The Occurrence of Legacy P Soils and Potential Mitigation Practices Using Activated Biochar
The long-term application of manures in watersheds with dense animal production has increased soil phosphorus (P) concentration, exceeding plant and soil assimilative capacities. The P accumulated in soils that are heavily manured and contain excess extractable soil P concentrations is known as legacy P. Runoff and leaching can transport legacy P to ground water and surface water bodies, contributing to water quality impairment and environmental pollution, such as eutrophication. This review article analyzes and discusses current and innovative management practices for soil legacy P. Specifically, we address the use of biochar as an emerging novel technology that reduces P movement and bioavailability in legacy P soils. We illustrate that properties of biochar can be affected by pyrolysis temperature and by various activating chemical compounds and by-products. Our approach consists of engineering biochars, using an activation process on poultry litter feedstock before pyrolysis to enhance the binding or precipitation of legacy P. Finally, this review article describes previous examples of biochar activation and offers new approaches to the production of biochars with enhanced P sorption capabilities.
Soybean stem growth under high-pressure sodium with supplemental blue lighting
High-pressure sodium (HPS) lamps are popular for plant lighting because of their high energy conversion efficiencies. Yet their spectrum has very little blue light (BL), which may cause undesirable morphological responses. To study this, McCall' soybean [Glycine max (L.) Merr.] plants were grown for 28 d in growth chambers using HPS lamps, with or without supplemental light from blue phosphor fluorescent lamps. Total photosynthetic photon flux (PPF) levels (including blue fluorescent) were kept near 300 or 500 micromoles m-2 s-1. Blue fluorescent levels ranged from 7 to 20 micromoles m-2 s-1, providing from 6 to 18 micromoles m-2 s-1 of supplemental BL (400-500 nm). Stem and internode lengths were longest under 300 micromoles m-2 s-1 HPS lighting and became progressively shorter with increasing supplemental BL until a total of approximately 30 micromoles m-2 s-1 of BL (from HPS and BL supplement) was present in the spectrum. Beyond this, extra BL had no effect. Two other lamps rich in BL, metal halide (Optimarc) and fluorescent (Vita-Lite), also produced plants with short stems, as did HPS lighting maintained at 500 micromoles m-2 s-1. Results suggest that use of high-pressure sodium or other blue-deficient sources for lighting at low to moderate photosynthetic photon flux levels may cause abnormal stem elongation, but this can be prevented by adding a small amount of supplemental blue light.
Regression models for calculating gas fluxes measured with a closed chamber
Portable closed chambers provide a valuable tool for measuring crop photosynthesis and evapotranspiration. Typically, the rates of change of CO2 and water vapor concentration are assumed to be constant in the short time required to make the closed-chamber measurement, and a linear regression model is used to estimate the CO2 and H2O fluxes. However, due to the physical and physiological effects the measurement system has on the measured process, assuming a constant rate and using a linear model may underestimate the flux. Our objective was to provide a model that estimates the CO2 and H20 exchange rates at the time of chamber closure. We compared the linear regression model with a quadratic regression model using field measurements from two studies. Generally, 60 to 100% of all chamber measurement data sets were significantly nonlinear, causing the quadratic model to yield fluxes 10 to 40% greater than those calculated with the linear regression model. The frequency and degree of nonlinearity were related to the measured rate and chamber volume. Closed-chamber data should be tested for nonlinearity and an appropriate model used to calculate flux. The quadratic model provides users of well-mixed closed chambers an alternative to a simple linear model for data sets with significant nonlinearity.
Wheat response to differences in water and nutritional status between zeoponic and hydroponic growth systems
Hydroponic culture has traditionally been used for controlled environment life support systems (CELSS) because the optimal environment for roots supports high growth rates. Recent developments in zeoponic substrate and microporous tube irrigation (ZPT) also offer high control of the root environment. This study compared the effect of differences in water and nutrient status of ZPT or hydroponic culture on growth and yield of wheat (Triticum aestivum L. cv. USU-Apogee). In a side-by-side test in a controlled environment, wheat was grown in ZPT and recirculating hydroponics to maturity. Water use by plants grown in both culture systems peaked at 15 to 20 L m-2 d-1 up to Day 40, after which it declined more rapidly for plants grown in ZPT culture due to earlier senescence of leaves. No consistent differences in water status were noted between plants grown in the two culture systems. Although yield was similar, harvest index was 28% lower for plants grown in ZPT than in hydroponic culture. Sterile green tillers made up 12 and 0% of the biomass of plants grown in ZPT and hydroponic culture, respectively. Differences in biomass partitioning were attributed primarily to NH4-N nutrition of plants grown in ZPT compared with NO3-N in hydroponic nutrient solution. It is probable that NH4-N-induced Ca deficiency produced excess tillering and lower harvest index for plants grown in ZPT culture. These results suggest that further refinements in zeoponic substrate would make ZPT culture a viable alternative for achieving high productivity in a CELSS.
Response of Grain Legumes to Phosphorus Application in the Guinea Savanna Agro-Ecological Zones of Ghana
Grain legumes (cowpea, peanut, and soybean) play important roles in household food and income security in smallholder farming systems in the Guinea Savanna agro-ecological zones of Ghana. However, yields are low, rarely exceeding 600 kg ha, prompting the need to evaluate responses of grain legumes to P fertilizer applications for two seasons. Conducting P studies is critical to help farmers adopt economic-based recommendations. Treatments evaluated in 2015 for the three crops were (i) farmers' practice (no input and planted by farmer); (ii) control (no input and planted by researcher), and (iii) triple super phosphate (TSP) fertilizer. However, for soybean, an additional two treatments (inoculant only and inoculant plus TSP fertilizer) were included. In 2016, the treatments were the same, except on-farm demonstrations were not conducted on cowpea. The demonstrations were laid out in a Randomized Complete Block Design with each demonstration rep-resenting a replicate within a region. On average, P-fertilizer application increased yields by 296; 527, and 390 kg ha for cowpea, peanut, and soybean grains, respectively. On average over the two seasons, P-fertilizer increased yield by 9.85; 13.00, and 17.56 per kg ha kg P applied for cowpea, soybean, and peanut, respectively, and these applications were cost effective. Peanut showed little response to P in the Upper East Region compared with a greater response in the Northern and Upper West Regions, suggesting that benefits from P-fertilizer for peanut may be location-specific. On average, rhizobium inoculation increased grain yield by 157 kg ha across the three regions and significantly positive effects of inoculation were observed in both seasons. Our results show that substantial increases in grain legume yield may be achieved by applying P fertilizers, but farmers cannot afford them because of their relatively high cost. Planting adapted and improved varieties and using rhizobium inoculants may provide the most economically viable and low risk options for increasing yields of grain legumes in the savanna agro-ecological zones of Ghana.
Assessing inbred-hybrid relationships for developing drought-tolerant provitamin A-quality protein maize hybrids
Drought-tolerant early-maturing maize ( L.) inbred lines with high levels of provitamin A (PVA) and quality protein (QPM) are urgently needed for development of superior hybrids to mitigate malnutrition and to intensify maize production and productivity in sub-Saharan Africa (SSA). This study was designed to identify early-maturing inbred lines with combined tolerance to drought, elevated tryptophan, and PVA contents; to examine inbred-hybrid relationships for tryptophan and PVA accumulation; and to select hybrids with outstanding grain yield (GY) performance. A total of 64 inbred lines and six checks, plus 96 hybrids and four checks, were evaluated under drought and well-watered environments in Nigeria for 2 yr. Eighteen parental lines and 54 derived hybrids were assayed for tryptophan and PVA contents. Ten drought-tolerant inbred lines with high tryptophan and elevated PVA levels were identified in the top 10 hybrid combinations across managed drought and well-watered conditions. The inbred-hybrid relationship was significant for GY under each and across the two contrasting environments. Significant average heterosis was found for tryptophan and PVA under well-watered conditions. This indicated that the selected inbred lines could be used for developing high-yielding PVA-QPM hybrids tolerant to drought stress in SSA. The 10 top-performing PVA-QPM hybrids identified are being extensively evaluated in different locations and subsequently in on-farm trials for commercialization throughout SSA.
Global food security post COVID-19: Dearth or dwell in the developing world?
Today, global food systems are highly susceptible to food safety risks, economic shocks, price volatility, and natural disasters and pandemics, such as the novel coronavirus (COVID-19). This paper draws from research on food and nutritional security, food fraud and associated economic ecosystem, and the disruptions due to COVID-19 for socio-economic inequality globally. It is concluded that the safety risks have pushed enforcement of measures to reduce food supplies, adversely impacting food availability. Also, COVID-19 is likely to raise fleeting food security and nutritional concerns across the globe, resulting in rises in poverty and food fraud, limiting food supply and access. Accelerated investments intended to develop more inclusive, sustainable, and resilient food systems will help shrink the effect of the pandemic and, hence, offer a way to control the foreseen food security crisis and economic growth.
Assessment of peri-urban livestock producers' willingness to pay for improved forages as cash crops
Availability of quality feed is a major constraint for livestock production in Burkina Faso. Despite previous efforts to test improved forages at research stations to overcome the dry-season feed gap, little has been done to promote them as cash crops that can contribute to meeting the growing feed demand in the country. This study was undertaken to evaluate the willingness to pay (WTP) for improved forage by livestock producers in the peri-urban livestock production systems of Burkina Faso. A total of 202 livestock producers were interviewed using semi-structured questionnaires. The contingent valuation method and Tobit econometric model were used to analyze the survey data. Exactly 79% of the interviewed livestock producers were willing to pay for improved forages for their livestock. Key factors that significantly affect this decision were the price of cottonseed cakes used as supplemental feed (= .001), farmers' knowledge about improved forage crops (= .001), farmers' ethnicity (= .05), and farmers' practice of daily grazing and transhumance (= .01). The estimated WTP for improved forage as a cash crop was US$0.32 kg for all livestock producers and $0.58 kg for those who only expressed a positive WTP. The positive WTP for improved forages and factors affecting that decision suggest that producing improved forages is a viable alternative to expensive cottonseed cakes and the practice of transhumance to overcome the dry-season feed gap. Therefore, dissemination of improved forages is recommended to market-oriented crop farmers to meet the growing feed demand in Burkina Faso.
Livestock feed resources in the West African Sahel
Limited supply of quality feed is the most important factor limiting livestock productivity in many sub-Saharan African (SSA) countries. Having a systematic inventory of available feed resources, identifying main challenges and potentials for improvement is the first step towards designing development strategies to improve feed quality and quantity. The objective of this study was to review the available feed resources and their quality in West African Sahel across different agro-ecological zones and to identify the research gaps and strategies to improve feed resource availability. The West African Sahelian zone is home to 135 million people who herd 173 million head of ruminant livestock. The main feed resources for grazing ruminants are pastures and crop residues; commercially formulated feeds are increasingly being used in poultry and pig production, particularly in peri-urban areas. Feed resources for livestock are diverse and vary markedly across agro-ecological zones in the West African Sahel and across seasons in terms of type, quantity, and quality. Given that crop residues are among the most important feed resources, there is need to invest in promoting adoption of proven methods for improving their quality and preserving it. Given poorly developed feed markets in the Sahelian rural areas and cities, strengthening the feed value chain is critical for improving the feed resource base in West Africa. Additional critically important needs are to increase awareness about the importance of feed quality, to create quality-based feed marketing systems, and to appreciate and enhance women's roles in feed production.
From FAIR to FAIRS: Data security by design for the global burden of animal diseases
Solving complex global problems involving data and data analysis can require data from both the public and private sectors. The sharing of data has traditionally been restricted to open data. To facilitate the use of both open and private data, a new data-sharing framework has been constructed as an extension to the popular Findable-Accessible-Interoperable-Reusable (FAIR) framework. The "Secure by Design" approach has been taken to define the FAIRS data-sharing framework where S stands for Secure. A Cloud infrastructure architecture is proposed that would allow data brokers to implement FAIRS. This architecture is being constructed for the Global Burden of Animal Diseases (GBADs) to facilitate the sharing of livestock data.