Nitrogen mineralisation in relation to previous crops and pastures

Soil Research ◽  
2006 ◽  
Vol 44 (4) ◽  
pp. 355 ◽  
Author(s):  
J. F. Angus ◽  
T. P. Bolger ◽  
J. A. Kirkegaard ◽  
M. B. Peoples
Keyword(s):  
Field Experiments ◽  
Perennial Grasses ◽  
The Other ◽  
Continuous Cropping ◽  
N Mineralisation ◽  
Total N ◽  
Stubble Retention ◽  
Direct Drilling ◽  
Net Mineralisation ◽  
Crop System

Most of the nitrogen (N) used by Australian crops is mineralised from the residues of previous crops and pastures. Net N mineralisation was studied in 2 field experiments in southern NSW, one comparing different residue-management and tillage systems during continuous cropping and the other comparing residues of annual and perennial pastures in a pasture–crop system. After 14 years of continuous cropping, soil total N concentration had decreased by 50%. Neither stubble retention nor direct drilling affected potential N mineralisation or the decrease in total N. However, soil mineral N in the field was greater after direct drilling than cultivation and greater after stubble retention than stubble burning. There were 2 reasons for the discrepancy. One was because retained stubble conserved soil water, leading to periods of increased mineralisation. The other was that direct drilling and stubble retention reduced growth and N uptake by crops. In contrast to the similar rates of potential mineralisation under different tillage and stubble systems, there were significant differences following different pasture species. In a 5-year study of a pasture–crop system we measured net mineralisation following annual pasture based on subterranean clover and perennial pasture based on lucerne and/or the grasses phalaris and cocksfoot. Mineralisation generally decreased with number of years after pasture removal. Previous lucerne pastures led to slow net mineralisation in the first year after removal, apparently because of immobilisation by high C : N residues. Mineralisation in soil containing perennial grass residues was the highest measured. This high rate may be due to redistribution of N to the topsoil by roots of perennial grasses. The comparison of continuous crop and pasture–crop systems showed that the decline in soil N supply was not prevented by direct drilling and stubble conservation, but N mineralisation was increased by pastures, particularly those containing perennial grasses.

Effect of cropping practices on soil organic carbon: evidence from long-term field experiments in Victoria, Australia

Soil Research ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 636 ◽  
Author(s):  
Fiona Robertson ◽  
Roger Armstrong ◽  
Debra Partington ◽  
Roger Perris ◽  
Ivanah Oliver ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Field Experiments ◽  
Residue Management ◽  
Continuous Cropping ◽  
Zero Tillage ◽  
Stubble Retention ◽  
Soc Stocks

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.

Long-term effects of tillage, stubble, and nitrogen management on properties of a red-brown earth

1995 ◽  
Vol 35 (7) ◽  
pp. 923 ◽  
Author(s):  
NA Fettell ◽  
HS Gill
Keyword(s):  
Management Practices ◽  
Soil Organic C ◽  
Long Term Effects ◽  
Total N ◽  
Organic C ◽  
Stubble Retention ◽  
South Wales ◽  
Direct Drilling ◽  
N Management

Differences in soil organic carbon (C), total nitrogen (N), and pH resulting from 14 and 15 years of different tillage, stubble, and fertiliser N management practices were measured for a red-brown earth at Condobolin in western New South Wales. The 5 main treatments comprised stubble burning or retention in factorial combination with cultivation and direct drilling, and stubble incorporation combined with cultivation. Two rates of N fertiliser (0 and 40 or 50 kg/ha) were applied annually, and wheat was grown each year. There were no significant differences between tillage and stubble treatments for soil organic C, total N, or pH. Fertiliser N application caused small but significant increases in organic C and total N but decreased the pH of the surface 2.5 cm of soil by 0.4-0.5 units compared with the nil fertiliser rate. The study indicates that direct drilling and stubble retention with continuous wheat have had little long-term effect on soil organic C and total N in this low rainfall environment.

The effect of stubble management on the availability of 15N-labelled residual fertilizer nitrogen and crop stubble nitrogen in an irrigated black earth

1986 ◽  
Vol 26 (1) ◽  
pp. 99 ◽  
Author(s):  
PJ White ◽  
I Vallis ◽  
PG Saffigna
Keyword(s):  
Ammonium Sulfate ◽  
Field Experiments ◽  
Crop Yields ◽  
N Uptake ◽  
Fertilizer Application ◽  
Wheat Crop ◽  
Total N ◽  
Stubble Retention ◽  
Residual Fertilizer N ◽  
Subtropical Environment

Field experiments on an irrigated alkaline black earth soil of the Darling Downs, south-east Queensland, examined transformations of nitrogen (N) and its subsequent availability for the growth of wheat after stubble had been removed, mulched or incorporated. Two crop sequences were used: sorghum-3- month fallow-wheat (S-W); and wheat-7-month fallow-wheat (W-W). The crops were grown in microplots enclosed by steel cylinders (75 cm diam. and 35 cm deep) to a depth of 30 cm. For the initial crop, some plots were fertilized with l5N-labelled ammonium sulfate and others with unlabelled ammonium sulfate (50 kg N/ha). After harvest of the initial crop, labelled stubble was added to unlabelled soil, either as a mulch or incorporated, and unlabelled stubble was similarly added to soil labelled with residual 15N from the fertilizer application. Uptake of 15N by a test wheat crop and distribution of 15N in the soil-plant system were then determined. In the test crop fertilized with unlabelled urea (50 kg N/ha), incorporation of stubble depressed plant growth and N uptake by 35% in the S-W sequence but had no effect in the W-W sequence. Residual fertilizer 15N in the soil was more available to the test crop than was 15N in retained stubble (6 v. 2% and 12 v. 6% for the S-W and W-W sequences respectively). However, the test crop obtained only 0.9-1.2% of its total N uptake from residual fertilizer N and 0.4-2.9% from the stubble of the initial crop. The effects of stubble management on the availability of N from these two sources were small. If suitable rates of N fertilizer are applied, it is unlikely that crop yields will be adversely affected by stubble retention in this subtropical environment.

Turnover of nitrogen from components of lupin stubble to wheat in sandy soil

Soil Research ◽  
1999 ◽  
Vol 37 (3) ◽  
pp. 575 ◽  
Author(s):  
C. A. Russell ◽  
I. R. P. Fillery
Keyword(s):  
Field Experiments ◽  
Root Zone ◽  
Lignin Content ◽  
N Uptake ◽  
Organic N ◽  
Inorganic N ◽  
Short Term ◽  
Total N ◽  
N Concentration ◽  
Net Mineralisation

The rate of decomposition of 15N-labelled lupin (Lupinus angustifolius) stubble and the use of mineralised 15N by wheat were determined in field experiments on a deep loamy sand previously cropped to lupin. In one experiment, leaf, stem, and pod (pod-valve) components were applied separately to mini-plots that were either left unplanted or subsequently planted to wheat. In the second experiment, leaf and stem components, each of either low or high N concentration, were applied separately to mini-plots which were subsequently planted to wheat. Soil was recovered in layers to a maximum depth of 1 m and subsequently analysed for 15N in NH + 4 , NO-3 , and total N. The net mineralisation of stubble 15N was estimated from the decrease in soil organic 15N (total 15N – inorganic 15N), and the uptake of 15N by wheat was measured periodically. All treatments were characterised by the high retention of lupin stubble 15N in the soil organic matter. Between 9 and 34% of stem and pod 15N, and 19–49% of leaf 15N, was mineralised within a 10-month period. From these data the annual net mineralisation of a typical lupin stubble was estimated at 25–42 kg N/ha, an N benefit similar to that estimated from agronomic trials. Wheat uptake of lupin-stubble 15N ranged from 9 to 27%. Of the stubble components, only the leaf contained sufficient quantities of mineralisable N to be an important source of N for wheat. At wheat maturity in the first experiment, losses of stubble 15N ranged from 13% (leaf) to 7% (stem). In the second experiment, losses of 15N were only observed from the high N treatments (leaf 8%, stem 15·5%). Stubble component chemistry appeared to affect net mineralisation and plant uptake differently. Across both experiments, annual net mineralisation best correlated (R = 0·69) with the N concentration of the stubble components. Wheat N uptake was strongly positively correlated with polysaccharide content (R = 0·89) but negatively correlated with lignin content (R = – 0·79). Although large quantities (58 and 98 kg N/ha) of soil-derived inorganic N were found in the root-zone (–1·0 m) of wheat sown after lupins, and attributed to the decomposition of lupin root systems and surface residues prior to the establishment of each experiment, it is concluded that the short-term decomposition of lupin stubble 15N results in a modest release of inorganic N. Consequently, the primary value of lupin stubble in the N economy of lupin : cereal rotations is to replenish the soil organic N reserve.

The rates of nitrification of peat soils in British Guiana

1954 ◽  
Vol 44 (4) ◽  
pp. 377-382 ◽  
Author(s):  
H. Paul ◽  
M. A. A. Shariff
Keyword(s):  
Field Experiments ◽  
Ammonia Nitrogen ◽  
The Other ◽  
Appreciable Amount ◽  
Continuous Cropping ◽  
Peat Soils ◽  
British Guiana ◽  
Other Hand ◽  
Short Period ◽  
Before And After

A study has been made of some of the nitrogen fractions of the pegasse soils of British Guiana in virgin and exhausted conditions, that is, before and after cropping.1. Preliminary field experiments on the virgin and exhausted soils adduced strong evidence in support of the complaints made by farmers that the productivity in yields of the pegasse soils after continuous cropping for a comparatively short period is considerably impaired.2. The virgin soil showed an appreciable amount of nitrate nitrogen, while the exhausted sample indicated no nitrate. The latter soil, on the other hand, contained a higher amount of ammonia nitrogen measured by KCl extraction than the former soil.3. Nitrification studies with added ammonium salts indicated that under optimum conditions the nitrifying power of the exhausted soil was extremely low. Additions of sodium nitrate indicated that the nitrate was partially reduced to ammonia by the worn-out pegasse soil. The virgin pegasse, on the other hand, showed an appreciable rate of nitrification.

Effects of tillage practices on soil and water phosphorus and nitrogen fractions in a Chromosol at Rutherglen in Victoria, Australia

Soil Research ◽  
2009 ◽  
Vol 47 (1) ◽  
pp. 46 ◽  
Author(s):  
Nicole J. Mathers ◽  
David M. Nash
Keyword(s):  
Surface Runoff ◽  
Water Soluble ◽  
Nutrient Concentrations ◽  
Total N ◽  
Stubble Retention ◽  
Nitrate N ◽  
Ammonium N ◽  
Extractable P ◽  
Direct Drilling ◽  
Stubble Burning

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.

scholarly journals Effects of novel bioorganic fertilizer application on soil enzymes and bacterial community in multi-site rice paddies in China

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zuren Li ◽  
Jincai Han ◽  
Haodong Bai ◽  
Di Peng ◽  
Lifeng Wang ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Field Experiments ◽  
Chemical Properties ◽  
Soil Bacterial Community ◽  
General Function ◽  
Rice Paddies ◽  
Phylogenetic Groups ◽  
Total N ◽  
Bioorganic Fertilizer ◽  
Soil Bacterial

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.

scholarly journals The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Field Experiments ◽  
N2o Emission ◽  
N2o Emissions ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Tropical Regions ◽  
The Impact

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.

An assessment of the factors controlling the productivity of maize in England

1951 ◽  
Vol 41 (3) ◽  
pp. 271-281 ◽  
Author(s):  
E. S. Bunting ◽  
G. E. Blackman
Keyword(s):  
Dry Matter ◽  
Field Experiments ◽  
Plant Density ◽  
Spatial Arrangement ◽  
The Other ◽  
Mass Selection ◽  
Grain Production ◽  
Forage Production ◽  
Field Scale ◽  
Other Hand

Between 1942 and 1950, some thirty field experiments have been carried out in the southern half of England to assess the potential value, either for grain or forage production, of seventeen openpollinated flint or dent maizes together with twentynine single or double hybrids of American or Canadian origin.Early-maturing flint varieties will consistently ripen grain, but before mechanical threshing or storage, the cobs require drying. Sibthorp, a mass selection made from an unknown German variety, is the earliest and most productive flint maize so far tested, and in the experiments has yielded as much as 39 cwt. of grain per acre with an average of 24 cwt. The earliest American hybrids, i.e. those with a U.S.A. rating of 80 days from sowing to maturity, give very high yields of grain in favourable seasons. Within the group Wisconsin 240–275, a yield level equal to or exceeding 50 cwt./acre has on occasion been recorded. On the other hand, in the most unfavourable years, such hybrids just failed to produce ripe cobs.Attempts to maintain sixty-five parent inlines of the earliest hybrids have largely failed. However, many of the parent single crosses have matured, and the production on a field scale of the double-cross seed of both Wisconsin 240 and 255 has been carried out.Spacing experiments indicate that for optimum grain production a density of 6 plants/sq.yd. is required for both flint varieties and the earliest hybrids. A spatial arrangement of individual plants is to be preferred to that of groups or hills.American hybrids, in the class of ‘90 days’ to maturity, will in all but the most unfavourable seasons reach the ‘early-dent’ stage of the grain before the incidence of autumn frosts. Yields of dry matter of plants harvested in this phase have ranged from 30 to 85 cwt. of dry matter per acre. In these trials, the plant density was standardized at 4 plants/sq.yd. and higher densities may be demanded for optimal yields.The ratio of the ‘ear’ (that is, the cob, immature grain and enclosing leaf sheaths) to the total shoot weight at harvest varies greatly with the variety or hybrid. With White Horsetooth, the usual variety grown for fodder in England, no cobs are formed before the plants are killed by frost, while with the early hybrids, the ear may be half the weight of the whole shoot.The earliest variety Sibthorp from an early May sowing takes approximately 70–80 days to reach full anthesis, while ‘80-day’ American hybrids are a week later. From sowing to full maturity the period in England is from 140 to 160 days, thus compared to conditions in Minnesota the period is nearly twice as long. Because of the much slower rate of development and because of the humidity of English autumns, it is concluded that until the date of maturity can be advanced some 14 days, grain production on a field scale is not yet feasible. On the other hand, many of the American hybrids are well fitted to the production of silage. The greatest drawback to the introduction of such hybrids is the liability of the seed and seedlings to be attacked by rooks.

A field study of competition and interaction between Lemna minor and Lemna trisulca

1989 ◽  
Vol 67 (10) ◽  
pp. 2904-2911 ◽  
Author(s):  
Alexander L. McIlraith ◽  
Gordon G. C. Robinson ◽  
Jennifer M. Shay
Keyword(s):  
Life History ◽  
Field Study ◽  
Key Words ◽  
Field Experiments ◽  
Lemna Minor ◽  
Survey Methods ◽  
The Other ◽  
Transplant Experiment ◽  
Replacement Series ◽  
Vegetative Biomass

Field experiments and survey methods were used to assess competition and interaction between Lemna minor L. and Lemna trisulca L. at Delta Marsh, Manitoba. Sites were dominated by one or the other species or codominated by both. Replacement series experiments predicted codominance of L. minor and L. trisulca in an unshaded eutrophic site but predicted L. minor dominance when run for a longer time. Similar experiments conducted in a shaded eutrophic site predicted L. minor dominance. Addition series experiments showed that intraspecific and interspecific competition occurred in the unshaded site. In a eutrophic unshaded ditch, high densities of L. minor suppressed L. trisulca. In a eutrophic shaded site, high densities of L. minor and green algae inhibited L. trisulca, and in a sunny, less eutrophic site high density of each species inhibited the other. In a transplant experiment, L. minor biomass in shaded enclosures approached that found naturally in two shaded sites. Lemna trisulca persisted when shaded. Vegetative biomass trends in an unshaded eutrophic marsh ditch indicated spring and fall L. trisulca dominance and summer L. minor dominance. Shaded eutrophic sites were dominated by L. minor, whereas a less eutrophic site was dominated by L. trisulca. A model is developed to explain dominance patterns, and seasonal life-history responses are considered. Key words: Lemna, duckweed, competition, interaction, resources, light, nutrients.

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