Covariance Structures in Conventional and Organic Cropping Systems

Table 2

Summary of model statistics for cumulative yield, CumY, temporal yield variance, TYV, and coefficient of variation, CV, for a long-term experiment in each of the two cycles of a long-term experiment (LTE).

Variable cycle	Model	Nugget variance	Structural variance	Range (m)	𝑐/[𝑐0+𝑐]	𝑅^2
CumY	Spherical
LTE		6.5–34.3	9.2–95.9	9.9–66.4	0.89–0.64	0.35–0.90
Cycle 1		15.2	31.6	67.4	0.52	0.86
Cycle 2		12.1	24.9	68.4	0.51	0.89
TYV	Exponential
LTE		3.1–0.83	29.3–7.8	5.4–16.2	0.89–0.25	0.25–0.57
Cycle 1		6.1	18.9	8.7	0.89	0.23
Cycle 2		2.5	13.2	46.5	0.51	0.56
CV%	Exponential
LTE		37.5–33.8	655.0–196.0	3.6–12.6	0.83–0.91	0.23–0.49
Cycle 1		40.1	302.6	2.3	0.86	0.36
Cycle 2		20.2	138.1	8.4	0.82	0.52