Large-Scale and Long-Term Trends and Magnitudes in Irrigated and Rainfed Maize and Soybean Water Productivity: Grain Yield and Evapotranspiration Frequency, Crop Water Use Efficiency, and Production Functions

2015 ◽  
pp. 103-120 ◽  
2017 ◽  
Vol 60 (4) ◽  
pp. 1189-1208 ◽  
Author(s):  
Meetpal S. Kukal ◽  
Suat Irmak

Abstract. Sustainable agricultural utilization of the limited water resources demands improvements in understanding the changes in crop water productivity (CWP) in space and time, which is often presented as a potential solution to relieve the growing pressure on fresh water resources. In addition, crop yield needs to be studied in relation to precipitation received annually and during the growing season for its contribution to reduce irrigation water requirements, which is quantified through precipitation use efficiency (PUE). Hence, systematic quantifications, mapping, and analyses of large-scale CWP and PUE levels are needed. This study aims to quantify long-term (1982-2013) information on grain yield, PUE, and CWP for maize and soybean in the U.S. Great Plains counties and to map and analyze them. Multiple public data sources were used, including weather, satellite, and yield datasets for the 834 counties over a 32-year period. Long-term average maize grain yield ranged from 1.56 to 12.81 t ha-1 with a regional average of 6.66 t ha-1. Long-term average soybean grain yield ranged from 0.47 to 3.46 t ha-1 with an average of 2.17 t ha-1. About 87% and 89% of the counties in the region showed increasing trends in grain yield for maize and soybean, respectively, with regional average increasing trends for maize and soybean yield of 0.1014 and 0.0328 t ha-1 year-1, respectively. The regional annual PUE (ANNPUE) and growing season PUE (GRSPUE) were 1.09 and 1.90 kg m-3, respectively, for maize and 0.32 and 0.55 kg m-3, respectively, for soybean. In addition, the regional average increasing trends in maize ANNPUE (exhibited by 88% of counties) and GRSPUE (exhibited by 85% of counties) were 0.0174 and 0.0316 kg m-3 year-1. For soybean, regional average increasing trends in ANNPUE (exhibited by 91% of counties) and GRSPUE (exhibited by 87% of counties) were 0.0048 and 0.0081 kg m-3 year-1. The magnitude of maize CWP varied from 0.30 to 2.97 kg m-3 with a regional average of 1.08 kg m-3, and soybean CWP varied from 0.15 to 0.67 kg m-3 with a regional average of 0.40 kg m-3. It was found that 79% and 86% of the counties showed positive trends in maize and soybean CWP, respectively, and the increasing trend magnitudes were 0.0144 and 0.0047 kg m-3 year-1. Pooled data from all counties and growing seasons were used to develop frequency distribution histograms to quantify the inter-annual variation and distribution characteristics. The level of CWP variability represented via maps revealed regions where opportunity exists for improvements in production system efficiency. A comprehensive understanding of the spatial and temporal patterns in these efficiency indices will provide a basis for decision-making in resource assessments, planning, evaluation, and investment by state and federal agencies and stakeholders. Keywords: Agriculture, Climate, Evapotranspiration, Great Plains, Water productivity.


2019 ◽  
Author(s):  
Jannis Groh ◽  
Jan Vanderborght ◽  
Thomas Pütz ◽  
Hans-Jörg Vogel ◽  
Ralf Gründling ◽  
...  

Abstract. Future crop production will be affected by climatic changes. In several regions, the projected changes in total rainfall and seasonal rainfall patterns will lead to lower soil water storage (SWS) which in turn affects crop water uptake, crop yield, water use efficiency, grain quality and groundwater recharge. Effects of climate change on those variables depend on the soil properties and were often estimated based on model simulations. The objective of this study was to investigate the response of key variables in four different soils and for two different climates in Germany with different aridity index: 1.09 for the wetter (range: 0.82 to 1.29) and 1.57 for the drier climate (range: 1.19 to 1.77), by using high-precision weighable lysimeters. According to a “space-for-time” concept, intact soil monoliths that were moved to sites with contrasting climatic conditions have been monitored from April 2011 until December 2018. Evapotranspiration was lower for the same soil under the relatively drier climate whereas crop yield was significantly higher, without affecting grain quality. Especially non-productive water losses (evapotranspiration out of the main growing period) were lower which led to a more efficient crop water use in the drier climate. A characteristic decrease of the SWS for soils with a finer texture was observed after a longer drought period under a drier climate. The reduced SWS after the drought remained until the end of the observation period which demonstrates carry-over of drought from one growing season to another and the overall long term effects of single drought events. In the relatively drier climate, water flow at the soil profile bottom showed a small net upward flux over the entire monitoring period as compared to downward fluxes (ground water recharge) or drainage in the relatively wetter climate and larger recharge rates in the coarser- as compared to finer-textured soils. The large variability of recharge from year to year and the long lasting effects of drought periods on SWS imply that long term monitoring of soil water balance components is necessary to obtain representative estimates. Results confirmed a more efficient crop water use under less optimal soil moisture conditions. Long-term effects of changing climatic conditions on the SWS and ecosystem productivity should be considered when trying to develop adaptation strategies in the agricultural sector.


Author(s):  
G Genemo ◽  
T Seyoum

Flow rate and furrow length are the main irrigation decision variables currently affecting yield and water productivity at farm level. Improper selection of these variables produces an over use of water and loss in crop production. The general objective was to investigate the effect of decision variables on yield and water productivity of onion under conventional furrow irrigation system, with specific objective to analyze the effect of flow rate, furrow length and their interaction on yield and water productivity of onion. The field experiment was laid out in randomized complete block design with factorial arrangement of three levels of flow rate (0.7, 0.98 and 1.3 L/S) and three levels of furrow length (25, 35 and 50 m) with three replications. Inflow out flow method was used to determine the infiltration characteristics of the soil and Irrigation depth was controlled by using 3-inch Parshall flume. The maximum non-erosive flow rate to the experimental site was fixed through design equation considering soil textural class and furrow bed slope. Effect of furrow length and flow rate on yield and water productivity of the onion were used for evaluation. Their analyses indicated that effect of furrow length and their interaction with flow rate on yield were not significant (p<0.05). However, the flow rate showed highly significant (p<0.01) effect on yield of onion. The ranges of mean yield gained from furrow length and flow rate were F1 (14.75 ton ha-1) to F3 (15.96 ton ha-1) and Q1 (13.59 ton ha-1) to Q3 (19.69 ton ha-1), respectively. The effect of furrow length on crop water use efficiency and field water use efficiency was not significant (p<0.05). However, the flow rate has showed highly significant (p<0.01) effect on crop water use efficiency and field water use efficiency. The range of mean crop water use efficiency and field water use efficiency from furrow length and flow rate were F1 (33.65 kg/ha/mm) to F3 (36.41 kg/ha/mm) and Q1 (30.99 kg/ha/mm) to Q3 (38.65kg/ha/mm) and F1 (2.06 kg/m3) to F3 (2.23 kg/m3) and Q1 (1.89 kg/m3) to Q3 (2.36 kg/m3), respectively. Therefore, it can be concluded that a furrow length of 50 m is suitable to use 1.3 L/S of flow rate for better onion yield and water productivity under similar soil type of study area. Int. J. Agril. Res. Innov. Tech. 11(1): 92-100, June 2021


2020 ◽  
Vol 24 (3) ◽  
pp. 1211-1225 ◽  
Author(s):  
Jannis Groh ◽  
Jan Vanderborght ◽  
Thomas Pütz ◽  
Hans-Jörg Vogel ◽  
Ralf Gründling ◽  
...  

Abstract. Future crop production will be affected by climatic changes. In several regions, the projected changes in total rainfall and seasonal rainfall patterns will lead to lower soil water storage (SWS), which in turn affects crop water uptake, crop yield, water use efficiency (WUE), grain quality and groundwater recharge. Effects of climate change on those variables depend on the soil properties and were often estimated based on model simulations. The objective of this study was to investigate the response of key variables in four different soils and for two different climates in Germany with a different aridity index (AI): 1.09 for the wetter (range: 0.82 to 1.29) and 1.57 for the drier (range: 1.19 to 1.77) climate. This is done by using high-precision weighable lysimeters. According to a “space-for-time” (SFT) concept, intact soil monoliths that were moved to sites with contrasting climatic conditions have been monitored from April 2011 until December 2017. Evapotranspiration (ET) was lower for the same soil under the relatively drier climate, whereas crop yield was significantly higher, without affecting grain quality. Especially “non-productive” water losses (evapotranspiration out of the main growing period) were lower, which led to a more efficient crop water use in the drier climate. A characteristic decrease of the SWS for soils with a finer texture was observed after a longer drought period under a drier climate. The reduced SWS after the drought remained until the end of the observation period which demonstrates carry-over of drought from one growing season to another and the overall long-term effects of single drought events. In the relatively drier climate, water flow at the soil profile bottom showed a small net upward flux over the entire monitoring period as compared to downward fluxes (groundwater recharge) or drainage in the relatively wetter climate and larger recharge rates in the coarser- as compared to finer-textured soils. The large variability of recharge from year to year and the long-lasting effects of drought periods on the SWS imply that long-term monitoring of soil water balance components is necessary to obtain representative estimates. Results confirmed a more efficient crop water use under less-plant-available soil moisture conditions. Long-term effects of changing climatic conditions on the SWS and ecosystem productivity should be considered when trying to develop adaptation strategies in the agricultural sector.


2018 ◽  
Vol 10 (11) ◽  
pp. 1682 ◽  
Author(s):  
Kelly Thorp ◽  
Alison Thompson ◽  
Sara Harders ◽  
Andrew French ◽  
Richard Ward

Improvement of crop water use efficiency (CWUE), defined as crop yield per volume of water used, is an important goal for both crop management and breeding. While many technologies have been developed for measuring crop water use in crop management studies, rarely have these techniques been applied at the scale of breeding plots. The objective was to develop a high-throughput methodology for quantifying water use in a cotton breeding trial at Maricopa, AZ, USA in 2016 and 2017, using evapotranspiration (ET) measurements from a co-located irrigation management trial to evaluate the approach. Approximately weekly overflights with an unmanned aerial system provided multispectral imagery from which plot-level fractional vegetation cover ( f c ) was computed. The f c data were used to drive a daily ET-based soil water balance model for seasonal crop water use quantification. A mixed model statistical analysis demonstrated that differences in ET and CWUE could be discriminated among eight cotton varieties ( p < 0 . 05 ), which were sown at two planting dates and managed with four irrigation levels. The results permitted breeders to identify cotton varieties with more favorable water use characteristics and higher CWUE, indicating that the methodology could become a useful tool for breeding selection.


2020 ◽  
Vol 249 ◽  
pp. 107763 ◽  
Author(s):  
Yang Gao ◽  
Guangcheng Shao ◽  
Jia Lu ◽  
Kun Zhang ◽  
Shiqing Wu ◽  
...  

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