Understanding subsoil acidification: effect of nitrogen transformation and nitrate leaching

Soil Research ◽  
2000 ◽  
Vol 38 (4) ◽  
pp. 837 ◽  
Author(s):  
Z. Rengel ◽  
C. Tang ◽  
C. Raphael ◽  
J. W. Bowden
Keyword(s):  
Soil Ph ◽  
Nitrate Leaching ◽  
Root Length ◽  
Root Length Density ◽  
Soil Column ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Nitrogen Transformation ◽  
Column Experiments ◽  
Excess Water

Nitrification and nitrate leaching have been suggested to be major causes of soil acidification. However, it is unknown whether these processes cause subsoil acidification. Soil column experiments examined the effect of the addition of Ca(NO3)2 or (NH4)2SO4 to the topsoil horizon on subsoil acidification under nodulated lupins (Lupinus angustifolius L.) and subterranean clover (Trifolium subterraneum L.). Nitrate leaching was achieved by adding excess water to the surface of the columns. Where basal nutrients were applied only to the top 10-cm layer, about 60–70% of the total root length of lupin and over 50% of subterranean clover were distributed in that layer. Plants grown without added nitrate for 105 days decreased soil pH at all layers but more significantly in the top 20 cm (by up to 0.7 units); the decrease in pH correlated well with increased root length density of both species (r 2 = 0 .9 8 , n = 9). The addition of Ca(NO3)2 to the top 10-cm layer caused less acidification by about 0.1 pH units at all depths than the treatment without Ca(NO3)2 . Where basal nutrients were applied uniformly throughout the column, root length density of lupin and subterranean clover tended to increase with depth. The addition of (NH4)2SO4 in the top 10 cm significantly increased NO3– concentration in all layers but NH4+ was mainly retained in the top 30-cm layer. Lupin and subterranean clover grown without added NH4+ for 82 days decreased soil pH by 0.3 units at all depths. Compared with the plants receiving no (NH4)2SO 4 , lupin grown with (NH4)2SO4 at 0–10 cm depth in the column caused more acidification by 0.05–0.2 pH units in the top 10 cm but less acidification by 0.15–0.17 units at 10–40 cm depth in the column; subterranean clover grown with (NH4)2SO4 caused more acidification by 0.35–0.46 units in the top 10 cm and less acidification by 0.14–0.19 units in the 20–50 cm layer. The results suggest that the leaching of nitrate from topsoil is unlikely to cause subsoil acidification. In contrast, the uptake of nitrate by the roots reduces net acid production in subsoil layers.

scholarly journals Root architecture, rooting profiles and physiological responses of potential slope plants grown on acidic soil

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9595
Author(s):  
Deivaseeno Dorairaj ◽  
Muhammad Fahmi Suradi ◽  
Nursyamimi Syafiqah Mansor ◽  
Normaniza Osman
Keyword(s):  
Plant Species ◽  
Soil Ph ◽  
Root Length ◽  
Root Length Density ◽  
Average Diameter ◽  
Progressive Increase ◽  
Acidic Soil ◽  
Melastoma Malabathricum ◽  
Root Anchorage ◽  
Healthy Growth

Globally, there has been an increase in the frequency of landslides which is the result of slope failures. The combination of high intensity rainfall and high temperature resulted in the formation of acidic soil which is detrimental to the healthy growth of plants. Proper plant coverage on slopes is a prerequisite to mitigate and rehabilitate the soil. However, not all plant species are able to grow in marginal land. Thus, this study was undertaken to find a suitable slope plant species. We aimed to evaluate the effect of different soil pH on root profiles and growth of three different potential slope plant species namely, Melastoma malabathricum, Hibiscus rosa-sinensis and Syzygium campanulatum. M. malabathricum showed the highest tolerance to acidic soil as it recorded the highest plant height and photosynthetic rate. The root systems of M. malabathricum, H. rosa-sinensis and S. campanulatum were identified as M, VH- and R-types, respectively. The study proposed M. malabathricum which possessed dense and shallow roots to be planted at the toe or top of the slope while H. rosa-sinensis and S. campanulatum to be planted in the middle of a slope. S. campanulatum consistently recorded high root length and root length density across all three types of soil pH while M. malabathricum showed progressive increase in length as the soil pH increased. The root average diameter and root volume of M. malabathricum outperformed the other two plant species irrespective of soil pH. In terms of biomass, M. malabathricum exhibited the highest root and shoot dry weights followed by S. campanulatum. Thus, we propose M. malabathricum to be planted on slopes as a form of soil rehabilitation. The plant species displayed denser rooting, hence a stronger root anchorage that can hold the soil particles together which will be beneficial for slope stabilization.

Root distribution in space and time in Trifolium subterraneum

1985 ◽  
Vol 36 (4) ◽  
pp. 601 ◽  
Author(s):  
CJ Pearson ◽  
BC Jacobs
Keyword(s):  
Leaf Area ◽  
Root Length ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Coarse Sand ◽  
Horizontal Distribution ◽  
Dry Matter Partitioning ◽  
Rooting Zone ◽  
Root Death ◽  
Vertical And Horizontal Distribution

Distribution of length and weight of roots of subterranean clover cultivars Northarn and Nungarin were measured in the field throughout a growing season. Plants were grown at seven populations from 2 to 1510 plants per m2 in coarse sand which had a bulk density of 1.4 g cm-3. Root growth was described by its vertical and horizontal distribution as functions of population and time after emergence. Differences in growth between cultivars were small. Root depth, which reached a maximum (plateau) at about 90 days, did not vary with plant population. Root density (length per volume of soil) increased faster at high population due to a higher density of' roots beneath the mainstream and an attenuation with distance away from the mainstem which did not appear to be affected by population. Root densities were 10 cm cm-3 in the uppermost core (0-10 cm depth) and 1.6 -3.5 cm cm-3 throughout the rooting zone (0-50 cm) at 119 days after emergence. Root death, estimated from dichlorotrianzinyl staining, was negligible. Leaf area per plant declined with population above 16 plants per m2; leaf area per unit root length (in cores beneath the mainstream) declined 90-fold with increase in population. Top weight and burr yield per plant at final harvest also declined with increasing population; burr yield per m2 also fell significantly at the highest population. It is concluded that the amount of root per unit area increases with population and that plants appear to adjust conservatively in some respects (to much lower leaf area per root length) while being unable to sustain dry matter partitioning (reducing burr/top yields) at the highest population studied.

Banding phosphorus and ammonium enhances nutrient uptake by maize via modifying root spatial distribution

2013 ◽  
Vol 64 (10) ◽  
pp. 965 ◽  
Author(s):  
Qinghua Ma ◽  
Hongliang Tang ◽  
Zed Rengel ◽  
Jianbo Shen
Keyword(s):  
Spatial Distribution ◽  
Nutrient Uptake ◽  
Root Length ◽  
Root Length Density ◽  
Soil Column ◽  
Calcareous Soils ◽  
Ammonium Phosphate ◽  
P Uptake ◽  
Uptake Rates ◽  
P Uptake Rates

Localised supply of phosphorus (P) plus ammonium improves root proliferation and nutrient uptake by plants grown on calcareous soils, but how nitrogen (N) forms (ammonium and urea) and placements affect maize (Zea mays L.) root distribution and nutrient uptake is not fully understood. A soil column study was conducted with four N and P combinations including P plus urea (UP), mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP) and P plus ammonium sulfate (ASP), and two fertiliser application methods (banding in the 10–25 cm layer or mixing throughout the 45-cm soil profile). Shoot N and P content increased by 11–31% and 14–37% in the treatments with banding P plus ammonium (MAP, DAP or ASP) compared with banding UP and the mixing treatments. Shoot N and P uptake rates per root dry weight or root length were higher with banding P plus ammonium than their respective mixing treatments. Banding P plus ammonium increased root-length density in the fertiliser-banded layer compared with banding UP and the mixing treatments. The results show that modifying root spatial distribution by banding P plus ammonium leads to an increase in N and P uptake rates, and consequently enhances nutrient accumulation by maize.

Effect of waterlogging and soil pH on the micro-distribution of naturalised annual legumes

1997 ◽  
Vol 48 (2) ◽  
pp. 223 ◽  
Author(s):  
M. R. Gibberd ◽  
P. S. Cocks
Keyword(s):  
Root Growth ◽  
Soil Ph ◽  
Soil Seed Bank ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Waterlogging Tolerance ◽  
Patchy Distribution ◽  
Shoot Dry Weight ◽  
Waterlogging Treatment

Variation in the size and composition of the soil seed bank of 3 naturalised legumes, subterranean clover (Trifolium subterraneum L.), woolly clover (T. tomentosum L.), and cluster clover (T. glomeratum L.), was related to soil characteristics on a transect that ascended from a winter waterlogged area in a wheatbelt pasture. Growth of the 3 species was compared with other species from section Vesicaria (T. resupinatum and T. clusii) in waterlogged and freely drained pots for 34 days. Of the 3 naturalised legumes present in the transect, cluster clover was rare, and woolly and subterranean clovers were separated on the basis of their response to soil pH and the likelihood of winter waterlogging. Subterranean clover was absent from soil with pH > 7·0; these areas were dominated by woolly clover. Areas with pH < 7·0 were dominated by subterranean clover, except where winter waterlogging was likely, in which case they were once again dominated by woolly clover. The waterlogging tolerance of woolly clover, together with that of other species in section Vesicaria, was confirmed in the pot experiment. After 34 days, shoot dry weight of the waterlogged Vesicaria species was an average of 39% greater than the freely drained controls. Root length continued to increase for the duration of the waterlogging treatment with much of the new root growth as laterals. Conversely, shoot and root growth in subterranean and cluster clovers was severely reduced by waterlogging. The patchy distribution of woolly clover in many wheatbelt pastures can be explained by its response to high pH and winter waterlogging compared with subterranean clover.

A study of inoculation and sowing methods for Trifolium subterraneum in New South Wales

1973 ◽  
Vol 13 (62) ◽  
pp. 284 ◽  
Author(s):  
RJ Roughley ◽  
MH Walker
Keyword(s):  
Soil Ph ◽  
New South ◽  
New South Wales ◽  
Previous History ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Positive Effects ◽  
Ph Values ◽  
South Wales ◽  
History Of

The effects of treatments known to influence the nodulation of subterranean clover (Trifolium subterraneum) were tested at 32 sites in New South Wales. The influence of the treatments varied but where positive effects were obtained the results generally corroborated earlier findings. At soil pH values below 5.5, lime pelleting was generally superior to slurry inoculation without lime but still better nodulation resulted from drilling inoculated seed with equal parts of lime and superphosphate. The results highlighted the difficulty of predicting the need to inoculate seed to achieve effective nodulation. The soil texture and pH, presence of the host plant and the previous history of the site were not reliable guides. Nodulation was generally improved by separating seed and superphosphate and by drilling seed rather than broadcasting it even if covered later.

Intrinsic capacity for nutrient foraging predicts critical external phosphorus requirement of 12 pasture legumes

2018 ◽  
Vol 69 (2) ◽  
pp. 174 ◽  
Author(s):  
Graeme A. Sandral ◽  
Rebecca E. Haling ◽  
Megan H. Ryan ◽  
Andrew Price ◽  
Wayne M. Pitt ◽  
...  
Keyword(s):  
Root Length ◽  
Root Length Density ◽  
Maximum Yield ◽  
Root Hairs ◽  
Specific Root Length ◽  
Trifolium Subterraneum ◽  
Legume Species ◽  
Pasture Legumes ◽  
Phosphorus Requirement ◽  
Pasture Legume

The mainstream pasture legume species such as Trifolium subterraneum, T. repens and annual Medicago spp. used in the temperate pasture systems of southern Australia have high critical external requirements for phosphorus (P) (i.e. P required to achieve 90% of maximum yield). This work aimed to identify alternative pasture legume species that could be used in systems with lower P input. Shoot and root biomass of 12 species of pasture legume was measured in response to seven rates of P applied to the top 48 mm of soil in a pot experiment. Most species had maximum yields similar to T. subterraneum, but some required only one-third of the applied P to achieve this. The critical external P requirement of the species, ranked from lowest to highest, was as follows: Ornithopus compressus = O. sativus < Biserrula pelecinus < T. michelianum = T. vesiculosum = T. glanduliferum < T. hirtum = Medicago truncatula = T. purpureum = T. incarnatum < T. spumosum = T. subterraneum. An ability to maximise soil exploration through a combination of high root-length density, high specific root length and long root hairs (i.e. a large specific root-hair-cylinder volume) was associated with a low critical external P requirement. The results indicate that Ornithopus spp. could be used to achieve productive, low P-input pasture systems.

The role of calcium in alleviating aluminium toxicity

1986 ◽  
Vol 37 (4) ◽  
pp. 375 ◽  
Author(s):  
AK Alva ◽  
CJ Asher ◽  
DG Edwards
Keyword(s):  
Ionic Strength ◽  
Root Growth ◽  
Root Length ◽  
Protective Action ◽  
Primary Root ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Aluminium Toxicity ◽  
Solution Ionic Strength ◽  
Soybean Root

Effects of varying calcium (Ca) concentration at constant or varying solution ionic strength on root elongation of soybean (Glycine max (L.) Merr.) and subterranean clover (Trifolium subterraneum L.) were determined in aluminium (Al) free nutrient solution or solutions containing monomeric Al activities (+aAl mono) of 8-10 8M for subterranean clover and 20-22 8M for soybean. In Al-free solutions, the root length for subterranean clover was not significantly influenced by Ca or ionic strength. However, soybean root length was greater at 500 8M Ca than at higher Ca concentrations. Raising the ionic strength at 500 and 5000 8M Ca significantly decreased root length. In the presence of Al, maximum root length of both species occurred at 15 000 8M Ca. Soybean root length at 500 and 5000 8M Ca was 35% and 87% respectively of that at 15000 8M Ca. The corresponding values for subterranean clover were 53% and 81%. The positive effect of Ca concentration on root length, despite a nearly constant +aAL mono, confirms the existence of a protective action of Ca against Al toxicity. Raising the solution ionic strength at 500 8M Ca in the presence of Al improved the root growth of soybean by 86% and that of subterranean clover by 45%. At 5000 8M Ca, a small beneficial effect of increased ionic strength (14%) was found only in subterranean clover. Increasing Ca concentration in solution decreased water extractable and 0-1 M HNO3 extractable Al in roots of both plant species. Transfer of soybean seedlings to Al-free nutrient solutions containing 500, 1500 or 5000 pM Ca after 24, 48 or 96 h in a solution containing +aAL mono of 22 8M resulted in a substantial recovery in primary root growth. Relative root lengths were in each case significantly higher at 5000 8M Ca than at 1500 or 500 pM Ca. Roots transferred to 500 8M Ca after exposure to Al for 6 or 18 h underwent a period of accelerated elongation after a lag period of 30-40 h. By 138 h there were no significant differences in root length between the unstressed control plants and those subjected to 6 or 18 h Al-stress.

Soil acidification under subterranean clover (Trifolium subterraneum L.) pastures in north-eastern Victoria

1990 ◽  
Vol 30 (2) ◽  
pp. 195 ◽  
Author(s):  
AM Ridley ◽  
KR Helyar ◽  
WJ Slattery
Keyword(s):  
Soil Ph ◽  
Soil Acidification ◽  
Acid Soils ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Farming Systems ◽  
Mineral Dissolution ◽  
Acid Addition ◽  
North Eastern ◽  
Capacity Data

Eleven paired soil samples to 60 cm depth were collected from grazing properties in north-eastern Victoria. Soils were naturally acid and most were red or yellow podsolics. At each site unfertilised soils (unimproved) and soils which had received regular superphosphate applications (improved) were sampled from either side of a fenceline. The percentage of organic carbon was higher on improved sites but pH was usually lower. Using pH and pH buffering capacity data, the rate of soil acidification under improved pasture, relative to unimproved pasture, was estimated. The improved pastures, on average, required 39 kg CaCO3ka.year to balance the net acid accumulated. The estimated rates of acidification are much lower than those reported previously for similar environments and soil types in New South Wales. There was a relationship between initial profile pH and net acid addition, lower measured net acid addition being associated with low initial soil pH. This paper demonstrates the need for both standardisation of soil pH buffer capacity measurements, and more direct assessment of the role of soil mineral dissolution processes in buffering the pH of strongly acid soils. Until such data exists it will be very difficult to provide convincing information to primary producers regarding the long term alkali input requirements needed for sustainable farming systems.

Sex-specifically responsive strategies to phosphorus availability combined with different soil nitrogen forms in dioecious Populus cathayana

2021 ◽  
Author(s):  
Xiucheng Liu ◽  
Yuting Wang ◽  
Shuangri Liu ◽  
Miao Liu
Keyword(s):  
Root Length ◽  
Root Length Density ◽  
Specific Root Length ◽  
P Uptake ◽  
Root Tip ◽  
P Availability ◽  
P Deficiency ◽  
Populus Cathayana ◽  
Leaf P ◽  
P Supply

Abstract Aims Phosphorus (P) availability and efficiency are especially important for plant growth and productivity. However, the sex-specific P acquisition and utilization strategies of dioecious plant species under different N forms are not clear. Methods This study investigated the responsive mechanisms of dioecious Populus cathayana females and males based on P uptake and allocation to soil P supply under N deficiency, nitrate (NO3 −) and ammonium (NH4 +) supply. Important Findings Females had a greater biomass, root length density (RLD), specific root length (SRL) and shoot P concentration than males under normal P availability with two N supplies. NH4 + supply led to higher total root length, RLD and SRL but lower root tip number than NO3 − supply under normal P supply. Under P deficiency, males showed a smaller root system but greater photosynthetic P availability and higher leaf P remobilization, exhibiting a better capacity to adaptation to P-deficiency than females. Under P deficiency, NO3 − supply increased leaf photosynthesis and PUE but reduced RLD and SRL in females while males had higher leaf P redistribution and photosynthetic PUE than NH4 + supply. Females had a better potentiality to cope with P deficiency under NO3 − supply than NH4 + supply; the contrary was true for males. These results suggest that females may devote to increase in P uptake and shoot P allocation under normal P availability, especially under NO3 − supply, while males adopt more efficient resource use and P remobilization to maximum their tolerance to P-deficiency.

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