scholarly journals Impact of subsoil constraints on wheat yield and gross margin on fine-textured soils of the southern Victorian Mallee

2006 ◽  
Vol 57 (3) ◽  
pp. 355 ◽  
Author(s):  
D. Rodriguez ◽  
J. Nuttall ◽  
V. O. Sadras ◽  
H. van Rees ◽  
R. Armstrong

The APSIM-Wheat module was used to investigate our present capacity to simulate wheat yields in a semi-arid region of eastern Australia (the Victorian Mallee), where hostile subsoils associated with salinity, sodicity, and boron toxicity are known to limit grain yield. In this study we tested whether the effects of subsoil constraints on wheat growth and production could be modelled with APSIM-Wheat by assuming that either: (a) root exploration within a particular soil layer was reduced by the presence of toxic concentrations of salts, or (b) soil water uptake from a particular soil layer was reduced by high concentration of salts through osmotic effects. After evaluating the improved predictive capacity of the model we applied it to study the interactions between subsoil constraints and seasonal conditions, and to estimate the economic effect that subsoil constraints have on wheat farming in the Victorian Mallee under different climatic scenarios. Although the soils had high levels of salinity, sodicity, and boron, the observed variability in root abundance at different soil layers was mainly related to soil salinity. We concluded that: (i) whether the effect of subsoil limitations on growth and yield of wheat in the Victorian Mallee is driven by toxic, osmotic, or both effects acting simultaneously still requires further research, (ii) at present, the performance of APSIM-Wheat in the region can be improved either by assuming increased values of lower limit for soil water extraction, or by modifying the pattern of root exploration in the soil profile, both as a function of soil salinity. The effect of subsoil constraints on wheat yield and gross margin can be expected to be higher during drier than wetter seasons. In this region the interaction between climate and soil properties makes rainfall information alone, of little use for risk management and farm planning when not integrated with cropping systems models.

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1225 ◽  
Author(s):  
Zilong Guan ◽  
Zhifeng Jia ◽  
Zhiqiang Zhao ◽  
Qiying You

Mulched drip irrigation has been widely used in agricultural planting in arid and semi-arid regions. The dynamics and distribution of soil salinity under mulched drip irrigation greatly affect crop growth and yield. However, there are still different views on the distribution and dynamics of soil salinity under long-term mulched drip irrigation due to complex factors (climate, groundwater, irrigation, and soil). Therefore, the soil salinity of newly reclaimed salt wasteland was monitored for 9 years (2008–2016), and the effects of soil water on soil salinity distribution under mulched drip irrigation have also been explored. The results indicated that the soil salinity decreased sharply in 3–4 years of implementation of mulched drip irrigation, and then began to fluctuate to different degrees and showed slight re-accumulation. During the growth period, soil salinity was relatively high at pre-sowing, and after a period of decline soil salinity tends to increase in the late harvest period. The vertical distribution of soil texture had a significant effect on the distribution of soil salinity. Salt accumulated near the soil layer transiting from coarse soil to fine soil. After a single irrigation, the soil water content in the 30–70 cm layer under the cotton plant undergoes a ‘high–low–high’ change pattern, and the soil salt firstly moved to the deep layer (below 70 cm), and then showed upward migration tendency with the weakening of irrigation water infiltration. The results may contribute to the scientific extension of mulched drip irrigation and the farmland management under long-term mulched drip irrigation.


2013 ◽  
Vol 20 (3) ◽  
pp. 507-517
Author(s):  
Hao Chen

Abstract In semi-humid Loess Plateau of northern China, water is the limiting factor for rain-fed crop yields. In this region, long-term traditional ploughing with straw removal has resulted in poor soil structure, water conservation and crop yield. Controlled traffic, combined with no-till and straw cover has been proposed to improve soil water conservation and crop yield. From 1999 to 2007, a field experiment on winter wheat was conducted in the dryland area of Loess Plateau of northern China, to investigate the effects of traffic and tillage on soil water conservation and crop yield. The field experiment was conducted using two controlled traffic treatments, no tillage with residue cover and no compaction (NTCN), shallow tillage with residue cover and no compaction (STCN) and one conventional tillage treatment (CK). Results showed that controlled traffic system reduced soil compaction in the top soil layer, increased soil water infiltration. The benefit on soil water infiltration translated into more soil conservation (16.1%) in 0-100 cm soil layer in fellow period, and achieved higher soil water availability at planting (16.5%), with less yearly variation. Consequently, controlled traffic system increased wheat yield by 12.6% and improved water use efficiency by 5.2%, both with less yearly variation, compared with conventional tillage. Within controlled traffic treatments, no tillage treatment NTCN showed better overall performance. In conclusion, controlled traffic combined with no-tillage and straw cover has higher performance on conserving water, improving yield and water use efficiency. It is a valuable system for soil and water conservation for the sustainable development of agriculture in dryland China.


2007 ◽  
Vol 58 (4) ◽  
pp. 349 ◽  
Author(s):  
L. D. Prior ◽  
A. M. Grieve ◽  
K. B. Bevington ◽  
P. G. Slavich

This study documents changes in yield, growth, soil salinity (ECe) and leaf sodium (Na) and chlorine (Cl) concentrations in mature Valencia orange [Citrus sinensis (L.Osbeck)] trees on sweet orange (Citrus sinensis) rootstock in response to increased levels of Na and Cl in irrigation water. Four levels of salt, ranging from the river-water control (0.44 dS/m) to 2.50 dS/m, were applied over a 9-year period through an under-tree microsprinkler system to trees in the Sunraysia area of the Murray Valley in south-eastern Australia. A salt-balance model showed that evapotranspiration was reduced by salinity, whereas leaching fractions increased from an average 24% in the control to 51% in the most saline treatment. The high leaching fractions were achieved as a result of freely draining soils and good irrigation management, and allowed us to maintain low to moderate levels of soil salinity throughout the trial and minimised the effect of salt treatment on fruit yield. Soil salinity increased almost linearly in response to irrigation-water salinity during the first year, and fluctuated seasonally thereafter; however, very few readings exceeded 3 dS/m, even in the highest treatments. By contrast, leaf Na and Cl concentrations in the highest salt treatment continued to increase over the first 4 years. The relationship between yield and soil salinity was extremely weak, but yield did decrease as foliar concentrations of Na and Cl increased: in Year 9, leaf Na in the highest treatment relative to the control was associated with a predicted reduction of 17% in yield and 59% in annual trunk-diameter growth.


Soil Research ◽  
2010 ◽  
Vol 48 (2) ◽  
pp. 125 ◽  
Author(s):  
J. G. Nuttall ◽  
R. D. Armstrong

Subsoil physicochemical constraints can limit crop production on alkaline soils of south-eastern Australia. Fifteen farmer paddocks sown to a range of crops including canola, lentil, wheat, and barley in the Wimmera and Mallee of Victoria and the mid-north and Eyre Peninsula of South Australia were monitored from 2003 to 2006 to define the relationship between key abiotic/edaphic factors and crop growth. The soils were a combination of Calcarosol and Vertosol profiles, most of which had saline and sodic subsoils. There were significant correlations between ECe and Cl– (r = 0.90), ESP and B (r = 0.82), ESP and ECe (r = 0.79), and ESP and Cl– (r = 0.73). The seasons monitored had dry pre-cropping conditions and large variations in spring rainfall in the period around flowering. At sowing, the available soil water to a depth of 1.2 m (θa) averaged 3 mm for paddocks sown to lentils, 28 mm for barley, 44 mm for wheat, and 92 mm for canola. Subsoil constraints affected canola and lentil crops but not wheat or barley. For lentil crops, yield variation was largely explained by growing season rainfall (GSR) and θa in the shallow subsoil (0.10–0.60 m). Salinity in this soil layer affected lentil crops through reduced water extraction and decreased yields where ECe exceeded 2.2 dS/m. For canola crops, GSR and θa in the shallow (0.10–0.60 m) and deep (0.60–1.20 m) layers were important factors explaining yield variation. Sodicity (measured as ESP) in the deep subsoil (0.80–1.00 m) reduced canola growth where ESP exceeded 16%, corresponding to a 500 kg/ha yield penalty. For cereal crops, rainfall in the month around anthesis was the most important factor explaining grain yield, due to the large variation in rainfall during October combined with the determinant nature of these crops. For wheat, θa in the shallow subsoil (0.10–0.60 m) at sowing was also an important factor explaining yield variation. Subsoil constraints had no impact on cereal yield in this study, which is attributed to the lack of available soil water at depth, and the crops’ tolerance of the physicochemical conditions encountered in the shallow subsoil, where plant-available water was more likely to occur. Continuing dry seasonal conditions may mean that the opportunity to recharge soil water in the deeper subsoil, under continuous cropping systems, is increasingly remote. Constraints in the deep subsoil are therefore likely to have reduced impact on cereals under these conditions, and it is the management of water supply, from GSR and accrued soil water, in the shallow subsoil that will be increasingly critical in determining crop yields in the future.


2003 ◽  
Vol 54 (5) ◽  
pp. 487 ◽  
Author(s):  
J. G. Nuttall ◽  
R. D. Armstrong ◽  
D. J. Connor

Soil salinity, sodicity, and high extractable boron (B) are thought to reduce wheat yields on alkaline soils of south-eastern Australia; however, little quantitative information on yield penalties to edaphic constraints is available. The relationships between wheat yield of a B-tolerant cultivar and soil physicochemical conditions in the Victorian Mallee were explored using ridge regression analysis, using natural variation in the field. Wheat yields in the survey ranged from 1.3 to 6.1 Mg/ha, with low yields attributed to inadequate soil water supply during pre-anthesis growth. Crop sequences, fallow–wheat, and pulse–wheat left greatest soil water prior to sowing of the wheat crop, and lucerne–wheat the least. A descriptive model explained 54% of variation in wheat yield, with rainfall around anthesis, available soil water in the 0.10–0.40 m layer, nitrate in the 0–0.10 m layer at sowing and salinity, and sodicity in the 0.60–1.00 m layers being important factors. Subsoil salinity (ECe) and sodicity (ESP) appear to be effective surrogates for estimating the likelihood of water extraction in the deep subsoil. The analyses suggest that subsoils need to have an ECe <8 dS/m and ESP < 19% for crops to make use of water deep in the profile. Although soluble B ranged from 2 to 52 mg/kg in the 0.60–1.00 m layer of the alkaline soils considered, B appeared to have little correlation with root growth, water extraction, or yield of wheat, which has been attributed to B-tolerance of the cultivar tested and/or the overbearing effect of high Na+ in these soils.


2004 ◽  
Vol 44 (8) ◽  
pp. 787 ◽  
Author(s):  
I. A. M. Yunusa ◽  
W. D. Bellotti ◽  
A. D. Moore ◽  
M. E. Probert ◽  
J. A. Baldock ◽  
...  

The Agricultural Production Systems Simulator (APSIM) suite of models was used to predict dynamics in water and nitrogen in soil, as well as the growth and yield of sequential crops of wheat and barley in pasture–wheat–barley rotations, between 1995 and 1997 at Roseworthy, South Australia. The NWHEAT model satisfactorily predicted above-ground dry matter, leaf area index and grain yields for both crops in rotations with either grassy (Grass) or medic (Medic) pastures, including the lack of significant response of yield to nitrogen fertiliser applied to wheat at sowing. Simulation data for soil water, from SOILWAT2, was consistent with measured data. Simulation with SOILN2, however, largely underestimated soil nitrogen, due to excessive uptake by the simulated wheat during the season when nitrogen was abundant and water supply readily available. Thus, the soil nitrate had to be reset at sowing for the following barley crop; simulated soil nitrate agreed with the measured data in this season when this nutrient was low. For most variables of crop growth and soil water, the simulated data were mostly within 2 standard errors of the measured means. Prediction of grain protein was underestimated in all cases, including where nitrogen in the shoot was overestimated. This was possibly due to inadequate remobilisation of nitrogen from the straw and roots to the grain by the simulated crop. A satisfactory prediction of dry matter, grain yield and grain weight was obtained for wheat when the models were extended to other trials at Roseworthy (Lower North), Minnipa (Upper Eyre Peninsula) and Wunkar (Murray Mallee), based on limited soil data. Long-term simulations of wheat yields showed that, with early sowing in the Lower North, median wheat yield increased by 50 kg/ha for every kilogram of nitrogen applied at sowing, up to a maximum nitrogen rate of 50 kg/ha. In the drier districts of the Upper Eyre Peninsula and the Murray Mallee, nitrogen fertiliser of no more than 25 kg/ha, applied at sowing, was enough to achieve yield benefits in any given season. At these drier sites, crop failures occurred in 5% (Upper Eyre Peninsula) and 10% (Murray Mallee) of the seasons simulated. Median sowing dates from these simulations were 15 May for the Lower North, 30 May for the Upper Eyre Peninsula and 24 May for Murray Mallee. This suggested that sowing could be conducted at least a week earlier than currently practised in the 3 environments. This study demonstrated the capability of APSIM to predict growth and grain yield of wheat and barley, as well as the associated dynamics of soil water in the main cereal belts of South Australia.


1993 ◽  
Vol 33 (7) ◽  
pp. 885 ◽  
Author(s):  
M Incerti ◽  
PWG Sale ◽  
GJ O'Leary

Two experiments were conducted at the Mallee Research Station, Walpeup, between 1985 and 1989 to determine whether increases in wheat yield that occur after long fallows result from improvements in the supply and use of additional soil water conserved during the fallow. Although long fallows increased the amount of water stored in the soil at sowing (average 22 mm) and the yield of wheat (0.26 to 1.37 t/ha) in the first experiment, the results suggest no causal relationship between these increases. Improvements in wheat yield were attributed to increases in soil nitrogen availability and to control of cereal root diseases rather than to any increase in soil water conservation. This was confirmed in the second experiment, which was managed to ensure that nitrogen supply and cereal root diseases were not limiting crop production. Increases in soil water content at sowing resulting from long fallows did not result in higher wheat yields. This study suggests that long fallows cannot be justified on the basis of this increased soil water storage, as much of the additional soil water accumulated during the fallow period is stored in the lower part of the rootzone. Movement of this water below the rootzone during the growing season appears to be the main reason for the additional water stored at sowing, with long fallows failing to increase wheat growth and yield.


2008 ◽  
Vol 59 (4) ◽  
pp. 321 ◽  
Author(s):  
Y. P. Dang ◽  
R. C. Dalal ◽  
D. G. Mayer ◽  
M. McDonald ◽  
R. Routley ◽  
...  

Salinity, sodicity, acidity, and phytotoxic levels of chloride (Cl) in subsoils are major constraints to crop production in many soils of north-eastern Australia because they reduce the ability of crop roots to extract water and nutrients from the soil. The complex interactions and correlations among soil properties result in multi-colinearity between soil properties and crop yield that makes it difficult to determine which constraint is the major limitation. We used ridge-regression analysis to overcome colinearity to evaluate the contribution of soil factors and water supply to the variation in the yields of 5 winter crops on soils with various levels and combinations of subsoil constraints in the region. Subsoil constraints measured were soil Cl, electrical conductivity of the saturation extract (ECse), and exchangeable sodium percentage (ESP). The ridge regression procedure selected several of the variables used in a descriptive model, which included in-crop rainfall, plant-available soil water at sowing in the 0.90–1.10 m soil layer, and soil Cl in the 0.90–1.10 m soil layer, and accounted for 77–85% of the variation in the grain yields of the 5 winter crops. Inclusion of ESP of the top soil (0.0–0.10 m soil layer) marginally increased the descriptive capability of the models for bread wheat, barley and durum wheat. Subsoil Cl concentration was found to be an effective substitute for subsoil water extraction. The estimates of the critical levels of subsoil Cl for a 10% reduction in the grain yield were 492 mg cl/kg for chickpea, 662 mg Cl/kg for durum wheat, 854 mg Cl/kg for bread wheat, 980 mg Cl/kg for canola, and 1012 mg Cl/kg for barley, thus suggesting that chickpea and durum wheat were more sensitive to subsoil Cl than bread wheat, barley, and canola.


2006 ◽  
Vol 57 (3) ◽  
pp. 257 ◽  
Author(s):  
R. M. Norton ◽  
N. G. Wachsmann

The effect of management and crop selection on water use and profile drying was investigated using 2 series of experiments conducted in the Victorian Wimmera. The effect of applied nitrogen on growth and water use of canola was assessed from 3 field experiments on a Vertosol soil. Across these sites, 140 kg N/ha increased crop water use by a mean of 30 mm, and the biological response averaged 3.68 t/ha of shoot dry matter and seed yield increased by 73% from 1.46 to 2.52 t/ha. The additional nitrogen enabled roots to go deeper into the soil and also to extract water to higher tensions, but the increases in water use were far less than the growth and yield responses. Estimated average soil evaporation was 120 mm across these experiments, but ranged from 26 to 57% of total water use. It was concluded that increased crop vigour in response to applied nitrogen does increase total water use, but the main way that water-use efficiency increases is through reduced soil evaporation. In a second series of experiments, the growth, yield, and water use of wheat, canola, linseed, mustard, and safflower were compared across 4 sites with differing soil moisture contents. Wheat was the highest yielding crop at all sites. Mustard and canola produced similar amounts of biomass and seed yields, whereas linseed produced seed yields that were generally less than the brassica oilseeds. Safflower grew well and produced large amounts of biomass at all sites, but this increased growth did not necessarily translate into increased seed yields. Safflower yielded less seed than all other crops at the 2 dry sites, but yields were similar to canola at the wetter sites. On 2 drier sites, soil water extraction occurred to approximately 1 m for all crops, and all available water was used within that zone by all crops. Where the soil was wet beyond 1 m, safflower was able to extract water from deeper in the profile than the other crops and generated a soil water deficit of about 100 mm more than the other crops at maturity. This deficit persisted into the subsequent autumn–winter period. The potential of using safflower as a management option to extract water from deep in the profile, and so create a soil buffer, is discussed.


2002 ◽  
Vol 53 (5) ◽  
pp. 587 ◽  
Author(s):  
Víctor Sadras ◽  
David Roget ◽  
Garry O'Leary

The responses of wheat grain yield to soil properties, weather, root diseases, and management practices were investigated in 75 grower-managed crops in the Mallee region of South Australia, Victoria, and New South Wales during 3 growing seasons. Fourteen cultivars were represented in the sampled crops, with Frame being the most common (56%). The most widespread crop sequence was wheat after pasture (43% of wheat crops), followed by wheat after fallow or cereal (both about 20%); 12% of the wheat was sown after legumes. Wheat after cereal was more common in drier sites, and wheat after fallow in wetter sites. Wheat yield was proportional to Fischer’s photothermal coefficient around flowering, and ranged from nil to 4.7 t/ha. On average, wheat crops sown after cereals yielded 0.4 t/ha less than their counterparts sown after fallow, and 0.7 t/ha less than those after legumes. Sowing date ranged from 24 April to 21 July; yield declined with delayed sowing at an average rate of 17 kg/ha.day. Growing season rainfall (April–October) ranged from 111 to 266 mm, and accounted for 27% of the variation in grain yield. Soil water content at sowing (0–1 m) ranged from 32 to 330 mm; yield increased with initial soil water at an average rate of 6 kg/ha.mm. Grain yield per unit growing season rainfall was generally low, with 75% of crops producing <12 kg grain/ha.mm; the maximum ratio was 21 kg/ha.mm. Soil constraints, including sodicity, alkalinity, salinity, and boron toxicity, reduced yield in part by reducing availability of stored soil water. Owing to severity of chemical constraints increasing with soil depth, grain yield and yield per unit growing season rainfall were both inversely related to the proportion of water stored deeper in the soil (0.5–1 m). Yield was unrelated to nitrogen, both initial and applied. Larger amounts of nitrogen accumulated in soils with more severe constraints partially accounted for the lack of association between yield and nitrogen.


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