Nitrate and chloride leaching in Vertosols for different tillage and stubble practices in fallow - grain cropping

Soil Research ◽  
1998 ◽  
Vol 36 (1) ◽  
pp. 31 ◽  
Author(s):  
J. E. Turpin ◽  
J. P. Thompson ◽  
S. A. Waring ◽  
J. MacKenzie

Research conducted in the mid 1980s on a ‘long-term fallow management trial’, located on a black Vertosol at the Hermitage Research Station, indicated that leaching may have been the cause of low concentrations of nitrate-N within the root-zone of zero-tillage stubble-retained treatments. The ‘fallow management trial’ has 12 management treatments: a factorial combination of zero or conventional tillage×stubble retention or burning×3 nitrogen fertiliser rates (0, 23, and 69 kg N/ha). To test the leaching hypothesis, all trial treatments were analysed for nitrate and chloride concentrations to a depth of 5·4 m in order to assess the relative rates of drainage, solute movement, and nitrate leaching between treatments. Similar analyses were conducted on 2 cultivated sites and 2 permanently grassed sites on-farm, also on black Vertosols, to compare solute movement rates under the continuous winter cereal rotation (trial site) with a winter–summer cropping regime and permanent pasture. Results from the Hermitage trial site showed zero tillage with stubble retention had a chloride concentration peak 2 m deeper down the profile (4·5 m) than all other management treatments, indicating that drainage rates were greatest in zero tillage–stubble retained treatments. Nitrate profiles, however, showed that movement of nitrate-N to below the root-zone was greatest under zero tillage with stubble burning with 69 kg N/ha applied (Z-B 69N), followed by zero tillage with stubble retention and 69 kg N/ha. The large nitrate loss from the root-zone of Z-B 69N (about 30% of applied fertiliser) was considered to be a result of high concentrations of nitrate-N in the top 1·5 m associated with stubble burning and fertilisation. The on-farm cultivated sites had very little nitrate-N throughout the whole profile, suggesting that either the use of summer as well as winter crops reduced residual or ‘spared’ nitrate-N (through control of root-lesion nematodes) and/or mineralisation rates were lower on these sites.

Soil Research ◽  
1999 ◽  
Vol 37 (1) ◽  
pp. 75 ◽  
Author(s):  
J. E. Turpin ◽  
J. P. Thompson ◽  
B. J. Bridge ◽  
D. Orange

Recent work on the Hermitage long-term fallow management found increased rates of anion movement under zero tillage systems compared with conventional tillage. Four separate experiments have been used to determine relative rates of water movement through different fallow management treatments on the Hermitage long-term fallow management trial and the causes of any differences. Photography of the aggregation patterns at the depth of tillage (approx. 15 cm) showed that conventional tillage combined with stubble burning has led to the formation of large massive peds up to 20 cm across below the tillage layer, whereas zero-tillage with stubble retention has maintained much smaller aggregates in this zone. Measurements of hydraulic conductivity at 15 cm under both dry and moist conditions indicated that, when the soil is dry and cracked, all tillage treatments have similar conductivities, but when the soil swells and cracks close, zero tillage–stubble retention maintains a greater volume of large pores and thereby greater conductivity. This effect was further demonstrated when a bromide tracer solution was applied to a relatively wet soil by ring infiltrometer, where only 15% of the solution moved below 15 cm in conventional tillage–stubble burning compared with 26% and 38% in zero tillage{stubble retention. In the final experiment, which followed the movement of surface applied bromide over a 6-month fallow, there were no significant differences in rates of leaching between management treatments.


Soil Research ◽  
2009 ◽  
Vol 47 (1) ◽  
pp. 46 ◽  
Author(s):  
Nicole J. Mathers ◽  
David M. Nash

Phosphorus (P) and nitrogen (N) exports from cropping areas can be greater than those from uncropped areas. Conservation farming methods, involving minimal tillage and full stubble retention, offer significant benefits to grain cropping, but may increase nutrient concentrations in surface (i.e. 0–20 mm) soils, resulting in increased risks of nutrient mobilisation and loss. The effects of tillage and stubble management on soil nutrients that are potentially mobilised into runoff from a long-term trial site at Rutherglen (established in 1981) were investigated. On 2 different sampling dates (February and August 2006) soils from the 0–20, 20–50, and 50–150 mm depths were collected from 3 treatments: conventional cultivation with stubble burning (CCb); direct drill with stubble burning (DDb); and direct drill with stubble retained (DDr). In 2004, the trial was sown with wheat (Triticum aestivum cv. Dollarbird), followed by faba beans in 2005 (Vicia faba L.) and wheat again in 2006. In August 2006, a rainfall simulation experiment was also conducted on these sites. All nutrient concentrations decreased with depth to 150 mm in all treatments, when both sampling dates were analysed together. This indicated that soil nutrient stratification was occurring in all 3 treatments. The CCb treatment only displayed differences between the 0–20 and 20–50 mm depths for soil organic C and ammonium-N. DDr significantly increased some nutrient concentrations in the 0–20 mm soil depth compared with the CCb treatment, including CaCl2-extractable P (0.76 and 0.50 mg/kg, for DDr and CCb, respectively), total N (1.23 and 1.00 g/kg, for DDr and CCb, respectively), and nitrate-N (12.6 and 8.63 mg/kg, for DDr and CCb, respectively), while the ammonium-N concentration was greater under CCb (9.71 mg/kg) than DDr (6.46 mg/kg). Being water-soluble, CaCl2-extractable P and nitrate-N are more likely be mobilised into streams from the 0–20 mm depth, where they are highly bioavailable and may contribute to increased eutrophication. Direct drilling with stubble retention contributed a greater proportion of particulate P and N to TP (Total P) and TN (Total N) in surface runoff than either of the burnt systems. Particulate P accounted for 75%, 67%, and 83% of TP in surface runoff from the CCb, DDb, and DDr treatments, respectively. However, the highly bioavailable dissolved reactive P (DRP) was the dominant form of dissolved P, with concentrations exceeding the recommended guidelines of 0.05 mg P/L in the lowlands of south-east Australia. Total N (0.44, 0.68, and 0.73 mg N/L for DDr, DDb, and CCb, respectively) in surface runoff was dominated by nitrate-N and also exceeded current Australian guidelines of 0.5 mg N/L, except for TN from the DDr treatment. These results would indicate that P, particularly the non-dominant but highly bioavailable form of DRP, exported from these systems is more likely to adversely affect catchment water quality than N exports. The increase in surface runoff volumes and nutrient loads from the CCb treatment observed in this study indicate that DDr systems have increased soil infiltration properties and retained nutrients within the soil–plant system. Therefore, direct drilling with stubble retention in the high rainfall zone cropping areas of north-east Victoria is more likely to retain nutrients on-site and improve soil fertility than burning stubble and cultivating the soil.


1992 ◽  
Vol 32 (4) ◽  
pp. 473 ◽  
Author(s):  
G Gibson ◽  
BJ Radford ◽  
RGH Nielsen

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.


2020 ◽  
Vol 27 (2) ◽  
pp. 2217-2225 ◽  
Author(s):  
Poomadathil Mohammed Shafeeq ◽  
Pramila Aggarwal ◽  
Prameela Krishnan ◽  
Vikas Rai ◽  
Pragati Pramanik ◽  
...  

1994 ◽  
Vol 45 (3) ◽  
pp. 511 ◽  
Author(s):  
JA Kirkegaard ◽  
JF Angus ◽  
PA Gardner ◽  
W Muller

An experiment was conducted on a red earth at Harden, N.S.W., to investigate the effects of tillage and stubble management on the growth and yield of wheat in the first year of conservation cropping. Treatments involved stubble-management systems of incorporation, burning or retention combined with tillage systems of either direct drilling or minimum tillage. The experiment was conducted on an oat stubble of 3.9 t ha-1. Direct drilling and stubble retention both reduced seedling growth by 15%, compared to cultivated and stubble burnt treatments, but had no effect on plant density or tillering. The effects on shoot growth were additive and persisted until maturity, leading to grain yields which varied from 2.16 t ha-1 for the stubble-mulched, direct-drilled treatment to 3.20 t ha-1 for the burned-stubble, minimum-till treatment. Direct drilling reduced the total root length in the profile (0-160 cm) at anthesis by 40%, but there was no effect of stubble retention. Reduced shoot growth and rooting depth on direct-drilled and stubble-retained treatments reduced the recovery of water and mineral N by the crop and increased the leaching of mineral N below the root zone. Early shoot growth reductions on direct-drilled plots were not related to levels of soil water, mineral nitrogen (N) or soil temperature. Reduced shoot growth was associated with increased severity of Rhizoctonia in some direct drilled plots, but growth reductions often occurred in the absence of obvious symptoms. High soil strength (>2 MPa) in the top 10 cm of soil may have contributed to reduced growth, although the exact mechanism remains unclear. Reduced growth associated with the presence of stubble was not caused by immobilization of N or increased leaf disease, although reduced soil temperatures may have been partly responsible.


1996 ◽  
Vol 36 (2) ◽  
pp. 223 ◽  
Author(s):  
SR Walker ◽  
GR Robinson

Chlorsulfuron persistence was measured in soils (to a depth of 150 cm) at 4 sites in the winter cereal region of southern Queensland. The residual herbicide had been applied 6-14 times in the previous 7-14 years. Residues here measured using a bioassay based on suppression of root growth of maize (Zea mays cv. GH5010). Less than 3% of the total applied chlorsulfuron (96-210 g a.i./ha) was detected 6-12 months after the last application, and residues were <0.7 ng/g soil in the surface 30 cm, and <0.3 ng/g below 30 cm. The limited vertical movement of residues was associated with the herbicide being applied in early winter, several months before leaching rains. Changes in residue concentration with time were also measured at a site in central Queensland, and in a fallow management experiment in southern Queensland. Persistence was greater at the cooler, drier site in southern Queensland than in central Queensland; 4544% compared with 3 4 % of applied dose remained 3 months after application respectively. Stubble retention had no effect on persistence, but tillage during the summer fallow increased persistence slightly. There was no evidence of chlorsulfuron residues accumulating and only limited leaching in these alkaline agricultural soils of southern Queensland. Persistence within a season was influenced by soil and climatic factors.


Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 329 ◽  
Author(s):  
V. Rasiah ◽  
J. D. Armour

Recent research on the fate of applied fertiliser N in the Ferrosols of the wet tropics of Far North Queensland (FNQ) has shown that the nitrate leaching below the crop root-zone is a major pathway of N loss from paddocks. Information on the fate of this nitrate is essential to develop best N fertiliser management practices and for the long-term sustainability of land and water resources. Because of the ability of Ferrosols to adsorb anions in the soil matrix, it was speculated that the leached nitrate may be accumulating at depth in the Ferrosol profiles. The objectives of this study were to (i) verify whether the leached nitrate has been accumulating in the Ferrosols under the major cropping systems in the Johnstone River Catchment (JRC) of FNQ, and (ii) provide preliminary estimates for nitrate retention capacity of the Ferrosols. Soil cores to a depth of 10 m were taken from under sugarcane (Saccharum officinarum-S), banana (Musa (AAA group, Cavendish subgroup) cv. Williams), dairy pasture, and rainforest in JRC during August 1995. The cores were segmented at 0.5-m depth increments and soil samples were analysed for nitrate- and ammonium-N, cation- (CEC) and anion- (AEC) exchange capacities, pH, Ca2+ , Mg 2+ , K + , Na + , and Cl – . Nitrate-N concentration under sugarcane was as high as 33 mg/kg, compared with 6.9 mg/kg for banana, 0.3 mg/kg under rainforest, and that under pasture was below detection limit. Nitrate-N load in the top 10 m of the profiles under sugarcane ranged from 345 to 1875 kg nitrate-N/ha compared with 145 kg/ ha for banana, and 21 kg/ha under rainforest. Most of the nitrate accumulation was found between 2 and 8 m, i.e. well below the crop root-zone. From 7% to 70% of the nitrate that leached below crop root-zone was retained at depths >1 m. In general, Cl – and total cation (TC = sum of Ca2+ , Mg 2+ , K + , and Na + ) concentrations in the profiles under cropping were higher than those under rainforest, and the pH under sugarcane was more acidic. Simple correlation analysis indicated associations existed between the accumulated nitrate and Cl – , pH, AEC, or TC. The estimated nitrate holding capacity of the Ferrosols ranged from 17 to 32 t N/ha. The results show that large quantities of the nitrate that leached below crop root-zone have accumulated at depth under long-term sugarcane and banana cropping in the Ferrosols of FNQ.


Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 223 ◽  
Author(s):  
RC Dalal

The effects of conservation practices, zero-tillage and stubble retention, on long-term trends in total N (0-0.1 m depth) of a Vertisol used mainly for wheat cropping were studied in a semi-arid subtropical environment (28�12'S. and 152�06' E.) in Queensland. Trends in total N content of a Vertisoi (65% clay, pH 7.2) were discerned during a 22-year period of management practices including: zero-tillage (ZT) and conventional tillage (CT); stubble retention (SR) and stubble burning (SB); and fertilizer N application of nil (Nl), 23 kg N ha-1 yr-1 (N2) and 69 kg N ha-1 yr-1 (N3). Soil total N (0-0.1 m) declined under all treatments at an overall rate of 25f 2 kg N ha-1 yr-1 although after 22 years soil under ZT, SR and N3 treatments still contained higher soil total N than under CT, SB and N1 treatments. Apparent fertilizer N recovery in the soil-plant system was poor (34 64%) under CTSB, CTSR and ZTSB and ZTSR treatments, because N removed by the wheat crop was equivalent to less than 20% of fertilizer N in the first 12 years of management practices, due mainly to disease. Deep leaching losses of NO3-N was the likely factor for poor recovery of N. The ZTSR treatment showed better apparent N recovery than the CTSB treatment, most likely due to greater immobilization of fertilizer N, more N uptake in grain due to additional available soil water and hence less leaching losses of NO3-N. Under the current cultural practices, soil total N (0-0.1 m) may decline further to reach a steady state (about 1000 kg N ha-1). However, the apparent N recovery in the soil-plant system can be increased by disease control (for example, resistant cultivars and winter-summer crop rotations) and optimum utilisation of soil water (opportunity cropping) to minimize NO3-N leaching losses and to maximise production of crop biomass.


Author(s):  
Peter B. Tinker ◽  
Peter Nye

This is a completely revised edition of the previously titled Solute Movement in the Soil-Root System. It describes in detail how plant nutrients and other solutes move in the soil in response to plant uptake, and it provides a basis for understanding processes in the root zone so that they can be modeled realistically in order to predict the effects of variations in natural conditions or our own practices.


Soil Research ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 636 ◽  
Author(s):  
Fiona Robertson ◽  
Roger Armstrong ◽  
Debra Partington ◽  
Roger Perris ◽  
Ivanah Oliver ◽  
...  

Despite considerable research, predicting how soil organic carbon (SOC) in grain production systems will respond to conservation management practices, such as reduced tillage, residue retention and alternative rotations, remains difficult because of the slowness of change and apparent site specificity of the effects. We compared SOC stocks (equivalent soil mass to ~0–0.3 m depth) under various tillage, residue management and rotation treatments in three long-term (12-, 28- and 94-year-old) field experiments in two contrasting environments (Mallee and Wimmera regions). Our hypotheses were that SOC stocks are increased by: (1) minimum tillage rather than traditional tillage; (2) continuous cropping, rather than crop–fallow rotations; and (3) phases of crop or pasture legumes in rotations, relative to continuous cropping with cereals. We found that zero tillage and stubble retention increased SOC in some circumstances (by up to 1.5 Mg C ha–1, or 8%) but not in others. Inclusion of bare fallow in rotations reduced SOC (by 1.4–2.4 Mg C ha–1, or 8–12%) compared with continuous cropping. Including a pulse crop (field pea, where the grain was harvested) in rotations also increased SOC in some instances (by ~6–8 Mg C ha–1, or 29–35%) but not in others. Similarly, leguminous pasture (medic or lucerne) phases in rotations either increased SOC (by 3.5 Mg C ha–1, or 21%) or had no significant effect compared with continuous wheat. Inclusion of a vetch green manure or unfertilised oat pasture in the rotation did not significantly increase SOC compared with continuous wheat. The responses in SOC to these management treatments were likely to be due, in part, to differences in nitrogen and water availability (and their effects on carbon inputs and decomposition) and, in part, to other, unidentified, interactions. We conclude that the management practices examined in the present study may not reliably increase SOC on their own, but that significant increases in SOC are possible under some circumstances through the long-term use of multiple practices, such as stubble retention + zero tillage + legume N input + elimination of fallow. The circumstances under which increases in SOC can be achieved require further investigation.


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