4,307 research outputs found

    Pasture fertilization experiments at Reymann Memorial Farm

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    Corn as a Nurse Crop

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    Corn as a nurse crop for establishing hay and pasture continues to look promising. Wide-spaced corn rows are making this possible. Results of tests in 1953 were encouraging-in spite of the long summer drouth

    Forage Crops in Corn?

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    By widening corn rows and taking certain precautions, it\u27s possible to establish interplantings without a great loss in corn yields. Some problems remain to be overcome, but the future of this practice looks bright

    Empirical logic of finite automata: microstatements versus macrostatements

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    We compare the two approaches to the empirical logic of automata. The first, called partition logic (logic of microstatements), refers to experiments on individual automata. The second one, the logic of simulation (logic of macrostatements), deals with ensembles of automata.Comment: late

    The water problem in Iowa

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    Water deficiencies throughout Iowa and other Midwest states the past 3 years have re-emphasized the importance of water to our farms and cities. Cities have had to resort to more costly means of procuring adequate water for their citizens. Farmers have been digging deeper wells, constructing ponds and hauling water to meet their domestic and livestock needs. Many farmers have started to use or have contemplated using water from streams and wells to irrigate their crops. Industries are becoming increasingly concerned with the availability of water as a major factor in locating and expanding plants. Experience during the last 3 years has demonstrated that water problems are aggravated periodically by rainfall deficiencies. However, these periodic aggravations emphasize but do not explain the basic water problem before us. In the main our water problems result from greatly increased demands upon available water supplies. These increasing demands stem from two factors: (1) a growing population and (2) an increasing per capita consumption. These two elements of the increasing demand for water show no indication of relaxing their rates of increase

    Quantifying the impact of emission outbursts and non-stationary flow on eddy covariance CH<sub>4</sub> flux measurements using wavelet techniques

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    Methane flux measurements by the eddy-covariance technique are subject to large uncertainties, particularly linked to the partly highly intermittent nature of methane emissions. Outbursts of high methane emissions, termed event fluxes, hold the potential to introduce systematic biases into derived methane budgets, since under such conditions the assumption of stationarity of the flow is violated. In this study, we investigate the net impact of this effect by comparing eddy-covariance fluxes against a wavelet-derived reference that is not negatively influenced by non-stationarity. Our results demonstrate that methane emission events influenced 3–4 % of the flux measurements, and did not lead to systematic biases in methane budgets for the analyzed summer season; however, the presence of events substantially increased uncertainties in short-term flux rates. The wavelet results provided an excellent reference to evaluate the performance of three different gapfilling approaches for eddy-covariance methane fluxes, and we show that none of them could reproduce the range of observed flux rates. The integrated performance of the gapfilling methods for the longer-term dataset varied between the two eddy-covariance towers involved in this study, and we show that gapfilling remains a large source of uncertainty linked to limited insights into the mechanisms governing the short-term variability in methane emissions. With the capability to broaden our observational methane flux database to a wider range of conditions, including the direct resolution of short term variability at the order of minutes, wavelet-derived fluxes hold the potential to generate new insight into methane exchange processes with the atmosphere, and therefore also improve our understanding of the underlying processes
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