Modern planting research: mulch and planting depth affect potato canopy development, subsurface morphology and tuber yield
During the period 2010-2013, the response of potatoes to mulching and different planting depths was evaluated. Two different plastic mulches were compared to the unmulched controls, and seed tubers were planted at depths of 5, 10, 15, and 20 cm in each treatment.
Especially in the lower part of the underground stem, the tuber formation ratio is higher regardless of the mulch and planting depth. In 20 of the 80 seasons, the harvest index of transparent PE mulch was significantly higher, regardless of planting depth.
1. Materials and methods
1.1. Experimental site and design
The effects of mulch and planting depth on canopy development, belowground morphology and tuber yield of potatoes were studied. All experiments were conducted at the farm of the Highland Agricultural Research Institute in Gangneung.
The seed tubers are cut by hand into small pieces weighing about 30-50 g and planted by hand using conical tubers of 5 cm, 10 cm, 15 cm and 20 cm deep into sandy soil in coarse loam soils, the planting depth is determined by measurements from the top of the seed to the top of the mountain.
1.2. Growth length-day, plant emergence, ground cover and growth analysis
Immediately after each season of sowing, the temperature and soil moisture harvester is buried next to the seed blocks in the seed hill to record the soil temperature and humidity. The temperature is recorded every hour, and 5°C is selected as the base temperature for calculating the growth day.
As plants begin to emerge, plant numbers are recorded twice a week to find out that DAP emerges > 80% per year. Plants are considered to emerge when green leaves are seen sticking out from the surface of the soil. During canopy development, the percentage of ground cover plants is recorded weekly or twice a week.
2. Results
2.1. Emergence and early development of the canopy
When measuring soil temperature during the growing season, the number of growing days of plastic mulch was higher than that of unmulched soil. In 2013, the number of days of growth length of transparent mulch film was also higher, but the number of days of growth length of black PE mulch film was lower than that of no mulch.
With the increase of planting depth, the daily value of growing length decreased by 5-2169% from 1941 to 1836 and 2011 to 2289 years in 2013 years, respectively. Before the early stages of plant growth, soils without mulch have less moisture content than plastic mulch, especially at depths of 5 cm and 10 cm.
Canopy development, expressed in days, is significantly affected by cover and planting depth. The only exception was in 3 years, when potato plants treated with each mulch covered the ground at the same time. In 2013, the number of days of complete ground cover was not affected by mulch, but was still affected by the depth of planting.
2.2. Final harvest and tuber yield
When the data were averaged for each season, mulch and planting depth had a significant effect on tuber yield. The total yield of plants grown with PE mulch was 17-29% and 13-34% higher compared to no mulch.
In particular, transparent PE mulch produces the highest plant yields. Planting depth had a significant effect on total yield in 6 of the 80 growing seasons, but not on yield in all seasons.
3. Discussion
Seed blocks that are close to the soil surface and have a plastic mulch appear earlier and produce more stems than seeds that are planted deeper and have no mulch. The effect of mulch and planting depth on the development of the ground cover canopy depends on the time after planting.
The number of days after planting to 50% ground cover increased significantly at planting depth and without mulching, while the number of days planted to 90% ground cover was mostly non-responsive. This difference in groundcover over time can be explained by the smaller difference in soil temperature between covered and uncovered plants as the plant canopy expands.
Tuber yields usually increase with the planting of seed pieces. Potatoes responded more strongly to mulching than other crops, with an average 24% increase in marketable tuber yields compared to no plastic mulch. The main benefit of mulching is considered to be higher soil temperature and moisture, especially in early spring, which accelerates the emergence and development of potato tubers.
However, in areas with shorter growing seasons, this is largely expected, as early emergence becomes more important. Because the extensive growing season is able to overcome the potential side effects associated with delayed emergence, which is associated with the absence of mulch.
conclusion
Most people attribute the mulching effect to the regulation of soil temperature, lengthening tuber swelling through improved and early emergence, reducing competition with weeds, and changing the quality or quantity of light reflected by mulch. In 2014, it was reported that increased transpiration under mulch was the main reason for improved maize grain yield and water use efficiency compared to no mulching.
The results of this study showed that the effect of changing the planting depth under plastic mulching on the underground morphology of potatoes was different compared with the unmulched control. By increasing the soil temperature and humidity in the early season, grape growth in the mulch was improved.
