Fertiliser application rates, kg nutrients/ha arable land, 2006/08 average

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mart B. H. Ros ◽  
Gerwin F. Koopmans ◽  
Kees Jan van Groenigen ◽  
Diego Abalos ◽  
Oene Oenema ◽  
...  

Abstract Because phosphorus (P) is one of the most limiting nutrients in agricultural systems, P fertilisation is essential to feed the world. However, declining P reserves demand far more effective use of this crucial resource. Here, we use meta-analysis to synthesize yield responses to P fertilisation in grasslands, the most common type of agricultural land, to identify under which conditions P fertilisation is most effective. Yield responses to P fertilisation were 40–100% higher in (a) tropical vs temperate regions; (b) grass/legume mixtures vs grass monocultures; and (c) soil pH of 5–6 vs other pHs. The agronomic efficiency of P fertilisation decreased for greater P application rates. Moreover, soils with low P availability reacted disproportionately strong to fertilisation. Hence, low fertiliser application rates to P-deficient soils result in stronger absolute yield benefits than high rates applied to soils with a higher P status. Overall, our results suggest that optimising P fertiliser use is key to sustainable intensification of agricultural systems.


Soil Research ◽  
2004 ◽  
Vol 42 (8) ◽  
pp. 913 ◽  
Author(s):  
C. G. Dorahy ◽  
I. J. Rochester ◽  
G. J. Blair

Abstract. Seventeen field experiments were conducted on alkaline soils in eastern Australia between 1997 and 2000 to evaluate irrigated cotton response to phosphorus (P) fertilisation. Only 3 experiments demonstrated significant (P < 0.05) increases in crop P uptake or lint yield with P application. Comparison of several soil P tests revealed that Colwell (bicarbonate) P provided the best correlation with P uptake at early flowering and lint yield. Soil P may limit cotton growth where Colwell-P concentrations are <6 mg/kg. Soil P concentrations at most of the sites were well above this critical limit, so P fertiliser application was not required. Average P uptake at physiological cut-out and P removal in seed cotton was 21 and 15 kg P/ha, respectively. Apparent P fertiliser recovery was variable (0–67%) and may have contributed to the lack of response that was observed in 14 out of the 17 experiments. It is recommended that at least 40 kg P/ha be applied to soils with Colwell-P concentrations <6 mg/kg to increase soil P reserves. Application rates of at least 20 kg P/ha are recommended where Colwell-P falls between 6 and 12 mg/kg to maintain soil P fertility.


1995 ◽  
Vol 125 (2) ◽  
pp. 245-252 ◽  
Author(s):  
J.-F. Moal ◽  
J. Martinez ◽  
F. Guiziou ◽  
C.-M. Coste

SUMMARYField experiments were carried out in Brittany (Western France) in 1993 to measure ammonia losses from surface-applied pig and cattle slurry. Experiments were conducted on grass, stubble (wheat and maize) and arable land using a wind tunnel system. Ammonia losses were followed during periods ranging from 20 to 96 h after slurry application. Rates of slurry applied varied from 40 to 200 m3/ha. In two experiments, losses from cattle slurry were respectively 75 and 54% of the ammoniacal nitrogen applied in the slurry. Ammonia emissions from pig slurry applied at a rate of 40 m3/ha, during spring and summer experiments, were higher on grass (45–63% of the total ammoniacal nitrogen applied) than on wheat stubble (37–45%). On average, 75% of the total loss in all experiments occurred within the first 15 h after spreading. Significant correlations were found between ammonia losses (kg N/ha) and mean soil temperature and slurry dry matter content (%) using simple linear regressions and stepwise procedures. The time of application was also found to influence the magnitude of ammonia loss: 83% of the total loss occurred within 6 h when the slurry was applied at midday compared with 42% when it was applied in the evening.


2017 ◽  
Vol 68 (12) ◽  
pp. 1100 ◽  
Author(s):  
K. G. Pembleton ◽  
R. P. Rawnsley ◽  
L. R. Turner ◽  
R. Corkrey ◽  
D. J. Donaghy

A key goal of temperate pasture management is to optimise nutritive value and production. The influence of individual components such as irrigation, nitrogen (N) fertiliser, and grazing interval and intensity has been well researched, yet conjecture remains regarding practices that optimise pasture nutritive value, largely because interactions between inputs and grazing management have not been quantified. A 2-year, split-split-plot experiment was undertaken to investigate these interactions in a perennial ryegrass (Lolium perenne L.) dominant pasture at Elliott, Tasmania. Irrigation treatments (rainfed or irrigated) were main plots and defoliation intervals (leaf regrowth stage: 1-, 2- or 3-leaf) were subplots. Defoliation intensity (defoliation height: 30, 55 or 80 mm) and N fertiliser (0, 1.5 or 3.0 kg N/ha.day) were crossed within sub-subplots. Herbage samples were collected from each plot four times during the experiment and analysed for concentrations (% dry matter, DM) of neutral detergent fibre (NDF), acid detergent fibre (ADF) and crude protein (CP). Metabolisable energy (ME) concentration (MJ/kg DM) was estimated from these values. ME concentration decreased as defoliation height and interval increased for all time points except during winter. Crude protein concentration increased with increasing N fertiliser applications in the plots defoliated at the 1-leaf stage, but only as N applications increased from 1.5 to 3.0 kg N/ha.day for the plots defoliated at the 2- and 3-leaf stages. As N application rates increased from 0 to 1.5 kg N/ha.day, plots defoliated at the 3-leaf stage had greater increases in NDF concentration than plots defoliated at the 1-leaf stage, except during spring. As defoliation height and interval increased, ADF concentration increased in both spring and summer. Although defoliating at frequent intervals (1-leaf stage) and lower heights (30 mm) produced pasture of marginally higher nutritional value, these benefits are mitigated by the previously established, negative consequences of lower pasture yield and poor pasture persistence. Consequently, grazing management that maximises pasture productivity and persistence (i.e. defoliation between the 2- and 3-leaf regrowth stages to a height of 55 mm) should be applied to perennial ryegrass pastures irrespective of input management.


2021 ◽  
Author(s):  
Sheng Tang ◽  
Jingjie Zhou ◽  
Wankun Pan ◽  
Rui Tang ◽  
Qingxu Ma ◽  
...  

Abstract Aims Soil in tea plantations is characterised by severe acidification and high aluminium and fluorine content. Applying excessive nitrogen (N) is a common strategy in tea plantations. Fungal and bacterial responses to N fertiliser addition in tea plantations, especially their relationship with tea growth, quality, and soil microbiome composition, remain unclear. Methods We performed a field experiment using different N fertiliser application rates for 5 years (2016‒2020) in a tea-producing region of China. Results Application of excessive N (600 kg ha− 1 y− 1) reduced tea yield and quality. High N application rates (360 and 600 kg ha− 1 y− 1) significantly decreased bacterial and fungal diversity and altered the compositions of bacterial and fungal communities (P < 0.05). Fungi were more tolerant than bacteria to soil environmental changes induced by N fertiliser application. Succession of bacterial and fungal communities was mostly driven by pH. Partial least square path modelling suggested that N addition directly influenced the diversity and communities of bacteria and fungi, and indirectly influenced bacterial community and fungal diversity by mediating soil nutrients and pH. The assembly of fungal communities was more regulated by dispersal limitation and deterministic processes than that of bacterial communities. High microbial diversity was not a requirement for tea growth. Conclusions Fungi had a greater impact on tea yield and quality than bacteria; therefore, more attention should be given to fungi, which play a stable role in nutrient cycling and organic matter decomposition in tea plantation, eventually favouring tea growth.


2017 ◽  
Vol 10 (1) ◽  
pp. 133
Author(s):  
Obert Jiri ◽  
Paramu L. Mafongoya

In a field experiment on legume-maize cropping sequence, the effect of nitrogen and phosphate fertiliser application on nutrient budgeting after a two year cropping cycle was studied. The results of this work showed that partial nutrient balances can give an indication about the sustainability of a system unless a full stock of all the nutrients is known. It is also clear from these results that there would unlikely be a carryover of N to the next season, probably due to leaching of N from the top soil. Positive partial P balances would, on the other hand, be of residual value. However, it should be noted that the positive partial P balances were only observed where maize yield was low. The long-term perspectives of a crop production system cannot be assessed solely on the basis of partial nutrient balances. The nutrient stock: balance ratio may be a better indicator of sustainability, giving a more accurate indication of how long farming can continue in the same way, given the available nutrients. These points towards taking a fresh look at the existing recommended application rates for maize crops.


2019 ◽  
Vol 457 (1-2) ◽  
pp. 25-41 ◽  
Author(s):  
Diriba B. Kumssa ◽  
J. Alan Lovatt ◽  
Neil S. Graham ◽  
Sarah Palmer ◽  
Rory Hayden ◽  
...  

Abstract Aim Magnesium (Mg) deficiency (known as grass tetany) is a serious metabolic disorder that affects grazing ruminants. We tested whether Mg-fertiliser can increase Mg concentration of Italian ryegrasses (Lolium multiflorum L.) including a cultivar (cv. Bb2067; ‘Magnet’), bred to accumulate larger concentrations of Mg. Methods Under controlled environment (CE) conditions, three cultivars (cv. Bb2067, cv. Bb2068, cv. RvP) were grown in low-nutrient compost at six fertiliser rates (0–1500 μM MgCl2.6H2O). Under field conditions, the three cultivars in the CE condition and cv. Alamo were grown at two sites, and four rates of MgSO4 fertiliser application rates (0–200 kg ha−1 MgO). Multiple grass cuts were taken over two-years. Results Grass Mg concentration increased with increasing Mg-fertiliser application rates in all cultivars and conditions. Under field conditions, cv. Bb2067 had 11–73% greater grass Mg concentration and smaller forage tetany index (FTI) than other cultivars across the Mg-fertiliser application rates, sites and cuts. Grass dry matter (DM) yield of cv. Bb2067 was significantly (p < 0.05) smaller than cv. Alamo. The effect of Mg-fertiliser rate on DM yield was not significant (p ≥ 0.05). Conclusions Biofortification of grass with Mg through breeding and agronomy can improve the forage Mg concentration for grazing ruminants, even in high-growth spring grass conditions when hypomagnesaemia is most prevalent. Response to agronomic biofortification varied with cultivar, Mg-fertiliser rate, site and weather. The cost:benefit of these approaches and farmer acceptability, and the impact on cattle and sheep grazing on grasses biofortified with Mg requires further investigation.


2014 ◽  
Vol 54 (3) ◽  
pp. 234 ◽  
Author(s):  
J. Tharmaraj ◽  
D. F. Chapman ◽  
J. Hill ◽  
J. L. Jacobs ◽  
B. R. Cullen

A dairy farmlet experiment was conducted at Terang in south-west Victoria, Australia, over 4 years to test the hypothesis that a 30% increase in forage harvested per ha could be achieved in a production system that incorporated a range of Complementary Forages with perennial ryegrass (CF) compared with a well managed perennial ryegrass-only farmlet (‘Ryegrass Max’, RM). The CF farmlet included perennial ryegrass pasture (44% of the farmlet area on average over 4 years), but also incorporated oversowing perennial ryegrass with short-term ryegrasses (average 16% of farmlet area) to increase winter growth, tall fescue-based pasture (average 20% of farmlet area) to increase production in the late spring–summer period, a double cropping rotation (15% of farmlet area) based on winter cereal for silage production followed by summer brassica crops for grazing, and summer crops used in the pasture renovation process (average 5% of farmlet area). The RM and CF farmlets were stocked at 2.2 and 2.82 June-calving cows/ha, respectively and average annual nitrogen (N) fertiliser application rates (pasture only) were 141 and 153 kg N/ha, respectively. The total amount of forage harvested per year was generally less than predicted from pre-experimental modelling of both farmlets. However, the proposed target of a 30% increase in home-grown forage harvest per ha in the CF system compared with RM was exceeded in 2005–06 (+33%), with 21, 16 and 11% higher forage harvest achieved in CF in 2006–07, 2007–08 and 2008–09, respectively (average for all 4 years = 20%). Annual forage harvested in RM ranged between 6.5 and 8.9 t DM/ha compared with 7.9–10.3 t DM/ha in CF. Approximately two-thirds of the increased forage harvest in CF came from higher rates of pasture consumption per ha and one-third from the double cropping component of the system, although the performance of the double crop (mean annual production of 11.5 t DM/ha) was well below the expected 20 t DM/ha based on pre-experimental modelling. The higher per-hectare pasture harvest rates in CF were primarily due to increased perennial ryegrass pasture consumption achieved through higher stocking rates and efficient responses to higher N inputs from both higher fertiliser rates and additional supplementary feeding. In CF, the DM harvested from pastures oversown with short-term ryegrasses was lower than perennial ryegrass, while tall fescue-based pastures were similar to perennial ryegrass. Poor spring rainfall in 2006–07 and 2008–09 likely contributed to the lower than expected DM yields of tall fescue-based pasture and the summer crops within the double cropping component. Home-grown forage harvest rates can be increased by 11–33% above what is currently achieved by best industry practice with perennial ryegrass-only pastures using complementary forages but perennial ryegrass will remain a key component of the forage base for dairy production in southern Australia.


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