 2020 cropping seasons. A randomized complete block design (RCBD) was used to assess varying P (0, 10, 20, 30 kg P ha-1) and Zn (0, 5, 10 kg Zn ha-1) application rates. Results showed that applying up to 20 kg P ha-1 significantly increased wheat grain and biomass yield, while 5 kg Zn ha-1 also boosted yield. However, excessive rates of both nutrients reduced yields, highlighting the importance of balanced application. The best results were achieved with 20 kg P ha-1 and 5 kg Zn ha-1, improving yield, nutrient efficiency, and zinc bioavailability, which can enhance wheat quality and support food security in diverse agro-climatic conditions.