Effect of Different Planting Techniques and Puddling Methods on Soil Properties, Growth, Yield, and Grain Quality Characteristics of Rice (Oryza sativa L.)

The soil structure and production in paddy fields are affected by different options such as planting techniques and puddling methods. To evaluate the effects of planting techniques on soil structure, yield, grain dimensions, and quality of rice at different puddling intensities, a two-year field experiment was conducted as a split plot based on randomized complete block design with three replications at Rice Research Institute of Guilan, Iran, during the spring-summer cropping seasons in 2017 and 2018. The main plots were assigned to three puddling levels (rotary tractor, power tiller conventional puddler, and power tiller rotary puddler), and subplots included three levels (manual transplanting, mechanized transplanting, and direct seeding). The results showed that different puddling practices had significance in the soil bulk density and penetrating depth of the falling cone. The puddling method significantly decreased soil bulk density under a rotary tractor (0.86 g/m³) over the Power tiller rotary puddler (0.96 g/cm³) and conventional puddler (0.95 g/cm³), while the penetrating depth of the falling cone was found to increase in the rotary tractor as compared to puddlers. The tiller number (tillers m⁻²), spikelet number per panicle, panicle length (cm), and panicle weight were higher under direct seeding in both years. The highest grain yields (4951 kg ha⁻¹and 4681 kg ha⁻¹) were obtained under mechanical transplanting in 2017 and under direct seeding in 2018, respectively. Significantly higher dry matter accumulation (972.37 g/m²) and leaf area index (2.23) were consistently recorded under mechanical transplanting and direct seeding of rice, respectively. Also, direct seeding showed a higher amylose content (AC), gelatinization temperature (GT), and gel consistency (GC) than transplanting. The findings suggest that maintaining a structure of paddy soil through the selection of appropriate puddling intensity and direct seeding could help soil management and provide an alternative to the conventional practice of transplanting.