scholarly journals Genotypic Variation in Nitrogen Uptake during Early Growth among Rice Cultivars under Different Soil Moisture Regimes

2013 ◽  
Vol 16 (3) ◽  
pp. 238-246 ◽  
Author(s):  
Maya Matsunami ◽  
Toshinori Matsunami ◽  
Kazuhiro Kon ◽  
Atsushi Ogawa ◽  
Ikuko Kodama ◽  
...  
2021 ◽  
Author(s):  
Daniel McKay Flecher ◽  
Siul Ruiz ◽  
Tiago Dias ◽  
Katherine Williams ◽  
Chiara Petroselli ◽  
...  

<p>Half of the nitrogen applied to arable-fields is lost through several processes linked to soil moisture. Low soil moisture limits nitrogen mobility reducing nitrogen-uptake while wetter conditions can increase nitrogen leaching. Rainfall ultimately governs soil moisture and the fate of nitrogen in soil. However, the interaction between rainfall and nitrogen use efficiency (NUE) remains poorly understood.</p> <p>We developed a field-scale modelling platform that describes coupled water and nitrogen transport, root growth and uptake, rainfall, the nitrogen-cycle and leaching to assess the NUE of split fertilisations with realistic rainfall patterns. The model was solved for every possible split fertilisation timing in 200+ growing seasons to determine optimal timings. Two previous field trials regarding rainfall and NUE had contrasting results: wetter years have enhanced fertiliser loss and drier years reduced plant nitrogen uptake. By choosing appropriate fertilisation timings in the model we could recreate the two contrasting trends and maintain variability in the data. However, we found by choosing other fertilisation timings we could mitigate the leaching in wetter years. Optimised timings could increase plant nitrogen uptake by up to 35% compared to the mean in dry years. Plant uptake was greatest under drier conditions due to mitigated leaching, but less likely to occur due to low nitrogen mobility. Optimal fertilisation timings varied dramatically depending on the rainfall patterns. Historic and projected rainfall patterns from 1950-2069 were used in the model. We found optimal NUE has a decrease from 2022-2040 due to increased heavy rainfall events and optimal fertilisation timings are later in the season but varied largely on a season-to-season basis.</p> <p>The results are a step towards achieving improved nitrogen efficiency in agriculture by using the ‘at the right time’ agronomic-strategy in the ‘4Rs’ of improved nitrogen fertilisation. Our results can help determine nitrogen fertilisation timings in changing climates.</p>


2017 ◽  
Vol 9 (12) ◽  
pp. 241 ◽  
Author(s):  
Casinga Mubasi Clérisse ◽  
Neema Ciza Angélique ◽  
Kajibwami Cikuru Marie-Angélique ◽  
Nabahungu Nshwarasi Leon ◽  
Mambani Banda Pierre

This study investigated the influence of three soil moisture irrigation regimes on concentration of seed iron and zinc content of four biofortified bean varieties promoted for eradication of malnutrition in Sud-Kivu highlands. A field experiment was conducted in the Hogola marsh highlands during two cultural seasons B2013 and B2014. The experiment design was a RCBD with a split plot arrangement where the main plots were 110 m2 and split plots 20 m2. A strategic application of homogenisation of the experimental site’s soil fertility by chemical fertilizers of the type: CaCO3, KCl and DAP was conducted out. Four biofortified varieties (CODMLB001, RWR2245, HM21-7 and RWK10) constituted main factor, while water regimes respectively [bottom of the slope: R1 = 48% soil moisture, at the middle of the slope R2 = 37% soil moisture and at the top of the slope: R3 = 29% soil moisture according to the gradient of humidity] represented secondary factor and seasonality, tertiary factor. The study showed that the concentrations of iron and zinc were highly correlated with soil moisture regimes. The variety HM21-7 demonstrated better adaptability because it showed a low rate of reduction of iron and zinc concentration under the three soil moisture regimes and was therefore best suited to fight malnutrition in the Sud-Kivu province.


2017 ◽  
Vol 9 (3) ◽  
pp. 1465-1468 ◽  
Author(s):  
Naveen Kumar ◽  
Suresh Kumar ◽  
Parveen Kumar ◽  
Meena Sewhag

A field experiment was conducted during rabi season 2011-2012 at Research Farm, CCS Haryana Agri-cultural University, Hisar, Haryana (India) to study the periodic soil moisture depletion and ground water use by bed planted barley as influenced by cultivars, crop geometry and moisture regimes under shallow water table conditions. The experiment was laid out in split plot design with three replications keeping combinations of three cultivars viz., BH 393, BH 902 and BH 885 and two crop geometries viz 2 rows per bed and 3 rows per bed (70 cm wide with 40 cm top and 30 cm furrow) in main plots and three moisture regimes (irrigation at IW/CPE 0.3, 0.4 & 0.5) in sub plots. The results revealed that maximum soil moisture depletion (105 mm) and ground water contribution (62 mm) were recorded in BH 902, followed by BH 393 and BH 885. Among crop geometries, soil moisture depletion (96.6 mm) and ground water contribution (61 mm) were recorded higher in 3 rows per bed than 2 rows per bed. Among three moisture regimes, the soil moisture depletion (108 mm) and ground water contribution (65 mm) decreased with increase in moisture regime from irrigation at IW/CPE 0.3 to irrigation at IW/CPE 0.4 or 0.5.


2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Eric B. Kouam ◽  
Simon M. Ndo ◽  
Marie S. Mandou ◽  
Asafor H. Chotangui ◽  
Christopher M. Tankou

AbstractThis study was carried out to determine effects of salinity on germination and seedling development of commercially important common bean genotypes in Cameroon. The seeds of eight genotypes were used for both trials. The germination experiments were carried out on petri dishes in the laboratory while early growth trials continued in plastic pots in the screenhouse. Both stages were setup using a randomized complete block design with three replications. Germination and early growth trials of the different genotypes were studied using distilled water as control or osmotic potentials of 50, 100, 150 and 200mM NaCl to study the effects of salinity on germination and seedling growth characteristics. Leaf concentrations of Na+ and K+ were determined. At the germination level, germination percentage, germination index and the coefficient of velocity of germination decreased with increasing salinity while the mean germination time and time to 50% germination increased with increasing level of salt. All the growth variables decreased with increasing salinity with the exception of the root length which was not affected by salinity. It was observed that increasing salinity induced a significant increase in leaf Na+ and substantial reduction in the accumulation of K+ in the leaves. For ions accumulation, germination variables and growth parameters, significant differences at 0.001 probability levels were found among salinity treatments, common bean genotypes and most of their interactions. Significant correlations were found between all germination variables and between most growth parameters. From the effect of salt application, the common bean genotypes namely KEBCB049, KEB-CB053 and Mac-33 were the most tolerant while KEB-CB055 and KEB-CB050 were the most sensitive. The results confirm that there is genotypic variation in salinity tolerance and that the most tolerant genotypes should be further explored in selection programs, with the aim that they should be promoted for cultivation in tropical zones affected by salinity.


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