Effect Of Nitrogen, Phosphorus And Potassium On Yield And Nutrient Uptake Of Rice

In this paper, field plot experiment and laboratory analysis are studied to effects of the unit of nitrogen, phosphorus and potassium, including NPK, NP, NK and PK combination in rice fields of Sanjiang plain. The results show that:1. Fertilization has no significant impact on Total N, Total P, and Available K-content of soils. Changes of Soil Organic N-content are more complex under different treatments. Organic nitrogen forms change complexly, total HYD N change in the parabolic-shaped curve. Amm-N shows a downward trend, but Ami acid N has different influence on different fertilization combinations.2. Increase of dry weight of rice goes with its growing process, and the difference in early growth stage in treatments is more visible than the later. The dry weight of NPK and NK is higher than other combinations and CK. Nitrogen is more important for the formation of tillering, and the maximum tiller stage of NPK, NP and NK is postponed for one week in contrast with PK and CK, and the maximum is 34.4,29.9 and 32.6 respectively. Fertilization has less influence on the height of plants.3. In contrast with CK, other treatment yields have been increased by 5.55%-28.88%. As the results of variance analysis, yields of NPK and NP are higher than other treatments and CK, and there's no obvious differences in NK, PK and CK, which indicates the production will be reduced when lack of P. But yields cannot be increased obviously by fertilize application alone. Ear number has greatest impact on yields(r=0.8773**), the second ear heavy, solid rate and 1000-grain weight and the third is grain number, and the impact of ear length on rice production is the smallest.4. N-content of jointing and mature stage has significant impacts on yields, and the influence of mature stage is greater than that of jointing stage. P-content at tiller and mature stage has a significant impact on yields, and the influence of mature stage is greater than that of tiller stage.5. The N absorption curve of rice accords with the Logistic model. Tiller stage is an important stage in the absorption of N in roots. In the growth phase, there is a continued downward trend of the SARN value, the absorption of N in roots almost stops at the mature stage.6. Superior and lower grain filling of rice all accords with Richards equation, and the superior final value is: NPK>NK> NP>PK>CK, and the lower final value is CK> NPK > NP> NK> PK. Filling period of IG is longer than one of SG. Whatever SG or IG, former and medium term occupies most of filling.