Irrigation impacts on minimum and maximum surface moist enthalpy in the Central Great Plains of the USA

Agricultural activities notably alter weather and climate including near-surface heat content. However, past research primarily focused on dry bulb temperature without considering the role of water vapor (dew point temperature) on surface air heat content. When using dry bulb temperature trends to assess these changes, for example, not including concurrent trends in absolute humidity can lead to errors in the actual rate of warming or cooling. Here we examined minimum and maximum surface moist enthalpy, which can be expressed as “equivalent temperature.” Using hourly climate data in the Central Great Plains (Nebraska and Kansas) from 1990 to 2014, the averages and trends of minimum and maximum equivalent temperature (TE_min; TE_max) were analyzed to investigate the potential impacts of irrigation. During the growing season, TE_max averages were significantly higher in irrigated cropland sites compared to grassland sites. This can be explained by increased transpiration linked to irrigation. In addition, TE_max exhibits a decreasing trend in most sites over the growing season. However, the difference of the trends under irrigated croplands and grasslands is not statistically significant. A longer time series and additional surface energy flux experiments are still needed to better understand the relationships among temperature, energy, and land cover

Recent Ogallala Aquifer Region Drought Conditions as Observed by Terrestrial Water Storage Anomalies from GRACE

Recent severe drought events have occurred over the Ogallala Aquifer region (OAR) during the period 2011–2015, creating significant impacts on water resources and their use in regional environmental and economic systems. The changes in terrestrial water storage (TWS), as indicated by the Gravity Recovery and Climate Experiment (GRACE), reveals a detailed picture of the temporal and spatial evolution of drought events. The observations by GRACE indicate the worst drought conditions occurred in September 2012, with an average TWS deficit of ~8 cm in the northern OAR and ~11 cm in the southern OAR, consistent with precipitation data from the Global Precipitation Climatology Project. Comparing changes in TWS with precipitation shows the TWS changes can be predominantly attributable to variations in precipitation. Power spectrum and squared wavelet coherence analysis indicate a significant correlation between TWS change and the El Nino- Southern Oscillation, and the influence of equatorial Pacific sea surface temperatures on TWS change is much stronger in the southern OAR than the northern OAR. The results of this study illustrate the value of GRACE in not just the diagnosis of significant drought events, but also in possibly improving the predictive power of remote signals that are impacted by nonregional climatic events (El Nino), ultimately leading to improved water resource management applications on a regional scale. Editor’s note: This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series

Corn and Soybean Production – 2023 Summary

Soybean and corn varieties were tested in replicated field trials at the Southeast Research and Extension Center in Parsons through the Kansas State University variety testing program. In total, 21 corn varieties and full-, mid-, and short-season maturity checks were tested. Fifteen full-season and nine double-cropped soybean varieties were tested, with three maturity checks ranging in maturity from 3.1 to 5.2. Fourteen sunflower varieties were also tested. The 2023 summer crop growing season was nearly average for both temperature and rainfall. Yields from the variety tests were slightly lower than the 13-year average

Observational evidence of temperature trends at two levels in the surface layer

Citation: Lin, X., Pielke, R. A., Mahmood, R., Fiebrich, C. A., & Aiken, R. (2016). Observational evidence of temperature trends at two levels in the surface layer. Atmospheric Chemistry and Physics, 16(2), 827-841. doi:10.5194/acp-16-827-2016Long-term surface air temperatures at 1.5m screen level over land are used in calculating a global average surface temperature trend. This global trend is used by the IPCC and others to monitor, assess, and describe global warming or warming hiatus. Current knowledge of near-surface temperature trends with respect to height, however, is limited and inadequately understood because surface temperature observations at different heights in the surface layer of the world are rare especially from a high-quality and long-term climate monitoring network. Here we use high-quality two-height Oklahoma Mesonet observations, synchronized in time, fixed in height, and situated in relatively flat terrain, to assess temperature trends and differentiating temperature trends with respect to heights (i.e., near-surface lapse rate trend) over the period 1997 to 2013. We show that the near-surface lapse rate has significantly decreased with a trend of -0.18 +/- 0.03 degrees C (10 m)(-1) per decade indicating that the 9m height temperatures increased faster than temperatures at the 1.5m screen level and/or conditions at the 1.5m height cooled faster than at the 9m height. However, neither of the two individual height temperature trends by themselves were statistically significant. The magnitude of lapse rate trend is greatest under lighter winds at night. Nighttime lapse rate trends were significantly more negative than daytime lapse rate trends and the average lapse rate trend was three times more negative under calm conditions than under windy conditions. Our results provide the first observational evidence of near-surface temperature changes with respect to height that could enhance the assessment of climate model predictions

Global total precipitable water trends from 1958 to 2021

This study investigates the trend in global total precipitable water(TPW), surface skin temperature (Ts) and surface air temperature (T2m) from 1958 to 2021 using ERA5 and Jra-55 reanalysis datasets. We found that TPW trends in most regions of the world are moistening. Larger moistening trends were in tropical land areas from 1958 to 2021. Such moistening trends over large tropical lands, the Indian Ocean, high latitudes in the Northern Hemisphere (NH) were confirmed by the Atmospheric Infrared Sounder (AIRS) satellite and the Integrated Global Radiosonde Archive version 2 (IGRA2) observations. The average global TPW trend ranged from 0.16 and 0.21 mm decade-1 for ERA5 and JRA-55, respectively. We also found that significant warming of T2m and Ts was found in almost all regions especially the Arctic where the temperature anomaly trend (0.55 K decade-1) was three times more than the global average trend (around 0.15 K decade-1). In addition, this warming over land was obviously larger than ocean's warming. The TPW trend was positively correlated with surface warming over oceans while this correlation over land was negative. The TPW change in response to temperature T2m or Ts changes showed larger variations of 5-11% K-1 over oceans than over land (below 4 % K-1 and even negative). In view of global dTPW/dT in the banded-latitudes, two stronger response zones were in the southern high-latitudes and tropical zones, and the dTPW/dT ratios over land were mostly lower than the theoretical ratio of 7%/K-1 in tropical zones.Comment: 23 pages, 10 figure

Improving Resilience of Corn to Weather through Improved Fertilizer Efficiency

Fertilization is a critical management tool to improve crop productivity. Corn requires more N fertilizer than some other crops, but the fertility needs of the crop vary based on the growing environment. In this study, we used a modeling approach to examine the historical record and delineate the interaction between fertilizer and weather on the sensitivity of corn yield to climate in southeastern Kansas. Providing optimal fertilizer can improve corn yield. However, too much fertilizer can be expensive and wasteful. This study demonstrated that the climate resilience of corn is moderated by how much fertilizer is applied. The model results concluded that the optimal N fertilizer rate should be adjusted based on weather conditions

Corn and Soybean Production – 2022 Summary

Soybean and corn varieties were tested in replicated field trials at the Southeast Research and Extension Center in Parsons through the Kansas State University variety testing program. In total, nine corn varieties and three maturity checks were tested. Fourteen full season and ten double-cropped soybean varieties were tested, with three maturity checks. Additionally, sorghum and sunflower varieties were tested. The 2022 summer crop growing season was challenging. High temperatures and low rainfall reduced crop production. Crop production was severely impacted by the hot, dry conditions, both across the state and in the cultivar trials at Parsons. No yield results are available for the variety tests from Parsons

Hard Red and Soft Red Winter Wheat Variety Testing - 2023

This is a summary of the winter wheat production conditions in Kansas, with particular emphasis on the variety trial results from southeast Kansas in 2023. After the dry conditions of 2022, adequate rain for wheat establishment and growth in the fall in southeast Kansas was received, although drought conditions were observed in central and western Kansas. The growing season had slightly below average rainfall, with adequate soil moisture in the fall for good stand establishment. Overall yields of hard and soft red wheat varieties were above multi-year averages, but slightly below the yields from 2022. As in previous years, soft red winter wheat out-yielded hard red winter wheat varieties, but the extent was not as dramatic as in previous years

Hard Red and Soft Red Winter Wheat Variety Testing - 2023

This is a summary of the winter wheat production conditions in southeast Kansas in 2021-2022 and the results of the winter wheat variety testing. Wheat production in 2022 benefited from dry conditions at flowering and harvest. Overall yields of hard red wheat were above multi-year averages, while soft red wheat yields were below the 15-year average. As in previous years, soft red winter wheat out-yielded hard red winter wheat varieties, but the extent was not as dramatic as in previous years

Narrowing the Agronomic Yield Gaps of Maize by Improved Soil, Cultivar, and Agricultural Management Practices in Different Climate Zones of Northeast China

Citation: Liu, Z. J., Yang, X. G., Lin, X. M., Hubbard, K. G., Lv, S., & Wang, J. (2016). Narrowing the Agronomic Yield Gaps of Maize by Improved Soil, Cultivar, and Agricultural Management Practices in Different Climate Zones of Northeast China. Earth Interactions, 20, 18. doi:10.1175/ei-d-15-0032.1Northeast China (NEC) is one of the major agricultural production areas in China, producing about 30% of China's total maize output. In the past five decades, maize yields in NEC increased rapidly. However, farmer yields still have potential to be increased. Therefore, it is important to quantify the impacts of agronomic factors, including soil physical properties, cultivar selections, and management practices on yield gaps of maize under the changing climate in NEC in order to provide reliable recommendations to narrow down the yield gaps. In this study, the Agricultural Production Systems Simulator (APSIM)-Maize model was used to separate the contributions of soil physical properties, cultivar selections, and management practices to maize yield gaps. The results indicate that approximately 5%, 12%, and 18% of potential yield loss of maize is attributable to soil physical properties, cultivar selection, and management practices. Simulation analyses showed that potential ascensions of yield of maize by improving soil physical properties PAY(s), changing to cultivar with longer maturity PAY(c), and improving management practices PAY(m) for the entire region were 0.6, 1.5, and 2.2 ton ha(-1) or 9%, 23%, and 34% increases, respectively, in NEC. In addition, PAY(c) and PAY(m) varied considerably from location to location (0.4 to 2.2 and 0.9 to 4.5 ton ha(-1) respectively), which may be associated with the spatial variation of growing season temperature and precipitation among climate zones in NEC. Therefore, changing to cultivars with longer growing season requirement and improving management practices are the top strategies for improving yield of maize in NEC, especially for the north and west areas