Experiment code 21.7.3.41
Experiment Title Comparative Study of Empirical and Mathematical Approaches for Optimum Plot Size Determination in Marigold
Research Type Departmental Research
Experiment Background Marigold (Tagetes spp.) is a commercially important flower crop widely cultivated in South Gujarat, including Navsari district. It is widely cultivated for loose flowers and garland making. During the year 2024–25, marigold was cultivated over an area of about 700 ha in Navsari district, with a total production of 4,467 MT (Director of Horticulture, Gujarat). Despite its economic importance, no systematic uniformity trials have been conducted to study yield variability and determine scientifically justified plot size for marigold experiments. Application of statistical and mathematical approaches such as Fairfield Smith’s Variance law, maximum curvature method, Mathematical approach for point of maximum curvature and modified maximum curvature method can provide an objective basis for determining optimum plot size. Accurate determination of optimum plot size is a fundamental requirement for improving the precision and reliability of agricultural experiments. Generally, experimental plot sizes for marigold are decided based on traditional practices or convenience rather than scientific evidence. Such arbitrary selection of plot size often results in higher experimental error, reduced precision in treatment comparisons and inefficient utilization of land and resources.
Experiment Group Social Science
Unit Type (02)EDUCATION UNIT
Unit (12)NAVINCHANDRA MAFATLAL COLLEGE OF AGRICULTURE (NAVSARI)
Department (247)Statistics Department, NMCA, Navsari
BudgetHead (303/12712/03)303/03/REG/01784
Objective

1. To determine optimum plot size for marigold using different approaches
2. To compare various methods for optimum plot size

PI Name (NAU-EMP-2025-001990)SEJALBEN DINESHBHAI MUNIYA
PI Email muniyasejal@nau.in
PI Mobile 8980958757
Year of Approval 2026
Commencement Year 2026
Completion Year 2028
Research Methodology

Research Design: In the present study uniformity trial will be conducted on marigold
crop (Variety: Punjab Gainda 1). It involves planting an experimental site with a single
crop variety, applying recommended cultural and management practices as uniform as per

possible. The total experimental area will be subdivided into a large number of small,
equal-sized units known as basic units. Flower yield from each basic unit will be recorded
separately.
 Sampling Design: -
 Data Collection Tools & Techniques: Primary data on flower yield from each basic unit
of the uniformity trial field will be recorded jointly by the Principal Investigator and Co-
Investigator.
Following methods will be used for determining optimum plot size in the present study:
A. Empirical / Graphical Approaches
1. Fairfield Smith’s Variance Law (Smith, H. F., 1938)
2. Maximum Curvature Method (Federer, 1955).
B. Mathematical / Analytical Approaches
3. Mathematical Approach for Point of Maximum Curvature (Patel and Patel, 1968)
4. Modified Maximum Curvature Method (Meier and Lessman, 1971)
The different approaches will be compared based on the estimated optimum plot size and the
most suitable approach will be identified. Finally, an optimum plot size for marigold
experiments will be recommended.

(NAU-EMP-2025-001990)
SEJALBEN DINESHBHAI MUNIYA
muniyasejal@nau.in 8980958757 13-02-2026
Active
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