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Background and Aims Infection by the hemi-parasitic plant Striga hermonthica causes severe host plant damage and seed production losses. Increased availability of essential plant nutrients reduces infection. Whether, how and to what extent it also reduces striga-induced host plant damage has not been well studied. Methods The effects of improved macro- and micronutrient supply on host plant performance under striga-free and infected conditions were investigated in glasshouse pot assays. One striga-sensitive and two striga-tolerant genotypes were compared. Plants growing in impoverished soils were supplied with (1) 25 % of optimal macro- and micronutrient quantities, (2) 25 % macro- and 100 % micronutrients, (3) 100 % macro- and 25 % micronutrients, or (4) 100 % macro- and micronutrients. Key Results Photosynthesis rates of striga-infected plants of the sensitive genotype increased with improved nutrition (from 12.2 to 22.1 μmol m−2 s−1) but remained below striga-free levels (34.9–38.8 μmol m−2 s−1). For the tolerant genotypes, increased macronutrient supply offset striga-induced photosynthesis losses. Striga-induced relative grain losses of 100 % for the sensitive genotype were reduced to 74 % by increased macronutrients. Grain losses of 80 % in the tolerant Ochuti genotype, incurred at low nutrient supply, were reduced to 5 % by improved nutrient supply. Conclusions Increasing macronutrient supply reduces the impact of striga on host plants but can only restore losses when applied to genotypes with a tolerant background. [ABSTRACT FROM AUTHOR]

Crop rotations with residue incorporation can be beneficial to the sustainability of agriculture, however as long-term studies are required to determine effects on soil properties, farmers usually don't practice crop rotations. The objective of this study was to evaluate the effects of crop rotations with residue incorporation (0%, 50%, 100%, and 200%) on soil chemical properties of a volcanic soil after 4 years of cultivation. The evaluated rotations were canola (Brassica napus L.)-bread wheat (Triticum aestivum L.), canola-durum wheat (Triticum turgidum L.), canola-corn (Zea mays L.), bean (Phaseolus vulgaris L.)-bread wheat, bean-durum wheat, and bean-corn. The experiment consisted of six crop rotations, four levels of residue incorporation, and four replicates, analyzed as split-plot design. Samples were taken from the topsoil, and the following soil chemical properties were evaluated: pH, organic matter, electrical conductivity, nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), aluminum (Al), and sulfur (S). The results showed that crop rotations affected all the chemical properties evaluated, whereas the level of residue incorporation only affected the concentrations of exchangeable Mg and K. Most of the evaluated crops rotations had beneficial effects on the soil properties. The canola-durum wheat crop rotation recorded the lowest values in OM, available N and the exchangeable Ca, Mg, and Na. Exchangeable Mg and K had a directly proportional relationship with the level of residue incorporation. In conclusion, the incorporation of residues in different doses during 4 years of crop rotation in this volcanic soil had little effect on its chemical properties. [ABSTRACT FROM AUTHOR]

Given the importance of soil for the global carbon cycle, it is essential to understand not only how much carbon soil stores but also how long this carbon persists. Previous studies have shown that the amount and age of soil carbon are strongly affected by the interaction of climate, vegetation, and mineralogy. However, these findings are primarily based on studies from temperate regions and from fine‐scale studies, leaving large knowledge gaps for soils from understudied regions such as sub‐Saharan Africa. In addition, there is a lack of data to validate modeled soil C dynamics at broad scales. Here, we present insights into organic carbon cycling, based on a new broad‐scale radiocarbon and mineral dataset for sub‐Saharan Africa. We found that in moderately weathered soils in seasonal climate zones with poorly crystalline and reactive clay minerals, organic carbon persists longer on average (topsoil: 201 ± 130 years; subsoil: 645 ± 385 years) than in highly weathered soils in humid regions (topsoil: 140 ± 46 years; subsoil: 454 ± 247 years) with less reactive minerals. Soils in arid climate zones (topsoil: 396 ± 339 years; subsoil: 963 ± 669 years) store organic carbon for periods more similar to those in seasonal climate zones, likely reflecting climatic constraints on weathering, carbon inputs and microbial decomposition. These insights into the timescales of organic carbon persistence in soils of sub‐Saharan Africa suggest that a process‐oriented grouping of soils based on pedo‐climatic conditions may be useful to improve predictions of soil responses to climate change at broader scales. [ABSTRACT FROM AUTHOR]

Agronomic biofortification, encompassing the use of mineral and organic nutrient resources which improve micronutrient concentrations in staple crops is a potential strategy to promote the production of and access to micronutrient-dense foods at the farm level. However, the heterogeneity of smallholder farming landscapes presents challenges on implementing agronomic biofortification. Here, we test the effects of zinc (Zn)- and selenium (Se)-containing fertilizer on micronutrient concentrations of wheat (Triticum aestivum L.) and teff (Eragrostis tef (Zucc.) Trotter) grown under different landscape positions and with different micronutrient fertilizer application methods in the western Amhara region of Ethiopia. Field experiments were established in three landscape positions at three sites, with five treatments falling into three broad categories: (1) nitrogen (N) fertilizer rate; (2) micronutrient fertilizer application method; (3) sole or co-application of Zn and Se fertilizer. Treatments were replicated across five farms per landscape position and over two cropping seasons (2018 and 2019). Grain Zn concentration ranged from 26.6 to 36.4 mg kg−1 in wheat and 28.5–31.2 mg kg−1 in teff. Grain Se concentration ranged from 0.02 to 0.59 mg kg−1 in wheat while larger concentrations of between 1.01 and 1.55 mg kg−1 were attained in teff. Larger concentrations of Zn and Se were consistently attained when a foliar fertilizer was applied. Application of ⅓ nitrogen (N) yielded significantly larger grain Se concentration in wheat compared to a recommended N application rate. A moderate landscape effect on grain Zn concentration was observed in wheat but not in teff. In contrast, strong evidence of a landscape effect was observed for wheat and teff grain Se concentration. There was no evidence for any interaction of the treatment contrasts with landscape position except in teff, where an interaction effect between landscape position and Se application was observed. Our findings indicate an effect of Zn, Se, N, landscape position, and its interaction effect with Se on grain micronutrient concentrations. Agronomic biofortification of wheat and teff with micronutrient fertilizers is influenced by landscape position, the micronutrient fertilizer application method and N fertilizer management. The complexity of smallholder environmental settings and different farmer socio-economic opportunities calls for the optimization of nutritional agronomy landscape trials. Targeted application of micronutrient fertilizers across a landscape gradient is therefore required in ongoing agronomic biofortification interventions, in addition to the micronutrient fertilizer application method and the N fertilizer management strategy. [ABSTRACT FROM AUTHOR]

The article "Climate change mitigation through soil carbon sequestration in working lands: A reality check" questions the validity and realism of claims made by Almaraz et al. regarding the potential magnitude of soil carbon sequestration (SCS) in agricultural soils. The authors argue that Almaraz et al. overestimate the availability of organic matter for compost and biochar, inaccurately interpret carbon sequestration rates, and make premature assumptions about the applicability of enhanced rock weathering. They emphasize the need for realistic evaluations of the limitations and trade-offs of SCS practices and caution against overly optimistic estimates that can mislead policymakers. The authors declare no conflicts of interest. [Extracted from the article]

In sub-Saharan Africa there is increasing focus on identifying women's trait preferences within crop breeding to enable gender-responsive product development. In the case of maize, breeding programs are ready to incorporate specific traits to increase gender-responsiveness but lack guidance on what these specific traits might be. We propose an inductive approach to determine a pathway towards increasing gender-responsiveness within maize breeding. A survey of 306 farmers was conducted to determine gender differences in maize varieties used together with key agronomic practices. Variety was a significant predictor of the gender of the plot manager and of the household head in contrast to previous surveys conducted in researcher-led on-farm trials. On-farm trials are conducted using pre-defined agronomic management practices and preferences identified at harvest are likely to centre around yield. This study highlighted significant differences in several agronomic practices used by female plot managers and female household heads. Although further studies are required to understand preferences associated with varietal choice, our results suggest that current researcher-led on-farm trials may not identify gender-specific trait preferences driving varietal choice. Furthermore, a trait-specific approach is not the only avenue towards increasing gender-responsiveness in maize breeding in southern Africa. The scope for increasing gender-intentionality in maize breeding could be expanded to incorporate selection environments more relevant to agronomic management practices used by female plot managers and households at advanced stages of the breeding pipeline. This approach could provide an immediate entry point to increase gender-intentional maize breeding in southern Africa. [ABSTRACT FROM AUTHOR]

Resulting from the positive effect on rice productivity, the application of biochar and controlled-release urea in the form of polymer-coated urea (PCU) in crop production attracts more and more interest. However, field studies considering the combined effect of biochar and PCU are rare. This 2-year study examined the combined effects of biochar and PCU on yield, yield components, plant height, plant nitrogen concentration and nitrogen recovery efficiency in a waterlogged rice field. Experimental treatments combined two biochar rates (0 and 2800 kg ha−1) and three nitrogen rates (0, 120 and 180 kg N ha−1). The results showed a yield decrease under biochar application without nitrogen fertilizer. The application of 120 kg N ha−1 PCU and biochar had the highest yield in 2017. No significant differences of grain yields were indicated between 120 and 180 kg N ha−1. High grain yield and nitrogen use efficiency was obtained with 120 kg N ha−1 PCU. Therefore, 120 kg N ha−1 PCU can be recommended for rice production in this area. [ABSTRACT FROM AUTHOR]