Integrated Soil Fertility Management Research Articles

Does integrated soil fertility management increase returns to land and labor?

AbstractIntegrated Soil Fertility Management (ISFM) is promoted to enhance soil fertility and agricultural productivity among smallholders. Its core is the combined use of organic and inorganic fertilizers with improved crop varieties. Adoption of these practices potentially involves additional monetary and labor investments, and it remains unclear whether these pay off. This study analyzes the effects of the three core ISFM practices and their combinations on key agricultural outcomes, including land and labor productivity as well as net crop value, in which we account for the shadow costs of unpaid labor. We employ a multinomial endogenous switching model to original survey data from over 6000 teff, maize and wheat plots owned by around 2000 households in Ethiopia. All ISFM practices and their combinations increase land and labor productivity, despite higher labor demand, with the largest effects stemming from the joint use of all three practices. Effects on net crop value are positive for most combinations, but suggest that organic fertilizer with improved seeds may be more beneficial compared to combinations with inorganic fertilizer. The importance of organic fertilizer applications is also supported by our regionally disaggregated analysis that reveals important agroecological heterogeneity.

Effects of Using Different Organic Sources in Combination with Mineral Nitrogen Fertilizer on Soil Fertility, Grain Yield, and Maize Quality

Integrated soil fertility management is critical for crop productivity and soil health management. The study was carried out to determine the effects of different organic sources with mineral nitrogen application on soil fertility, grain yield, and maize quality on the Andisols of Sidama, Ethiopia. The treatments were: control, 100% of RNP - (138 N and 92 P), 100% of RN from vermicompost, 100% RN from conventional compost, 25% RNP +75% of RNP from vermicompost, 50% of RNP + 50% of RNP from vermicompost, 75% of RNP +25% of RNP from vermicompost, 25% of RNP +75% of RNP from conventional-compost, 50% of RNP+ 50% of RN from conventional-compost, and 75% of RNP +25% of RN from conventional-compost. The treatments were arranged in a randomized complete block design and replicated three times. The highest maize grain yield (7494.3 kg ha-1) and biomass yield (18718.0 kg ha-1) were obtained from the applications of 50% recommended NP fertilizer plus 50% vermicompost, which is based on recommended N equivalent respectively. The soil fertility analysis result shows that the combined application of organic with mineral fertilizer had brought significant changes to soil fertility and showed a positive effect on the soil pH, organic carbon content, total nitrogen, CEC, available P, available K, and CEC. Similarly, the use of organic fertilizer in conjunction with mineral fertilizer resulted in a significant change in the protein and oil content of maize. The protein content % and oil content % ranges from 7.1 %- 13.9 %-4.2%-7.2% respectively. These results suggest that an appropriate proportion of organic fertilizer with mineral fertilizer not only provides enough nutrients but also improves the soil environment, leads to increased yields, and plays an important role in maize quality. Therefore, the combined application of this 50% recommended NP fertilizer plus 50% vermicompost (based on N equivalent rate) can be recommended to farmers for production that increases maize yields with an assurance of sustainable soil fertility and quality maize production in , Sidama of Ethiopia. Keywords: Grain yield, Maize, protein and oil content, Organic and Mineral fertilizers DOI: 10.7176/ALST/92-02 Publication date: February 28 th 2022

Effect of Blended Npsznb Fertilizer Rates on Yield and Yield Components of Bread Wheat (<i>Triticum aestivum</i> L.) Varieties in Mao-komo, Benshangule Gumuz Regional State

Bread wheat (<i>Triticum aestivum</i> L.) is the most important cereal crop in the Poaceae (<i>Gramineae</i>) family originated in the Near-Eastern Fertile Crescent in the Middle East. It is the second most influential staple food crop after rice, grown in 89 countries with climates ranging from temperate to tropical but the production did not meet demand. The field experiment was conducted during 2020 cropping season in Mao-Komo District, western Ethiopia to evaluate the effects of blended NPSZnB fertilizer on bread wheat varieties. The experiment consisted of five levels of NPSZnB (0, 100, 150, 200, 250 kg ha^-1) and four bread wheat varieties Kingbird, Danda, Shorima and Ogolcho combined factorially and laid out in Randomized Complete Block Design with three replications. Days to 90% maturity were delayed with increased rates of fertilizer for all varieties. The highest mean plant height (81.4cm), number of grains per spike (52.5), and harvest index (39%), leaf area (30.15cm²), total tillers (6.29), productive tillers (6.1), grain yield (3.54), thousand grain weight (33.83g) and hectoliter weight (81.2) were obtained at 200 kg ha^-1 NPSZnB with Kingbird variety. Moreover, the highest straw yield (7.53t ha^-1) and spike length (8.2 cm) were recorded at 200 kg NPSZnB ha^-1 with Danda variety. The highest biomass (9.97 tha^-1) and hectoliter weight (81.2) were obtained at 250 kg ha^-1 NPSZnB with Ogolcho and Kingbird varieties, respectively. The maximum net benefit (85047ETB ha^-1) was obtained due to use of 200 kg ha^-1 NPSZnB with Kingbird bread wheat variety. Due to soil acidity of the study area, use of integrated soil fertility management practices is important to improve the production and productivity of bread wheat.

Contributions of Integrated Soil Fertility Management (Isfm) to Various Sustainable Intensification Impact Domains: A Meta-Analysis

Contributions of Integrated Soil Fertility Management (Isfm) to Various Sustainable Intensification Impact Domains: A Meta-Analysis

Soil Bacterial Community Dynamics are Influenced by Long-Term Integrated Soil Fertility Management Practices in a Ferralsol in Western Kenya

Soil Bacterial Community Dynamics are Influenced by Long-Term Integrated Soil Fertility Management Practices in a Ferralsol in Western Kenya

Effect of Compost and Blended NPS Fertilizers on Yield and Yield Components of Food Barley (&amp;lt;i&amp;gt;Hordeum Vulgare &amp;lt;/i&amp;gt;L.) at Welmera District, Central Highland of Ethiopia

Soil nutrient depletion under losing of soil organic matter consequently continuous cultivation and low input are among the major issues that oblige the sustainable productivity of the yield of barley at Welmera area. A study was, hence, lead to explore the impact of compost and NPS fertilizer combination on yield and yield components of food barley at Holeta Agricultural Research Center on Nitisols in the central highlands of Ethiopia in 2019/2020 cropping season. To achieve this objective, a field trial was arranged in a randomized complete block design in a factorial arrangement. The treatments consisted of four rates of compost (0, 4, 8, and 12 t/ha), five rates of blended NPS fertilizer (0, 100, 150, 200, and 250 kg/ha) and blanket recommended NP fertilizer (60 kg/ha N + 69 kg/ha P₂O₅) as standard check. Food barley (HB-1304 variety) was used as a test crop. The result revealed that 50% day to heading, 90% day to maturity, plant height, and spike length were positively influenced by NPS fertilizer applied to the experimental plots. On the contrary, synergistic nutrient interaction effect sourced from compost and NPS fertilizer brought positive influence on yield parameters (total number of tillers, effective tillers per plant, and grain per spike, thousand-grain yield, biomass yield, straw yield, grain yield, and harvest index). Moreover, the collective use of compost at (8 t/ha) and mineral NPS fertilizer at (150 kg/ha) has a better-improved yield of the barley crop. Likewise, the outcome of the economic analysis showed that the application of 8 t/ha compost and 150 kg/ha NPS fertilizer gave the highest economic benefit of 70528 Ethiopian birr ha^-1 with the maximum marginal rate of return of 1504%. Hence, the current study recommends that to maintain soil fertility and sustain barley crop production combined use of 8 t/ha compost and 150 kg/ha NPS fertilizer was the best alternate integrated soil fertility management choice in the position of the sole application of inorganic fertilizers for barley production at this area reluctantly. Nevertheless, further studies at different locations for more than one cropping season ought to be considered to provide a more conclusive recommendation for sustainable food barley production.

Soil macrofauna response to integrated soil fertility management under maize monocropping in Zimbabwe

The continued decline in both populations and diversity of soil macrofauna in agroecosystems remains a major concern for sustainable food production in Southern Africa. Macrofauna abundance and diversity were examined in a maize monocropping system following repeated incorporation of Calliandra calothyrsus, Crotalaria juncea, cattle manure, maize stover, and Pinus patula sawdust at 1.2 or 4.0 t C ha−1 with or without nitrogen (120 kg N ha−1) for 13 years (seasons). All treatments received phosphorus (P), potassium (K), and sulphur (S) at 16.0, 14.7 and 4.6 kg ha−1, respectively, at each planting time in December. Using the ISO/TSBF (Tropical Soils Biology and Fertility Institute) monoliths procedure, macrofauna were collected to a depth of 0.30 m fortnightly from February to mid-May 2016. Lumbricus terrestris and Isoptera were significantly (P < 0.001) affected by organic treatment and seasonal time, while organic treatment alone significantly affected Elateridae. A fluctuating trend characterised Diplopoda, L. terrestris and Isoptera with two general peaks for L. terrestris and a significant Isoptera peak under maize stover. Rainfall significantly influenced L. terrestris and Isoptera abundance, while within-season sampling time explained the observed fluctuations in Diplopoda, Holotrichia serrata, Araneae, Acrididae, and Formicidae. While Araneae was prevalent under maize stover, Elateridae, H. serrata and Araneae showed no distinct pattern in abundance. At low application rate, higher Shannon-Wiener diversity indices were apparent except for maize stover. Increasing application rate of the different organics amplified stimulation, abundance and persistence of macrofauna, and significantly increased diversity relative to the control. Application of N-based mineral fertiliser appeared to be detrimental to selective macrofauna (e.g., L. terrestris, Isoptera and Elateridae). Monte Carlo permutation test identified ammonium nitrate as the most influential and detrimental variable followed by organic resource quality, soil organic carbon (SOC) and application rate. Long-term co-application of organic and inorganic resources thus stimulated macrofaunal populations and maintained diversity. To sustain the productivity of the predominantly maize-based smallholder cropping systems, it is proposed that extension packages promote the inclusion of a minimum of at least 1.2 t carbon ha−1 annually towards improved soil health.

Uptake of integrated soil fertility management technologies in heterogeneous smallholder farms in sub-humid tropics

Low soil fertility strongly affects environmental sustainability and Sustainable Development Goals (SDGs) worldwide. Integrated soil fertility management (ISFM) is a potential remedy for declining soil fertility. We addressed determinants of ISFM technologies and identified the sources of soil fertility information using cluster and ordered probit analyses in two counties of the Central Highlands of Kenya. In Tharaka-Nithi county, the uptake of ISFMclass1 (Animal manure +anti-erosion + inorganic fertilizer +crop rotation + legume intercrop), positively correlated with membership to cooperatives, religious groups, SACCOs, and ownership of wheelbarrow but negatively associated with gender, level of education, low farming experience and increased off-farm income. The uptake of ISFMclass2 (Compost +Tithonia diversifolia +minimum tillage +agroforestry + crop residue retention) significantly correlated with religious group membership and ownership of radio. The uptake of ISFMclass3 (sole green manure) positively correlated with a household with an adult offering outside labor but negatively associated with distance to agro-dealers. In Murang'a, ISFMclass2 (Animal manure +inorganic fertilizer +anti-erosion + legume intercrop) is positively associated with farmers' age, membership to cooperatives, television ownership, and access to handhoe and distance to tarmacked roads. Access to drought power, distance to tarmacked road, and buyers positively correlated with ISFMclass1 (Agroforestry +green manure +minimum tillage +crop residue retention + crop rotation). There was a positive correlation between access to drought power and uptake of ISFMclass3 that combined compost and Tithonia diversifolia. We conclude that the region's uptake of unique ISFM combinations is influenced by socioeconomic, bio-physical determinants, and farmers' perception of soil fertility status. We thus recommend that increased upscaling of uptake of unique combinations of ISFM technologies require robust collaboration among various local development stakeholders to address the prohibitive factors while strengthening enabling ones.

Bio-Compost-Based Integrated Soil Fertility Management Improves Post-Harvest Soil Structural and Elemental Quality in a Two-Year Conservation Agriculture Practice

The impacts of integrated soil fertility management (ISFM) in conservation agriculture need short-term evaluation before continuation of its long-term practice. A split-split plot experiment with tillage (minimum tillage, MT vs. conventional tillage, CT) as the main plot, residue (20% residue, R vs. no residue as a control, NR) as the sub-plot, and compost (Trichocompost, LC; bio-slurry, BS; and recommended fertilization, RD) as the sub-sub plot treatment was conducted for two consecutive years. Composite soils were collected after harvesting the sixth crop of an annual mustard-rice-rice rotation to analyze for nutrient distribution and soil structural stability. The LC increased rice equivalent yield by 2% over RD and 4% over BS, and nitrogen (N) uptake by 11% over RD and 10% over BS. Likewise, LC had higher soil organic carbon (SOC), N, and available sulphur (S) than BS and RD. Conversion of CT to MT reduced rice equivalent yield by 11%, N uptake by 26%, and N-use efficiency by 28%. Conversely, soil structural stability and elemental quality was greater in MT than in CT, indicating the potential of MT to sequester C, N, P, and S in soil aggregates. Residue management increased rice yield in the second year by 4% and corresponding N uptake by 8%. While MT reduced the yield, our results suggest that ISFM with Trichocompost and residue retention under MT improves soil fertility and physical stability to sustain crop productivity.

Soil fungal community structure and seasonal diversity following application of organic amendments of different quality under maize cropping in Zimbabwe.

Recent advocacy for Integrated Soil Fertility Management (ISFM) in smallholder farming systems in east and southern Africa show substantial evidence of increased and sustained crop yields associated with enhanced soil productivity. However, the impact ISFM on soil fungi has received limited attention, yet fungi play key roles in crop growth. Following total soil DNA extraction with ZR soil microbe miniprep kit, illumina sequencing was used to, examine the fungal communities (ITS1F) under a maize crop following co-application of organic nutrient resources including Crotalaria juncea, cattle manure and maize stover with inorganic fertilizers at three-time periods (T1-December, T2-January, and T3-February) in Zimbabwe. Ninety-five fungal species were identified that were assigned to Ascomycota (>90%), Basidiomycota (7%) and Zygomycota (1%). At T1, Ascomycota and Basidiomycota were identified across treatments, with Ascomycota attaining > 93% frequency. Fungal succession was noted and involved reduction of Ascomycota coupled by increase in Basidiomycota under the different treatments. For example at T3, Basidiomycota increased to 34% while Ascomycota declined to 66% under manure but remained unchanged in other two organics. Pre-season mineral nitrogen (N) associated with the ‘Birch effect’ apparently influenced the fungal community structure at T1 while readily available fertilizer N was critical at T2 and T3. The low-quality maize stover promoted the presence of Exophiala sp SST 2011 and this was linked to N immobilization. The impact of N addition was more pronounced under medium (manure) to low-quality (maize stover) resources. Fungi required phosphorus (P) and N for survival while their proliferation was dependent on substrate availability linked to resource quality. Interactive-forward test indicated that soil available P and N were most influential (P < 0.05) factors shaping fungal communities. Co-application of medium to high quality organic and inorganic resources show promise as a sustainable entry point towards enhancing belowground fungal diversity critical in driving nutrient supply.

Tillage system and integrated soil fertility inputs improve smallholder farmers’ soil fertility and maize productivity in the Central Highlands of Kenya

We designed and implemented an on-farm trial in Meru South and Gatanga sub-counties to understand the effects of integrated soil fertility management (ISFM) technologies on soil nitrogen (N), phosphorus (P), potassium (K), and maize productivity. The technologies included combinations of mineral fertiliser and maize stover (CrMf); crop residue, Tithonia diversifolia and rock phosphate (CrTiP); crop residue, Tithonia diversifolia and goat manure (CrTiMan); crop residue, inorganic fertiliser and goat manure (CrMfMan); crop residue, goat manure and Dolichos lablab (CrManLeg), and sole inorganic fertiliser (Mf) executed under conventional (ConC) and minimum (MinTill) tillage methods. We interviewed the farmers who participated in implementing the trials at the end of the study to understand the likelihood to uptake the technologies. We observed that the technologies increased soil N, P, K, and maize productivity compared to ConC (the control). There was a high likelihood of uptake of high-performing ISFM technologies. We recommend CrTiP for the two sub-counties for the short-term. However, a long-term experiment is needed to evaluate performances of CrTiMan, CrTiP, CrMfMan, and CrManLeg under the two tillage methods for site-specific recommendations taking into consideration rainfall variations.

Predictors of integrated soil fertility management practice among cocoa farmers in Ghana

This study defines and estimates the proportion of organic and inorganic crop-land husbandry practices in the composite of Integrated Soil Fertility Management (ISFM) by cocoa farmers in Ghana using their socioeconomic and ecological attributes. A binary logistic regression was used to determine how these factors predict the proportion of organic materials in the composite. The results showed that only 13% of farmers use pure organic-based ISFM while 87% use different combinations of organic-based and inorganic ISFM. The estimates revealed that frequency of access to ISFM information and awareness, level of education and age of farmers below 30 years significantly influenced various degrees of organic-based ISFM. Among the significant ecological predictors were locations of cocoa agroforests, and intercropping cocoa with food crops and other tree crops at establishment phase (0–5 years) of cocoa plantations. These results imply that during the establishment phase, farmers are more likely to use low (<50%) organic-based ISFM. In contrast, farmers who manage matured monocrop cocoa plantations (21–30 years) are more likely to utilize high (≥50%) organic-based ISFM. The use of high organic-based ISFM by farmers can be improved by increasing their access to ISFM information, education and awareness. • There is no scientific evidence of ISFM practice among cocoa farmers in Ghana. • This study predicted factors of ISFM practice by Ghanaian cocoa farmers. • Majority of farmers use combinations of inorganic and organic-based ISFM practice. • Access to extension, education and age influenced adoption of ISFM practice. • Ecological predictors include farm age, farm location and intercropping systems.

The influence of organic and inorganic nutrient inputs on soil organic carbon functional groups content and maize yields

Locally available organic inputs to soil, solely or in combination with inorganic fertilizers, are used to reverse declining soil fertility and improve soil organic matter content (SOM) in smallholder farms of most Sub-Saharan Africa (SSA) countries. Soil organic matter characterization can indicate soil organic input, carbon (C) sequestration potential, or even an authentication tool for soil C dynamics in C stocks accounting. This study determined the effects of the long-term application of selected integrated soil fertility management (ISFM) technologies on SOM functional group composition and maize yields. The study was carried out on an ongoing long-term soil fertility field experiment established in 2004 in Mbeere South sub-county, the drier part of upper Eastern Kenya. The experimental design was a randomized complete block design. The ISFM treatments were 60 kg ha−1 nitrogen (N) from goat manure (GM60); 30 kg ha−1 inorganic N fertilizer (IF30); 60 kg ha−1 inorganic N fertilizer (IF60); GM30+IF30; 90 kg ha−1 inorganic N fertilizer (IF90); 60 kg ha−1 N from lantana (Lantana camara) (LC60); LC30+IF30; 60 kg ha−1 N from mucuna beans (Mucuna pruriens) (MP60); MP30+IF30; 60 kg ha−1 N from Mexican sunflower (Tithonia diversifolia) (TD60); TD30+IF30, and a control with no inputs. The C compositions of ground soil samples and organic amendments were analyzed using 13C solid-state NMR. The GM60, GM30+IF30, LC60, and TD60 treatments had much higher Alkyl and O-Alkyl C SOM functional groups than the control and other treatments. The average soil C for the control was 7.47 mg kg−1 and ranged from 5.03 to 7.37, 9.57 to 18.77, and 7.03–14.50 mg kg−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The mean grain yield for the control was 0.56 Mg ha−1 and ranged from 1.51 to 1.99, 1.94 to 4.16, and 2.98–4.60 Mg ha−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The results showed that a long-term application of sole organic fertilizers or combined with inorganic fertilizers increases maize yield and soil C sequestration potential. The increase was attributed to high Alkyl and O-Alkyl C SOM functional groups. Hence, knowing the C fraction content of organic inputs is vital in determining the best-fit management technologies for ameliorating soil fertility and sustaining and/or improving crop yields.

Selected Physicochemical Properties of the Soils Under Different Land Uses in Some Areas of Ethiopia

Agriculture is the primary source of income for most developing countries, including Ethiopia. However, Ethiopian agriculture is under risk due to unwise use of land resources and changes in land use. In Ethiopia, land use changes such as conversion of natural forest to farming, open grazing, and homestead land are common. These activities have resulted in the degradation of agricultural soil quality and a decrease in land productivity, resulting in low agricultural production and food insecurity in the country. As a result, long-term advantages for environmental health and economic growth are provided through sustainable management of agricultural resources such as soil. As a result, Ethiopia has recently developed an interest in assessing the quality of soil resources. Understanding the impact of agro-ecosystem change on agricultural soil quality and long-term land production requires assessing soil physicochemical parameters and their implications on soil fertility. Thus, many studies have been conducted with regards to designated physicochemical properties of the soils under different land use types. Therefore, this review papers were aimed to assess selected physicochemical properties of the soils under different land use in some areas of Ethiopia. Different studies showed that soil physicochemical properties such as Soil texture (sand, silt, clay), Bulk density, Total porosity (%), OC, C: N ratio, TN, pH, CEC Ava-P, and Ava (EB: K + , Ca 2+ , and Mg 2+ ), Ava (EX; Fe 2+ , Mn 2+ , Zn 2+ , Cu 2+ ) were influenced by different land use systems. The findings of the various research revealed that the degree and direction of changes in soil attributes under various land uses reflect the long-term impact of humans on land resources, as well as the repercussions of expanding human and animal populations. In comparison to the neighboring forest and grazing area soils, the soil properties under farmed land indicated an overall trend in the direction of loss of fertility. In general, continuous cultivation has degraded greatest of the important soil physicochemical attributes of the area as compared to the uncultivated lands. Therefore, the studies have been showed that reducing the continues cultivation and the use of integrated soil fertility management could help to sustain current soil conditions and restore the country’s damaged soil qualities. Keywords : land uses, soil fertility, soil physicochemical properties DOI: 10.7176/JBAH/11-15-02 Publication date: August 31 st 2021

Factors influencing adoption of integrated soil fertility management technologies by smallholder farmers in Ghana

This study examines smallholder farmers’ adoption of both a full set of and multiple bundles of integrated soil fertility management technologies, and estimates the determinants of and assesses the relationship among adoption practices using the logistic model and multivariate probit model respectively. A cross-sectional survey was used to collect data from 300 smallholder farmers who benefitted from a sustainable food security and environmental health project in three districts in Ghana. Four ISFM technologies (zero or minimal tillage, inorganic fertilizer, leguminous crop, and crop rotation) serve as outcome variables. The result revealed that only 26.7% of the respondents adopted the full set of the ISFM technologies. Agroecological zone, a spatial variable has been found to significantly influence smallholder farmers adoption of the full ISFM technologies. One or more of the predictor variables, purpose of farming, land ownership, distance from house to the nearest input shop, access credit and agroecological zone, have been found to significantly influence the adoption of the multiple ISFM technologies. However, the computed correlation coefficients of the independent determinants show inconsistent significant values. The implication of this finding is that the adoption of multiple ISFM technologies cannot be estimated utilizing common determinants. Therefore, extension service in the region should focus on crucial factors that influence adoption of specific multiple ISFM technologies to maximize adoption options.

A review of the Current State of Soil Infertility and Management Options in Kenya: The Case of Maize Growing Regions

Inappropriate soil fertility management has caused fertility to decline considerably over the years leading to low maize yields despite the growing human population with high food demand in Kenya. Despite high nutrient mining, fertilizer use and adoption of soil fertility improvement practices have remained low among maize farmers in the country. At the current yield levels, maize crops extract over 40, 8, 40.6, and 5.4 kg of N, P, K, and S per growing season, respectively. These extracted nutrients must be replaced to avoid nutrient depletion. Maize crop response to secondary macronutrients (S, Ca, and Mg) and micronutrients (Zn and B) is evidenced, signifying that these nutrients have also reached critical levels in Kenya soils. The rate of replenishing these lost nutrients is still low, farmers apply an average of 43.25 kg of fertilizer per hectare per season. The situation is worsened further by increasing soil acidity- currently below pH 5.5 in most maize-growing regions. Poor agronomic practices applied by farmers directly reduce yields and facilitate other factors leading to nutrient losses. For example, farmers across the country recycle seeds, apply low fertility rates, and rarely keep their fields weed-free. These practices lower the capacity of the crops to tolerate the impact of other production constraints including infertility. To realize yield improvement and return on investments, farmers must adapt and adopt crucial practices under integrated soil fertility management. Managing soil acidity should be the first approach to unlocking fixed nutrients. Fertilizer application should follow the right rate, right source, right time, and right placement approach. Also, improved cropping systems such as maize-legume rotation and intercropping should be considered for sustainable soil fertility management and crop production.

Enhancing yellow maize production for sustainable food and nutrition security in Kenya

Maize is a strategic staple crop serving both as human food and feed in the livestock sector. It therefore has a critical socioeconomic value safeguarding against food and nutrition insecurity. Maize yields are however low especially among smallholder farmers who rely on this crop for their livelihood and sustenance. This has rendered most Sub-Saharan Africa countries such as Kenya to be net importers and depended on food aid mainly in form of maize. Even though white maize variety is nutritionally inferior, it is the most produced and consumed with little regard placed on yellow maize. We reviewed 154 articles and reports to highlight challenges facing maize production and sustainable agricultural practices that should be embraced to overcome them, nutritional benefits of yellow maize, factors hindering its consumption and research gaps that need to be addressed to enhance its production and utilization. Key production challenges identified include shrinking land sizes, declining soil fertility, adverse and unpredictable weather patterns and the devastating striga weed. Intercropping especially cereals with legumes have great potential for efficient land, water and nutrient resource utilization, manage weeds and minimize crop failure and adverse weather effects. This combined with integrated soil fertility management will ensure increased yields. It was found that yellow maize has higher carotenoid content hence superior to white maize and when taken with grain legumes provides a low-cost balanced diet. Despite this, yellow maize utilization is low because it is regarded as poor man’s crop, associated with food aid and reserved as livestock feed. This negative perception can be changed through educational campaigns on its nutritional value in order to enhance local production and encourage social acceptability to aid alleviate vitamin A deficiency, a key limiting micronutrient. In conclusion, tapping in the nutritional superiority of yellow maize through legume intercropping should be enhanced.

PERCEPTIONS ET STRATEGIES PAYSANNES DE GESTION DE LA FERTILITE DES SOLS DANS LA REGION DE TILLABERY DE LOUEST DU NIGER

Farms face declining soil fertility. Maintaining this fertility becomes a concern for famers who adopt several strategies to this end. Hence, it is important to know these strategies to better improve and value them. It is in this context that a study was carried out in 15 villages within three municipalities of Tillabery region in Niger. Its objective is to study farmers soil fertility management perceptions and strategies in the municipalities of Gotheye, Tagazar and Torodi. Data collection was carried out through individual surveys of 300 farm managers, with 20 per village, or 100 per municipality. The respondents are mainly illiterate (56%) with agriculture (82%) and house farming (88%) as main activities. They said the soils are poor. Their indicators are soil color (40%), good germination (24%), yield (23%), and soil poorness indicator species (13%). To overcome this, farmers use more manure which is managed sparingly. However, the fallow, neglected by the majority of farmers, lasts only 2 or 3 years. The promotion of integrated soil fertility management through ANR, the use of manures and degraded lands restoration techniques are necessary for the sustainability and improvement of production systems.

Physico-chemical soil attributes under conservation agriculture and integrated soil fertility management

Conservation Agriculture (CA) and Integrated Soil Fertility Management (ISFM) have been promoted in Sub Saharan Africa as a means to improve soil quality. A four season research (March, 2017 to March, 2019) was conducted to evaluate CA-based treatment, no tillage with residue retention (NTR), ISFM-based treatment, conventional tillage with use of manure (CTM), a combination of CA + ISFM, no tillage with residue retention and use of manure (NTRM) and a control, (C) on soil quality attributes. In the two locations (sub-humid and semi-arid) the effect of soil fertility gradients (high and low) were considered. Trials were set out using a one farm one replicate randomized design. In either high or low fertility fields, soil chemical and physical properties were significantly different between the control and NTR, CTM and NTRM with no significant differences between NTR, CTM and NTRM. SOC was higher under NTR and NTRM practices, which consequently had higher hydraulic conductivity, air permeability, mean weight diameter and available phosphorus. For all the treatments and in both locations, the low fertility fields had significantly lower agronomic use efficiency (AUE) compared to the high fertility fields. In both soil types, plant available water capacity and relative water capacity values were below the recommended thresholds indicating low soil water uptake, suboptimal microbial activity and consequently low nutrient uptake which explains the observed low AUE.

English

Mineral and organic fertilizers have great potential to enhance crop yields in low fertility soils of the Buganda catena. However, the need for site-specific knowledge on use and yield of the two fertilizer types in a complex soil scape is acute among smallholder farmers exploiting any soil differences. This study evaluated on-farm grain yield response of common bean (Phaseolus vulgaris L.) to organic and mineral N and P fertilizers on three soils. Treatments included poultry manure at 0, 2.5 and 5.0 t ha-1, and N and P each at 0, 7.5, and 15 kg ha-1 in a complete factorial for two rainy seasons on each of the local farmers&rsquo; soils classified as Phaeozem, Cambisol, and Umbrisol.&nbsp; Fertilizer application resulted in 20, 25 and 36% maxima grain yield increase relative to soils (Phaeozem, Cambisol and Umbrisol soil, respectively) potentials when no nutrient inputs is applied. Mineral fertilizers applied separately reduced yield on the Cambisol while on Umbrisol soil, there was no particular increase; hence these were risky applications on highly degraded soils. Yield increases were greater with manure, with or without mineral fertilizers, but yield increase was not particularly fundamental on Phaeozem sites but was on Cambisol and marginal on the Umbrisol, resulting into positive and negative interaction effects, respectively. Thus, soil specific rates of manure nutrient ratios or with N and P mineral fertilizers are an effective strategy for targeting improved common bean yield under indigenous soil taxonomy of Buganda catena soils. Key words: Phaseolus vulgaris L, integrated soil fertility management, smallholder farming, soil type.