Showing 3 results for Nutrient Uptake
R. Hajeeboland, N. Asgharzadeh, Z. Mehrfar,
Volume 8, Issue 2 (7-2004)
Abstract
A great number of studies have been conducted on the role of Azotobacter - a free living N2-fixer - in agricultural soils, but our information is lacking on the importance of Azotobacter in pasture soils. This research was conducted to study the relationship between ecological and edaphical factors with the population of the bacteria in soil. Soil samples were taken from two sites in Azarbaidjan (Mishou-dagh and Khadjeh), having different ecology, soils and vegetation types. We investigated also the effect of inoculation of rhizosphere with soil-isolated A. chroococcum on the growth of wheat (Triticum aestivum L. cv. Omid) during 56 days of growth in a pot experiment. The treatments included: 1) inoculation with A. chroococcum (+A), 2) N fertilizer at a rate of 35 mg/Kg as (NH4)2SO4 (+N), 3) +A+N and 4) –A–N as control with four replications. Results showed that the population of Azotobacter chroococcum correlated positively with organic carbon and negatively with soil pH. In soils covered with vegetation the population of bacteria was higher than that in uncovered soils and the highest population of bacteria was found in soil samples collected from the rhizosphere of grass species and the lowest in that of legume species. In inoculation experiment, shoot and, particularly root growth, increased in the order of +N, +A and +A+N in comparison with control (–A–N) plants. These treatments also stimulate uptake and transport of K into shoot. Interestingly, the effect of +A treatment was significantly higher than that of +N and +A+N treatments. The same results were obtained for nitrogen. A higher uptake and particularly transport of K into shoot was attributed to low molecular weight organic molecules produced in inoculated roots and transport K into shoot. Results showed that inoculation with Azotobacter not only enhanced growth and chlorophyll content, but also stimulated uptake and translocation of ions into shoot. The stimulatory impact of inoculation is most likely a general effect that could also be important in micronutrients translocation into shoot.
S. Rajaee, H. A. Alikhani, F. Raiesi,
Volume 11, Issue 41 (10-2007)
Abstract
Azotobacter chroococcum is an important PGPR (Plant Growth Promoting Rhizobacteria) producing compounds needed for plant growth. The aim of this research was to study the effects of different native strains of Azotobacter chroococcum on growth and yield of wheat under greenhouse counditions. Seeds of spring wheat (Triticum aestivum L. var. Pishtaz) were inoculated with some Azotobacter chroococcum strains capable of producing IAA, HCN, sidrophore and fixing molecular nitrogen. The inoculation of wheat with those strains had a positive, significant effect on biological yield, seed protein percentage, thousand seed weight, leaf area, N, P, Fe and Zn uptake, in particular, by wheat. The increased growth of wheat was most likely due to the production of IAA and enhanced nitrogen fixation by inoculated strains. Some strains of Azotobacter chroococcum native to Chaharmahal va Bakhtiari are established as PGPR. Results also support the efficiency of Azotobacter chroococcum as an important biofertilizer in wheat cropping systems. The selected strains had a significant effect on wheat growth and yield, including biological yield and seed quality under greenhouse counditions. This beneficial effect of Azotobacter chroococcum on wheat is attributed mainly to IAA production and, to some extent to non symbiotic nitrogen fixation in the rhizosphere. So, these strains can potentially be used to improve wheat nutrition of micronutrients such as Fe and Zn, in particular.
L. Piri Moghadam, A. Vaezi,
Volume 23, Issue 4 (2-2020)
Abstract
Sloping farmlands are the major sources of soil, water and nutrient losses in arid and semi-arid regions. Information about the impacts of different tillage practices on soil erosion, nutrient loss and crop nutrient uptake on the sloping farmland of semi- arid soil is, however, limited. This study was carried out to investigate the effects of tillage direction on soil, water, nitrogen and phosphorous losses and their uptake by plant in a rainfed wheat land. Field experiments were conducted in two tillage directions: downslope tillage and contour line tillage with four fertilization treatments: control, urea, triple superphosphate, and urea + triple superphosphate at the field plots with 1.75 m ´ 8 m in dimensions by using the randomized completely block design at three replications in Zanjan Township during 2014-2015. According to the results, Significant differences were found between the two tillage practices in soil loss (P < 0.001), water loss (P < 0.001), nitrogen loss soil loss (P < 0.001), and nitrogen uptake by wheat grain (P < 0.001), while phosphorous loss and its uptake did not show any statistically significant difference. Soil and water loss in the downslope tilled plots was 1.65 and 2.50 times higher than the contour line tillage, respectively. Nitrogen loss in the downslope tilled plots was 1.29 times more than that in the contour line tilled plots. Nitrogen loss in the plots was attributed to soil and water loss, so significant relationships were observed between nitrogen loss and soil loss (R2 = 0.59)
and water loss (R2 = 0.55). This study, therefore, revealed that the tillage direction is an important factor controlling runoff, soil loss, and nitrogen loss and its uptake by wheat in the rainfed lands of semi-arid regions. Application of the contour tillage is, therefore, the first step to conserve soil and water and to improve soil productivity in these regions.
