Measuring Soil Nitrogen Mineralization Under Field Conditions

The amount and rate of soil N mineralization are important components that can be used to predict preplant N fertilizer application and to evaluate the need for N fertilization during crop growth. This study's purpose was to evaluate the buried polyethylene bag technique as a method for characterizing the N mineralized under field conditions during the cropping season. Soil (Xerollic Calciorthids) was placed in polyethylene bags and buried in the 0 to 45 cm root zone of fallowed soils and where corn (Zea mays L.) and potato (Solanum tuberosum L.) were being grown. The NO?-N content of the soil in the bags was compared with that in the root zone at selected time intervals (10 to 14 days) from April to October. The soil NO?-N concentrations in the buried polyethylene bags were similar to those in irrigated fallow soils from April to October after correction for different soil water contents. The N-mineralization rate between sampling intervals had an average temperature coefficient (Q??) of 2.3 between 10 C and 30 C. The relative N mineralization rate was proportional to the soil water content expressed as a percentage of the available water-holding capacity. The N uptake by corn and potato crops predicted from NO?-N changes in the rooting zone and in the buried polyethylene bags resembled those measured by plant sampling. The buried polyethylene bag technique has potential for monitoring the soil N mineralization process during the cropping season and for estimating N uptake by crops. It also provides an alternative method for estimating soil N availability for future crops and its use should maximize N-fertilizer efficiencies

Nitrogen fertilization of wheat no-till planted in alfalfa stubble

Conservation tillage practices significantly reduce soil erosion, improve water distribution, and decrease environmental concerns in furrow-irrigated fields. Developing optimum N fertilization practices after legumes in these systems will help their adoption. We conducted three field studies on a silt loam soil to determine if N fertilizer is required for furrow-irrigated wheat (Triticum aestivum L.) planted in herbicide killed alfalfa (Medicago sativa L.) stubble. Fall regrowth of alfalfa was sprayed with a mixture of 1 qt glyphosphate and 2 qt 2,4-D/acre. `Stephens', a soft white winter wheat was planted with a double disk opener drill in two experiments and 'Bronze Chief', a hard red spring wheat in a third experiment. Nitrogen fertilizer (ammonium nitrate) was spring broadcast at four rates from 0 to 200 or 240 lb N/acre. The buried plastic bag technique estimated available N (EAN); above ground whole plant samples estimated root zone nitrate-N; and grain plot yields estimated with a combine. Nitrogen fertilization increased grain yield in all experiments because sufficient N had not mineralized from soil and legume residues before uptake needs of the wheat. The wheat plant at the soft dough growth stage contained about 109 lb N/acre from N mineralized from soil and legume residue sources. The apparent N fertilizer recovery calculated by a combined regression relationship between N uptake and fertilizer rates was 76%. The average plant recovery of mineralized N at maximum grain yields was calculated at 78%. Crops planted in herbicide killed alfalfa should be selected so sufficient nitrate-N can accumulate from mineralization before maximum crop uptake and for N uptake ability in late summer. Nitrogen fertilizer applications should be based on a spring soil test for nitrate-N in this no-till system. Both practices will reduce the potential for nitrate-N leaching losses

Plant Population Effects on the Seed Yield of Phaseolus vulgaris L

Seed yields of Phaseolus vulgaris L. have not increased under the current production systems even with more precise management inputs. Recent studies of snap beans grown for processing suggested that yields could be increased by high density planting. Our study was made to evaluate the effects of plant populations on the seed yields of four representative field and snap bean cultivars grown under sprinkler irrigation on a Portneuf silt loam (Xerollic Calciorthid). Two cultivars each of bush snap beans and semivining field beans were grown in plant populations of 107,600 to 968,700 plants/ha in nearly equidistant plant arrangements. The optimum plant population or seed yield for the bush cultivars was approximately 400,000 plants/ ha and less than 300,000 plants/ha for the semivining cultivars. At smaller plant populations, seed yields decreased for the bush cultivars and remained constant for the semivining cultivars. The harvest index (seed weight/ total plant weight) increased slightly for the bush cultivars as their plant population decreased, but remained constant for the semivining cultivars up to 300,000 plants/ ha, then increased rapidly. The production index (seed yield/amount seeded) increased curvilinearly as plant population decreased for all cultivars. Plant maturity was advanced 7 to 10 days at the highest plant populations for all cultivars. Pods were located at upper nodes on the plants as the populations increased. These results suggest that greater seed yields could be expected with the equidistant plant arrangements as compared with conventional row plantings for the bush cultivars, but not for the semivining cultivars, primarily because of the ability of the semivining cultivars to compensate for the increased area/plant at smaller plant populations

Sulfur Fertilization of Alfalfa in the Mountain Valleys of Southern Idaho

Areas of S deficiency are still being identified in the Pacific Northwest even though S has been applied to some soils in this region for at least 50 years. Recent studies dealing with the S fertilization of legumes for the Northwest have been conducted by Pumphrey and Moore (1965a, 1965b) in northeastern Oregon; Smith, et al., (1968) in western Montana; Dawson (1969) on pasture legumes in western Oregon; and Koehler (1965), and Roberts and Koehler (1968) in Washington

Plant Population Effects on the Seed Yield Components of Beans

Knowledge of the effect of plant populations on the seed yield components of beans (Phaseolus vulgaris L.) is needed to design management systems utilizing the genetic potential of different cultivars and to aid in the development of higher seed-yielding cultivars. The objectives of this study were to evaluate (a) the effect of different plant populations (area/plant) on the seed yield components as related to seed yield/plant, and (b) the relative differences between determinate ('Canyon', and 'Blue Lakes 274') and indeterminate ('UI-114', and 'Big Bend') bean cultivars. Seed yield/plant and the seed yield components were measured on plant populations from 107,600 to 968,700 plants/ha (100 to 930 cm²/plant) grown in a systematic design. Data were evaluated by path coefficient analysis based on correlations calculated from logarithmically transformed data. Pods/plants increased linearly as area/plant increased (decreasing plant population) for all cultivars studied, and had the largest effect on seed yield/plant. Seeds/pod and g/seed also increased as area/plant increased for the indeterminate cultivars, but remained relatively constant for the determinate cultivars. As a result, the seed yield/area is relatively constant over a wide range of plant populations for the indeterminate cultivars, but decreases at the smaller plant populations for the determinate cultivars. It also indicates that the determinate cultivar is subject to less competitive stress than the indeterminate one at the higher plant populations. The greatest potential for seed yield increases in high plant populations is with determinate cultivars

Adiabatic following criterion, estimation of the nonadiabatic excitation fraction and quantum jumps

An accurate theory describing adiabatic following of the dark, nonabsorbing state in the three-level system is developed. An analytical solution for the wave function of the particle experiencing Raman excitation is found as an expansion in terms of the time varying nonadiabatic perturbation parameter. The solution can be presented as a sum of adiabatic and nonadiabatic parts. Both are estimated quantitatively. It is shown that the limiting value to which the amplitude of the nonadiabatic part tends is equal to the Fourier component of the nonadiabatic perturbation parameter taken at the Rabi frequency of the Raman excitation. The time scale of the variation of both parts is found. While the adiabatic part of the solution varies slowly and follows the change of the nonadiabatic perturbation parameter, the nonadiabatic part appears almost instantly, revealing a jumpwise transition between the dark and bright states. This jump happens when the nonadiabatic perturbation parameter takes its maximum value.Comment: 33 pages, 8 figures, submitted to PRA on 28 Oct. 200

Future research directions in pneumonia

Pneumonia is a complex pulmonary disease in need of new clinical approaches. Although triggered by a pathogen, pneumonia often results from dysregulations of host defense that likely precede infection. The coordinated activities of immune resistance and tissue resilience then dictate whether and how pneumonia progresses or resolves. Inadequate or inappropriate host responses lead to more severe outcomes such as acute respiratory distress syndrome and to organ dysfunction beyond the lungs and over extended time frames after pathogen clearance, some of which increase the risk for subsequent pneumonia. Improved understanding of such host responses will guide the development of novel approaches for preventing and curing pneumonia and for mitigating the subsequent pulmonary and extrapulmonary complications of pneumonia. The NHLBI assembled a working group of extramural investigators to prioritize avenues of host-directed pneumonia research that should yield novel approaches for interrupting the cycle of unhealthy decline caused by pneumonia. This report summarizes the working group’s specific recommendations in the areas of pneumonia susceptibility, host response, and consequences. Overarching goals include the development of more host-focused clinical approaches for preventing and treating pneumonia, the generation of predictive tools (for pneumonia occurrence, severity, and outcome), and the elucidation of mechanisms mediating immune resistance and tissue resilience in the lung. Specific areas of research are highlighted as especially promising for making advances against pneumonia

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research