Temperature and precipitation changes impact the yields of small grain cultivars from 1978 to 2018 in Fairbanks and Delta Junction, Alaska

Figures & data

Table 1. Average and standard deviation of variety yield, flowering and maturity dates, and the number of testing years of eight varieties of barley, four of oat, and three of wheat in Delta Junction and Fairbanks, Alaska.

Location	Crop	Variety	No. of testing years	Heading date	Maturity date	Mean of yield (kg/hectare)	SD of yield (kg/hectare)
Delta Junction	Barley	Albright	12	2 Jul.	31 Jul.	2,411	941
		Datal	19	2 Jul.	7 Aug.	2,838	1,152
		Eero	19	3 Jul.	9 Aug.	3,209	1,410
		Finaska	14	2 Jul.	31 Jul.	2,091	1,024
		Lidal	13	2 Jul.	1 Aug.	2,433	1,082
		Otal	29	4 Jul.	2 Aug.	2,509	1,192
		Thual	28	4 Jul.	5 Aug.	2,045	945
		Weal	20	2 Jul.	7 Aug.	2,481	1,301
	Oat	Athabasca	18	6 Jul.	15 Aug.	3,090	1,425
		Cascade	16	7 Jul.	17 Aug.	3,424	1,677
		Nip	16	8 Jul.	20 Aug.	3,069	1,387
		Toral	26	7 Jul.	11 Aug.	2,894	1,369
	Wheat	Ingal	26	1 Jul.	8 Aug.	1,675	1,082
		Nogal	18	2 Jul.	15 Aug.	2,163	1,207
		Roblin	12	2 Jul.	13 Aug.	1,502	1,176
Fairbanks	Barley	Albright	19	29 Jun.	26 Jul.	3,907	1,664
		Datal	23	28 Jun.	26 Jul.	3,375	1,232
		Eero	20	2 Jul.	4 Aug.	4,207	1,382
		Finaska	19	27 Jun.	25 Jul.	3,291	1,436
		Lidal	18	29 Jun.	26 Jul.	3,515	1,361
		Otal	38	28 Jun.	27 Jul.	3,583	1,188
		Thual	30	1 Jul.	27 Jul.	2,848	1,127
		Weal	26	28 Jun.	26 Jul.	3,338	1,074
	Oat	Athabasca	17	6 Jul.	4 Aug.	3,556	967
		Cascade	15	4 Jul.	5 Aug.	4,273	1,305
		Nip	14	4 Jul.	6 Aug.	3,811	831
		Toral	32	29 Jun.	1 Aug.	3,972	1,301
	Wheat	Ingal	29	26 Jun.	31 Jul.	2,657	1,063
		Nogal	21	27 Jun.	2 Aug.	3,014	847
		Roblin	16	27 Jun.	4 Aug.	2,837	1,284

Figure 1. Average yield change per year of barley (‘Albright,’ ‘Datal,’ ‘Eero,’ ‘Finaska,’ ‘Lidal,’ ‘Otal,’ ‘Thual,’ and ‘Weal’) (red), oat (‘Athabasca,’ ‘Cascade,’ ‘Nip,’ and ‘Toral’) (green), and wheat (‘Ingal,’ ‘Nogal,’ and ‘Roblin’) (blue) in (a) Fairbanks and (b) Delta Junction from 1978 to 2018. The bars indicate 95 percent credible interval of yield loss based on a Bayesian simulation (n = 500).

Figure 2. Median cultivar yield loss (%) for 1°C (average, maximum, and minimum temperature) or 1 cm cumulative precipitation increase over the period June to July from 1978 to 2018 in Fairbanks (a, c, d) and Delta Junction (b, d, f). ‘Albright,’ ‘Datal,’ ‘Eero,’ ‘Finaska,’ ‘Lidal,’ ‘Otal,’ ‘Thual,’ and ‘Weal’ are barley (red); ‘Athabasca,’ ‘Cascade,’ ‘Nip,’ and ‘Toral’ are oat (green); ‘Ingal,’ ‘Nogal,’ and ‘Roblin’ are wheat (blue). ∆Yield indicates percentage loss of yield. Bars represent 95 percent credible interval calculated from Bayesian simulation (n = 500).

Table 2. The equations and R² of the best-fitted cultivar models derived from full models ∆LogY = ∆T_max + ∆T_min + ∆P_tot.

Location	Crop	Variety	Best models	R^2
Fairbanks	Barley	Albright	∆LogY = −0.027 − 0.19 ∆Tmax	0.58
		Datal	∆LogY = −0.015 − 0.17 ∆Tmin + 0.09 ∆Ptot	0.58
		Eero	∆LogY = 0.015	NA
		Finaska	∆LogY = −0.14 − 0.17 ∆Tmax + 0.088 ∆Ptot	0.64
		Lidal	∆LogY = 0.003 + 0.23 ∆Ptot	0.53
		Otal	∆LogY = −0.003 + 0.085 ∆Ptot	0.18
		Thual	∆LogY = −0.005 − 0.12 ∆Tmin + 0.13 ∆Ptot	0.47
		Weal	∆LogY = 0.005 − 0.11 ∆Tmin + 0.07 ∆Ptot	0.55
	Oats	Athabasca	∆LogY = −0.016 − 0.085 ∆Ptot	0.11
		Cascade	∆LogY = −0.0013	NA
		Nip	∆LogY = 0.0014	NA
		Toral	∆LogY = 0.008 − 0.11 ∆Tmin	0.16
	Wheat	Ingal	∆LogY = −0.018 + 0.15 ∆Ptot	0.25
		Nogal	∆LogY = −0.017 − 0.072 ∆Tmin + 0.08 ∆Ptot	0.48
		Roblin	∆LogY = −0.043 − 0.64 ∆Tmax + 0.32 ∆Tmin − 0.24 ∆Ptot	0.52
Delta Junction	Barley	Albright	∆LogY = 0.018 + 0.48 ∆Tmax + 0.71 ΔPtot	0.67
		Datal	∆LogY = −0.008 − 0.14 ∆Tmax + 0.094 ∆Ptot	0.58
		Eero	∆LogY = 0.002 + 0.081 ∆Tmax − 0.097 ∆Tmin + 0.17 ∆Ptot	0.57
		Finaska	∆LogY = −0.029 − 0.43 ∆Tmin − 0.16 ∆Ptot	0.73
		Lidal	∆LogY = 0.03 − 0.1 ∆Tmin + 0.14 ∆Ptot	0.77
		Otal	∆LogY = −0.01 − 0.20 ∆Tmin	0.52
		Thual	∆LogY = 0.029 − 0.17 ∆Tmin	0.22
		Weal	∆LogY = 0.003 + 0.21 ∆Ptot	0.37
	Oats	Athabasca	∆LogY = 0.001 + 0.11 ∆Ptot	0.19
		Cascade	∆LogY = −0.05 + 0.11 ∆Ptot	0.20
		Nip	∆LogY = 0.003 + 0.17 ∆Tmax − 0.28 ∆Tmin	0.40
		Toral	∆LogY = −0.007 + 0.088 ∆Ptot	0.12
	Wheat	Ingal	∆LogY = 0.006 − 0.25 ∆Tmin	0.25
		Nogal	∆LogY = 0.006 + 0.23 ∆Ptot	0.27
		Roblin	∆LogY = −0.028 − 0.15 ∆Tmin + 0.26 ∆Ptot	0.71

Note. ∆LogY, ∆T_max, ∆T_min, and ∆P_tot are the first-difference values of time series of logarithms yield, mean maximum temperature, mean minimum temperature, and cumulative precipitation over the period June to July from 1978 to 2018, respectively. The variables ∆T_max, ∆T_min, and ∆P_tot were standardized before the models were fit. The best model was the model with the lowest Akaike information criterion.