Study On Nutrients Absorption Characteristic And NPK Fertilization Effects Of Several Different Types Of Rice

Rice is one of the most important food crops in China and the yield of rice directly relate to the level of Chinese food security. The nutrients uptake distinction among different rice varieties affected the potential ability on rice production. In this study, the field experiments were carried out to study the characteristics of nutrient absorption of different efficiency types of rice under planting density design. In order to achieve stable yield of rice, this research objected to provide reasonable fertilization management based on the different rice varieties, planting density and fertilization amount on field experiments. The main results were shown as following:1. The characteristics of nutrients absorption on different types of riceThe uptake peak of dry matter accumulation by 4 rice types (conventional rice, two-line hybrid rice, three-line hybrid rice and transgenic rice) continued from late Tillering to maturity and the three growth stages ratio of Tillering-booting, Booting-heading and Heading-maturity was about 3:4:3 under fertilizer application. The mainly accumulation period of nitrogen and phosphorus for different type rice were at Tillering-booting and Booting-heading under different fertilizer application. The maximum amount of nitrogen accumulation percentage was 47.4%～67.9% and 13.8%33.9%, phosphorus was 27.8%～37.4% and 46.5%～58.5%, respectively. Potassium accumulation mainly accumulated in the Tillering-booting stage, followed by booting-heading stage under fertilizer application. The Potassium accumulation maximum amount were 57.3%～74.0% and 12.2%～33.1%. The nutrient accumulation of conventional rice variety was significantly lower than other varieties at whole growth stages, but there was no significantly different among two-line hybrid rice, three-line hybrid rice and transgenic rice. However, the nutrients accumulation still appeared significant difference of 4 types rice during growth stages.Grain was the accumulation center of nitrogen and phosphorus, approximately 60% nitrogen and 70% phosphorus accumulation on grain. Straw was the center of potassium accumulation as accumulation 90% potassium. There was non significant difference in nutrients requirment for producing every 100 kg seeds and absorption ratio of NPK among different varieties rice. Nutrients required for producing every 100 kg seed needed N 1.6～2.4 kg (N average of 1.9 kg), P2O5 1.39～2.11 kg (P2O5 average of 0.9 kg), K2O 5.91～9.57 kg (K2O average of 3.2 kg), and the mean ratio of N, P2O5 and K2O production 100 kg seed yield was 1:0.49:1.65. There was no significant difference in the fertilizer requirements for produce equivalent grain among different varieties rice. So for the high-yielding rice varieties, output should be improved by increasing proportions of fertilizer inputs.2. Nutrient absorption characteristics of nutrient efficiency types of different varieties riceFor N, P efficiency type, highly effective absorption type could produce higher yields under high density conditions while lowly effective absorption type could produce higher yields in the normal density. For K efficiency type, highly effective absorption type produce higher yields under the high density, while on significant effects under low uptake type. The nutrient accumulation of highly effective absorption type was N 183.7～206.7 kg/hm2, P2O 572.3～87.4 kg/hm2 and K2O 262.0～309.8 kg/hm2; low uptake type was N 129.9～158.1 kg/hm2, P2O5 58.0～66.0 kg/hm2 and K2O 189.6～221.2 kg/hm2 under different planting density and which the nutrient accumulation of high uptake type was significantly higher than lowly effective absorption typelow uptake type.Under conventional planting density, type A (both high nutrient uptake and utilization efficiency) had the higher yield (7956～8198 kg/hm); Type B (high nutrient uptake and low utilization efficiency) and type C (low nutrient uptake and high utilization efficiency) had the similar levels of yield as variation range 6971～7753 kg/hm2, which was significantly lower than that of type A. Under high planting density, the higher yield occurred in type A and type B and reached 8277～8982 kg/hm2, type C reached 6564～6942 kg/hm2 with the secondly yield level; Type D has the lowest yield with the yield 5660～6070 kg/hm2. For producing every 100 kg seeds, the higher requirement of N, P2O5 occurred on low N, P utilization type compared high N, P utilization type under different planting density, but the K2O uptake was non-significant difference among different vatieties. The requirement of K2O of K utilization type was significantly higher than that of high K utilization type under different planting density on producing 100 kg seeds, but there was non-significant difference for N, P2O5 required.Considering the efficiency types and production levels, the varieties of No.8, No.11 etc. were suitable for cultivation in normal density, while the variety of No.3, No.9 etc. fitted for high density plantation.3. Effect on NPK fertilization of different rice varietiesThis research selected six varieties of rice to study the effect of NPK fertilization. Include conventional rice (No.1 and No.6), two-line hybrid rice (No.2 and No.4) and three-line hybrid rice (No.3 and No.5).The results showed that the yield increased significantly for NPK application among different varieties rice, and the highest increase rate was 18.7%-29.1% under nitrogen fertilizer application,9.3%-20.7% under phosphorus fertilizer application and 10.2%-24.2% under potassium fertilizer application. Different varieties has different reaction on fertilizer application level, variety No.4 and No.6 were sensitive on high nitrogen fertilizer application, and yield reduced under excessive application condition; variety No.2 and No.3 were insensitive on high nitrogen fertilization, and yield sustainably increased under excessive application condition. The yield of No.1 and No.2 were rasied with increasing phosphorus fertilizer; on the contrary, the yield of variety No.3 and No.4 were reduced with increasing phosphorus fertilize; the yield of variety No.5 and No.6 were priority to increased and then decreased with more phosphorus fertilize. The yield of No.1 was reduced with increasing potassium fertilization; the yield of No.2 was raised with increasing potassium fertilization; the yield of other varieties was increased earlier and following as decreasing with more potassium fertilization. The production levels, two-line and three-line rice were significantly increased yield and economic benefits compared conventional rice, but which were no significant difference between two-line and three-line rice.Recommendation amount of NPK fertilization was significant difference among different varieties rice. The NPK requirements of variety No.1 (conventional rice) were low, but that of variety No.3 (three-line rice) were high. Variety No.4 (two-line rice) only needed more P fertilizer as well as more N, K application on variety No.2 (two-line rice) and No.5 (three-line rice).In summary, there were significant differences on dry matter accumulation and nutrient absorption among conventional rice, two-line hybrid rice, three-line hybrid rice and transgenic rice, and fifferent vatieties of rice. However, nutrients requirment appeared non-significant different on producing every 100 kg seeds. Under different planting density, nutrient absorption indicatied significant differences among different efficiency types. Low efficiency varieties can be increased nutrients efficiency by changing planting density. The yield of rice also coulde be increased significantly by fertilization, and different varieties showed different reaction on optimum recommendation amount.