The effects of straw-returning and inorganic K fertilizer on the carbon–nitrogen balance and reproductive growth of cotton

Table 2 The fitting of reproductive organ biomass accumulation and main eigenvalues of reproductive organ biomass accumulation for different treatments in 2012 and 2013

Year	Treatment	Regression equations	R²	Fast accumulation period				Fastest accumulation point
Year	Treatment	Regression equations	R²	DAS₁ /d	DAS₂/d	T/d	V_T/(kg·d⁻¹)	V_m/(kg·d⁻¹)	DAS_m/d
2012	CK	Bio = 1 979.8/(1 + 563 429.6e^{−0.136 5DAS})	0.991 3^**	87.4	106.7	19.3	59.6	67.5	97.0
	K150	Bio = 3 718.6/(1 + 722 502.4e^{−0.113 0DAS})	0.987 8^**	107.7	131.0	23.3	92.8	105.0	119.4
	W9000	Bio = 3 829.4/(1 + 238 847.9e^{−0.100 8DAS})	0.999 2^**	109.8	136.0	26.1	85.1	96.4	122.9
2013	CK	Bio = 2 220.2/(1 + 4 127 754.6e^{−0.138 5DAS})	0.992 6^**	100.5	119.5	19.0	67.9	76.9	109.9
	K150	Bio = 4 617.7/(1 + 667 640.8e^{−0.117 0DAS})	0.991 6^**	103.3	125.8	22.5	119.3	135.1	114.6
	W9000	Bio = 4 926.3/(1 + 321 420.9e^{−0.107 0DAS})	0.996 2^**	106.2	130.7	24.5	116.3	131.8	118.5

CK, no crop straw and K fertilizer were applied as the blank control treatment; K150, 150 kg·ha⁻¹ K₂O was applied before transplanting the cotton seedlings; and W9000, 9 000 kg·ha⁻¹ wheat straw was crushed and incorporated in 0∼10 cm soil before transplanting. DAS₁, DAS₂ and T mean the start time, termination time and duration of rapid accumulation of reproductive organ biomass; V_m and DAS_m present the maximum accumulation rate and occurrence time of maximum accumulation rate of reproductive organ biomass; V_T refers to the average speed of reproductive organ biomass accumulation during T. ** significant at P < 0.01

ISSN: 2523-3254