Crop yields can be similar in organic and conventional systems even when weed biomass is greater in organic systems. Greater weed tolerance in organic systems may be due to differences in management-driven soil fertility properties. The goal of this experiment was to determine whether soil collected from a long-term organic cropping system with a diverse crop rotation and organic fertility inputs would support higher soil nitrogen (N) resource partitioning, as indicated by overyielding of corn–weed mixtures, than a cropping system with a less diverse crop rotation and inorganic N inputs. A replacement series greenhouse experiment was conducted using corn : smooth pigweed and corn : giant foxtail proportions of 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0 and harvested at 29, 40, or 48 d after experiment initiation (DAI). The monoculture density of corn was 4 plants pot⁻¹and the monoculture density of each weed species was 36 plants pot⁻¹. Corn was consistently more competitive than both weed species at 40 and 48 DAI when soil inorganic N was limiting to growth. Corn–smooth pigweed mixtures had greater shoot biomass and shoot N content than expected based on the shoot biomass and shoot N content of monocultures (i.e., overyielding) at the onset of soil inorganic N limitation, providing some evidence for N resource partitioning. However, soil management effects on overyielding were infrequent and inconsistent among harvest dates and corn–weed mixtures, leading us to conclude that management-driven soil fertility properties did not affect corn–weed N resource partitioning during the early stages of corn growth.

Boxwood blight caused by Calonectria pseudonaviculata is a newly emergent disease of boxwood (Buxus spp. L.) in the United States that causes leaf drop, stem lesions, and plant death. A rapid and reliable laboratory assay that enables screening hundreds of boxwood genotypes for resistance to boxwood blight is needed to enable breeding and selection of resistant cultivars. Using eight boxwood cultivars with differing susceptibilities, we examined parameters for a screening assay comparing whole plant inoculation with detached leaf inoculation, use of mycelium versus spores as the inoculum, comparison of times of the year for inoculation, and comparison of two leaf inoculation methods. Inoculation of detached leaves gave comparable results to inoculation of whole plants when compared across genotypes, although the detached leaf assay resulted in greater percentages of symptom expression. The time of year of plant inoculation (spring, summer, or winter) did not affect the relative expression of symptoms among the most resistant and susceptible genotypes. Inoculating plants with mycelium was as effective as spore inoculation for causing disease symptoms and allowed us to distinguish the more resistant genotypes, yet mycelium inoculation was much easier to prepare in large quantities for multiple assays.

Sweetness drives the consumption of added sugars, so understanding how to best measure sweet hedonics is important for developing strategies to lower sugar intake. However, methods to assess hedonic response to sweetness vary, making results across studies difficult to integrate. We compared methods to measure optimal sucrose concentration in 21 healthy adults (1) using paired-comparison preference tracking vs. ratings of liking, (2) with participants in the laboratory vs. at home, and (3) using aqueous solutions vs. vanilla milk. Tests were replicated on separate days to assess test-retest reliability. Test-retest reliability was similar between laboratory and home testing, but tended to be better for vanilla milk and preference tracking. Optimal sucrose concentration was virtually identical between laboratory and home, slightly lower when estimated via preference tracking, and about 50% lower in vanilla milk. However, optimal sucrose concentration correlated strongly between methods, locations, and stimuli. More than 50% of the variability in optimal sucrose concentration could be attributed to consistent differences among individuals, while much less variability was attributable to differences between methods. These results demonstrate convergent validity between methods, support testing at home, and suggest that aqueous solutions can be useful proxies for some commonly consumed beverages for measuring individual differences.

Experimental statistics are a key element for innovation in the agricultural sector. Commonly used statistical methods in experimentation are relatively simple, reliable, and widely used. However, the many problems in the quality of statistical analyses reported in the agricultural science literature highlight a need for continuing discussion on and updating of this topic. This article reviews critical points about classic linear models procedures commonly used in agricultural statistics, frequent procedures in publications in the agricultural sciences. Due to the evolution of statistical science some common recommendations from the past should no longer be followed.

An earlier in vitro screening of N,N-diethyl-3-methylbenzamide (Deet) and N,N-diethylphenylacetamide (DEPA) analogs showed that two DEPA analogs, N,N-diethyl(3-bromophenyl) acetamide and N,N-diethyl[(alpha,alpha,alpha-trifluoro-m-tolyl)]acetamide, and one Deet analog, N,N,diethyl[3-(trifluoromethyl)]benzamide, had biting-deterrent activities that were superior to Deet against Aedes aegypti (L.) and Anopheles stephensi Liston. In the current study, the three analogs and (1S,2'S)-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) were applied topically to the skin of human volunteers at 24 nmol compound/cm2 skin and compared with the activity of Deet at the same dose against biting by Ae. aegypti, An. stephensi, and Phlebotomus papatasi Scopoli females. SS220 proved to be as effective as Deet against Ae. aegypti and P. papatasi but more effective than Deet against An. stephensi. Contrary to the earlier in vitro tests, results with humans (in vivo testing) showed that neither of the DEPA analogs nor the Deet analog performed more effectively than Deet against the insects. The in vivo results showed that the analogs were not sufficiently effective to warrant further development. Notably, in vivo and in vitro methods used in discovery of personal protection chemicals for human use against blood-feeding flies can both be effective discriminating tools, but results obtained with the respective methods may not always agree. Ultimately, we surmise that in vivo testing methods with humans must be used to discriminate among compounds that superficially seem effective when screened using an in vitro method.