Effect of N-fertilizer Application on Yield,Grain Quality and N-fertilizer Use Efficiency of the Rapeseed Cultivars with Normal and High Oil Content

In this study,seed yield,quality and N-fertilizer use efficiency in rape(Brassica napus L.) were researched in normal oil content cultivar(Yangyou 6) and two high oil content cultivars(Zhongshuang 11 and Zheyou 50). Results showed that the average oil content of all treatments in Yangyou 6,Zhongshuang 11 and Zheyou 50 was 42. 87%,47. 37% and 48. 28%,respectively. The average protein content of all treatments in Yangyou 6,Zhongshuang 11 and Zheyou 50 was 24. 15%,22. 71% and 21. 84%,respectively. The increased ratio of total nitrogen accumulation amount in Yangyou 6 was higher than that in Zhongshuang 11 and Zheyou 50. Among three cultivars,the total protein accumulation amount in Yangyou 6 was highest,and the total oil accumulation amount was highest in Zheyou 50. With increasing nitrogen fertilization,the value of different parameters of N-fertilizer use efficiency decreased. The average N use efficiency in Yangyou 6 was 68. 70%,which was higher than that in Zhongshuang 11 and Zheyou 50(65. 06% and 60. 30%,respectively). The average N-fertilizer agronomic use efficiency in Yangyou 6 was also highest among three cultivars,which was 8. 97 kg seed / kg N. On the contrary,the average N-fertilizer physiological use efficiency in Zhongshuang 11 and Zheyou 50 was 13. 03 kg seed / kg N and 13. 84 kg seed / kg N,respectively,which was higher than that in Yangyou 6(12. 91 kg seed / kg N). Differences in partial factor productivity of N-fertilizer were slight among three cultivars.

Effects of mechanized deep placement of nitrogen fertilizer rate and type on rice yield and nitrogen use efficiency in Chuanxi Plain, China

This paper investigates the yield and nitrogen use efficiency (NUE) of machine-transplanted rice cultivated using mechanized deep placement of N fertilizer in the rice–wheat rotation region of Chuanxi Plain,China.It provides theoretical support for N-saving and improves quality and production efficiency of machine-transplanted rice.Using a single-factor complete randomized block design in field experiments in 2018 and 2019,seven N-fertilization treatments were applied,with the fertilizer being surface broadcast and/or mechanically placed beside the seedlings at (5.5±0.5) cm soil depth when transplanting.The treatments were:N0,no N fertilizer;U1,180 kg N ha^(–1) as urea,surface broadcast manually before transplanting;U2,108 kg N ha^(–1) as urea,surface broadcast manually before transplanting,and 72 kg N ha^(–1) as urea surface broadcast manually on the 10th d after transplanting,which is not only the local common fertilization method,but also the reference treatment;UD,180 kg N ha^(–1) as urea,mechanically deep-placed when transplanting;M1,81.6 kg N ha^(–1) as urea and 38.4 kg N ha^(–1) as controlled-release urea (CRU),mechanically deep-placed when transplanting;M2,102 kg N ha^(–1) as urea and48 kg N ha^(–1) as CRU,mechanically deep-placed when transplanting;M3,122.4 kg N ha^(–1) as urea and 57.6 kg N ha^(–1) as CRU,mechanically deep-placed when transplanting.The effects of the N fertilizer treatments on rice yield and NUE were consistent in the 2 yr.With a N application rate of 180 kg ha^(–1),compared with U2,the N recovery efficiency (NRE),N agronomic use efficiency (NAE) and yield under the UD treatment were 20.6,3.5 and 1.1% higher in 2018,and 4.6,1.7 and 1.2% higher in 2019,respectively.Compared with urea alone (U1,U2 or UD),the NRE,NAE and yield achieved by M3 (combined application of urea and controlled-release urea) were higher by 9.2–73.3%,18.6–61.5% and 6.5–16.5%(2018),and 22.2–65.2%,25.6–75.0% and 5.9–13.9%(2019),respectively.Compared with M3,the lower-N treatments M1 and M2 significantly increased NRE by 4.0–7.8% in 2018 and 3.1–4.3% in 2019,respectively.Compared with urea surface application (U1 or U2),the yield under the M2 treatment was higher by 4.3–12.9% in 2018 and 3.6–10.1% in 2019,respectively.Compared with U2,the NRE and NAE under the M2 treatment was higher by 36.9 and 36.3% in 2018,and 33.2 and 37.4% in 2019,mainly because of higher N uptake.There was no significant difference in the concentration of nitrate in the top 0–20 cm soil under U1,U2 and M2 treatments during the full heading and maturity stages.During the full heading stage,U2 produced the highest concentration of nitrite in 0–20 cm and 20–40 cm soil among the N fertilizer treatments.In conclusion,mechanized deep placement of mixed urea and controlled-release urea (M2) at transplanting is a highly-efficient cultivation technology that enables increased yield of machine-transplanted rice and improved NUE,while reducing the amount of N-fertilization applied.

Experimental Study of the <i>Aphanizomenon ovalisporum</i>Response to Nitrogen Fertilization in the Sub-Tropical Eu-Meso-Trophic Lake Kinneret (Israel)

First record of a bloom of filamentous-heterocystous nitrogen fixer cyanobacterium, Aphanizomenon ovalisporum, was documented in the summer of1994 inLake Kinneret (Israel). Awareness of such a bloom outbreak was predicted earlier based on documentation of Nitrogen deficiency and Phosphorus Sufficiency developed conditions. The concept of Nitrogen fertilization aimed at suppression of Nitrogen fixers Cyanobacteria was worldwide discussed and successfully implemented, but mostly in temperate oligotrophic lake ecosystems. This paper presents an experimental testing of this concept by additional Nitrogen. The results of the present study did not verify this hypothesis probably related to the ecological differences between Kinneret and the temperate ecosystems and using only one factor (Nitrogen) to test it.

Nitrogen fertilization effects on grain quality of durum wheat (<i>Triticum turgidum</i>L. var. durum) varieties in central Ethiopia

Four released durum wheat varieties, two medium tall (Arsi-Robe and Kilinto) and two recently released semidwarfs (Ude and Yerer) were evaluated under five different N rates (0, 60, 120, 180 and 240 kg·ha-1) in 2005/06 growing season at Akaki and Debre Zeit, central Ethiopia. The quality responses of durum wheat varieties to different N-fertilizer rates and the N responses between tall and short durum wheat varieties were assessed. Protein and gluten content, vitreous kernel count, thousand kernel weight, test weight and lodging were considered. Vitreous kernel count, protein and gluten content were higher at Debre Zeit than at Akaki. Unlike Debre Zeit, there were significant relationships between response variables and fertilizer levels at Akaki. Lodging slightly affected the medium tall varieties at Debre Zeit whereas it was not a problem at Akaki. At Akaki, varieties response to each additional N rate was entirely below the quality standard set by ICC, 2000 except for thousandkernel weight. Therefore, it is unwise to promote durum wheat scaling up/out program for quality production at Akaki.

Effects of water deficit and high N fertilization on wheat storage protein synthesis,gluten secondary structure,and breadmaking quality

The content and composition of wheat storage proteins are the major determinants of dough rheological properties and breadmaking quality and are influenced by cultivation conditions.This study aimed to investigate the effects of water deficit and high N-fertilizer application on wheat storage protein synthesis,gluten secondary structure,and breadmaking quality.Reverse-phase ultrahigh-performance liquid chromatography analysis showed that storage protein and gluten macropolymer accumulation was promoted under both independent applications and a combination of water-deficit and high N-fertilizer treatments.Fourier-transform infrared spectroscopy showed that water deficit and high N-fertilizer treatments generally improved protein secondary structure formation and lipid accumulation,and reduced flour moisture.In particular,high N-fertilizer application increasedβ-sheet content by 10.4%and the combination of water-deficit and high N-fertilizer treatments increased random coil content by 7.6%.These changes in gluten content and secondary structure led to improved dough rheological properties and breadmaking quality,including superior loaf internal structure,volume,and score.Our results demonstrate that moderately high N-fertilizer application under drought conditions can improve gluten accumulation,gluten secondary structure formation,and baking quality.

Measurements of atmospheric N_2O concentration and its emission fluxes from soil in China

Air samples in China were collected and determined for the concentration of N2O.The production rates of N2O from agricultural soils were measured with the chamber method.The results in-dicate that the background concentration of N2O averages（308±5）×10-9in 1989,which is close to that ob-tained at the other background stations abroad.However,at both urban and rural areas,atmospheric N2Oconcentrations are higher.N2O emission fluxes from several farmlands are different and dependent on the fac-tors of agricultural practice and climate.But their magnitudes are at the same order.Preliminary calculationshows that the released N2O-N from agricultural sources（cultivated soil and N-fertilizers）amounts to 122Gg/a in China in 1990.