Effect of Row Spacing and Seeding Rate on Seed Yield and Yield Components of Winter Oilseed Rape cv. Okapi in Flat versus Ridge Planting

Document Type : Research Article

Author

• M Yazdandoost Hamedani

Hamedan Agricultural and Natural Resources Research and Education Center

10.22067/gsc.v16i2.62026

Abstract

Introduction
Rapeseed shows great sensitivity to farm management and agronomic operations. Specially, planting method, seeding rate and row spacing have big effects on yield. The seeding rate and row spacing are critical factors for achieving optimum plant density and this is one of the most important factors affecting the seed yield of rapeseed. In addition, uniform distribution of plants per unit area is required for yield sustainability. Rapeseed is planted in narrow and wide row spacing. With decreasing in row spacing and increasing of distance between plants, plants distribution becomes more uniform, competition between plants is reduced and finally, seed yield increases. In cold and semi-cold areas of Iran, rapeseed is planted as an irrigated crop. Plants arrangement and distribution in surface area are affected by irrigation system, too. In furrow irrigation, rapeseed is planted only on the upper level of the ridges and thus plant distribution is non-uniform. With the using of sprinkler systems, flat planting is possible and plant arrangement becomes more uniform.
Materials and Methods
In order to compare the flat with ridge planting and to determine the best row spacing and seeding rate in flat planting of winter rapeseed, a field experiment was conducted in Hamedan Agriculture and Natural Resources Research Center in 2011-2013 cropping seasons. Combination of four row spacing (15, 20, 25 and 30 centimeters) with three seeding rates (6, 8 and 10 kg ha-1) in flat planting method and check treatment (ridge planting with two rows on each ridge using 8 kg ha-1 seeding rate), totally 13 treatments, were studied in a Randomized Complete Block design with three replications during the growing season and in harvest time, some agronomic traits such as number of plants per m2, plant height, number of branches and pods per plant, seeds per pod, 1000-seed weight, biological and seed yield and harvest index were measured. RCBD and factorial analysis of variance were done using SAS software and mean comparison was carried out using Duncan's multiple range test 5% probability level.
Results and Discussion
The plant densities between flat and ridge planting, seeding rates and row spacing were different because of difference in plant arrangement. Ridge planting (check treatment) had the highest plant height, number of branches and pods per plant, and the lowest 1000-seed weight and seed yield in comparison with flat planting treatments. In flat planting, seed yield and yield components significantly affected by row spacing. Row spacing of 15-20 centimeters produced the highest seed yield. In flat planting, using of 6-10 kg seeds per hectare had not significant effects on biological and seed yield. Narrower than the wider row spacing increased grain yield due to more uniform distribution of plants in the ground, Which leads to better absorption of solar radiation in plant canopy and consequently reduce competition between plants.

Conclusions
The results of this experiment showed that in ridge planting, competition between plants increased and final plant density reduced. In contrast, flat planting had more uniform arrangement that decreased inter and intra row competition, increased plant density per unit area and finally produced higher biological and seed yield. Average seed yield in flat planting method was 4381 kg ha-1 which was about 18% higher than ridge planting. Based on these results, it seems that flat planting with 15-20 cm row spacing and 6-10 kg ha-1 could be used for winter oilseed rape.

Keywords

• Planting arrangement
• Plant density
• Sprinkler irrigation
• Winter oilseed rape

20.1001.1.20081472.1397.16.2.8.1

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