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Understanding land use/land cover (LULC) effects on tropical soil infiltration is crucial for maximizing watershed scale hydro‐ecosystem services and informing land managers. This paper reports results from a multiyear investigation of LULC effects on soil bulk infiltration in steep, humid tropical, and lowland catchments. A rainfall simulator applied water at measured rates on 2 × 6 m plots producing infiltration through structured, granulated, and macroporous Ferralsols in Panama's central lowlands. Time‐lapse electrical resistivity tomography (ERT) helped to visualize infiltration depth and bulk velocity. A space‐for‐time substitution methodology allowed a land‐use history investigation by considering the following: (a) a continuously heavy‐grazed cattle pasture, (b) a rotationally grazed traditional cattle pasture, (c) a 4‐year‐old (y.o.) silvopastoral system with nonnative improved pasture grasses and managed intensive rotational grazing, (d) a 7 y.o. teak (Tectona grandis) plantation, (e) an approximately 10 y.o. secondary succession forest, (f) a 12 y.o. coffee plantation (Coffea canephora), (g) an approximately 30 y.o. secondary succession forest, and (h) a >100 y.o. secondary succession forest. Within a land cover, unique plot sites totalled two at (a), (c), (d), (e), and (g); three at (b); and one at (f) and (h). Our observations confirmed measured infiltration scale dependency by comparing our 12 m² plot‐scale measurements against 8.9 cm diameter core‐scale measurements collected by others from nearby sites. Preferential flow pathways (PFPs) significantly increased soil infiltration capacity, particularly in forests greater than or equal to 10 y.o. Time‐lapse ERT observations revealed shallower rapid bulk infiltration and increased rapid lateral subsurface flow in pasture land covers when compared with forest land covers and highlighted how much subsurface flow pathways can vary within the Ferralsol soil class. Results suggest that LULC effects on PFPs are the dominant mechanism by which LULC affects throughfall partitioning, runoff generation, and flow pathways.

It is challenging to demonstrate the ideas of infiltration capacity and actual infiltration rates into soil from a water supply (such as rainfall) event because infiltration capacity models are usually given as a function of time. This article outlines a new visual method by which the actual infiltration rate can be demonstrated using an Excel spreadsheet file. The visual method is appropriate for junior/senior and graduate students interested in water resources management courses such as hydrology, groundwater engineering, or soil physics. The first step is to construct a relationship between the capacity infiltration rate and the cumulative infiltration depth. This relationship serves as the basis to determine the actual infiltration rate. The next step is to use a visual iterative approach in Excel to determine the timing of runoff and the actual infiltration rates. Three representative examples are presented to illustrate the method. The first example represents a case of constant water supply rate. In the second example, we present a scenario with unsteady water supply rate, but having large enough rate to sustain continuous runoff once it started. The third example is a case of unsteady water supply rate with intermittent runoff after it started. This new approach is a valuable tool by which students and researchers can better understand the concepts related to infiltration capacity and actual infiltration rate in real-world applications. Impact Statement Relationships between water supply rates and actual infiltration rates into a soil are important concepts of many real-world applications. This article outlines a new visual method by which the actual infiltration rate can be determined using a spreadsheet file in a trial-and-error manner. With this new method, the infiltration and runoff concepts can be quantitatively demonstrated to better understand the difference between the infiltration capacity and actual infiltration.

A facile and efficient synthesis of fully substituted pyridin-2(1H)-ones has been developed by the reaction of readily available α-oxoketene-S,S-acetals with malononitrile in the presence of sodium methoxide in methanol under reflux.