scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland .VIII. Available nitrogen indexes and their relationships to crop yield and N uptake

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 563 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer

Six major soil series of southern Queensland were studied for the changes in the levels of available N indices (determined by both biological and chemical methods) and nitrate-N, with continuous cultivation and cereal cropping for up to 70 years. The biological N indices, measured in soil collected at planting of winter cereals, were anaerobic mineralizable N, aerobic mineralizable N and nitrate-N down to 1.2 m depth. The chemical indices were autoclave N and oven N. The predictive capabilities of various available N indices, and total N and organic C, were assessed from dry matter and N uptake of winter cereals in the field in 1983 as well as in the glasshouse. Anaerobic mineralizable N levels increased with mean annual rainfall but decreased with mean annual temperatures of the sampling sites of the six soil series. Therefore, it was possible to predict closely anaerobic mineralizable N from soil total N, and mean annual rainfall and temperature. Autoclave N showed no such trends. Anaerobic mineralizable N declined with period of cultivation, exponentially in Waco, Langlands-Logie and Cecilvale soils (0.112, 0.111 and 0.247 year-1, respectively) and linearly in the other three soil series. No consistent trends were discerned in autoclave N and oven N in four of the soil series with period of cultivation. Generally, nitrate-N (measured at planting) declined with period of cultivation. However, in Billa Billa soil, it increased in the soil profile (0-1.2 m) during the initial 7 years of cultivation and declined rapidly after 12 years. Although a number of available N indices, including total N and organic C, were significantly correlated with crop dry matter yield and N uptake, the best prediction of crop performance was provided by a combination of anaerobic mineralizable N (0-0.3 m) and nitrate-N (0-0 6 m) in the six soil series.

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 265 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer

Changes in fertility of some southern Queensland soils resulting from extended periods of cultivation are presented, together with trends in yields of winter cereals on these soils. Six major soils of the cereal-belt, cropped for maximum periods of 20-70 years were examined. These were: Black earths, Waco soil; grey, brown and red clays (brigalow), Langlands-Logie soil; grey, brown and red clays (poplar box), Cecilvale soil; grey, brown and red clays (belah), Billa Billa soil; grey, brown and red clays (coolibah), Thallon soil; red earths, Riverview soil. Organic matter and its constituents, especially total organic C, organic C in the light fraction, total N and mineralizable N, were affected most by cultivation, showing decreases of 19-67% overall. Other soil properties probably associated with organic matter, including bulk density and DTPA (diethylenetriaminepentaacetic acid) extractable manganese, were also significantly affected by cultivation in all soils. Soil properties affected least by cultivation were concentrations of inorganic phosphorus, total and exchangeable potassium, calcium carbonate, and dithionite extractable iron and aluminium. Most other soil properties studied (organic P, total sulfur, pH, exchangeable magnesium and sodium, exchangeable sodium percentage, and oxalate-extractable iron and aluminium) were affected by cultivation in at least four soils. Four factors accounted for 70% of the total variation among the 45 soil properties considered. They appeared to represent organic matter, clay colloids, iron and aluminium oxides, and soluble salts. Dry matter yield and/or N uptake of winter cereal crops (wheat and barley) measured in 1983 showed significant decreasing trends with period of cultivation in all soils.


Soil Research ◽  
1987 ◽  
Vol 25 (4) ◽  
pp. 461 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer

The dynamics of nitrogen mineralization potential (N0) and mineralization rate constant (k) were studied in six major soils which had been used for cereal cropping for up to 20-70 years. In the top 0.1 m layer of virgin soils, N0 varied from 110 � 22 mg kg-1 soil (Riverview) to 217 � 55 mg kg-1 soil (Langlands-Logie), representing about 13% and 11%, respectively, of total N in these soils. Upon cultivation and cropping, N0 declined by 1 7 � 0.5 mg kg-1 yr-1 (Riverview) to 4.8 � 2.0 mg kg -1 yr -1 (Billa Billa). This represented < 20% of total N lost annually from the top layer (0-0.1 m depth) of these soils. The k values varied less than the N0 values, both within and among soils, and were also less affected by cultivation than N0. The mineralizable N in cultivated soil during cropping for periods up to 70 years can be estimated from N0 and k values, taking No as 5% of total N for soils of <40% clay and 15% of total N for soils of >40% clay and k as 0.066 week-1 at 40�C (0.027 week-1 and 0.054 week-1 at 25�C and 35�C, respectively). Organic C and N contained in the 'stabilized' microbial biomass (determined after 30 weeks' pre-incubation) accounted for 1.7-38% of total organic C and 2.0-5.1% of total N in the six soils studied. The microbial biomass C and N declined with cultivation in most soils, biomass N representing 10-23% of the total annual loss of N0. The microbial biomass, urease activity and total N, in addition to a number of other soil properties [e.g. light-fraction (<2 Mg m-3) C, sand-size C, CEC and ESP], were significantly correlated with N0 and k, thus indicating the existence of a myriad of environments for the activity, association and stability of microbial biomass and potentially mineralizable N in soil.


1973 ◽  
Vol 9 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M. J. Jones

SUMMARYMaize was grown for three years at three levels of nitrogen, 56, 112 and 224 kg. N ha.−1, involving altogether nine different timing and splitting treatments. Measurements were made of grain yield, plant nitrogen status and total-N-uptake, and, in one year, movement of nitrate-N in control plot soils. Where only 56 kg. N ha.−1was applied, its time of application made very little difference to yield; at higher rates of nitrogen an unsplit application as late as seven weeks was very inefficient, but only at the highest rate did a split application give any appreciable yield increase over an unsplit application to the seed bed. Consideration of the soil nitrate-N data and the long-term pattern of rainfall distribution leads to the conclusion that leaching is unlikely to be a serious problem in the nitrogen nutrition of early-planted maize.


Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 281 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer

The kinetics of organic C loss were studied in six southern Queensland soils subjected to different periods (0-70 years) of cultivation and cereal cropping. The equation: Ct = Ce + (C0 - Ce)exp(- kt), where C0, Ce and C, are organic C contents initially, at equilibrium and at time k respectively, and k is the rate of loss of organic C from soil, was employed in the study. The parameter k was calculated both for %C (kc) and for weight of organic C/volume of soil (k,), determined by correcting for differences in sampling depth due to changes in bulk density upon cultivation. Mean annual rainfall largely determined both C, and Ce, presumably by influencing the amount of dry matter produced. Values of kc and kw varied greatly among the soils studied. For the 0-0.1 m depth, kw was 0.065, 0.080, 0.180, 0.259, 0.069 and 1.224 year-1 respectively for Waco (black earth - initially grassland), Langland-Logie (grey brown and red clays - brigalow), Cecilvale (grey, brown and red clays - poplar box), Billa Billa (grey, brown and red clays - belah), Thallon (grey, brown and red clays - coolibah) and Riverview (red earths - silver-leaved ironbark). The k values were significantly correlated with organic Chrease activity ratio (r = 0.99***) and reciprocal of clay content (r = 0.97**) of the virgin soils. In stepwise multiple regression analysis, aggregation index (for kc values) or exchangeable sodium percentage (for kw) and organic C/urease activity ratio of soils were significantly associated with the overall rate of loss of organic C. It was inferred, therefore, that the relative inaccessibility and protection of organic matter against microbial and enzymic attack resulted in reduced organic C loss. Losses of organic C from the deeper layers (0-0.2 m, 0-0.3 m) were observed in Waco, Langlands-Logie, Cecilvale and Riverview soils, although generally rate of loss decreased with depth.


1993 ◽  
Vol 73 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Régis R. Simard ◽  
Adrien N'dayegamiye

An understanding of the mineralization factors in contrasting cultivated soils is necessary for accurate predictions of plant-available N. The objective of this work was to determine the N-mineralization potential and mathematical models that can properly describe the dynamics of the mineralization process in 20 meadow soils from Quebec. The mineralization was monitored over 55.4 wk in a laboratory incubation at 20 °C with intermittent leaching. The cumulative mineralization curves in most soils were characterized by definite lags or a sigmoidal pattern and near-linear release with time after 20 wk. The data were best described by the Gompertz equation; first-order models were inadequate. The total amount of mineralizable N and the potential mineralization rate were very closely correlated with the total amounts of C or N (r > 0.73; P < 0.01). The clay content was also correlated with these mineralization parameters and significantly improved the prediction of the cumulative and potential N-mineralization rate estimated from the total N or C content of soils. The relationships with other soil characteristics such as soil pH and available nutrient contents were weak but significant. The results of this study suggest that textural classes be added in the correction for organic matter content to improve the precision in N-fertilizer recommendation and in soil-quality classifications based on potential mineralization rate. Key words: Soil quality, potentially mineralizable N, Gompertz equation, soil organic matter, soil texture, C, N


2008 ◽  
Vol 23 (03) ◽  
pp. 250-259 ◽  
Author(s):  
Derek H. Lynch ◽  
Zhiming Zheng ◽  
Bernie J. Zebarth ◽  
Ralph C. Martin

AbstractThe market for certified organic potatoes in Canada is growing rapidly, but the productivity and dynamics of soil N under commercial organic potato systems remain largely unknown. This study examined, at two sites in Atlantic Canada (Winslow, PEI, and Brookside, NS), the impacts of organic amendments on Shepody potato yield, quality and soil mineral nitrogen dynamics under organic management. Treatments included a commercial hog manure–sawdust compost (CP) and pelletized poultry manure (NW) applied at 300 and 600 kg total N ha−1, plus an un-amended control (CT). Wireworm damage reduced plant stands at Brookside in 2003 and those results are not presented. Relatively high tuber yields (~30 Mg ha−1) and crop N uptake (112 kg N ha−1) were achieved for un-amended soil in those site-years (Winslow 2003 and 2004) when soil moisture was non-limiting. Compost resulted in higher total yields than CT in one of three site-years. Apparent recovery of N from CP was negligible; therefore CP yield benefits were attributed to factors other than N availability. At Winslow, NW300, but not NW600, significantly increased total and marketable yields by an average of 5.8 and 7.0 Mg ha−1. Plant available N averaged 39 and 33% for NW300 and NW600, respectively. Soil (0–30 cm) NO3−-N at harvest was low (&lt;25 kg N ha−1) for CT and CP, but increased substantially both in season and at harvest (61–141 kg N ha−1) when NW was applied. Most leaching losses of NO3−-N occur between seasons and excessive levels of residual soil NO3-N at harvest, as obtained for NW600, must be avoided. Given current premiums for certified organic potatoes, improving yields through application of amendments supplying moderate rates of N or organic matter appears warranted.


2018 ◽  
pp. 53-70
Author(s):  
Clea Anne Corsiga ◽  
Rodrigo Badayos ◽  
Pearl Sanchez ◽  
Erlinda Paterno ◽  
Pompe Sta. Cruz

Five major soil series (Guimbalaon, Isabela, Luisiana, San Manuel, and Silay) in Negros Occidental were evaluated to assess the suitability of major soil series grown to sugarcane and identify possible constraints of the soils for sugarcane production. Specifically, the study assessed the morphological, physical, and chemical properties of soils associated with the growing of sugarcane; evaluated the land quality requirements for major soil series grown to sugarcane; determined the suitability of major soil series for sugarcane production; and evaluated the possible soil constraints to sugarcane production. Soil pH, total N, percent organic C, and available P were found highest in Isabela series; exchangeable K in Guimbalaon series; exchangeable Na, Ca, and Mg, extractable Fe, and CEC in San Manuel series; and exchangeable Al in Luisiana series. All of the soil series evaluated were classified as marginally suitable (S3) for sugarcane production, although soil constraints varied across soil series. Topography and wetness were the severe constraints common to all soil series. Limitations on fertility and physical soil characteristics were considered moderate and manageable.


2013 ◽  
Vol 59 (No. 6) ◽  
pp. 235-240 ◽  
Author(s):  
Bordoloi LJ ◽  
Singh AK ◽  
Manoj-Kumar ◽  
Patiram ◽  
S. Hazarika

Plant&rsquo;s nitrogen (N) requirement that is not fulfilled by available N in soil has to be supplied externally through chemical fertilizers. A reliable estimate of soil N-supplying capacity (NSC) is therefore essential for efficient fertilizer use. In this study involving a pot experiment with twenty acidic soils varying widely in properties, we evaluated six chemical indices of soil N-availability viz. organic carbon (C<sub>org</sub>), total N (N<sub>tot</sub>), acid and alkaline-KMnO<sub>4</sub> extractable-N, hot KCl extractable-N (KCl-N) and phosphate-borate buffer extractable-N (PBB-N), based on their strength of correlation with available-N values obtained through aerobic incubation (AI-N) and anaerobic incubation (ANI-N), and also with the dry matter yield (DMY), N percentage and plant (maize) N uptake (PNU). In general, the soils showed large variability in NSC as indicated by variability in PNU which ranged from 598 to 1026 mg/pot. Correlations of the N-availability indices with AI-N and ANI-N decreased in the order: PBB-N (r = 0.784** and 0.901**) &gt; KCl-N (r = 0.773** and 0.743**) &gt; acid KMnO<sub>4</sub>-N (r = 0.575** and 0.651**) &ge; C<sub>org</sub> (r = 0.591** and 0.531**) &ge; alkaline KMnO<sub>4</sub>-N (r = 0.394** and 0.548**) &gt; N<sub>tot</sub> (r = 0.297** and 0.273*). Of all the indices evaluated, PBB-N showed the best correlations with plant parameters as well (r = 0.790** and 0.793** for DMY and PNU, respectively). Based on the highest correlations of PBB-N with biological indices as well as plant responses, we propose PBB-N as an appropriate index of N-availability in the acidic soils of India and other regions with similar soils.


1997 ◽  
Vol 48 (5) ◽  
pp. 635 ◽  
Author(s):  
C. J. Birch ◽  
S. Fukai ◽  
I. J. Broad

The effect of nitrogen application on the grain yield and grain protein concentration of barley was studied in 13 field trials covering a wide range of soil N conditions over 4 years at locations in south-eastern Queensland. The main objectives of the study were to quantify the response of barley to N application rate over a range of environmental conditions, and to explain the response in terms of soil mineral N, total N uptake, and N distribution in the plants. Barley made efficient use of N (60 kg grain/kg N) until grain yield reached 90% of maximum yield. Grain protein concentration did not increase to levels unacceptable for malting purposes until grain yield exceeded 85–90% of maximum yield. Nitrogen harvest index was generally high (above 0·75), and did not decrease until the total N supply exceeded that necessary for maximum grain yield. Rates of application of N for malting barley should be determined on the basis of soil analysis (nitrate-N) to 1 m depth and 90% of expected maximum grain yield, assuming that 17 kg N is taken up per tonne of grain produced. It can further be assumed that the crop makes full use of the nitrate N to 1 m present at planting, provided the soil is moist to 1 m. A framework relating grain yield to total N uptake, N harvest index, and grain N concentration is presented. Further, total N uptake of fertilised barley is related to N uptake without fertiliser, fertiliser application rate, and apparent N recovery. The findings reported here will be useful in the development of barley simulation models and decision support packages that can be used to aid N management.


2020 ◽  
Author(s):  
Pauline Sophie Rummel ◽  
Reinhard Well ◽  
Birgit Pfeiffer ◽  
Klaus Dittert ◽  
Sebastian Floßmann ◽  
...  

&lt;p&gt;Growing plants affect soil moisture, mineral N and organic C (C&lt;sub&gt;org&lt;/sub&gt;) availability in soil and may thus play an important role in regulating denitrification. The availability of the main substrates for denitrification (C&lt;sub&gt;org&lt;/sub&gt; and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;) is controlled by root activity and higher denitrification activity in rhizosphere soils has been reported. We hypothesized that (I) plant N uptake governs NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; availability for denitrification leading to increased N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sub&gt;2&lt;/sub&gt; emissions, when plant N uptake is low due to smaller root system or root senescence. (II) Denitrification is stimulated by higher C&lt;sub&gt;org&lt;/sub&gt; availability from root exudation or decaying roots increasing total gaseous N emissions while decreasing their N&lt;sub&gt;2&lt;/sub&gt;O/(N&lt;sub&gt;2&lt;/sub&gt;O+N&lt;sub&gt;2&lt;/sub&gt;) ratios.&lt;/p&gt;&lt;p&gt;We tested these assumptions in a double labeling pot experiment with maize (Zea mays L.) grown under three N fertilization levels S / M / L (no / moderate / high N fertilization) and with cup plant (Silphium perfoliatum L., moderate N fertilization). After 6 weeks, all plants were labeled with 0.1 g N kg&lt;sup&gt;-1&lt;/sup&gt; (Ca(&lt;sup&gt;15&lt;/sup&gt;NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;, 60 at%), and the &lt;sup&gt;15&lt;/sup&gt;N tracer method was applied to estimate plant N uptake, N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sub&gt;2&lt;/sub&gt; emissions. To link denitrification with available C in the rhizosphere, &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; pulse labeling (5 g Na&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;3&lt;/sub&gt;, 99 at%) was used to trace C translocation from shoots to roots and its release by roots into the soil. CO&lt;sub&gt;2&lt;/sub&gt; evolving from soil was trapped in NaOH for &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C analyses, and gas samples were taken for analysis of N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sub&gt;2&lt;/sub&gt; from the headspace above the soil surface every 12 h.&lt;/p&gt;&lt;p&gt;Although pots were irrigated, changing soil moisture through differences in plant water uptake was the main factor controlling daily N&lt;sub&gt;2&lt;/sub&gt;O+N&lt;sub&gt;2&lt;/sub&gt; fluxes, cumulative N emissions, and N&lt;sub&gt;2&lt;/sub&gt;O production pathways. In addition, total N&lt;sub&gt;2&lt;/sub&gt;O+N&lt;sub&gt;2&lt;/sub&gt; emissions were negatively correlated with plant N uptake and positively with soil N concentrations. Recently assimilated C released by roots (&lt;sup&gt;13&lt;/sup&gt;C) was positively correlated with root dry matter, but we could not detect any relationship with cumulative N emissions. We anticipate that higher C&lt;sub&gt;org&lt;/sub&gt; availability in pots with large root systems did not lead to higher denitrification rates as NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; was limited due to plant uptake. In conclusion, plant growth controlled water and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; uptake and, subsequently, formation of anaerobic hotspots for denitrification.&lt;/p&gt;


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