Split-plot design is a very popular experimental design in analyzing factorial treatments in horticultural experiments. Two different sizes or types of experimental units are assigned to main plot and the split-plot treatments. The SAS procedure GLM with the TEST option is commonly used to analyze the split-plot data by assigning the correct error term to test the main plot factor. In SAS GLM, no option is available to compare the two main factors within a split-plot factor. The CONTRAST tests and LSMEAN comparisons are valid only for comparing split-plot factors within a main plot treatment. The main factor standard error provided by the LSMEAN option is also incorrect. The new PROC MIXED procedure available in SAS 8.08 or above can be used to correct these problems in split-plot analysis. The analysis of split-plot experiments using the PROC MIXED is presented here.
George C.J. Fernandez
Benjamin G. Mullinix, Dean R. Evert, and Kerry Harrison
Two peach cultivars (Flordaking & Junegold) were planted in wheel-spoke design under a center pivot irrigation system. Main plots were sprays (Blast, Cheek, & Piggy-back) and cultivars. Sub-plots were training systems (Inside, Outside, & Standard). Sub-sub-plots were tree areas. Four rows were planted with two Inside rows and two Outside rows. Middle two rows of the standard plots were harvested. Intra-row spacing increased the further they were from the center. All trees harvested in 1990, standard plots were harvested every year, and Inside/Outside were harvested in alternate years. Most sources of variation in the model failed to be homogeneous among the 3 years. Since the number of trees harvested each year varied, all mean comparisons were done using the unequal N - unequal variance t-test.
Neo Edwin Nyakane, Moosa Mahmood Sedibe, and Elisha Markus
The objective of this study was to evaluate the effects of the Ca:Mg ratio, magnetic field (MF), and mycorrhizal amendment on the yield and mineral composition of rose geranium. The experiment was structured as a 3 × 2 factorial experimental design, with three levels of the Ca:Mg ratio (2.40:6.78, 4.31:4.39, and 6.78:2.40 meq·L−1), 6.78 Ca:2.40 Mg meq·L−1 denoted by “High-Ca:Low-Mg,” equal proportion of Ca and Mg (4.31 Ca:4.39 Mg meq·L−1) represented by “EP-Ca:Mg,” and 2.32 Ca:6.38 Mg meq·L−1 denoted by “Low-Ca:High-Mg,” two levels of MF (no MF, denoted by “0 MF,” and 110 mT, denoted by “1 MF”) and split treatments of mycorrhizae (zero mycorrhizae denoted by “0 Myco,” and 20 mL mycorrhizae denoted by “1 Myco”) were used in this study. The results show that the plant height and branch dry mass were significantly (P < 0.05) affected by the Ca:Mg ratio. No significant effect of Ca:Mg ratio, MF, or mycorrhizae on the number of leaves, foliar mass, leaf dry mass, or yield was detected. Phosphorus, K, S, Fe, and B accumulation in the stem were unaffected, as were leaf N, P, K, Ca, S, Fe, B, and Cu. However, some agronomic attributes (plant height, number of branches, root length, and chlorophyll content) and mineral composition (Stem-N) were optimized when the 1 MF exposed nutrient solution was used with about equal proportions of Ca and Mg. This Ca:Mg ratio in the nutrient solution, together with the exposure of rose geranium plants to 1 MF, yielded positive results. The findings of this study can be applied to improve the production of rose geranium by enhancing the growth and mineral concentration of this crop.
Solveig J. Hanson and Irwin L. Goldman
beet, a genotype × environment study is warranted that standardizes root size, compares multiple field environments, and uses mainstream commercial cultivars. Materials and Methods Split-split plot field experiment. Four table beet genotypes were
Clinton C. Shock, Erik B.G. Feibert, Alicia Riveira, and Lamont D. Saunders
design. The experiments had randomized complete block designs with split-split plots and six replicates. The main plots were the three irrigation treatments: “conventional bed” drip irrigation, “intense bed” drip irrigation, and “conventional bed” furrow
Cheryl A. Parris, Clinton C. Shock, and Michael Qian
cultivars were planted at each location in a randomized complete block, with split-plot designs. The in-row transplanting distances varied by bed width at each site and were adjusted to 40,000 plants/acre (99,000 plants/ha). The cultivars were the main plots
Gina E. Fernandez and James R. Ballington
was a randomized complete block design with split plots. The experimental cultivar was the main plot, and presence or absence of rowcover (+/−RC) was the split plot. Each split plot consisted of two plants. The treatment combinations were replicated
Kate A. Ivancic, Matthew D. Ruark, Francisco J. Arriaga, and Erin M. Silva
, and 66 mg·kg −1 potassium (K) Bray 1 extractable K. The 2013 fall soil test for the 2015 field indicated 6.5 pH, 0.9% OM, 121 mg·kg −1 P, and 85 mg·kg −1 K. The experimental design was a randomized complete block split-plot, replicated four times
Mack Thetford, Gary W. Knox, and Edwin R. Duke
-transplant. Following winter dormancy plants were pruned to 6 inches on 15 Mar. 2006. The experimental design was a split plot with a factorial arrangement of treatments. There were two levels of irrigation and three levels of fertilization. The main effect of
R. Kasten Dumroese, Jasmine L. Williams, Jeremiah R. Pinto, and Peng Zhang
split-split-plot experiment was applied with four replications. The whole plot treatment was oxyfluorfen (Goal ® 2XL; Dow AgroSciences, Indianapolis, IN) applied preemergence on 3 June over the larch seeds at four rates: 0, 0.28, 0.42, and 0.56 kg a