Response of Winter Wheat Grain Yield and Phosphorus Uptake to Foliar Phosphite Fertilization

Table 2

Initial 0 to 30 cm (1 ft) soil test NO₃-N, P, and K in hard red winter wheat grown field at five site locations in 2009/2010 and 2010/2011 winter wheat cropping seasons in OK.

Location	2009/2010			2010/2011
	NO3-N + NH4-N^†	P	K	NO3-N + NH4-N	P	K
	kg ha^−1			kg ha^−1
Perkins	28	45	300	27	43	297
Perry	34	39	295	25	42	302
Morrison	---^¶	—	—	45	17	284

†NO₃-N NH₄-N was extracted with 2 M KCl solution, and P and K were extracted with Mehlich III solution. ¶data were not available.