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Optimized Nitrogen Management for Wheat-rice Cropping System

Author: YiQiong
Tutor: HePing
School: Chinese Academy of Agricultural Sciences
Course: Plant Nutrition
Keywords: Winter wheat Rice Soil Nmin SPAD value The nitrogen fertilizer optimize management
CLC: S511
Type: Master's thesis
Year: 2011
Downloads: 31
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Abstract

Nitrogen excessive and unreasonable application and the resulting low rate of nitrogen fertilizer use is the main problems in the wheat and rice crops in the middle and lower reaches of the Yangtze River. Make sure that the wheat and rice suitable nitrogen fertilizer and Nitrogen Application soil N supply and crop demand synchronization of great significance to improve crop yield and nitrogen use efficiency, reduce nitrogen loss, sustainable development of agriculture. In this paper, by studying the characteristics of winter wheat and rice growth stage nitrogen nutrient absorption and utilization of different nitrogen management, the key growth period SPAD readings change, soil nitrogen supply and balance, clear rice and wheat suitable amount of nitrogen fertilizer and application time , as well as guidance key growth period of rice and wheat topdressing nitrogen fertilizer SPAD threshold; nitrogen fertilizer at the same time by setting basal and non-basal application processing, combined with soil background nitrogen supply value to determine the rice and wheat nitrogen fertilizer as basal conditions, aiming for the middle and lower reaches of the Yangtze River wheat and rice crop system to optimize nitrogen management to provide a scientific basis. Main progress achieved in this paper are as follows: 1 reveal the characteristics of winter wheat and rice nitrogen uptake and accumulation, indicating that the wheat nitrogen accumulation in the fastest stage in the tiller - jointing and booting - filling stage, the N uptake, respectively, of the total nitrogen uptake 26.4% and 27.2%; 31.3% of the nitrogen uptake peaked at jointing - filling stage, the period N uptake of total N uptake. 2 studies of winter wheat and rice suitable nitrogen fertilizer for 120-150 kg / hm ~ 2 and 150 kg / hm ~ 2. When the total amount of nitrogen fertilizer for wheat and rice is certain, appropriate nitrogen fertilizer after the shift, the increase in the number of nitrogen fertilizer will help improve nitrogen use efficiency. Comprehensive test results and practical operability, wheat nitrogen fertilizer for nitrogen fertilizer applied into the basal turn green manure and jointing fertilizer three times, the best rice nitrogen fertilizer nitrogen fertilizer was applied to the basal tillering and panicle three times. 3 soil background for nitrogen (nitrogen-free areas aboveground N uptake) as an important parameter of soil fertility, is an important source of nitrogen for crop growth process can not be ignored. In the background of the high soil nitrogen supply, base manure nitrogen does not significantly reduce wheat production. Under the experimental conditions, when the wheat soil background for nitrogen value of more than 39 kg N / hm ~ 2 base manure nitrogen does not affect the yield and soil nitrogen supply is sufficient to meet the needs of wheat growth; when the soil background for nitrogen value is less than 25 kg N / hm ~ 2 does not base manure nitrogen significantly reduced wheat production. 4 the SPAD threshold-based guidance wheat and rice dressing is of great significance to improve crop yields and nitrogen use efficiency; the different the crop varieties guidance dressing the SPAD threshold. Under the conditions of this study, real-time nitrogen management conditions, the guidance critical wheat growth stages (tillering and booting stage) dressing suitable SPAD threshold value should be 46; the SSNM conditions, guide the critical growth period of wheat (tillering and booting stage) the dressing suitable SPAD threshold should be 46-48. Real-time nitrogen management under the guidance of rice varieties Yang 2 U 6 and Peiliangyou 3076 critical growth stages (tillering and booting stage) suitable dressing SPAD threshold value of 41; the SSNM conditions, to guide rice varieties Yangliangyou 6 number and Peiliangyou 3076 critical growth stages (tillering and booting stage) dressing suitable SPAD threshold 39-41, the SPAD value was significantly higher than conventional rice.

Optimized Nitrogen Management for Wheat-rice Cropping System

Abstract

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