The Effect of Lenient Defoliation on the Nitrogen Economy of White Clover: The Contribution of Mineral Nitrogen to Plant Nitrogen Accumulation During Regrowth

1992 ◽  
Vol 69 (5) ◽  
pp. 429-435 ◽  
Author(s):  
CAROL A. MARRIOTT ◽  
A. HAYSTEAD
Keyword(s):  
White Clover ◽  
Mineral Nitrogen ◽  
Nitrogen Accumulation ◽  
Plant Nitrogen ◽  
Nitrogen Economy

INFLUENCE OF SINGLE STRAINS AND A COMMERCIAL MIXTURE OF Bradyrhizobium japonicum ON GROWTH, NITROGEN ACCUMULATION AND NODULATION OF TWO EARLY-MATURING SOYBEAN CULTIVARS

1988 ◽  
Vol 68 (2) ◽  
pp. 411-418 ◽  
Author(s):  
L. D. BAILEY
Keyword(s):  
Glycine Max ◽  
Soil Temperature ◽  
Bradyrhizobium Japonicum ◽  
Nodule Formation ◽  
Growth Stages ◽  
Nitrogen Accumulation ◽  
Plant Nitrogen ◽  
Commercial Mixture ◽  
Early Maturing ◽  
Glycine Max L

Seven single strains and a commercial mixture of Bradyrhizobium japonicum were evaluated in association with two early-maturing Canadian soybean (Glycine max (L.) Merrill) cultivars, Maple Presto and Maple Amber. Inoculated and uninoculated plants were grown in pails outdoors. Soil temperature at 15 cm depth was monitored throughout the experiment. At the V2, V3, R2 and R4 growth stages, whole plants were removed from the pails. Nodules were counted and weighed; roots and tops were separated, weighed and analyzed for total nitrogen. Bradyrhizobium japonicum strains 61A148, 61A196, 61A194 and 61A155 were similar in effectiveness, but superior to strains 61A124a, 61A118b, 61A101c and the commercial mixture in earliness of nodule formation, number and weight of nodules per plant, and in promoting greater root and top growth and plant nitrogen accumulation. There were indications that soil temperature may have affected nodulation. Maple Amber showed the greater potential for symbiotic nitrogen fixation. This cultivar supported earlier nodulation, had a greater number of nodules, accumulated more nitrogen in the tops and roots and had greater growth than Maple Presto.Key words: Soybean, Glycine max (L.) Merrill, soil temperature, soybean growth stages, Bradyrhizobium, nodulation

Fertility investigations on the black earth wheatlands of the Darling Downs, Queensland. III. Mineral nitrogen in the soil and its relation to the wheat crop

1960 ◽  
Vol 11 (1) ◽  
pp. 27 ◽  
Author(s):  
SA Waring ◽  
LJH Teakle
Keyword(s):  
Grain Yield ◽  
Ammonia Nitrogen ◽  
Mean Value ◽  
Mineral Nitrogen ◽  
Wheat Crop ◽  
Nitrogen Accumulation ◽  
A Value ◽  
The Mean ◽  
The One ◽  
Growing Crop

The level of mineral nitrogen in the soil under fallow and crop was measured for the years 1951 to 1953. Relationships of mineral nitrogen at planting to yield and nitrogen content of wheat grain and straw were examined. Values for nitrate nitrogen at the end of the fallow period ranged most commonly from 10 to 20 µg/g in the surface 2 ft and from 0 to 10 µg/g at 2-4 ft. Approximately one-third of the sites showed an increase from the third to the fourth foot. One site showed extremely high values throughout the profile, particularly at 3-4 ft where a value of 127 µg/g was recorded. Values for ammonia nitrogen were most commonly in the range of 0-3 µg/g . Under the growing crop, mineral nitrogen declined for most depths in the period from planting up to September or October, after which there was little further change to harvest. Uptake of mineral nitrogen was normally greatest from the surface 2 ft of soil. Below 3 ft there were two groups of sites. One group showed moderate to high uptake and the second group low uptake. The low uptake in the latter group provides a reason for mineral nitrogen accumulation below 3 ft at some sites. Mineral nitrogen to 4 ft at planting averaged 126 lb/ac, excluding the one site with exceptionally high values. This was double the mean value of 63 lb/ac for nitrogen recovered in grain and straw, for crops planted in May-June. These figures, combined with trends in the soil under crop, suggest that most of the nitrogen used by the crop was derived from that in the soil at planting. Correlations between mineral nitrogen at planting and grain yield were mostly non-significant, suggesting that in general nitrogen was not an important factor limiting yield. Low grain yield and protein percentage were recorded at a number of sites which had been cultivated more than 50 years.

Fallowing and wheat production in southern NSW

1966 ◽  
Vol 6 (22) ◽  
pp. 233 ◽  
Author(s):  
GD Kohn ◽  
RR Storrier ◽  
EG Cuthbertson
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Mineral Nitrogen ◽  
Yield Response ◽  
Winter Period ◽  
Wagga Wagga ◽  
Nitrogen Accumulation ◽  
High Fertility ◽  
Available Nitrogen ◽  
Nitrogen Concentrations

The response of wheat to the length of fallow, to the number of cultivations, and to pre-planting chemical control of weeds on high fertility soils was determined under winter rainfall conditions at Wagga Wagga, New South Wales, over four years commencing 1960-61. Length of fallow had little influence on the conservation of rainfall except in 1961-62, when approximately twice the average summer rainfall added 1.8 inches of soil moisture per acre 48 inches. Long fallow increased available nitrogen accumulation, but this did not increase yield over either the mechanically prepared shorter fallows, or pre-planting chemical weed control. This was due to losses during the autumn-winter period of some of the excess mineral nitrogen that accrued during the long fallow. High mineral nitrogen concentrations also occurred during the summer on weed-free, uncultivated soils. Grain yield after a single autumn cultivation was as high as after a long fallow except in 1961-62. In this year the long fallow (September to May) significantly increased yields over all other treatments. The absence of any positive yield response to the application of 60 to 80 lb nitrogen an acre to short fallows suggests that mineral nitrogen concentrations were generally adequate for grain production. The addition of nitrogen to long fallows often depressed yields. The dependence of grain yield on adequate weed control is illustrated by a highly significant negative correlation (r = -0.849 ; P<0.001) of grain yield with weed growth. It is concluded that in the Wagga Wagga environment weed control is more important than moisture conservation and mineral nitrogen accumulation through fallowing.

scholarly journals Enhancing the Nitrogen Signals of Rice Canopies across Critical Growth Stages through the Integration of Textural and Spectral Information from Unmanned Aerial Vehicle (UAV) Multispectral Imagery

2020 ◽  
Vol 12 (6) ◽  
pp. 957 ◽  
Author(s):  
Hengbiao Zheng ◽  
Jifeng Ma ◽  
Meng Zhou ◽  
Dong Li ◽  
Xia Yao ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Nitrogen Concentration ◽  
Leaf Nitrogen ◽  
Spectral Information ◽  
Growth Stages ◽  
Nitrogen Accumulation ◽  
Multispectral Imagery ◽  
Plant Nitrogen ◽  
N Nutrition ◽  
Aerial Vehicle

This paper evaluates the potential of integrating textural and spectral information from unmanned aerial vehicle (UAV)-based multispectral imagery for improving the quantification of nitrogen (N) status in rice crops. Vegetation indices (VIs), normalized difference texture indices (NDTIs), and their combination were used to estimate four N nutrition parameters leaf nitrogen concentration (LNC), leaf nitrogen accumulation (LNA), plant nitrogen concentration (PNC), and plant nitrogen accumulation (PNA). Results demonstrated that the normalized difference red-edge index (NDRE) performed best in estimating the N nutrition parameters among all the VI candidates. The optimal texture indices had comparable performance in N nutrition parameters estimation as compared to NDRE. Significant improvement for all N nutrition parameters could be obtained by integrating VIs with NDTIs using multiple linear regression. While tested across years and growth stages, the multivariate models also exhibited satisfactory estimation accuracy. For texture analysis, texture metrics calculated in the direction D3 (perpendicular to the row orientation) are recommended for monitoring row-planted crops. These findings indicate that the addition of textural information derived from UAV multispectral imagery could reduce the effects of background materials and saturation and enhance the N signals of rice canopies for the entire season.

The challenge of remobilisation in plant nitrogen economy. A survey of physio-agronomic and molecular approaches

2001 ◽  
Vol 138 (1) ◽  
pp. 69-81 ◽  
Author(s):  
CELINE MASCLAUX ◽  
ISABELLE QUILLERE ◽  
ANDRE GALLAIS ◽  
BERTRAND HIREL
Keyword(s):  
Plant Nitrogen ◽  
Nitrogen Economy ◽  
Molecular Approaches
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