Yield · Picea abies (Norway spruce)

1. fertilizationPositive and negative results4 papers: 3 positive, 1 negative or no effect
2. classPositive and negative results3 papers: 2 positive, 1 negative or no effect
3. in vitroPositive and negative results3 papers: 1 positive, 2 negative or no effect
4. pruningResults agree4 papers: 4 positive, 0 negative or no effect
5. droughtResults agree2 papers: 0 positive, 2 negative or no effect
6. nitrogenResults agree2 papers: 2 positive, 0 negative or no effect
7. transgenicResults agree2 papers: 0 positive, 2 negative or no effect

Claims are grouped by organism, treatment and what was measured or targeted. Claims that compare genotypes are left out; a claim about lacking a nutrient counts the other way round in that nutrient’s question. “Results differ” marks a question where two model reviewers, reading both claims, accepted at least one pair of papers whose results differ.