Possibilities of Multi-spectral Data for the Assessment of Soil Nitrogen Content

Author(s):  
L. Wang ◽  
D. Jia ◽  
H. Shi ◽  
Q. Lin ◽  
M. Ge ◽  
...  
2013 ◽  
Vol 664 ◽  
pp. 142-145
Author(s):  
Shan Shan Zhang ◽  
Li Yuan Yang ◽  
Hui Wang ◽  
Qing Lin Chen ◽  
Qian Li

In order to explore the variations and impact factors of soil nitrogen contents, 0-20 cm mineral soil under herb, shrub, Platycladus orientalis plantation of limestone mountains after restoration for 5 years and 10 years were collected and examined in Jinan, Shandong province. The results showed that there was different soil mineral nitrogen content under different vegetation during the natural succession and artificial restoration succession. Shrub community (14.35 mg/Kg) > herb community (12.73 mg/Kg); Platycladus orientalis plantation restored for 10 years (27.82 mg/Kg) > Platycladus orientalis plantation restored for 5 years (20.76 mg/Kg). NO3--N has highly significant positive correlations with soil organic carbon and total nitrogen content (r = 0.626, 0.564, p 4+-N has not significantly correlated with total nitrogen and organic carbon content (r = 0.218, 0.155). However, it has highly significant positive correlation with the NO3--N (r = 0.531, p 3--N and NH4+-N have highly significant negative correlations with soil pH (r = -0.657, -0.605, p < 0.01), respectively. But the correlation with the soil moisture was not significant (r = -0.181, 0.114). The research provided base information for the evaluation of restoration effects and restoration practice on the limestone mountains.


2016 ◽  
Vol 124 ◽  
pp. 29-36 ◽  
Author(s):  
Yao Zhang ◽  
MinZan Li ◽  
LiHua Zheng ◽  
Yi Zhao ◽  
Xiaoshuai Pei

1952 ◽  
Vol 24 (3) ◽  
pp. 127-134
Author(s):  
Armi Kaila ◽  
Pertti Kivinen

In the experiments reported above the effect of organic material upon the aggregation of soil particles and the simultaneous immobilization of mineral nitrogen by microorganisms were studied. The relative amount of water-stable aggregates larger than 0.5 mm in diameter was considered to indicate the aggregation state of the soil samples. Probably, somewhat different results were obtained if the crumb formation had been determined by some other method, but it is not sure that these would have been more reliable. Since the incubation of soil samples were performed under aerobic conditions, and all the samples were mineral soils, it seemed justifiable to take the nitrate-nitrogen content of the soil samples to characterize the amount of mineral nitrogen in them. On the basis of the results the general conclusion may be drawn that the more favourable the conditions are for the development of an active and large microflora in the soil, the more intensively the crumb formation and the immobilization of nitrogen takes place, but also the destruction of aggregates begins the more rapidlv. This appeared to be true with regard to the indigenous fertility of soil as well as to the fertilization. Liming, however, did not improve the conditions in these experiment, probably due to the rather slight acidity of the soil samples used. Under otherwise similar conditions the larger amount of straw produced larger amount of aggregates, but the differences in the nitrate-nitrogen content of soil in the presence of various amounts of straw were neglibigle. Generally, the degree of immobilization of soil nitrogen seemed largely to depend on the properties of soil and on other environmental conditions, and nitrogen applications, theoretically enough for the needs of microorganisms that decomposed the straw, could not always prevent an intensive absorption of soil nitrogen. The crumb formation appeared to need mere energy-yielding material than the immobilization of nitrogen, or the destruction of crumbs occurred more rapidly than the nitrification of microbiologically bound nitrogen.


Author(s):  
Martin Hajzler ◽  
Jana Klimešová ◽  
Petra Procházková ◽  
Tomáš Středa

Growing catch crops is one of the possible strategies to decrease erosion and nitrogen loss from soil profiles. Biomass yield and root system size have significant impacts on the soil nitrogen content. a three‑year field experiment with eight varieties of white mustard (Sinapis alba L.) was established to evaluate the effects of genotype and environment on biomass yield, soil nitrogen content and rooting parameters. Significant effects of genotype were found for root length density (RLD), root surface density (RSD) and specific root length (SRL) in the plow layer (0 – 20 cm) and for root system size (RSS), measured by electrical capacitance method, during three phenological phases. Higher biomass yield in varieties with higher RLD and RSD values during ripening and a larger RSS during flowering were found in dry conditions. Relationship of the root system and biomass yield to nitrate and ammonia nitrogen content varied in different environments. We found a significant relation between the RSS and ammonia nitrogen content in more fertile environment on average over the three years. The nitrate nitrogen content was related to the RLD, RSD and SRL in favorable year at shallow soil depths (0 – 20 cm).


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