| Effects of water management on growth, uptake and soil distribution of nitrogen and phosphorus in dry direct seeding rice |
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| DOI：10.7606/j.issn.1000-7601.2022.02.17 |
| Key Words: dry direct seeding rice water management growth nitrogen and phosphorus absorption soil nitrogen and phosphorus distribution |
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| Abstract: |
| Two water management methods, namely moist irrigation (T1) and critical water demand irrigation (T2), were used to study the effect of water management on the growth, nutrient absorption and nitrogen and phosphorus migration of dry direct seeding rice and improve the water use of dry direct seeding rice and reduce the environmental risk of soil nitrogen and phosphorus in dry direct seeding rice field. The results showed that T2 treatment was beneficial to promote the growth of dry direct seeding rice in the middle and late stage. The plant height was 80.61 cm at jointing booting stage, the SPAD value was 41.03, which were significantly higher than T1. The photosynthetic rate was 20.73% higher than T1, and the leaf areas were 40.08, 37.49 cm2 and 32.35 cm2 at tillering stage, jointing booting stage and filling stage, which was 9.24%, 6.11% and 13.51% higher than that of T1, respectively. The dry matter mass and total nitrogen uptake of T1 treatment were higher, which were 30 568.65 kg·hm-2 and 287.70 kg·hm-2， respectively. The total phosphorus uptake of T2 treatment was higher than T1, which was 44.85 kg·hm-2, and the phosphorus uptake of rice was 26.70 kg·hm-2. T1 had obvious advantages in yield components, with a higher yield of 12 666.00 kg·hm-2. Under T2 treatment, the activities of soil urease and alkaline phosphatase increased significantly, up to 38.21% and 73.33% compared with the basic value, and 3.94% and 6.82% compared with T1. In terms of soil nitrogen and phosphorus migration, T2 significantly reduced the content of nitrate nitrogen, available phosphorus and water\|soluble phosphorus in four soil layers (0~30, 30~60, 60~90 cm and 90~120 cm), with the decrease of 17.48%~65.92%, 16.18%~57.47% and 10.34%~7.53%， respectively. The reduction had a significant effect on slowing down soil nitrogen and phosphorus migration. |
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