The Effect Of Different Row Spacing And Planting Density On Sugarcane Growth And Photosynthetic Characteristics

Cultivating sugarcane should take the proper cultivation measures except select cultivars to produce high yield and high sugar. Sugarcane varieties FN15, FN28, FN39 were selected for the experiment to explore the changes of different sugarcane agronomic characters and photosynthetic parameter and canopy structure under two kinds of row distance (row distance1.1 m, row distance1.3 m)and three kinds of planting density (5,000 buds/666.7hm2 ,5,500 buds/666.7hm2 6,000 buds/666.7hm2). The results indicated:1. Sugarcane FN15: it was fit for planting in wide row (row distance1.3 m) ,and the rate of tillering in the wide row is 13%-16% higher than that in the narrow row, it was steady in the earlier stage of elongation , and grew quickly in the mid-term of elongation and slowly in later stage, the circumstance of growth in the wide row was obviously better 6cm-16cm per month than that in the narrow row. FN15 grew best under the planting density of 5,500 buds/666.7hm2 and in the narrow row. Sugarcane FN28: it was not fit for planting in wide row, and it grew steadily in the earlier stage of elongation and in the mid-term of elongation, and it sustained longer in the later stage of elongation, the circumstance of growth in the wide row was better 6cm-16cm per month than that in the narrow row. FN28 grew best under the planting density of 5,000 buds/666.7hm2. Sugarcane FN39: the rate of tillering in the wide row was 6%-25% lower than that in the narrow row, it grew steadily in the earlier stage of elongation and in the mid-term of elongation, and it sustained longest in the later stage of elongation. It started to show the obvious advantage in the mid-term of elongation, the growth in the wide row was 9cm-15cm higher than that in the narrow row in the later stage of elongation.2. The effects of different row distance and density on the chlorophyll content of the leaves of sugarcane in the seedling stage were notable, but the treatment under wide row was more notable than that of narrow row. The months from August to October were the key stage to the growth of sugarcane, the sugarcane hardly had light saturation point in the growth of the field, and the curve of photosynthesis daily changes was the single-peak, the highest net photosynthetic rate was about at 11:00 at noon, and the photosynthetic rate of leaves of sugarcane were the highest in the rapid elongation period under different growth stages. The main factor that limited the photosynthesis rate of the sugarcane was the stomatal conductance and the intercellular CO2 concentration.3. The leaf area index of three varieties had an increased tendency with the increase of the planting density. The leaf area index of FN15 was obviously higher than that of FN28 and FN39, the leaf area index was average higher about 5%-10%. The leaf area index of FN28 was highest under the planting density of 5500buds/666.7hm~2 and the row distance of 1.1m.