Studies on some deep sandy soils in Cape York Peninsula, North Queensland. 2. Plant nutrient status

1973 ◽  
Vol 13 (60) ◽  
pp. 89 ◽  
Author(s):  
RK Jones

The nutrient status of the deep siliceous sands which cover an extensive area in Cape York Peninsula has been studied in glasshouse and field experiments. Using Townsville stylo (Stylosanthes humilis) as a test legume, the soils were found to be extremely deficient in P and S, and moderately so in Zn, Cu, and K. Responses to Mo were found on most of the eight soils tested in the glasshouse but these were not confirmed at the field site in either of the two growing seasons. There was little response to Ca (lime) in spite of the very low levels of total and exchangeable Ca in these soils. Suggested reasons for this are the known tolerance of tropical legumes to low Ca supply and the fact that exchangeable Ca, although low, represented a fairly high percentage of the total exchange capacity. Levels of total N in these soils were also very low and the native grasses were able to absorb only 15 kg N ha-1 in an entire growing season. Two samples of rock phosphate (from north-western Queensland and Christmas Island) were found to be very poor alternatives to superphosphate, at least in the first season. In spite of the extreme infertility of these soils, very high levels of pasture production (> 10,000 kg of Townsville sty10 ha-1) could be achieved in well-fertilized pastures.


Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 752
Author(s):  
Aliasghar Montazar ◽  
Daniel Geisseler ◽  
Michael Cahn

Nitrogen (N) and irrigation water must be effectively used in mineral soils to produce carrots with high yield and minimal environmental impact. This study attempts to identify optimal N and irrigation management practices for low desert carrot production in California by investigating consumptive water use and N uptake and removal rates in fresh market and processing carrots. Field experiments were conducted at the University of California Desert Research and Extension Center and nine farmer fields during two growing seasons. The actual evapotranspiration (ETa) was measured using the residual energy balance method with a combination of surface renewal and eddy covariance equipment. Crop canopy coverage, actual soil nitrate-N from multiple depths as well as total N percentage, dry matter, and fresh biomass in roots and tops were measured over the growing seasons. The length of the crop season had a wide range amongst the experimental sites: from a 128-day period in a processing carrot field to as long as 193 days in a fresh market carrot field. The seasonal ETa varied between 305.8 mm at a silty loam furrow irrigated processing carrot field and 486.2 mm at a sandy clay loam sprinkler irrigated fresh market field. The total N accumulated at harvest ranged between 205.4 kg ha−1 (nearly 52% in roots) and 350.5 kg ha−1 (nearly 64% in roots). While the mean value of nitrogen removed by carrot roots varied from 1.24 to 1.73 kg N/Mg carrot roots, it appears that more N was applied than was removed by carrot roots at all sites. Within the range of N application rates examined at the experimental sites, there was no significant relationship between carrot fresh root yield and N application rate, although the results suggested a positive effect of N application on carrot yield. Sufficient soil N availability over the growing season and the lack of significant yield response to N application illuminated that optimal N rates are likely less than the total amounts of N applied at most sites.



2004 ◽  
Vol 34 (3) ◽  
pp. 560-572 ◽  
Author(s):  
Nicolas Bélanger ◽  
David Paré ◽  
Mireille Bouchard ◽  
Gaëtan Daoust

The renewed interest in the use of fast-growing tree species is accompanied by concerns about the adverse effects that these trees may have on soil. Four Norway spruce (Picea abies (L.) Karst.) provenance trials in Quebec were used to test the hypothesis that a more vigorous growth would not occur at the expense of marginalizing available nutrient pools. On these sites, the provenance showing the greatest overall productivity (high treatment) and the one showing the lowest productivity (low treatment) were studied. The divergence in total aboveground nutrient contents between the high and low treatments was high in all sites (i.e., 161%–209%). Increased nutrient immobilization in trees did not cause any significant soil depletion of available base cations or total N at any site. Moreover, exchangeable Ca concentrations, cation-exchange capacity, and exchangeable Ca pools in the forest floor were significantly higher in the high treatment. It is concluded that in the short term, increased nutrient immobilization in trees does not create an apparent depletion of available base cations, perhaps because of a stimulation of soil mineral weathering and (or) a better retention of nutrients by the trees. Also, an effort to simulate mineral weathering using PROFILE showed the need for model improvement for applications at the plot level.



2020 ◽  
Vol 8 (1) ◽  
pp. 105-114
Author(s):  
Kelvin Harrison Diri ◽  
Tate Oyinbrakemi Joseph

Fertility status of soils within the south-south region of Nigeria varies both inter and intra states. Therefore, the study investigated the macronutrient status of some selected soils in Bayelsa State. Two farm sites in Opume (OPF) and Amassoma (AMF) with records of long term cultivation were randomly selected and soil samples randomly collected from each locality for physico-chemical analyses. Data collected were subjected to statistical analysis of means and a post hoc regression analysis to determine relationships between soils and analyzed parameters. Results revealed that soils were loam to sandy clay loam and acidic with low pH levels. Exchangeable bases (Ca2+, Mg2+, K+) were low in AMF soils compared to OPF soils except for Na+. Organic carbon and organic matter were moderately low in both soils, however, AMF had lower contents. Total N were found to be critically low (0.03%) in both soils. OPF had higher available phosphorus (5.09 mg/kg) while AMF had higher available sulphur (6.55 mg/kg). Base saturation was high moderate in OPF (50.44 %), however, not significantly different (p<0.05) from AMF. Similarly, Effective Cation Exchange Capacity (ECEC) was low in soils of both localities. Regression analysis showed that pH had significant positive relationships with sand, Org C, Org M, available P, TN, % B.S and the basic cations (r=0.534*, 0.841***, 0.837***, 0.855***, 0.736***, 0.856**) with a negative relationship with Exchangeable acidity and SO42- (r=-0.799** and 0.844***). Org C, Org M and TN had significant negative relationships with silt at both localities (r=-0.592**, -0.592** and -0.491*) respectively. These results indicate clearly that the nutrient status of soils in the study areas are mostly controlled by pH and the textural distribution. It also indicates that improved soil management practices can improve the macronutrient status for increased crop production.



2018 ◽  
Vol 7 (2) ◽  
pp. 79-88
Author(s):  
MK Huda ◽  
MAM Chowdhury

Soil: Plant nutrient status in naturally regenerated garjan (Dipterocarpus turbinatus Gaertn.) seedlings of 3, 9, 15, 21, 27 and 33 months old were studied in twelve stands of three sites on late and early monsoon during 1994 to 1995 in Dulahazara garjan forest of Cox’s Bazar forest division. Soil samples were collected from two profiles (i.e. top soil and sub soil) of twelve stands in three sites. Soil moisture content, pH, texture, electrical conductivity, cation exchange capacity, organic carbon, total N and available P, K, Ca, Mg, Mn and Fe were determined. Soils were found to be silty loam to sandy loam with an average pH of 5.06. The average values of organic carbon and cation exchange capacity were 0.74% and 6.23 meq/100g respectively. The soils were poor in total nitrogen (689 μg g-1) and the average values of available mineral nutrients such as P, K, Ca, Mg, Mn and Fe in soil were 3.15, 53, 40, 47, 36 and 0.94 μg g-1, respectively. The soil in site -S2 appeared to be more fertile than those of site-S1 and site-S3. The average values of N, P, K, Ca, Mg, Mn and Fe in leaf- bud were found to be 1.80, 0.13, 0.94, 0.72, 0.23, 0.06 and 0.014% respectively. Leaf-bud nutrients showed a marked variation both with seasons as well as ages. Leaf-bud of late monsoon contained higher concentrations of P, Mg and Ca compared to leaf-bud of early monsoon which contained higher concentrations of N, K and Fe. Nutrient cycling in soil:leafbud system of regenerated garjan seedling of 3-33 months old varied with seasons and ages. The present study reveals that concentrations of Mn were significantly correlated between leaf-bud and soil whereas P showed the negative correlation indicating that in spite of low quantity of P in the soil, leaf bud had higher quantity. Jahangirnagar University J. Biol. Sci. 7(2): 79-88, 2018 (December)



1987 ◽  
Vol 27 (6) ◽  
pp. 863 ◽  
Author(s):  
MA Gilbert ◽  
KA Shaw

The nutrient status and fertiliser requirements of a red earth soil (Gn 2.14) were examined in glasshouse and field experiments in northern Queensland. From soil analyses and glasshouse experiments, deficiencies of phosphorus, potassium, sulfur and zinc were expected. However, the only nutrients limiting growth of Stylosanthes scabra cv. Seca pastures under field conditions were phosphorus and sulfur. In the first 2 years of the field experiments, applications of 20 kg/ha of phosphorus and sulfur (equivalent to 220 kg/ha of single superphosphate) gave near maximum response in DM yield of Seca. Fine elemental sulfur was as effective as gypsum as a sulfur source.



2013 ◽  
Vol 93 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Yaohong Zhang ◽  
Renying Li ◽  
Yanling Wang

Zhang, Y., Li, R. and Wang, Y. 2013. Night-time warming affects N and P dynamics and productivity of winter wheat plants. Can. J. Plant Sci. 93: 397–406. The daily night-time temperature has currently increased faster than the daily daytime temperature over much of the Earth's surface. To understand how night-time warming affects the dynamics of winter wheat performance, open-field experiments, in which temperatures were elevated by covering the plots at night with reflective curtains, were conducted in the 2010/2011 and 2011/2012 growing seasons. The results show that, on average, night-time temperatures increased by 0.9°C under night-time covered (NC) treatment compared with the uncovered (CK). Plant total N accumulation was 17–43% higher in NC treatment than CK during the jointing, anthesis and ripening stages, whereas plant total P was affected by NC treatment depending on growing stage. Night-time covered treatment substantially decreased N translocation efficiency, leading to more N retained in plant stems during grain filling. Although P translocated to grain was 29–41% higher in NC plots than CK plots, NC treatment decreased post-anthesis P uptake by 27–41%, depending on the growing season, resulting in evident reduction of P harvest index and P utilization efficiency. When night-time temperature increased, grain yield was reduced by 6–25% due to a combination of decreased productive spikes, a lower number of kernels per spike and reduced weight of grain per kernel.



2001 ◽  
Vol 60 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Lucia Savadori ◽  
Eraldo Nicotra ◽  
Rino Rumiati ◽  
Roberto Tamborini

The content and structure of mental representation of economic crises were studied and the flexibility of the structure in different social contexts was tested. Italian and Swiss samples (Total N = 98) were compared with respect to their judgments as to how a series of concrete examples of events representing abstract indicators were relevant symptoms of economic crisis. Mental representations were derived using a cluster procedure. Results showed that the relevance of the indicators varied as a function of national context. The growth of unemployment was judged to be by far the most important symptom of an economic crisis but the Swiss sample judged bankruptcies as more symptomatic than Italians who considered inflation, raw material prices and external accounts to be more relevant. A different clustering structure was found for the two samples: the locations of unemployment and gross domestic production indicators were the main differences in representations.



Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.



AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zuren Li ◽  
Jincai Han ◽  
Haodong Bai ◽  
Di Peng ◽  
Lifeng Wang ◽  
...  

AbstractApplication of a novel bioorganic fertilizer (BIO) has been effectively used to inhibit weeds in rice paddies. To identify changes in soil bacterial community and enzymes in response to BIO treatments, field experiments were carried out in five major rice-growing areas in China. The dominant phylogenetic groups recorded included Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria. Anaeromyxobacter, Bacteroides, Bifidobacterium, Escherichia- Shigella, Geobacter and Haliangium were significantly different between BIO-treatment and untreated control and aided in general function (R), amino acid transport, metabolism (E) and transcription (K) clusters. The soil chemical properties and enzyme activities were less affected by BIO at these study sites. RDA analysis showed that soil bacterial community had a significant positive correlations among northern latitude, eastern longitude, exchangeable K, total K, total P, soil pH, and total N, except for organic matter, hydrolytic N and extractable P. Overall, our work showed that application of BIO does not alter the main community structure and functional diversity of soil bacteria in rice paddies and should be encouraged for use as a sustainable weed management strategy.



Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.



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