Mineral nitrogen dynamics in a fallow grey clay

1991 ◽  
Vol 31 (2) ◽  
pp. 237 ◽  
Author(s):  
IJ Rochester ◽  
GA Constable ◽  
DA MacLeod
Keyword(s):  
Soil Water ◽  
Crop Residues ◽  
Water Status ◽  
Laboratory Data ◽  
Temperature Cycle ◽  
Late Winter ◽  
Soil Nitrate ◽  
Nitrate Accumulation ◽  
Nitrate N ◽  
Short Period

An annual cyclic pattern of nitrate accumulation and dissipation was identified in a fallow grey clay. The pattern was regular during the 3 years studied, with maximum values of nitrate nitrogen (N) (to 34 mg nitrate-N/kg) occurring in late autumn (May) and minimal values (to 7 mg nitrate-N/kg) in late winter (August). Ammonium levels were low throughout the 3 years, except for a short period following the incorporation of crop residues. The cycle of soil nitrate lagged behind the annual temperature cycle by about 3 months. Multiple regression using temperature and soil water deficit explained 68% of the variation in nitrate-N. The identification of this pattern of soil nitrate may now enable the prediction of September soil nitrate (currently used to estimate N fertiliser requirement for the forthcoming crop) from soil sampled up to 3 months earlier. Laboratory incubation studies confirmed temperature and soil water as highly significant in determining the soil's mineral N status. By applying the temperature and soil water deficits which prevailed during the field observations to the regression equation derived from the laboratory data, a similar fluctuating pattern of soil nitrate emerged. Incubation of intact field cores under low temperatures produced a net N immobilisation and high temperatures produced a net N mineralisation. Immobilisation and remineralisation of N by the soil biomass (rather than leaching or denitrification) were responsible for the oscillations in nitrate-N, and these processes were largely driven by temperature and soil water status.

scholarly journals Sensitivity analysis and parameterization of two agricultural models in cauliflower crops

2020 ◽  
Vol 17 (4) ◽  
pp. e1106
Author(s):  
Antonio Lidón ◽  
Damián Ginestar ◽  
Sofía Carlos ◽  
Carlos Sánchez de Oleo ◽  
Claudia Jaramillo ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Crop Residues ◽  
Field Capacity ◽  
Nitrate Content ◽  
Model Parameters ◽  
Soil Nitrate ◽  
Horticultural Crops ◽  
Influencing Parameters

Aim of study: The development of a procedure to calibrate the LEACHM and EU-Rotate_N models for simulating water and nitrogen dynamics in cauliflower crops.Area of study: Calibration was performed using experimental data obtained from measurements in a cauliflower crop sited in Valencia (Spain) region.Material and methods: A procedure based on generalized sensitivity indices for time-dependent outputs was used to determine the most influencing model parameters, in order to reduce the number of parameters to be calibrated and to avoid overparameterization. The most influencing parameters were introduced in an optimization process that uses the experimental measurements of soil water and nitrate content to determine its optimal value and obtain calibrated models.Main results: After this analysis, the most important hydraulic parameters found were the coefficients of Campbell’s equation for the LEACHM model and the soil water content at field capacity and drainage coefficient for the EU-Rotate_N model. For the N cycle, the most influencing parameters were those related with the nitrification, humus mineralization rate and residue decomposition for both models. Both calibrated models provided good simulation of soil water content with an error between 5-7%. However, larger errors in soil-nitrate content simulation were found, mainly in the period corresponding to the crop residues incorporation. The prediction of the calibrated models in a different plot gave error values of about 7-9% for soil water content, but for soil nitrate content errors computed were 34% and 58%.Research highlights: After calibration, both models can be used to optimize the farmer water management and fertilization practices in horticultural crops, although in the N case further studies should be performed.

Impact of biochar on nitrate accumulation in an alkaline soil

Soil Research ◽  
2013 ◽  
Vol 51 (6) ◽  
pp. 521 ◽  
Author(s):  
Qing-Zhong Zhang ◽  
Xia-Hui Wang ◽  
Zhang-Liu Du ◽  
Xin-Ren Liu ◽  
Yi-Ding Wang
Keyword(s):  
Grain Yield ◽  
Soil Water ◽  
Soil Depth ◽  
Soil Layer ◽  
Soil Nitrate ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Nitrate Accumulation ◽  
Nitrate Retention ◽  
Significant Difference

The effects of biochar on alkaline soils in high-yielding agricultural fields remain poorly understood. Nitrate variation in soils due to biochar application without a change in soil pH, is a great concern relating to both crop yield and nitrate leaching. In this study, we monitored changes in dynamics of soil nitrate accumulation and effects on grain yield due to biochar application in a temperate, high-yielding region. Biochar derived from corncob was applied to an alkaline soil at biochar rates (kg ha–1) of 0 (CK), 2250 (C1), and 4500 (C2) for each of two crop seasons in 2007. A treatment with 750 kg biochar-based fertiliser ha–1 (CN) for each of two crop seasons was also included. Biochar had no significant effect on soil water content to 1 m soil depth. Biochar tended to increase the soil cation exchange capacity (CEC) in the 0–20 cm soil layer and nitrate retention to 1 m soil profile, but there was no significant difference between biochar treatments and CK. Grain yield of C1, C2, and CN was improved by 10.3%, 16.9%, and 15.5% compared with CK, respectively, but only C2 was significantly different from CK. Grain yields of winter wheat with biochar application showed a trend similar to soil CEC and average soil-nitrate retention, suggesting that the increases in grain yield were mainly attributable to improvements in soil CEC and soil nitrate retention due to biochar application in the alkaline soil. In conclusion, the effects of biochar on soil water retention, soil nitrate retention, and grain yield were very limited in alkaline soil in a high-yielding region.

CHANGES IN SOIL WATER REGIME AFTER PIPELINE CONSTRUCTION IN SOLONETZIC MIXED PRAIRIE RANGELAND

1988 ◽  
Vol 68 (3) ◽  
pp. 603-610 ◽  
Author(s):  
M. A. NAETH ◽  
A. W. BAILEY ◽  
D. S. CHANASYK ◽  
W. B. McGILL ◽  
R. T. HARDIN
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Water Status ◽  
Pipeline Construction ◽  
Natural Gas Pipelines ◽  
Neutron Probe ◽  
Short Period ◽  
Southern Alberta ◽  
Construction Activity ◽  
Mixed Prairie

A study was conducted in the Solonetzic mixed prairie rangeland of southern Alberta to evaluate soil water responses to pipeline construction. Five adjacent natural gas pipelines on a series of rights-of-way (ROW) were studied at three sites. The pipelines were installed in 1957, 1963, 1968, 1972 and 1981. Soil water contents were monitored throughout the year using a neutron probe. Water-holding capacity of the soil was determined using the pressure-plate extraction method. Pipeline construction in Solonetzic mixed prairie ecosystems caused total soil water to a depth of 50 cm in the trench to increase over that in the undisturbed prairie. There were no significant effects on available water capacity. Berm construction over the trench impeded overland flow, particularly during springmelt, causing short periods of ponding. Construction activity had no significant effect on total water within zones of a given ROW. Soil water status was affected for a short period of time with a trend towards predisturbance conditions within 10 yr. Key words: Pipelines, Solonetzic soils, rangeland, reclamation, soil water

scholarly journals Root Response to Soil Water Status via Interaction of Crop Genotype and Environment

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 708
Author(s):  
Phanthasin Khanthavong ◽  
Shin Yabuta ◽  
Hidetoshi Asai ◽  
Md. Amzad Hossain ◽  
Isao Akagi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Root Distribution ◽  
Water Status ◽  
Soil Layer ◽  
Shoot Biomass ◽  
Soil Conditions ◽  
Crop Adaptation ◽  
Soil Moisture Status ◽  
Root Distributions

Flooding and drought are major causes of reductions in crop productivity. Root distribution indicates crop adaptation to water stress. Therefore, we aimed to identify crop roots response based on root distribution under various soil conditions. The root distribution of four crops—maize, millet, sorghum, and rice—was evaluated under continuous soil waterlogging (CSW), moderate soil moisture (MSM), and gradual soil drying (GSD) conditions. Roots extended largely to the shallow soil layer in CSW and grew longer to the deeper soil layer in GSD in maize and sorghum. GSD tended to promote the root and shoot biomass across soil moisture status regardless of the crop species. The change of specific root density in rice and millet was small compared with maize and sorghum between different soil moisture statuses. Crop response in shoot and root biomass to various soil moisture status was highest in maize and lowest in rice among the tested crops as per the regression coefficient. Thus, we describe different root distributions associated with crop plasticity, which signify root spread changes, depending on soil water conditions in different crop genotypes as well as root distributions that vary depending on crop adaptation from anaerobic to aerobic conditions.

Fallow management, soil water, plant-available soil nitrogen and grain sorghum production in south west Queensland

1992 ◽  
Vol 32 (4) ◽  
pp. 473 ◽  
Author(s):  
G Gibson ◽  
BJ Radford ◽  
RGH Nielsen
Keyword(s):  
Soil Water ◽  
Nitrate Nitrogen ◽  
Soil Nitrate ◽  
Zero Tillage ◽  
Fallow Management ◽  
South West ◽  
Primary Tillage ◽  
Grain Nitrogen ◽  
Texture Contrast ◽  
Gypsum Application

The effects of tillage frequency (conventional, reduced and zero), primary tillage implement (disc, blade and chisel plough), stubble management (retention and removal), gypsum application, and paraplowing were examined with respect to soil water storage, soil nitrate accumulation, crop establishment, crop growth, grain yield and grain nitrogen content for 4 successive sorghum crops on a sodic, texture-contrast soil in south west Queensland. Retention of sorghum stubble (v. removal) produced an increase in mean yield of sorghum grain of 393 kg/ha, due to increased soil water extraction and increased water use efficiency by the following crop. The highest mean yield occurred after reduced blade tillage with stubble retained. Zero tillage with stubble removed gave the lowest mean grain yield. Zero tillage always had the lowest quantity of soil nitrate-nitrogen at sowing. In one fallow, increased aggressiveness of primary tillage (disc v. blade plough) increased the quantity of nitrate-nitrogen in the top 60 cm of soil at sowing. These effects on available soil nitrogen did not result in corresponding differences in grain nitrogen content. Results indicate that for optimum fallow management on this texture-contrast soil in south west Queensland, sorghum residues should be retained, tillage frequency should be reduced, but not to zero, blade ploughing should be preferred to discing, and gypsum application should not be practised.

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