Comparison of Direct Seeding and Transplanting Systems in Maize (Zea Mays L.) Under The Usual and Early Planting Dates

Background and Objectives The use of transplanting is a safe method for adequate crop establishment. Its benefits include increasing yield, reducing the growing season, improving weed control, increasing water use efficiency, improving seedling establishment and increasing crop growth rate. Transplanting increases crop yield compared with direct seeding, this compensates for more cost of transplanting. Transplanting also increases maize yield compared with direct seeding through increasing radiation use efficiency and harvest index. The experiment was aimed to assess direct seeding and transplanting system under the usual time and early planting date for achieving maximum maize seed yield and dry matter.
Materials and Methods The experiment was conducted at Research Greenhouse and Field, Campus of Agriculture and Natural Resources, Razi University during two years (2015 and 2016). In the first year, factors included three planting methods (seeding, 4-week transplanting and 6-week transplanting) and two sowing dates (early sowing, common date sowing). In the second year, treatments included 6- week transplanting at early sowing (superior treatment in the first year) and seeding (control). Studied traits included plant height, leaf number, fresh weight, dry weight, stomatal conductance, SPAD, chlorophyll, leaf area, leaf relative water content and yield traits such as ear weight, ear length and diameter, seed number per ear row, row number per ear, 100-seed weight and seed yield. Data were analyzed by SAS software. Means were compared using LSD test.
Results The first year results showed that early sowing increased plant height, SPAD index and specific leaf weight compared to usual sowing date. 6-week transplanting at early sowing had the highest dry matter production and leaf to stem ratio. The second year results showed that transplanting increased the leaf number, chlorophyll content, fresh and dry weight, leaf area, ear length, ear diameter, seed number per ear row, row number per ear, ear weight, seed yield, 100-seed weight and tassel weight compared to direct seeding.
Discussion Yield increase in transplanting was probably due to high leaf area and plant height that plants greatly used environmental conditions such as light and water. So seed number per ear row, row number per ear and ear length were high. In conclusion, 6-week transplanting at early sowing (29 March) is suggested to achieve the highest seed yield in Kermanshah. Maize transplant ages except the ages studied in the experiment are recommended for the next experiments.