Nitrogen fertilizer is one of the most important factors that affect the yield and quality of rice. Excessive and unscientific fertilizer can not only decrease the yield, quality and economic benefit of rice, but also waste resources, pollute the environment and endanger human health. To effectively do the fertilization of rice, rice based on the target yield of 9000 kg/hm2, 9750 kg/hm2, 10500 kg/hm2, nitrogen utilization rate reached 40%, through the deepening of research, understand the main types of soil fertility and nitrogen free yield per 100 kg grain nitrogen uptake and nitrogen utilization rate, the establishment of high quality rice high precision application of nitrogen system technology, in order to reasonably determine the amount of nitrogen fertilizer and operation technology of rice producing areas, provide technical support for the realization of classified guidance. During 2012 to 2014 rice production by the provincial, city soil and Fertilizer Station unified the 21 rice production of precision nitrogen test.
1, materials and methods
1.1, treatment
The experiment was divided into three treatments, no repeated, no nitrogen treatment area of 0.0033 hm2 (net of 33.33 m2), the Precise Fertilization area of 0.0067 hm2 (66.66 M2). I: no nitrogen control N0, calcium superphosphate 746 base fertilizer kg/hm2, potassium chloride 248 kg/hm2 processing:
Precise n Nj, N 60% base fertilizer, 40% fertilizer as base fertilizer, calcium superphosphate 746 kg/hm2 and potassium chloride 248 kg/hm2; treatment with routine fertilization: Nc, according to the routine application of record.
1.2, fertilizer operation
5.0:5.0 (high soil fertility base tiller fertilizer and panicle fertilizer ratio); medium soil fertility: low soil fertility: 6:4 5.5:4.5. Which is 8:2 or 7:3: basal tillering (high soil fertility, fertilizer quantity, basic seedling is sufficient not applying tillering fertilizer), spikelet promoting fertilizer: Paul fertilizers =7:3. In the use of spikelet promoting fertilizer leaf stage, preserving flowers used in two leaf stage. Base: P and K once base fertilizer, other measures of the same. Treatment II, pure N application, high fertility by 273 kg/hm2, medium fertility by 255 kg/hm2, low fertility by 239 kg/hm2.
1.3, test crop varieties
Varieties for Ningjing 4, uniform density (x = 8 inch spacing spacing x 3.5 inches), three or four seedlings per hill.
1.4, field selection
The test set of 7 villages and towns, sand silt soil area 3, area 2, 2 kg soil area. The former rice. Each township high, medium and low fertility level of each piece (high fertility level of rice yield is about 9701 kg/hm2, in the fertility of rice yield was about 8209 kg/hm2, low fertility of rice yield at 6716 kg/hm2, respectively) to arrange a test point (three treatments), the district has organized a total of 21 precision nitrogen application test point. Each point with GPS positioning, and in pre sowing soil samples collected by S, sampling depth of 0 ~ 20 cm. laboratory index: soil organic matter, total nitrogen, available nitrogen, available phosphorus, available potassium, pH, test production technique management measures consistent.
1.5, inspection records
After the seedlings were selected, the emergence of uniform, a representative of 1 m2, the angle of the box after the four fixed position observation record. Before harvest, 10 d theory was used to measure the yield, and the yield of each plot was calculated by real estate, and the total grain number per plant was 1 kg.
2, analysis and discussion
2.1, no nitrogen fertility yield and soil nitrogen
In the whole area, the yield of the 21 nitrogen free blank test areas varied from 3481 to kg/hm2, and the absorption amount of nitrogen in 100 kg grains varied from 1.64 to 1.83 kg, and the total nitrogen uptake varied from 57.1 to 90.9 kg/hm2. The soil nitrogen supply capacity, sand land is low, no nitrogen blank area average yield of 4678 kg/hm2, the total nitrogen content of 79.3 kg/hm2; and the land is higher, the average yield of 4685 kg/hm2, the total nitrogen content of 79.9 kg kg/hm2; soil is the highest, the average yield was 4678 kg/hm2, the total nitrogen content of 80.3 kg/hm2.
2.2. The yield of different nitrogen levels
In different nitrogen application, the yield of rice with 19 kg/0.067hm2 was the highest in the pure nitrogen area, and the yield varied from 9719 to 9978 kg/hm2. The yield increased with the increase of nitrogen application rate, and the yield varied from 7743 to 9743 kg/hm2. Rice yield range of 9266 ~ 9704 kg/hm2 at moderate fertility level. Rice yield range of 7842 ~ 8964 kg/hm2 at low fertility level. The nitrogen application rate was 31.5 kg/hm2, with an average of about kg/hm2, which was increased by an average of 9311 kg/hm2, which was an increase of about, with an increase of about 9079 kg/hm2.
2.3 nitrogen uptake and nitrogen fertilizer in different yield levels
Seasonal utilization of precise nitrogen application area of 8209 ~ 8955kg/hm2, 100 kg grain nitrogen content of 1.9 kg, when the nitrogen utilization rate of 37.97% quarter; accurate fertilization from 8955 to 9701 kg/hm2, one hundred kilograms of grain nitrogen amount was 1.91 kg, when the nitrogen utilization rate of 38.14% quarter; accurate fertilization from 9701 to 10448 kg/hm2, 100 kg of grain nitrogen amount was 1.98 kg, when the nitrogen utilization rate of 38.48% quarter; the conventional fertilization area 7463 ~ 8209 kg/hm2, one hundred kilograms of grain nitrogen amount of 2.02 kg, when the nitrogen utilization rate of 27.13% quarter; the conventional fertilization area 8209 ~ 8955 kg/hm2, one hundred kilograms of grain nitrogen amount was 2.03 kg, nitrogen utilization rate 32.13%; conventional fertilization area 8955 ~ 9701 kg/hm2, one hundred kilograms of grain nitrogen amount was 2.04 kg, when the nitrogen utilization rate of 38.56% quarter. It can be seen from the above that the nitrogen use efficiency of the conventional fertilizer application area is lower than that of the nitrogen application rate in the precise nitrogen fertilizer application area.
3. Conclusion
3.1, Sucheng district overall fertility level difference
21 test points of nitrogen fertilization yield, the yield of less than 3750 kg/hm2, the output of 3750 to 4500kg/hm2, the yield of more than 4500 ~ to 17 ~ 5250kg/hm2.
That the level of soil fertility Sucheng district overall difference, belongs to the medium fertility level, a low level of fertility field.
3.2, the total amount of nitrogen absorbed by rice increased with the increase of yield
It was found that with the increase of yield, the nitrogen uptake of rice was increased with the increase of yield. The yield of rice was low, the utilization rate of nitrogen fertilizer was low, and the profit per hectare was low. The suitable amount of nitrogen fertilizer of rice could be increased nitrogen use efficiency, so as to increase production efficiency, not only excessive reduction of production, but also cause environmental pollution.