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This study aims to investigate the effects of polyacrylamide (PAM) alone or integrated with other soil amendments on soil fertility and Teff (Eragrostis tef (Zucc.) Trotter) yield. A field experiment was carried out for 2 years in three contrasting agroecological zones of the Upper Blue Nile basin, Ethiopia, using a randomized complete block design with 3 replicates. The amendments applied were PAM (40 kg ha−1), biochar (B, 8 t ha−1), lime (L, 4 t ha−1), gypsum (G, 5 t ha−1), farmyard manure (FYM, 5 t ha−1), PAM + B, PAM + L, and PAM + G, and control. The results showed that PAM + L, PAM + B, and L treatments noticeably improved pH, available phosphorus (Pav), total nitrogen (TN), organic carbon, and water infiltration in the Aba Gerima and Guder soils, whereas the PAM + B, B, and FYM treatments expressively increased soil water content, Pav, and TN in the Dibatie soil. Likewise, compared with the control, teff yield significantly (p

The temporal dynamics of soil respiration change in response to different land management practices is not well documented. This study investigated the effects of soil bunds on the monthly and diurnal dynamics of soil respiration rates in the highlands of the Upper Blue Nile basin in Ethiopia. Six plots (with and without soil bunds, three replicates) were used for measurement of seasonal soil respiration, and eighteen plots were used for measurement of diurnal soil respiration. We collected seasonal variation data on a monthly basis from September 2020 to August 2021. Diurnal soil respiration data were collected four times daily (5 a.m., 11 a.m., 5 p.m., and 11 p.m.) for two weeks from 16–29 September 2021. A Wilcoxon signed-rank test showed that seasonal soil respiration rates differed significantly (p 2 m− 2 s− 1, mean ± SE) and highest in October (14.54 ± 0.5 µmol CO2 m− 2 s− 1). Diurnal soil respiration rate was significantly (p

Soil structural stability is a vital aspect of soil quality and functions, and of maintaining sustainable land management. The objective of this study was to compare the contribution of four long-term land-use systems (crop, bush, grass, and forest) coupled with anionic polyacrylamide (PAM = 0, 25, and 200 mg L&minus, 1) application on the structural stability of soils in three watersheds of Ethiopia varying in elevation. Effect of treatments on soil structural stability indices were assessed using the high energy moisture characteristic (HEMC, 0&ndash, 50 hPa) method, which provides (i) water retention model parameters &alpha, and n, and (ii) soil structure index (SI). Soil (watershed), land use and PAM treatments had significant effects on the shape of the water retention curves (&alpha, n) and SI, with diverse changes in the macropore sizes (60&ndash, 250, &gt, 250 &mu, m). Soil organic carbon (SOC) content and SI were strongly related to soil pH, CaCO3 soil type-clay mineralogy, exchangeable Ca2+, and Na+ (negatively). The order of soil SI (0.013&ndash, 0.064 hPa&minus, 1) and SOC (1.4&ndash, 8.1%) by land use was similar (forest &gt, grass &gt, bush &gt, cropland). PAM effect on increasing soil SI (1.2&ndash, 2.0 times), was inversely related to SOC content, being also pronounced in soils from watersheds of low (Vertisol) and medium (Luvisol) elevation, and the cropland soil from high (Acrisol) elevation. Treating cropland soils with a high PAM rate yielded greater SI (0.028&ndash, 0.042 hPa&minus, 1) than untreated bush- and grassland soils (0.021&ndash, 0.033 hPa&minus, 1). For sustainable management and faster improvement in soil physical quality, soil properties, and land-use history should be considered together with PAM application.

Improving our understanding of how different land uses and management practices affect soil nutrient outflows in sub-Saharan Africa could aid in developing sustainable practices. The objective of this study was to analyse the variation in outflows of soil total nitrogen (TN) and available phosphorus (Pav) as influenced by land use types (cropland, grazing land, and bushland) and land management practices (soil bunds for cropland and exclosures for non-croplands) in the three contrasting agro-ecological zones of the Upper Blue Nile basin, Ethiopia. Field data were collected for TN and Pav outflows by water erosion (Eo), leaching (Lo), product harvest (Ho), and gaseous emissions (Go) from 18 runoff plots (30 m × 6 m) for two years (2018-2019). TN and Pav losses significantly varied (p 0.05) in nutrient losses. Cropland showed significantly higher TN and Pav losses than other land use types, but TN loss did not differ significantly between grazing and bushland. In all land use types at all sites, the magnitude of nutrient losses was Ho >Eo >Lo >Go. In plots with land management practices, TN and Pav losses associated with Eo, Lo, and Go were reduced on average by 44-76%, 9-47%, and 1%-36%, respectively. These practices were most effective to reduce Eo nutrient losses. Further study is required to analyzing the soil nutrient balance and identify priority areas for implementing mitigation measures.