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- ItemA Comparison of Approaches to Regional Land-Use Capability Analysis for Agricultural Land-Planning(2021-04-24) Tara A. Ippolito; Jeffrey E. Herrick; Ekwe L. Dossa ; Maman Garba; Mamadou Ouattara; Upendra Singh; Zachary P. Stewart; P.V.V. Prasad ; Idrissa A. Oumarou; Jason C. NeffSmallholder agriculture is a major source of income and food for developing nations. With more frequent drought and increasing scarcity of arable land, more accurate land-use planning tools are needed to allocate land resources to support regional agricultural activity. To address this need, we created Land Capability Classification (LCC) system maps using data from two digital soil maps, which were compared with measurements from 1305 field sites in the Dosso region of Niger. Based on these, we developed 250 m gridded maps of LCC values across the region. Across the region, land is severely limited for agricultural use because of low available water-holding capacity (AWC) that limits dry season agricultural potential, especially without irrigation, and requires more frequent irrigation where supplemental water is available. If the AWC limitation is removed in the LCC algorithm (i.e., simulating the use of sufficient irrigation or a much higher and more evenly distributed rainfall), the dominant limitations become less severe and more spatially varied. Finally, we used additional soil fertility data from the field samples to illustrate the value of collecting contemporary data for dynamic soil properties that are critical for crop production, including soil organic carbon, phosphorus and nitrogen.
- ItemA Fourth Principle is Required to Define Conservation Agriculture in Sub-Saharan Africa: The Appropriate Use of Fertilizer to Enhance Crop Productivity(2013-10-6) Bernard Vanlauwe ; Wendt John; Ken E. Giller; Marc Corbeels; B. Gerard; C. NolteIntensification of agricultural systems in sub-Saharan Africa (SSA) is considered a pre-condition for alleviation of rural poverty. Conservation Agriculture (CA) has been promoted to achieve this goal, based on three principles: minimum tillage, soil surface cover, and diversified crop rotations. CA originated in regions where fertilizer is commonly used and crop productivity is high, ensuring an abundance of crop residues. By contrast, crop yields are generally low in SSA and organic residues in short supply and farmers face competing demands for their use. Since minimal tillage without mulch commonly results in depressed yields, the use of fertilizer to enhance crop productivity and organic residue availability is essential for smallholder farmers to engage in CA. This is especially true since alternative ways to increase organic matter availability have largely failed. A case study from Kenya clearly demonstrates how fertilizer increases maize stover productivity above thresholds for minimal initial soil cover required for initiating CA (about 3 tonne ha−1). We conclude that strategies for using CA in SSA must integrate a fourth principle – the appropriate use of fertilizer – to increase the likelihood of benefits for smallholder farmers.
- ItemA Review of the Use of Engineered Nanomaterials to Suppress Plant Disease and Enhance Crop Yield(2015-02-03) Alia Servin; Wade H. Elmer ; Arnab Mukherjee; Roberto de la Torre-Roche ; Helmi Hamdi; Jason C. White; Bindraban, Prem S.; Christian O. DimkpaNanotechnology has the potential to play a critical role in global food production, food security, and food safety. The applications of nanotechnology in agriculture include fertilizers to increase plant growth and yield, pesticides for pest and disease management, and sensors for monitoring soil quality and plant health. Over the past decade, a number of patents and products incorporating nanomaterials into agricultural practices (e.g., nanopesticides, nanofertilizers, and nanosensors) have been developed. The collective goal of all of these approaches is to enhance the efficiency and sustainability of agricultural practices by requiring less input and generating less waste than conventional products and approaches. This review evaluates the current literature on the use of nanoscale nutrients (metals, metal oxides, carbon) to suppress crop disease and subsequently enhance growth and yield. Notably, this enhanced yield may not only be directly linked to the reduced presence of pathogenic organisms, but also to the potential nutritional value of the nanoparticles themselves, especially for the essential micronutrients necessary for host defense. We also posit that these positive effects are likely a result of the greater availability of the nutrients in the ‘‘nano’’ form. Last, we offer comments on the current regulatory perspective for such applications.
- ItemA Statistical Analysis of Three Ensembles of Crop Model Responses to Temperature and CO2 Concentration(2015-12-15) David Makowski; Senthold Asseng; Frank Ewert; Simona Bassu; Jean-Louis Durand; Tao Li; Pierre Martre; Myriam Adam; P.K. Aggarwal; Candy Angulo; Christian Baron; Bruno Basso; Patrick Bertuzzi; Christian Biernath; H. Boogaard; Kenneth J. Boote; Bas Bouman; Simone Bregaglio; Nadine Brisson; Samuel Buis; Davide Cammarano; Andrew J Challinor; Roberto Confalonieri; Conijn, J.G; Marc Corbeels; Delphine Deryng; Giacomo De Sanctis; Jordi Doltra; Tamon Fumoto; Donald Gaydon; Sebastian Gayler; R. Goldberg; R.F. Grant; Patricio Grassini; Jerry Hatfield; Toshihiro Hasegawa; Lee Heng; Steven Hoek; J. Hooker; Leslie Hunt; Joachim Ingwersen; R.C. Izaurralde; Jongschaap, R.E.E.; James W. Jones; Armen R. Kemanian; Kurt Christian Kersebaum; Soo-Hyung Kim; Jon I. Lizaso; Manuel Marcaida; Christoph Muller; H. Nakagawa; Soora Naresh Kumar; Claas Nendel; Gerard O’Leary; Jørgen Eivind Olesen; Philippe Oriol; Tom Osborne; Taru Palosuo; M. Virginia Pravia; Eckart Priesack; Dominique Ripoche; C. Rosenzweig; Alex C. Ruane; Françoise Ruget; F. Sau; Mikhail A Semenov; Iurii Shcherbak; Balwinder-Singh ; Upendra Singh; Soo-Hyung Kim; Pasquale Steduto; Claudio O. Stöckle ; Pierre Stratonovitch; T. Streck; I. Supit; Liang Tang; Fulu Tao; Edmar Teixeira; Peter J Thorburn; Dennis Timlin; M. Travasso; Reimund P. Rötter; Katharina Waha; Daniel Wallach; Jeffrey W. White; Paul W. Wilkens; J.R. Williams; Jonas Wolf; Xinyou Yin; Hiroe Yoshida; Zhao Zhang; Yan ZhuEnsembles of process-based crop models are increasingly used to simulate crop growth for scenarios of temperature and/or precipitation changes corresponding to different projections of atmospheric CO2 concentrations. This approach generates large datasets with thousands of simulated crop yield data. Such datasets potentially provide new information but it is difficult to summarize them in a useful way due to their structural complexities. An associated issue is that it is not straightforward to compare crops and to interpolate the results to alternative climate scenarios not initially included in the simulation protocols. Here we demonstrate that statistical models based on random-coefficient regressions are able to emulate ensembles of process-based crop models. An important advantage of the proposed statistical models is that they can interpolate between temperature levels and between CO2 concentration levels, and can thus be used to calculate temperature and [CO2] thresholds leading to yield loss or yield gain, without re-running the original complex crop models. Our approach is illustrated with three yield datasets simulated by 19 maize models, 26 wheat models, and 13 rice models. Several statistical models are fitted to these datasets, and are then used to analyze the variability of the yield response to [CO2] and temperature. Based on our results, we show that, for wheat, a [CO2] increase is likely to outweigh the negative effect of a temperature increase of +2 °C in the considered sites. Compared to wheat, required levels of [CO2] increase are much higher for maize, and intermediate for rice. For all crops, uncertainties in simulating climate change impacts increase more with temperature than with elevated [CO2].
- ItemA Trait-Based Model Ensemble Approach to Design Rice Plant Types for Future Climate(2022-01) Livia Palear; Tao Li; Yubin Yang; Lloyd T. Wilson; Toshihiro Hasegawa; Kenneth J. Boote; Samuel Buis; Gerrit Hoogenboom; Yujing Gao; Ermes Movedi; Françoise Ruget; Upendra Singh; Claudio O. Stöckle; Liang Tang; Daniel Wallach; Yan Zhu; Roberto ConfalonieriCrop models are powerful tools to support breeding because of their capability to explore genotype × environment×management interactions that can help design promising plant types under climate change. However, relationships between plant traits and model parameters are often model specific and not necessarily direct, depending on how models formulate plant morphological and physiological features. This hinders model application in plant breeding. We developed a novel trait-based multi-model ensemble approach to improve the design of rice plant types for future climate projections. We conducted multi-model simulations targeting enhanced productivity, and aggregated results into model-ensemble sets of phenotypic traits as defined by breeders rather than by model parameters. This allowed to overcome the limitations due to ambiguities in trait-parameter mapping from single modelling approaches. Breeders' knowledge and perspective were integrated to provide clear mapping from designed plant types to breeding traits. Nine crop models from the AgMIP-Rice Project and sensitivity analysis techniques were used to explore trait responses under different climate and management scenarios at four sites. The method demonstrated the potential of yield improvement that ranged from 15.8% to 41.5% compared to the current cultivars under mid-century climate projections. These results highlight the primary role of phenological traits to improve crop adaptation to climate change, as well as traits involved with canopy development and structure. The variability of plant types derived with different models supported model ensembles to handle related uncertainty. Nevertheless, the models agreed in capturing the effect of the heterogeneity in climate conditions across sites on key traits, highlighting the need for context-specific breeding programmes to improve crop adaptation to climate change. Although further improvement is needed for crop models to fully support breeding programmes, a trait-based ensemble approach represents a major step towards the integration of crop modelling and breeding to address climate change challenges and develop adaptation options.
- ItemAbove- and belowground Biomass, Nutrient and Carbon Stocks Contrasting an Open-grown and a Shaded Coffee Plantation(2008-02) Ekwe L. Dossa; E. C. M. Fernandes; W. S. Reid; K. EzuiCoffee (Coffea canephora var robusta) is grown in Southwestern Togo under shade of native Albizia adianthifolia as a low input cropping system. However, there is no information on carbon and nutrient cycling in these shaded coffee systems. Hence, a study was conducted in a mature coffee plantation in Southwestern Togo to determine carbon and nutrient stocks in shaded versus opengrown coffee systems. Biomass of Albizia trees was predicted by allometry, whereas biomass of coffee bushes was estimated through destructive sampling. Above- and belowground biomass estimates were respectively, 140 Mg ha-1 and 32 Mg ha-1 in the coffee–Albizia association, and 29.7 Mg ha-1 and 18.7 Mg ha-1 in the open-grown system. Albizia trees contributed 87% of total aboveground biomass and 55% of total root biomass in the shaded coffee system. Individual coffee bushes consistently had higher biomass in the open-grown than in the shaded coffee system. Total C stock was 81 Mg ha-1 in the shaded coffee system and only 22.9 Mg ha-1 for coffee grown in the open. Apart from P and Mg, considerable amounts of major nutrients were stored in the shade tree biomass in non-easily recyclable fractions. Plant tissues in the shaded coffee system had higher N concentration, suggesting possible N fixation. Given the potential for competition between the shade trees and coffee for nutrients, particularly in low soil fertility conditions, it is suggested that the shade trees be periodically pruned in order to increase organic matter addition and nutrient return to the soil.
- ItemAccuracy of Agricultural Data and Implications for Policy: Evidence from Maize Farmer Recall Surveys and Crop Cuts in the Guinea Savannah Zone of Ghana(Elsevier, 2023) William Adzawla; Edinam D. Setsoafia; Eugene D. Setsoafia; Solomon Amoabeng-Nimako; Williams K. Atakora; Bindraban, Prem S.CONTEXT: The need for accurate data in policy design aimed at agricultural transformation cannot be overemphasized. Unfortunately, the relevance of agricultural research in addressing the needs of farmers has been questioned due to debates about appropriate methodologies and approaches for establishing research activities and, in other instances, poorly reasoned premises and paltry delineation, definition, and understanding of the system being studied. For a country like Ghana, where agricultural transformation is a prerequisite for its sustainable development, an understanding of the accuracy of farm data measurement is necessary OBJECTIVES: The objective of this study is to estimate the yield measurement error and to analyze the sources of such measurement errors among the farmers of the Guinea Savannah zone of Ghana. METHODS: Two years of data for both farmer recall surveys and crop cuts was used. Descriptive statistics, regression and sensitivity analyses were done to achieve the objectives of the study. RESULTS AND CONCLUSIONS: On average, farmers’ recall of maize yields (1,544.6 kg/ha) was lower than the estimated crop cut yields (2,593.9 kg/ha), although about 11.2% of the farmers recalled higher yields than their estimated crop cut yields. The estimated average percentage error in yield measurement between crop cuts and farmer surveys was 36.4%. These yield measurement errors are due to systematic biases, including those involving the recall of farm size, and the socioeconomic conditions of the farmers. The yield estimation method also has implications on the estimated returns to scale from the use of production inputs. Although a crop cut is costly, it has limited bias in providing a better measure of yield than farmer recall surveys. Irrespective of the method used, however, more attention should be given to potential sources of systematic bias in the design and data collection. Moreover, for proper interpretation, yield estimates from recall surveys and crop cuts should be properly interpreted as economic yield or biological yields. SIGNIFICANCE: This paper provided clarity on the differences in maize yield estimates in Ghana and provided measures on how to obtain precise yield data.
- ItemAdapting to the Projected Epidemics of Fusarium Head Blight of Wheat in Korea under Climate Change Scenarios(2022-12-09) Jin-Yong Jung; Jin-Hee Kim; Minju Baek; Chuloh Cho; Jaepil Cho; Junhwan Kim; Willingthon Pavan; Kwang-Hyung KimFusarium head blight (FHB) of wheat, mainly caused by Fusarium graminearum Schwabe, is an emerging threat to wheat production in Korea under a changing climate. The disease occurrence and accumulation of associated trichothecene mycotoxins in wheat kernels strongly coincide with warm and wet environments during flowering. Recently, the International Panel for Climate Change released the 6th Coupled Model Intercomparison Project (CMIP6) climate change scenarios with shared socioeconomic pathways (SSPs). In this study, we adopted GIBSIM, an existing mechanistic model developed in Brazil to estimate the risk infection index of wheat FHB, to simulate the potential FHB epidemics in Korea using the SSP245 and SSP585 scenarios of CMIP6. The GIBSIM model simulates FHB infection risk from airborne inoculum density and infection frequency using temperature, precipitation, and relative humidity during the flowering period. First, wheat heading dates, during which GIBSIM runs, were predicted over suitable areas of winter wheat cultivation using a crop development rate model for wheat phenology and downscaled SSP scenarios. Second, an integrated model combining all results of wheat suitability, heading dates, and FHB infection risks from the SSP scenarios showed a gradual increase in FHB epidemics towards 2100, with different temporal and spatial patterns of varying magnitudes depending on the scenarios. These results indicate that proactive management strategies need to be seriously considered in the near future to minimize the potential impacts of the FHB epidemic under climate change in Korea. Therefore, available wheat cultivars with early or late heading dates were used in the model simulations as a realistic adaptation measure. As a result, wheat cultivars with early heading dates showed significant decreases in FHB epidemics in future periods, emphasizing the importance of effective adaptation measures against the projected increase in FHB epidemics in Korea under climate change.
- ItemAddition-Omission of Zinc, Copper, and Boron Nano and Bulk Oxide Particles Demonstrate Element and Size -Specific Response of Soybean to Micronutrients Exposure(2019-02-11) Christian O. Dimkpa; Upendra Singh; Bindraban, Prem S.; Ishaq O. Adisa; Wade H. Elmer; Jorge L. Gardea-Torresdey; Jason C. WhitePlant response to microelements exposure can be modulated based on particle size. However, studies are lacking on the roles of particle size and specific microelements in mixed exposure systems designed for plant nutrition, rather than toxicology. Here, an addition-omission strategy was used to address particle-size and elementspecific effects in soybean exposed to a mixture of nano and bulk scale oxide particles of Zn (2 mg Zn/kg), Cu (1 mg Cu/kg) and B (1 mg B/kg) in soil. Compared to the control, mixtures of oxide particles of both sizes significantly (p b 0.05) promoted grain yield and overall (shoot and grain) Zn accumulation, but suppressed overall P accumulation. However, the mixed nano-oxides, but not the mixed bulk-oxides, specifically stimulated shoot growth (47%), flower formation (63%), shoot biomass (34%), and shoot N (53%) and K (42%) accumulation. Compared by particle size, omission of individual elements from the mixtures evoked significant responses that were nano or bulk-specific, including shoot growth promotion (29%) by bulk-B; inhibition (51%) of flower formation by nano-Cu; stimulation (57%) of flower formation by bulk-B; grain yield suppression (40%) by nano-Zn; B uptake enhancement (34%) by bulk-Cu; P uptake stimulation by nano-Zn (14%) or bulk-B (21%); residual soil N (80%) and Zn (42%) enhancement by nano-Cu; and residual soil Cu enhancement by nano-Zn (72%) and nano-B (62%). Zn was responsible for driving the agronomic (biomass and grain yield) responses in this soil, with concurrent ramifications for environmental management (N and P) and human health (Zn nutrition). Overall, compared to bulk microelements, nanoscale microelements played a greater role in evoking plant responses.
- ItemAfrican Soil Properties and Nutrients Mapped at 30 m Spatial Resolution Using two‑scale Ensemble Machine Learning(2021) Tomislav Hengl; Matthew A. E. Miller; Josip Križan; Keith D. Shepherd; Andrew Sila; Milan Kilibarda; Ognjen Antonijević; Luka Glušica; Achim Dobermann; Stephan M. Haefele; Steve P. McGrath; Gifty E.Acquah; Jamie Collinson; Leandro Parente; Mohammadreza Sheykhmousa; Kazuki Saito; Jean‑Martial Johnson; Jordan Chamberlin; Francis B.T. Silatsa; Martin Yemefack; Wendt John; Robert A. MacMillan; Ichsani Wheeler; Jonathan CrouchSoil property and class maps for the continent of Africa were so far only available at very generalised scales, with many countries not mapped at all. Thanks to an increasing quantity and availability of soil samples collected at feld point locations by various government and/or NGO funded projects, it is now possible to produce detailed pan-African maps of soil nutrients, including micro-nutrients at fne spatial resolutions. In this paper we describe production of a 30 m resolution Soil Information System of the African continent using, to date, the most comprehensive compilation of soil samples (N ≈ 150, 000) and Earth Observation data. We produced predictions for soil pH, organic carbon (C) and total nitrogen (N), total carbon, efective Cation Exchange Capacity (eCEC), extractable— phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), sodium (Na), iron (Fe), zinc (Zn)—silt, clay and sand, stone content, bulk density and depth to bedrock, at three depths (0, 20 and 50 cm) and using 2-scale 3D Ensemble Machine Learning framework implemented in the mlr (Machine Learning in R) package. As covariate layers we used 250 m resolution (MODIS, PROBA-V and SM2RAIN products), and 30 m resolution (Sentinel-2, Landsat and DTM derivatives) images. Our fvefold spatial Cross-Validation results showed varying accuracy levels ranging from the best performing soil pH (CCC = 0.900) to more poorly predictable extractable phosphorus (CCC = 0.654) and sulphur (CCC = 0.708) and depth to bedrock. Sentinel-2 bands SWIR (B11, B12), NIR (B09, B8A), Landsat SWIR bands, and vertical depth derived from 30 m resolution DTM, were the overall most important 30 m resolution covariates. Climatic data images—SM2RAIN, bioclimatic variables and MODIS Land Surface Temperature—however, remained as the overall most important variables for predicting soil chemical variables at continental scale. This publicly available 30-m Soil Information System of Africa aims at supporting numerous applications, including soil and fertilizer policies and investments, agronomic advice to close yield gaps, environmental programs, or targeting of nutrition interventions.
- ItemAgro- Economic Characterization of Rice Production in a Typical Irrigation Scheme in Burkina Faso(2004-09) Zacharie Segda; S.M. Haefele; M.C.S. Wopereis; Michel P. Sedogo; Sita GuinkoYield, yield gaps, input use, N-use efficiency, productivity, and profitability of irrigated rice in Burkina Faso were determined for a typical irrigation scheme in the dry season (DS) 1999 and the wet season (WS) 2000. Objectives were to analyze agro-economic constraints and opportunities and determine ways to overcome such constraints. The simulation model RIDEV was used to analyze farmers' crop management practices, revealing considerable deviation between actual and optimal timing of crop management interventions. This diversity of cropping practices caused considerable variation of internal efficiency of N (IEN), partial factor productivity of N (PFPN), N recovery fraction (RFN), rice (Oryza sativa L.) grain yields, and net benefits of N-use. The results showed a clear relation between plant N uptake and yield (mean IEN of 48 kg grain kg-1 N uptake in farmer's fields), but the relation between N applied and yield was scattered. The PFPN varied from 16 to 52 kg grain kg-1 N applied (mean of 35 kg grain kg-1 N applied) due to a large range of fertilizer N recovery rates (RFN = 7-77%; mean of 37%). Farmers' average yields were 4.9 Mg ha-1 in the DS and 3.6 Mg ha -1 in the WS, but yields were very variable and ranged from 0.9 to 7.9 Mg ha-1 in the DS and from 1.0 to 7.9 Mg ha-1 in the WS. Yield gaps between average farmer's yield and best farmer's yield were high (3.0 Mg ha-1 in the DS and 4.3 Mg ha-1 in the WS), indicating considerable scope for yield increases in both seasons. Net benefits to irrigated rice cropping were mostly positive (avg. $418 (US) ha -1) in the dry season, but very low in the wet season (avg. $108 (US) ha-1). Partial budget analysis of fertilizer use revealed considerably lower value/cost ratios of fertilizer use in the wet season (mean V/C: 1.5) compared with the dry season (mean V/C: 2.9). It was concluded that improved crop management practices are the key to reach higher yields and financial returns without additional investments.
- ItemAgro-ecological Nitrogen Management in Soils Vulnerable to Nitrate Leaching: A case Study in the Lower Suwannee Watershed(2011-11-18) Sampson Agyin-Birikorang; Yoana C. Newman; Augustine K. Obour; Gabriel N. KasoziEnvironmental benefits associated with reduced rates of nitrogen (N) application, while maintaining economically optimum yields have economic and social benefits. Although N is an indispensable plant nutrient, residual soil N could leach out to contaminate groundwater and surface water resources, particularly in sandy soils. A 2-year field study was conducted in an established bermudagrass (Cynodon dactylon) pasture in the Lower Suwannee Watershed, Florida, to evaluate N application rates on forage yield, forage quality, and nitrate (NO3-N) leaching in rapidly permeable upland sandy soils. Four N application rates (30, 50, 70, and 90 kg N ha-1 harvest-1 ) corresponding to 0.33, 0.55, 0.77 and IX, respectively, of recommended N rate (90 kg N ha-1 harvest-1 ) for bermudagrass hay production in Florida were evaluated vis-a`-vis an unfertilized (0 N) control. Suction cups were installed near the center of each plot at two depths (30 and 100 cm) to monitor NO3-N leaching. The grass was harvested at 28 days intervals to determine dry matter yield, N uptake, and herbage nutritive value. Nitrogen application at the recommended rate produced the greatest total dry matter yield (*18.4 Mg ha-1 year-1 ), but a modeled economically optimum N rate of *57 kg N ha-1 harvest-1 (*60% of the recommended N rate) projected an average dry matter yield of *17.3 Mg ha-1 year-1 , which represents [90% of the observed maximum yield. Nitrogen application increased nutritive quality of the grass, but increases in N application rate above 30 kg N ha-1 did not result in significant increases in in vitro digestible organic matter concentration, and tissue crude protein was not significant above 50 kg N ha-1 . Across the sampling period, treatments with N rates B50 kg N ha-1 harvest-1 had leachate NO3-N concentration below the maximum contaminant limit of\10 mg l-1 . Conversely, applying N at rates C70 kg N ha-1 harvest-1 resulted in leachate N concentration that exceeded the maximum contaminant limit, and suggest high risk of impacting groundwater quality, if such rates are applied to soils with coarse (sand) textures. The study demonstrates that recommendation of a single N application rate may not be appropriate under all agro-climatic conditions and, thus, a site-specific evaluation of best N management strategy is critical.
- ItemAgroecological Analysis and Economic Benefit of Organic Resources and Fertiliser in Till and No-till Sorghum Production after a 6-year Fallow in Semi-arid West Africa(2006-12) Elisée Ouédraogo ; Leo Stroosnijder; Abdoulaye Mando; Lijbert Brussaard; Robert ZougmoreA field experiment was conducted in Gampela (Burkina Faso) in 2000 and 2001 to assess the impact of organic and mineral sources of nutrients and combinations thereof in optimising crop production in till and no-till systems and to assess the economic benefit of these options. The study showed that under conditions of rainfall deficiency, the use of a single organic resource at an equivalent dose of 40 kg N ha–1 better secured crop yield than the application of an equivalent amount as urea-N, while a combination of organic resources and fertiliser was better in increasing crop yield than the application of the same N amount in the form of urea. In a year of rainfall deficiency, a mix of organic resources and fertiliser in both till and no-till systems increased crop water use efficiency, with the result that the farmer was able to purchase only half of the normal quantity of N fertiliser to obtain a higher yield that he would have done when all of the N was supplied in the form of urea. Under conditions where soil N is deficient, an economic benefit was achieved when urea was combined with easily decomposable organic material (e.g. sheep dung); mixing the urea at a dose of 40 kg N ha–1 with maize straw was not sufficient in alleviating the negative interaction due to the enhanced N immobilisation. The results demonstrate that the use of N fertiliser alone was risky and that a higher yield, with the accompanying economic benefit, was scarcely achieved under the prevailing rainfall conditions. The application of soil and water conservation measures can contribute greatly to increasing the economic benefit of mineral, organic or combined organic and mineral-derived nutrient application under semi-arid conditions.
- ItemAgroecological Intelligence Needed to Prepare Agriculture for Climate Change(2013-03) Bindraban, Prem S.Gratefully, the quality of life for billions of people will improve drastically during the coming decades. This implies that the production of virtually every commodity will have to increase dramatically. Agriculture-related activities ought to provide food, feed, and non-edible plant-based products. The availability of natural resources per person will, however, continue to decline. Resource degradation like erosion, soil fertility decline, and water pollution further constrain production increases. Hence, the use efficiency of natural resources will have to be boosted drastically, while variability should be curtailed through enhanced buffering capacity of the production base to prevent shock in food systems. These changes in agricultural strategies also call for interdisciplinary research groups to seek for synergies between production factors. This paper provides an overview of the challenges to meet the above mentioned production conditions and stresses the need for agro-ecological intelligence in choosing agricultural development strategies and, therefore, in designing agro-ecosystems. Plant production is taken as a starting point where global change, including climate, are considered in an integral manner.
- ItemAgronomic Effectiveness of an Organically Enhanced Nitrogen Fertilizer(2017-04-03) John H. Winings; Xinhua Yin; Sampson Agyin-Birikorang; Upendra Singh; Joaquin Sanabria; Hubert J. Savoy; Fred L. Allen; Arnold M. SaxtonWith tighter environmental regulations and increasing energy costs over time, approaches to minimize losses from commercially available nitrogen (N) fertilizers have become more critical in recent times. An organically enhanced N fertilizer (OENF), manufactured from organic additives extracted from sterilized biosolids plus ammonium sulfate, was evaluated as an alternative N source relative to commercially available N sources, namely, ammonium sulfate and urea. The formulation was tested on corn in 2012 and 2013 at Jackson and Ames, Tennessee, under notill and plow lands, respectively. Chemically OENF contains 14.9% N, 4.3% P2O5, 18.1% S, 0.6% Fe, and 3.3% OC. The N fertilizer sources were applied at N rates of 0, 85, 128, and 170 kg ha-1 . The P, K, and Zn nutrients were adequately supplied. The OENF and ammonium sulfate produced plant biomass significantly greater than that of urea at N rates of C85 kg ha-1 . Despite the fact that less P was supplied to the OENF treatments (36% less P), grain yields from the OENF were similar to those from both ammonium sulfate and urea at N rate of B128 kg N ha-1 , but significantly greater than those from urea at 170 kg N ha-1 . The fertilizer type used did not have any significant effects on disease and physical damage to the corn ears at any application rate tested. The OENF could be an alternative N source for crop production and may provide all or some of the P needs for corn production. Therefore, with additional environment benefits of encouraging recycling of municipal and domestic waste and as sources of N, P, S, Fe and organic matter, the use of OENF should be incorporated in various corn production systems.
- ItemAgronomic Effectiveness of Urea Deep Placement Technology for Upland Maize Production(2020) Sampson Agyin-Birikorang; Ignatius Tindjina; Raphael Adu-Gyamfi; Haruna W. Dauda; Abdul-Rahman A. Fuseini; Upendra SinghEffective fertilizer management is critical for sustainable maize production. Field trials were conducted in six locations in northern Ghana during the 2016 and 2017 farming seasons to evaluate the agronomic effectiveness and economic viability of urea deep placement technology (UDP), which involves deep placement of urea supergranules (USG), for maize production. This fertilization strategy was compared with four other maize fertilization strategies: (1) microdosing (MD); (2) farmer practice (FP), which involves surface broadcasting of granular fertilizer; (3) modified farmer practice (MFP), where granular fertilizer was incorporated into the soil; and (4) NPK-only, where no supplemental N was added. Averaged across all six locations and both years, UDP produced 18% more grain yield than MFP, 38% more than MD, 155% more than FP, and 270% more than NPK-only. The greatest apparent N recovery efficiency of 73% occurred in MD, followed by UDP (68%), NPK-only (63%), MFP (61%) and FP (35%), in that order. However, agronomic efficiency followed the order: UDP > MFP = MD > NPK-only = FP. The greatest gross profit margin of 49% was obtained with UDP, followed by MFP (41%) and MD (33%). Farmer practice resulted in a break-even level (3%) whereas NPK-only resulted in a loss (< − 35%). From the combined results, we conclude that, barring other external factors such as drought, flooding, pests, diseases, etc., UDP could be one of the most efficient fertilizer management strategies for sustainable maize production. Further studies should evaluate optimum timing of USG application for increased productivity and profitability.
- ItemAgronomic Efficiency of Activated Rock Phosphate Granules on Maize Plants Treated with Mycorrhiza in a Calcareous Vertisol of Kenya(Springer, 2023-03-22) Mphatso Chongo; Wendt John; Ngunjiri Mercy; Mohamed Hafdi; Martin JemoThe agronomic efficiency of activated rock phosphate (RP) fertilizers to promote maize growth in the presence or absence of mycorrhizal inoculation was evaluated. Maize plants were treated with two reactive RP grades of medium (RPM) and low (RPL) solubility and their activated forms which were activated with a fraction of diammonium phosphate (DAP) to increase phosphorus (P) availability. We included in the trial design a control without P application and DAP (a positive control). Maize growth and N and P were measured. Activated RPM enhanced maize N and P uptake, biomass, and relative agronomic efficiency (RAE) to levels equivalent to DAP. These properties were unaffected by mycorrhizal inoculation. The mechanism underlying the activation of RP deserves further research investigation to promote local RP deposits too small to merit industrial transformation.
- ItemAmeliorating Incongruent Effects of Balanced Fertilization on Maize Productivity in Strongly Acid Soils with Liming(2022-04-18) Sampson Agyin-Birikorang; Raphael Adu-Gyamfi; Ignatius Tindjina; Job Fugice ; Haruna W. Dauda; Joaquin Sanabria; Upendra SinghSeveral studies have recommended balanced fertilization for increased and sustainable maize productivity in northern Ghana. However, the effectiveness of balanced fertilization in strongly acid soils is unknown. We conducted nutrient omission trials on strongly acid soils in four communities in northern Ghana to quantify impact of balanced fertilization and its synergism with liming on maize productivity. We evaluated the following treatments, each with and without liming: (i) balanced fertilization (BF), which contained all essential limiting nutrients, (ii) BF without sulfur (minus-S), (iii) BF without zinc (minus-Zn), (iv) BF without boron (minus-B), (v) NPK-only, and (vi) control. Without liming, maize yield was generally low (ranging from 0.4 to 2.2 t ha −1 ) and followed the order: minus Zn > NPK-only > BF = Minus-S = Minus-B > Control. However, regardless of fertilization treatment, liming significantly increased maize productivity with grain yields ranging from 0.7 to 4.2 t ha −1 , with BF having the greatest yield. With liming, the minus-Zn treatment resulted in a ≥ 30% yield decrease, compared to BF. The combined data suggest that in strongly acid soils, unless lime is applied, addition of micronutrients to NPK fertilizers would not have the desired effect on maize productivity. Without lime application to such soils, omission of Zn from BF in will not only reduce production cost but could have a positive impact on maize productivity. However, we recommend that BF in strongly acid soils should be accompanied by liming to ensure increased and sustainable productivity.
- ItemAn Equivalent Soil Mass Procedure for Monitoring Soil Organic Carbon in Multiple Soil Layers(2013-02) Wendt John; S . HauserSoil carbon stocks are commonly quantified at fixed depths as the product of soil bulk density, depth and organic carbon (OC) concentration. However, this method systematically overestimates OC stocks in treatments with greater bulk densities such as minimum tillage, exaggerating their benefits. Its use has compromised estimates of OC change where bulk densities differed between treatments or over time periods. We argue that its use should be discontinued and a considerable body of past research re-evaluated. Accurate OC estimations must be based on quantification in equivalent soil masses (ESMs). The objective of this publication is to encourage accurate quantification of changes in OC stocks and other soil properties using ESM procedures by developing a simple procedure to quantify OC in multiple soil layers. We explain errors inherent in fixed depth procedures and show how these errors are eliminated using ESM methods. We describe a new ESM procedure for calculating OC stocks in multiple soil layers and show that it can be implemented without bulk density sampling, which reduces sampling time and facilitates evaluations at greater depths, where bulk density sampling is difficult. A spreadsheet has been developed to facilitate calculations. A sample adjustment procedure is described to facilitate OC quantification in a single equivalent soil mass layer from the surface, when multiple-layer quantification is not necessary
- ItemAn Evaluation of The Effectiveness of Nonconventional P Fertilizers Derived from Zimbabwe Phosphate Rock using Ryegrass as a Test Crop(2005) Ephraim Govere; Sen H. Chien; Fox, R.HZimbabwe and many other African countries lack high-quality phosphate ores for the production of conventional phosphate fertilizers. The objective of this study was to investigate the agronomic potential of an igneous phosphate rock derived from Dorowa (Zimbabwe) in a greenhouse experiment using rye grass (Lolium perenne) as test crop on a Hartsells silt loam. Three phosphate fertilizer materials: finely ground (0.150-mm screen) Dorowa phosphate rock (DPR); DPR partially acidulated with 50 % of the sulfuric acid required for complete acidulation (PADPR); and a compacted mixture of DPR + triple superphosphate + urea + potassium chloride (DTUK) with half of phosphorus from DPR and half from TSP were made from Dorowa rock and their agronomic effectiveness compared with that of single superphosphate. The relative agronomic effectiveness of the fertilizers based on dry matter yield of ryegrass followed the orders: DTUK=SSP>PADPR>DPR=Check and SSP>DTUK=PADPR>DPR=Check during the first 12 weeks and the second 12 weeks, respectively. For phosphorus uptake by ryegrass, the orders were: DTUK>SSP>PADPR>DPR=Check, DTUK=SSP>PADPR>DPR=Check, and SSP>DTUK>PADPR>DPR=Check during the first six, second six, and last 12 weeks, respectively. The results confirmed that the effectiveness of DPR could be greatly enhanced by partially acidulating DPR or compacting DPR with TSP, urea, and KCl.