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Effect of Missing Hills on Yield

Dr. Kamal Rahim
CSO and Head
Agricultural Statistics Division, BRRI, Gazipur

Abstract/ Executive Summary:

The CV values were quite high for both the characters. For the cut size of 1- x 1-m, the CV values were 35.36 for yield and 36.06 for hills. The CV values decreased with the increase in cut size; but the rate of decrease was larger in east-west direction than north-south direction. This was true for both the characters, indicating that the cut size should be elongated in north-south direction. No specific reason for this directional change in CV could be identified, but this might be due to fertility gradient in the north-south direction. Smith's relationship between CV (Y) and cut size (X) were determined as : Y = 36.7012 X-0.1730 (R2 = 0.59**) for yield, and Y = 38.1376 X-0.2882 (R2 = 0.69**) for hills. The above models were well fitted as judged by the coefficient of determination (R2). From these models, the provisional optimum cut sizes were obtained as : Xopt = 3.94 m² for estimating yield, and Xopt = 4.33 m² for estimating number of hills. The optimum shapes were determined as : Y = 36.7012 Xl -0.2330 X₂ -0.1130 (R2 = 0.72**) for yield, and Y = 38.1376 x_i -0.3951 X₂ -0.1813(R2 = Q.85**) for hills. The optimum dimension of x_iand X₂ were estimated as: X_l= 2.58 m and X₂ = 1.53 m for yield estimation, and X_l= 2.45 m and X₂ = 1.77 m for hill estimation.

Keywords: Missing hill, Yield, Rice

Location:

Start Date: 01-07-1991

End Date: 30-06-1992

Program Area: Crop-Soil-Water Management

Commodity: Rice

Objectives:

The study on the effect of missing hills was a continuation of a similar study conducted in T. Aman in 1990 to examine the effect of missing hills occurring at different stages of plant growth and to determine a suitable correction factor for estimating the plot yield.

Methodology:

Two factors, namely, days after transplanting and percent of missing hills were included in this experiment conducted in a RCB design with three replications, making 0, 10, 20, 30, 40, and 50% of hills missing at 15-day interval, starting from 15 DAT up to 60 DAT. BR22 was used spaced with 20- x 20-cm. The crop was grown under normal agronomic practices. The missing hills at different dates were randomly selected from all the hills within the plot, each 3- x 3-m excluding the border rows. The missing hill pattern was the same for different replications. The ANOVA of yield data indicated that the interaction between percent of missing hills and days after transplanting was significant. These results are similar to those observed in the 1990 T. Aman experiment, but their main effects were insignificant in the 1990 Boro experiment.

Source of Information: BRRI Annual Report 1992,189-191, BRRI, Gazipur.

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Results indicate that the cut shape should be 2.58 m long and 1.53 m wide for estimating yield. On the other hand, the cut shape for estimating hills should be 2.45 m long and 1.77 m wide from the same field. It is difficult to take different cut sizes and shapes for estimating different characters from the same field. So, a compromise seems to be necessary to take a single cut size and shape for estimating both the characters. To avoid any risk in estimating the characters under study, the cut shape seems to be justified and adequate as 3 m long and 2 m wide. The contour maps for yield (gm/m2) and hills (no. 1m²) revealed that they were not uniform, rather patchy over the field. The optimum size of crop-cut for estimating the yield and the number of hills seems to be adequate and justified as 6 m². The shape of crop-cut should be rectangular where length should be elongated along the fertility gradient and the breadth as the perpendicular to it, and it should be 3- x 2-m.

Knowledge Management: Report/Proceedings