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[Objective] In order to explore the effects of low nitrogen stress on the growth and soil nutrients of tartary buckwheat in the hilly and gully regions of the Loess Plateau, the present paper determined plants and soil characteristics of tartary buckwheat with different nitrogen stress among the whole growth period It could provide a scientific basis for the optimal management of farmland nitrogen fertilizer in the loess hilly and gully region. [Method] The study took different nitrogen buckwheat (Heifeng No. 1, HF, intolerant to low nitrogen, Diqing Tartary Buckwheat, D Q, tolerant to low nitrogen) as the research objects, and set 3 levels of nitrogen application as follows : 0 kg/hm² (NO, no nitrogen treatment), 80 kg/hm² (Nl, low-nitrogen treatment), 160 kg/hm² (N², normal nitrogen treatment). Plant indexes (plant height, stem thickness, leaf area) and soil characteristics (soil water content, pH, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus, total potassium) were determined during the whole growth periods. [Result] (i) Cultivar, nitrogen treatment and the interaction between the two had extremely significant effects on tartary buckwheat plants (P < 0. 01 ). Under Nl treatment, the plant height, stem thickness and leaf area of DQ in the seedling stage were 9. 7 %, 10. 5 %, and 17. 7 % higher than that of HF. The plant height and stem thickness of DQ in the flowering stage were 9. 5 % and 7. 4 % higher than that of HF. The stem thickness and leaf area of DQ were 5. 4 % and 3 6. 2 % higher than those of HF. (ii) The cultivars, nitrogen treatments and the interaction between the two had a significant impact on soil nutrients (P < 0. 01). After the growth period, the soil nutrient indexes of the two cultivars were lower than those of the sowing period, but soil organic matter, available nitrogen, available phosphorus, available potassium, total nitrogen, and total potassium of DQ were higher than those of HF under Nl treatment of98. 8%, 11. 6%, 44. 7%, 11. 6%, 80. 41%, 4. 2%, respectively. [Conclusion] The DQ (low nitrogen tolerant) has better water conservation and green manure benefits than HF (intolerant to low nitrogen) as its larger leaf area and stem thickness could buffer the direct erosion of rainfall on the ground and resist wind to prevent plant lodging. In addition, the rhizosphere soil nutrient content of DQ was higher than HF after being harvested which could reduce the fertilizer consumption in the next season and was also more conducive to the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

[Objective] In order to explore the effects of low nitrogen stress on the growth and soil nutrients of tartary buckwheat in the hilly and gully regions of the Loess Plateau, the present paper determined plants and soil characteristics of tartary buckwheat with different nitrogen stress among the whole growth period It could provide a scientific basis for the optimal management of farmland nitrogen fertilizer in the loess hilly and gully region. [Method] The study took different nitrogen buckwheat (Heifeng No. 1, HF, intolerant to low nitrogen, Diqing Tartary Buckwheat, D Q, tolerant to low nitrogen) as the research objects, and set 3 levels of nitrogen application as follows : 0 kg/hm² (NO, no nitrogen treatment), 80 kg/hm² (Nl, low-nitrogen treatment), 160 kg/hm² (N², normal nitrogen treatment). Plant indexes (plant height, stem thickness, leaf area) and soil characteristics (soil water content, pH, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus, total potassium) were determined during the whole growth periods. [Result] (i) Cultivar, nitrogen treatment and the interaction between the two had extremely significant effects on tartary buckwheat plants (P < 0. 01). Under Nl treatment, the plant height, stem thickness and leaf area of DQ in the seedling stage were 9. 7 %, 10. 5 %, and 17. 7 % higher than that of HF. The plant height and stem thickness of DQ in the flowering stage were 9. 5 % and 7. 4 % higher than that of HF. The stem thickness and leaf area of DQ were 5. 4 % and 3 6. 2 % higher than those of HF. (ii) The cultivars, nitrogen treatments and the interaction between the two had a significant impact on soil nutrients (P < 0. 01). After the growth period, the soil nutrient indexes of the two cultivars were lower than those of the sowing period, but soil organic matter, available nitrogen, available phosphorus, available potassium, total nitrogen, and total potassium of DQ were higher than those of HF under Nl treatment of98. 8%, 11. 6%, 44. 7%, 11. 6%, 80. 41%, 4. 2%, respectively. [Conclusion] The DQ (low nitrogen tolerant) has better water conservation and green manure benefits than HF (intolerant to low nitrogen) as its larger leaf area and stem thickness could buffer the direct erosion of rainfall on the ground and resist wind to prevent plant lodging. In addition, the rhizosphere soil nutrient content of DQ was higher than HF after being harvested which could reduce the fertilizer consumption in the next season and was also more conducive to the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

[Objective ] The objective of the paper is to provide the scientific basis for reducing chemical fertilizer and improving efficiency for vegetable in acidic yellow soil area of Guizhou. [ Method] The effects of combined application of biochar and yellow phosphorus slag on yield and nutrient uptake and utilization of Chinese cabbage cultivated in acidic yellow soil are studied by a pot experiment in green house. [ Result] The yield of Chinese cabbage under different treatments of biochar and yellow phosphorus slag combination is increased by 37.22 % - 82.07% compared with that of non-fertilization treatment, and the yield of Chinese cabbage applied with chemical fertilizer + 70 glpot biochar + 11.7 glpot yellow phosphorus slag is the highest ( 553. 5 g/ pot) . The nitrogen, phosphorus and potassium content in Chinese cabbage under different treatments of biochar and yellow phosphorus slag combination is increased by 39.9% - 57.9%, 1.31% - 35.22% and 1.99 % -39.09% respectively compared with that of non-fertilization treatment. The nitrogen, phosphorus and potassium uptake of Chinese cabbage under different treatments of biochar and yellow phosphorus slag combination is increased by 107.8% - 188.9%, 65.89% - 128.82% and 61.73 % - 122.97% separately. Except there is no obvious difference in phosphorus uptake of Chinese cabbage applied chemical fertilizer + 18.0 glpot yellow phosphorus slag and non-fertilization treatment, the nitrogen, phosphorus and potassium uptake of Chinese cabbage under other treatments of biochar and yellow phosphorus slag combination is higher than that of nonfertilization treatment significantly. Among various fertilization treatment, chemical + 70 glpot biochar + 11.7 g/pot yellow phosphorus slag has the highest nitrogen and phosphorus utilization efficiency, respectively 59. 01 % and 8. 83 %, while chemical fertilizer+ 100 glpot biochar + 9.00 glpot yellow phosphorus slag has the highest potassium utilization efficiency, which is 92. 10 % . [Conclusion ] Rationally combined application of biochar and yellow phosphorus slag can improve yield, nutrient uptake and utilization of Chinese cabbage, and low amount of biochar combined with high amount of yellow phosphorus slag has the best effect. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore suitable water and fertilizer integration with reduced fertilization mode for flue-cured tobacco production on slope land in southern tobacco-growing areas [Method] Taking the local conventional water and fertilizer management as a comparison, the effects of water and fertilizer integration on dry matter accumulation, N and K absorption and distribution, fertilizer utilization rate and soil nutrient balance of Hue-cured tobacco on slope land were studied. [ Result] Results of two-year experiment showed that the dry matter accumulation, nitrogen and potassium absorption of flue-cured tobacco with water and fertilizer integrated management were still higher than those of control when fertifu.er was reduced, and fertilizer utilization ratio significantly increased, and the nutrient surplus and balance coefficient were reduced. T2 treatment with 20 % reduced fertilization increased the dry matter accumulation by 22. 28 % in maturing stage than that of conventional treatment, and promoted the absorption of nitrogen and potassium by 92. 64 % and 83. 23 % respectively in root extending stage. The apparent utilization rate, season recycling rate and economic utilization rate of nitrogen fertilizer of T2 treatment increased by 20. 98 %, 14. 6 % and 8. 6 % respectively compared with CK, even 15. 25 %, 16. 15 % and 17. 64 % higher than Tl treatment with the same amount fertilizer. Fertilizer productive efficiency of potassium increased by 35. 02 % on average, and the biggest difference of apparent utilization rate, season recycling rate and economic utilization rate between T2 and CK appeared in 2017, reaching 80. 62 %, 105. 6 % and 126. 03 % . From the soil nutrient balance, water and fertilizer- integration mode increased crop carrying capacity and reduced nutrient surplus. Compared with CK, T2 and T3 treatments reduced nitrogen surplus by 49. 3 and 54. 6 kg • hm -2, and the nutrient balance rate decreased 93. 85 and 103. 16 percentage points. The best performance on potassium balance was T2 treatment, it's potassium surplus decreased by 86. 69 kg·hm-2 compared with CK, and the balance rate fell 158. 75 percentage points. [ Conclusion] In conclusion, under the water and fertilizer integration mode, it can improve the fertilizer utilization rate and reduce the soil nutrient surplus by properly reducing the fertilizer consumption and increasing the topdressing ratio. [ABSTRACT FROM AUTHOR]

( Objective) The present paper aimed to solve at the deterioration of soil physical properties and decline of soil fertility by irrational fertilization in northern Liaoning province, and the effects of different fertilization treatments on soil physicochemical properties and spring maize yield in northern Liaoning province were studied. [Method] Successive 2 year field experiments were conducted in the main maize production area in the northern of Liaoning. Five different treatments with mixed chemical and organic fertilizers no nitrogen with chemical P and K ( CK),conventional fertilization( CK1), optimize fertilization(T1), organic manure combined with chemical fertilizer(T2), and humic acid combined with chemical fertilizer( T3) with three replications were examined. The soil bulk density, soil nutrients, maize yield and yield components of each treatment were compared. [Result] The humic acid and organic mature combined with chemical fertilizer could reduce soil bulk density, compared to conventional fertilization treatment, decreased soil bulk density by 2. 97 % and 3. 94 %, 1. 22 % and 3. 08 %, 2. 67 % and 3. 60 % in 5 -10, 10 - 15 and 15 - 20 cm of soil layers. Compared to conventional fertilization, applying humic acid and organic manure could significantly improve soil fertility, increased organic matter by 2. 38 % and 2. 98 %, alkali-hydrolyzed nitrogen by 5. 69 % and 9. 82 %,available phosphorus by 14.47 % and 19. 60 % and available potassium by 8.07 % and 7. 92 %. The maize yield of humic acid and organic manure treatment was higher than that of the conventional fertilization treatment, respectively, increased by 950 and 852 kg/hm 2 • (Conclusion ) The comprehensive analysis results showed that the measures of suitable fertilization in northern Liaoning province was that the amount of humic acid was 600 kg/hm² or organic mature was 1500 kg/hm² while the nitrogen application was 198. 9 kg/hm². [ABSTRACT FROM AUTHOR]

[Objective] The effects of different nitrogen and potassium application amounts on NK nutrition utilization and yield of rapeseed on different soil types in rapeseed-tobacco rotation area was studied. The purpose of this paper was to provide theoretical basis and technical support for precision nutrient management and reducing chemical fertilizer of rapeseed production. [ Method] Field trials were carried out in 3 kinds of soil type to investigate yield and nutrition utilization of rapeseed with different nitrogen and potassium application amounts. Egression equations of the quadratic model between N and K application amounts and N and K nutrition utilization of rapeseed were established. The effects of different nitrogen and potassium application amounts on different soil types on yield of rapeseed was analyzed. [ Result] Yield of rapeseed with N 90 kg/hm² was the highest in red soil. Yield of rapeseed with N 180 kg/hm² was the highest in paddy soil. Yield of rapeseed with N 270 kg/hm² was the highest in sandy loam. The yield increasing effect of N was sandy loam > paddy soil > red soil. Contribution of N to yield was red soil > paddy soil > sandy loam. In red soil, nitrogen use efficiencies of rapeseed with N 90,180 and 270 kg/hm² was 63. 68 %,31. 53 % and 18. 59 % respectively. In paddy soil, nitrogen use efficiencies of rapeseed with N 90,180 and 270 kg/hm² was 54.95 %,42. 5 % and 29. 45 % respectively. In 8&l'ldy loam, nitrogen use efficiencies of rapeseed with N 90,180 and 270 kg/hm² was 31. 95 %,37. 14 % and 33. 29 % respectively. There was no significant difference in yield of rapeseed between treatment with K and no K. In paddy soil and in sandy loam, yields of rapeseed with K SO kg/hm² was higher than other treatments. The yield-increasing effect of K was red soil > paddy soil > sandy loam. Contribution of K to yield was red soil > paddy soil > sandy loam. In red soil, K use efficiencies of rapeseed with K 50, 100, 150 kg/hm² was 46. 52 %,30. 2 % and 28. 18 %, respectively. In paddy soil, K use efficiencies of rapeseed with K SO, 100, 150 kg/hm² was 38. 91 %,22. 89 % and 19. 61 %, respectively. In sandy loam, K use efficiencies of rapeseed with K 50, 100, 150 kg/hm² was 55. 6 %,31. 29 % and 18. 39 %, respectively. [ Conclusion] In red soil of Luoping City, application amount of N and K on rapeseed production should be reduced. In paddy soil of Chengjiang City, application amount of K on rapeseed production should be controlled. In sandy loam of Tengchong City, application amount of N on rapeseed production should be increased and application amount of K on rapeseed production should be controlled. It was important that different nutrient management strategy should be adopted on different soil types in different area. [ABSTRACT FROM AUTHOR]

[Objective] This paper aims to provide optimal fertilization guidance for high-yield cultivation of P. frutescens and promotion of new P. frutescens varieties. [ Method] The effects of nitrogen, phosphorus and potassium fertilizers on the yield of two new P. frutescens varieties ( Qisu 2 and Qisu 3) were studied by ternary quadratic orthogonal rotation design. The regression equation and model analysis were constructed to optimize the high-yield fertilization mode. [ Result] N was the most important factor influencing the yield of P. frutescens. However, the two varieties varied in response to P and K fertilization. The regression models of nitrogen (x1) , phosphorus (x2) and potassium (x3) of the yield (Y) are Y = 2219.384 + 405.410x1, +304.926x2 - 156.723x12 -78.676x22 - 214. 479x1x2, and Y =2048.806 + 319.535x1, +54.722x3 -63. 102x12 - 113. 664x22 +76.017x32 -69.069x1x2, respectively. The best fertilization ratio of N, P and K fertilizer was (286.022 ±25.288),(139.059 ±20. 819),(180. 000 ± 35. 860) kg/hm2 , and (338. 180 ± 16.617) , (80. 923 ±21.314) , (203.529 ± 24. 278 ) kg/hm2, respectively. The yield of P. frutescens could reach 2250 kg/hm2. [ Conclusion ] Compound application of NPK fertilizers functioned significantly in enhancing P. frutescens yield. [ABSTRACT FROM AUTHOR]

[Objective] The aim of this paper was to provide a theoretical relerence for the application of loss-control urea in rice production in yellow soil. [Method] Based on the same application rates of phosphorus and potassium fertilizer, the rice cultivar Leyou 58 was employed to explore the ellects of loss-control urea, with various adding amount of loss-control agent (1 %,2%,3%,4%,5%,6%), on rice yield, nutrients uptake and utilization. Meanwhile, no nitrogen and common urea fertilizer were taken as the controls. [Result] No regular changes of rice yield observed with increasing the dosage of loss-control agent, while the accumulation of nitrogen in rice grain, nitrogen, phosphorus and potassium in rice straw, and potassium in aboveground parts showed regular variation. At the same time, regular changes were also observed on rice nitrogen, phosphorus, potassium harvest index and potassium absorption efficiency. Compared with common urea treatment, six kinds of loss-control urea with the loss-control agent of 1 % -6 % could increase the rice yield in some degree, among which 1 % adding amount performed the best. The yield increasing rate was up to 12.22 %. The adding amounts of 1 % , 2 % and 6 % enables absorption of nitrogen, phosphorus, potassium by rice and accumulation in the rice seeds sufficiently to promote the yield and quality of rice. The adding amount of 3 % enhanced the accumulation of nitrogen, phosphorus and potassium in rice straw, increased the resistance and promoted the growth. [Conclusion] To sum up, the effect of urea with 1 % loss-control agent performed the best in rice production. [ABSTRACT FROM AUTHOR]