High intensity wildfires in semiarid shrub and woodland plant communities can leave ecosystems incapable of self-repair and susceptible to weed invasion. Subsequently, land managers need effective restoration tools to reseed native vegetation back into these degraded systems. In order to develop successful post-fire restoration approaches in these communities, it is critical that we understand the mechanisms that impair reseeding success. Our objective was to quantify the influence of soil water repellency on seedling emergence and plant growth in a greenhouse study using soil cores obtained from beneath burned Juniperus osteosperma trees. Soil cores were seeded with either Elymus wawawaiensis or Agropyron cristatum, and watered with either a high (watered daily) or a low water regime (watered every 5 days). During the first watering event, water repellency was ameliorated in half the cores by adding a wetting-agent comprised of alkylpolyglycoside-ethylene oxide=propylene oxide block copolymers. Results showed that water repellency reduced seedling emergence and seedling survival by decreasing soil moisture availability. Wetting-agents improved ecohydrologic properties required for plant growth by decreasing runoff and increasing the amount and duration of available water for seedling emergence, survival, and plant growth. These results indicate that soil water repellency can act as an ecological threshold by impairing establishment of reseeded species after a fire. Where restoration efforts are limited by soil water repellency,

Core Ideas Meta‐analysis shows a significant yield increase of 2.1% with AVAIL+P fertilizer.Many AVAIL studies were not conducted under P responsive conditions.Likelihood of response increases with low soil test P and P rate and extreme pH.Average yield response increases to 4.6% when only likely to respond sites included.Enhanced efficiency fertilizer should be evaluated under P responsive conditions. AVAIL, a maleic‐itaconic copolymer acid marketed to enhance P fertilizers, has been studied on a variety of crop species. Data from all known field studies comparing P fertilization with and without AVAIL was amassed into a meta‐analysis of 503 field observations. The average yield increase was a modest, although statistically significant, 2.1% (P < 0.0001). However, only 116 of these observations were conducted under conditions where a positive yield response to a P enhancement product would be expected– that is, low soil test phosphorus (STP), strong alkaline or acid pH, and low P fertilizer rate. As such, the data was parsed into a subset of only those observations that were evaluated under responsive conditions, resulting in a greater magnitude of a yield response to AVAIL at 4.6% (P < 0.0001). Further parsing of the data, by eliminating any data not published in refereed or thesis/dissertation sources resulted in an average increase of 5.8% (P = 0.0039). AVAIL effectively increased yields when used appropriately under conditions where a P response was expected. Testing enhanced efficiency fertilizer products in a variety of conditions is useful, but the conclusions from the multitude of studies with AVAIL in environments where no response to P fertilizer enhancement product would be expected may lead to erroneous conclusions if the data is not further parsed and categorized. These data demonstrate the importance of applying fundamental soil fertility principles when designing and evaluating fertilizer crop response studies.

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Core Ideas Fixation of fertilizer phosphorus in soils often decreases phosphorus efficiency. Avail has been reported to enhance fertilizer phosphorus efficiency. A review on the effect of Avail on soil phosphorus‐fixation is critically discussed.