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ARS Home » Southeast Area » Mississippi State, Mississippi » Crop Science Research Laboratory » Genetics and Sustainable Agriculture Research » Research » Publications at this Location » Publication #324658

Research Project: Integration of Site-Specific Crop Production Practices and Industrial and Animal Agricultural Byproducts to Improve Agricultural Competitiveness and Sustainability

Location: Genetics and Sustainable Agriculture Research

Title: Simulated yield potential by irrigation and yield gap of rainfed soybean using APEX model in a humid region

Author
item Zhang, Bangbang - China Agricultural University
item Feng, Gary
item Kong, Xiangbin - China Agricultural University
item Lal, Rattan - The Ohio State University
item Ouyang, Ying - US Department Of Agriculture (USDA)
item Adeli, Ardeshir
item Jenkins, Johnie

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2016
Publication Date: 11/1/2016
Citation: Zhang, B., Feng, G.G., Kong, X., Lal, R., Ouyang, Y., Adeli, A., Jenkins, J.N. 2016. Simulated yield potential by irrigation and yield gap of rainfed soybean using APEX model in a humid region. Field Crops Research. 177(2016):440-453.

Interpretive Summary: Soybean is the cash crop in Mississippi, with value of production approximately US $2.81 billion, accounting for 50.6% of the total value of production of principle field crops in 2014. Yet, only about 25 to 30 % of Mississippi's soybean crop is irrigated. There has become a rapid increase in irrigated soybean area in the Mid-South states, especially in Mississippi with the largest percentage increase of 92% occurred from 1998 to 2008. It is of importance to investigate soybean yield potential and how much yield could be increased by supplemental irrigation. Statistic analysis on the amount, timing and numbers of irrigation determined by crop models using historical weather data could provide guidance for irrigation scheduling of high water use efficiency. The following conclusions were drawn from this simulation study: 1) Soybean yield potential (Yp) without water stress by irrigation on nine soil types in each year was close from 2002 to 2014. Yp varied widely from 4.47 to 6.51 Mg ha-1 across 13 years. 2) Compared with rainfed soybean, the yield increase by irrigation (yield gap, Yg) ranged greatly from 0.17 to 3.35 Mg ha-1. Griffith, Sumter and Demopolis soils had the highest average Yg ranging from 1.37 to 1.60 Mg ha-1, which should be strengthen management to close Yg. Meanwhile, Yg in dry years was much higher than that of normal and wet years. Yg simulated on all soils varied greatly in dry years, while the variation of Yg in normal and wets year was similar and relatively lower. 3) The average irrigation amount (Ia) in dry year was 308 mm, which was significantly greater than that for wet and normal years, with average Ia of 192.0 and 156.7 mm, respectively. The supplemental irrigation was primarily used in R2, R3, R4, R5, R6 and R7 stages, which accounted for 97% of total irrigation times among nine soil types from 2002 to 2014. Growing stages R5 and R6 had the largest probability to irrigate, which accounted for 31% and 22% of total irrigation times, respectively. The average irrigation amount was about 75 mm from R1 to R8. While V3 only had 45 mm average irrigation amount among nine soil types from 2002 to 2014. 4) Water use efficiency (WUE) of nine soil types from 2002 to 2014 under water non-limiting conditions, ranged from 9.54 to 13.80 kg ha-1 mm-1. The average IWUE of 13 years ranged from 1.8 to 7.8 Kg ha-1 mm-1 for nine soil types. 5) The average net return of irrigated soybean can be increased by about 93 $ ha-1 among nine soil types from 2002 to 2014, as compared to rainfed conditions. Irrigation can increase net return regardless of dry, normal or wet years. The average net return increased by 195, 58 and 70 $ ha-1 for dry, normal and wet years, respectively. Vaiden, Catlapa and Leeper had the relatively lower increase in average net return, ranging from 12 to 39 $ ha-1. In comparison, Griffith, Sumter and Demopolis had relatively higher increase in average net return, ranging from 172 to 216 $ ha-1.Soybean is the cash crop in Mississippi, with value of production approximately US $2.81 billion, accounting for 50.6% of the total value of production of principle field crops in 2014. Yet, only about 25 to 30 % of Mississippi's soybean crop is irrigated. There has become a rapid increase in irrigated soybean area in the Mid-South states, especially in Mississippi with the largest percentage increase of 92% occurred from 1998 to 2008. It is of importance to investigate soybean yield potential and how much yield could be increased by supplemental irrigation. Statistic analysis on the amount, timing and numbers of irrigation determined by crop models using historical weather data could provide guidance for irrigation scheduling of high water use efficiency. The following conclusions were drawn from this simulation study: 1) Soybean yield potential (Yp) without water stress by irrigation on nine soil types in each

Technical Abstract: Globally, soybean is typically grown under rainfed conditions. In order to determine how much maximum yield could be increased by irrigation, it is crucial to investigate the yield potential (Yp) under water unstressed condition and yield gap (Yg, between Yp and rainfed yield (Yw)). It is also important to determine the amount of irrigation to relieve any water stress during the entire growing season of soybean, and conduct cost-return analysis of irrigated soybean. Therefore, The objectives of this paper were to: (1) simulate Yp and Yg of soybean using the APEX model; (2) determine the amount, timing (growing stages) and number of irrigation to achieve potential yield without water stress; (3) conduct analysis of water use efficiency (WUE), irrigation water efficiency (IWUE) and components on water balance; (4) carry out cost-return analysis on irrigation events. Simulated Yp without water stress for nine soil types from 2002 to 2014 ranged from 4.47 to 6.51 Mg ha-1, and was highly correlated with accumulative solar radiation during the growing season (R2=0.71, P=0.01). The Yg in dry years was much higher than that in normal and wet years, with average Yg of 1.58, 0.60 and 0.71 Mg ha-1 for dry, normal and wet years, respectively. Griffith, Sumter and Demopolis had the highest average Yg over 13 years, ranging from 1.37 to 1.60 Mg ha-1. The average irrigation amount (Ia) in dry, normal and wet years was 308, 192 and 157 mm, respectively. The supplemental irrigation was mainly applied during R2, R3, R4, R5, R6 and R7 growing stages, which accounted for 97% of the total numbers of irrigation among nine soil types from 2002 to 2014. The average irrigation amount was 75 mm for these critical growth stages. Stages R5 and R6 had the highest probability to irrigate, which accounted for 31% and 22% of total irrigation times, respectively. The WUE of nine soil types from 2002 to 2014 under non-limiting water conditions, ranged from 10 to 14 kg ha-1 mm-1. Yg was the principle factor affected IWUE among nine soil types. The average IWUE over 13 years ranged from 2 to 8 Kg ha-1 mm-1 for nine soil types. Compared with a rainfed condition, average net return of irrigated soybean increased by US $89 per hectare among nine soil types from 2002 to 2014. The average net return increased by US $189, $55 and $67 each hectare for dry, normal and wet years, respectively.