How Long Will it Take Corn to Emerge?

It’s an understatement to say that March in Iowa was much warmer than normal (Figure 1). Although only a few record high daily temperatures were set, the average monthly temperature set a new record by a substantial margin. The consistent warm weather encouraged a few to plant corn as early as mid-March.Soil temperatures state-wide reached 50 F by March 15. Although not a first historically, it was a full month before soils normally warm to 50 F at the 4 inch depth

August 2011 Iowa Corn Yield Forecast

USDA released the first corn yield forecast for 2011 on Aug. 11. Forecast U.S. yields of 153 bushels per acre are similar to last years\u27 and six bushels below the 30-year trend line (Figure 1). This is not surprising. On the other hand, Iowa’s forecast of 177 bushels per acre matches that of the 30-year trend line and lies 12 bushels above last year’s final yield estimate. This, if realized, would rank third highest behind 2004 (181) and 2009 (182) bushels per acre for Iowa. This seems unlikely

Analog Years for Weather Forecasting and Correlating Corn Planting Dates with Yield in Iowa

As of May 12, 15 percent of Iowa’s corn was planted (USDA-NASS). This is a slower pace than what Iowan’s experienced even in the flood year, 1993, when 20 percent was planted at this time in May. The 8 percent planted before May 5 was subjected to dramatic soil temperature changes as well as up to a foot of snow in parts of Iowa. Many Integrated Crop Management News articles, blogs, Twitter posts, and other media document spring 2013 conditions and concerns

Soil Moisture Conditions and Crop Water Use

Soil moisture during the growing season is essential to obtain optimal yield. Optimal yield is affected by the availability of moisture as stored water in the soil profile or timely recharge during rain events. Soil texture, tillage practices, residue cover, drainage and weed control can play a significant role in soil moisture availability. Generally, the no-till system is the most effective practice in conserving soil moisture among other tillage systems, especially during dry periods in rain-fed agricultural areas

Short Corn and Variable Growth—2013

“Knee high by the fourth of July!” Some of us grew up with that old saying which either foreshadowed disaster or forecast bumper yields. If corn was knee high by the fourth, most thought it would mature before the first fall frost. That was good news! As we look back, the statement perhaps was valid back when the first target corn planting date was mid-May

Soybean Chlorosis Studies on High pH Bottomland Soils

Soybean varieties are different in tolerance to lime-induced chlorosis. Field trials were conducted to evaluate variety performance on soils where chlorosis in soybeans was a known problem. Thirty-six varieties out of 177 were identified as tolerant to soil conditions that cause chlorosis. Eleven varieties of these 36 were found to have the most consistent yield performance on high pH soils. Tolerant varieties must be planted at adequate densities for best performance. A seeding rate of 13.5 seeds per foot of row, the highest seeding rate employed, did not appear to maximize yield on soils where chlorosis was severe. On some soils, chlorosis is so severe that even tolerant varieties planted at adequate densities will not produce seed. Under conditions where soils cause moderate to severe chlorosis in tolerant varieties, yields were improved by the use of a high pH stable chelate (Fe-EDDHA) with the seed

Soybean Chlorosis Studies on High pH Bottomland Soils

Soybean varieties are different in tolerance to lime-induced chlorosis. Field trials were conducted to evaluate variety performance on soils where chlorosis in soybeans was a known problem. Thirty-six varieties out of 177 were identified as tolerant to soil conditions that cause chlorosis. Eleven varieties of these 36 were found to have the most consistent yield performance on high pH soils. Tolerant varieties must be planted at adequate densities for best performance. A seeding rate of 13.5 seeds per foot of row, the highest seeding rate employed, did not appear to maximize yield on soils where chlorosis was severe. On some soils, chlorosis is so severe that even tolerant varieties planted at adequate densities will not produce seed. Under conditions where soils cause moderate to severe chlorosis in tolerant varieties, yields were improved by the use of a high pH stable chelate (Fe-EDDHA) with the seed

Coherence loss and revivals in atomic interferometry: A quantum-recoil analysis

The coherence effects induced by external photons coupled to matter waves inside a Mach-Zehnder three-grating interferometer are analyzed. Alternatively to atom-photon entanglement scenarios, the model considered here only relies on the atomic wave function and the momentum shift induced in it by the photon scattering events. A functional dependence is thus found between the observables, namely the fringe visibility and the phase shift, and the transversal momentum transfer distribution. A good quantitative agreement is found when comparing the results obtained from our model with the experimental data.Comment: 18 pages, 4 figure

Corn Emergence Problems Across Iowa

Producers recently experienced good planting conditions; these could be the best planting dates for the year. Although we recommend having corn planted by early May if possible, these recommendations are based on research data accumulated from several locations and years where planting date is the only major variable. This kind of information provides insight as to when, on average, is the best time to plant corn in Iowa. Yield variation exists though in relation to planting dates due to the growing conditions which occur during the remainder of the season

Mammography Facility Characteristics Associated With Interpretive Accuracy of Screening Mammography

BackgroundAlthough interpretive performance varies substantially among radiologists, such variation has not been examined among mammography facilities. Understanding sources of facility variation could become a foundation for improving interpretive performance.MethodsIn this cross-sectional study conducted between 1996 and 2002, we surveyed 53 facilities to evaluate associations between facility structure, interpretive process characteristics, and interpretive performance of screening mammography (ie, sensitivity, specificity, positive predictive value [PPV1], and the likelihood of cancer among women who were referred for biopsy [PPV2]). Measures of interpretive performance were ascertained prospectively from mammography interpretations and cancer data collected by the Breast Cancer Surveillance Consortium. Logistic regression and receiver operating characteristic (ROC) curve analyses estimated the association between facility characteristics and mammography interpretive performance or accuracy (area under the ROC curve [AUC]). All P values were two-sided.ResultsOf the 53 eligible facilities, data on 44 could be analyzed. These 44 facilities accounted for 484 463 screening mammograms performed on 237 669 women, of whom 2686 were diagnosed with breast cancer during follow-up. Among the 44 facilities, mean sensitivity was 79.6% (95% confidence interval [CI] = 74.3% to 84.9%), mean specificity was 90.2% (95% CI = 88.3% to 92.0%), mean PPV1 was 4.1% (95% CI = 3.5% to 4.7%), and mean PPV2 was 38.8% (95% CI = 32.6% to 45.0%). The facilities varied statistically significantly in specificity (P < .001), PPV1 (P < .001), and PPV2 (P = .002) but not in sensitivity (P = .99). AUC was higher among facilities that offered screening mammograms alone vs those that offered screening and diagnostic mammograms (0.943 vs 0.911, P = .006), had a breast imaging specialist interpreting mammograms vs not (0.932 vs 0.905, P = .004), did not perform double reading vs independent double reading vs consensus double reading (0.925 vs 0.915 vs 0.887, P = .034), or conducted audit reviews two or more times per year vs annually vs at an unknown frequency (0.929 vs 0.904 vs 0.900, P = .018).ConclusionMammography interpretive performance varies statistically significantly by facility