Geo-tagged street level imagery collection set-up

Description of a mount to collect field data

Cost of the proposed scenarios expressed as the percentage of Agricultural GDP.

<p>Cost of the proposed scenarios expressed as the percentage of Agricultural GDP.</p

Relationship between historic FAO experimental corn field trials with at least five N and P input combinations and corn yields calculated with the Mitscherlich-Baule crop response function totaling 1358 unique nutrient-yield relations (r² = 0.94).

<p>Relationship between historic FAO experimental corn field trials with at least five N and P input combinations and corn yields calculated with the Mitscherlich-Baule crop response function totaling 1358 unique nutrient-yield relations (r² = 0.94).</p

Crosses indicate locations of 1358 historic FAO corn field trials with at least five N and P input combinations in Africa and South America carried out between 1969 and 1993.

<p>Colors indicate (subnational) maize (corn) yields (ton/ha) as collected by <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060075#pone.0060075-IFPRI1" target="_blank">[23]</a>.</p

Affordable Nutrient Solutions for Improved Food Security as Evidenced by Crop Trials

<div><p>The continuing depletion of nutrients from agricultural soils in Sub-Saharan African is accompanied by a lack of substantial progress in crop yield improvement. In this paper we investigate yield gaps for corn under two scenarios: a micro-dosing scenario with marginal increases in nitrogen (N) and phosphorus (P) of 10 kg ha⁻¹ and a larger yet still conservative scenario with proposed N and P applications of 80 and 20 kg ha⁻¹ respectively. The yield gaps are calculated from a database of historical FAO crop fertilizer trials at 1358 locations for Sub-Saharan Africa and South America. Our approach allows connecting experimental field scale data with continental policy recommendations. Two critical findings emerged from the analysis. The first is the degree to which P limits increases in corn yields. For example, under a micro-dosing scenario, in Africa, the addition of small amounts of N alone resulted in mean yield increases of 8% while the addition of only P increased mean yields by 26%, with implications for designing better balanced fertilizer distribution schemes. The second finding was the relatively large amount of yield increase possible for a small, yet affordable amount of fertilizer application. Using African and South American fertilizer prices we show that the level of investment needed to achieve these results is considerably less than 1% of Agricultural GDP for both a micro-dosing scenario and for the scenario involving higher yet still conservative fertilizer application rates. In the latter scenario realistic mean yield increases ranged between 28 to 85% in South America and 71 to 190% in Africa (mean plus one standard deviation). External investment in this low technology solution has the potential to kick start development and could complement other interventions such as better crop varieties and improved economic instruments to support farmers.</p> </div

Cereal yield trends since 1960 in Africa, Sub-Sahara Africa (SSA), South America and Asia.

<p>Cereal yield trends since 1960 in Africa, Sub-Sahara Africa (SSA), South America and Asia.</p

The median, 25^th and 75^th percentile values from the distributions of the Mitscherlich-Baule crop response function parameters (a₁, a₂, a₃ and a₄) fitted for the 1358 individual crop trials.

<p>The median, 25^th and 75^th percentile values from the distributions of the Mitscherlich-Baule crop response function parameters (a₁, a₂, a₃ and a₄) fitted for the 1358 individual crop trials.</p

Mean corn yield increase (%) across trial sites at additional applications of 10 kg N ha⁻¹, 10 kg P ha⁻¹ or 10 kg N and P ha⁻¹ (error bars refer to the standard deviation of the obtained yield increases observed across all trials).

<p>Mean corn yield increase (%) across trial sites at additional applications of 10 kg N ha⁻¹, 10 kg P ha⁻¹ or 10 kg N and P ha⁻¹ (error bars refer to the standard deviation of the obtained yield increases observed across all trials).</p

A typical example of a fitted crop response trial with experimental (blue line with circles) and modeled data (black line with squares) with eight N and P input combinations and resulting yields.

<p>A typical example of a fitted crop response trial with experimental (blue line with circles) and modeled data (black line with squares) with eight N and P input combinations and resulting yields.</p

Extending the regression to include an indicator of expertise, where <i>b_E</i> is the regression coefficient for this indicator and <i>b_X</i> is the regression coefficient for participant human impact scores.

<p>Extending the regression to include an indicator of expertise, where <i>b_E</i> is the regression coefficient for this indicator and <i>b_X</i> is the regression coefficient for participant human impact scores.</p