Lucerne removal before a cropping phase

2000 ◽  
Vol 51 (7) ◽  
pp. 877 ◽  
Author(s):  
J. F. Angus ◽  
R. R. Gault ◽  
A. J. Good ◽  
A. B. Hart ◽  
T. D. Jones ◽  
...  

Growing dryland crops after lucerne is known to be risky because of the lack of residual soil water. We investigated ways of reducing this risk by removing portions of a lucerne pasture, using either herbicides or cultivation, at monthly intervals between November and April, before sowing a wheat crop in May, followed by a canola crop in the following year. The experimental site was on a red-brown earth in southern New South Wales. Lucerne removal was incomplete when the wheat was sown, so all lucerne plants were removed from half of each plot with a post-emergence herbicide, to allow comparisons of intercropped wheat–lucerne and wheat monoculture. Measurements were made on crop growth, yield, grain quality, soil water, and soil mineral nitrogen (N) before and after both crops. On average, each additional month between lucerne removal and wheat sowing led to a yield increase of 8% and a grain protein increase of 0.3 percentage units. The main reason for the increases was additional soil mineral N, associated with a longer period of mineralisation. The soil water content at the time of wheat sowing was greater with early lucerne removal but the growing season rainfall did not limit yields, and there was more residual soil water at the time of wheat maturity where lucerne had been removed late and yields were lower. Method of lucerne removal did not significantly affect wheat yield, grain protein, soil water, or soil mineral N. The portions of the plots containing lucerne plants that survived the initial removal attempt produced similar wheat yields to the portions where lucerne had been totally removed, but grain protein was lower. The following growing season was drier, but despite less residual soil water where lucerne had been removed earlier in the previous year, the average canola yield was 2.5% greater for each additional month of fallow. The increase again appeared to be due to more residual mineral N. The seed oil concentration also decreased in response to later lucerne removal but seed protein increased. Where lucerne plants had been retained in the previous wheat crop, canola yield was lower than where they had been totally removed, apparently because of less soil water at sowing. Over the 2 years of the experiment, the net supply of mineral N was 374 kg N/ha, equivalent to an annual net mineralisation of 2% of the total soil N. The initial mineralisation rate was slow, suggesting that the soil may be deficient in mineral N soon after lucerne removal.

2013 ◽  
Vol 93 (3) ◽  
pp. 369-378 ◽  
Author(s):  
E. W. Bork ◽  
B. D. Lambert ◽  
S. Banerjee ◽  
L. J. Blonski

Bork, E. W., Lambert, B. D., Banerjee, S. and Blonski, L. J. 2013. Soil mineral nitrogen responses following liquid hog manure application to semiarid forage lands. Can. J. Soil Sci. 93: 369–378. Expansion of intensive livestock operations into semiarid regions lacking cultivated lands requires consideration of perennial forages for the efficient and sustainable disposal of manure. Little information exists on the nutrient dynamics associated with the application of manure to these areas. We examined soil mineral nitrogen (N) responses in four sites of the mixed-grass prairie, including two native grasslands and two introduced pastures, following different seasons (fall vs. spring), methods (dribble broadcast vs. coulter injected) and rates of liquid hog manure application (9.4, 18.8, 37.5, 75 and 150 kg ha−1available N). Soil mineral N, including NO3-N, NH4-N and total mineral N, were assessed after application but prior to plant growth in April 1999, and again one growing season later in April 2000. Initial soil N did not vary with season of application. Soil mineral N predictably increased with application rate, but only in the upper soil profile (0–20 cm). Decreases in soil mineral N after one growing season in all treatments highlighted the ability of these perennial forage lands to immobilize large amounts of soil N, a significant portion of which was related to N uptake by vegetation. Compared with broadcast application, manure injection led to 35% greater soil mineral N (both NO3and NH4) prior to plant growth, a response that persisted 1 yr later (+12%), thus demonstrating the N conserved benefits of manure incorporation. Overall, increases in soil mineral N within these forage lands appeared to be relatively short-term in nature, largely depleting over the course of a single growing season, suggesting one-time liquid hog manure application at low to moderate rates may be sustainable in this region of the mixed-grass prairie.


Soil Research ◽  
2017 ◽  
Vol 55 (6) ◽  
pp. 600 ◽  
Author(s):  
Mark B. Peoples ◽  
Antony D. Swan ◽  
Laura Goward ◽  
John A. Kirkegaard ◽  
James R. Hunt ◽  
...  

Nitrogen (N) contributed by legumes is an important component of N supply to subsequent cereal crops, yet few Australian grain-growers routinely monitor soil mineral N before applying N fertiliser. Soil and crop N data from 16 dryland experiments conducted in eastern Australia from 1989–2016 were examined to explore the possibility of developing simple predictive relationships to assist farmer decision-making. In each experiment, legume crops were harvested for grain or brown-manured (BM, terminated before maturity with herbicide), and wheat, barley or canola were grown. Soil mineral N measured immediately before sowing wheat in the following year was significantly higher (P < 0.05) after 31 of the 33 legume pre-cropping treatments than adjacent non-legume controls. The average improvements in soil mineral N were greater for legume BM (60 ± 16 kg N/ha; n = 5) than grain crops (35 ± 20 kg N/ha; n = 26), but soil N benefits were similar when expressed on the basis of summer fallow rainfall (0.15 ± 0.09 kg N/ha per mm), residual legume shoot dry matter (9 ± 5 kg N/ha per t/ha), or total legume residue N (28 ± 11%). Legume grain crops increased soil mineral N by 18 ± 9 kg N/ha per t/ha grain harvested. Apparent recovery of legume residue N by wheat averaged 30 ± 10% for 20 legume treatments in a subset of eight experiments. Apparent recovery of fertiliser N in the absence of legumes in two of these experiments was 64 ± 16% of the 51–75 kg fertiliser-N/ha supplied. The 25 year dataset provided new insights into the expected availability of soil mineral N after legumes and the relative value of legume N to a following wheat crop, which can guide farmer decisions regarding N fertiliser use.


2019 ◽  
Vol 56 (2) ◽  
pp. 239-254 ◽  
Author(s):  
Tanka P. Kandel ◽  
Prasanna H. Gowda ◽  
Brian K. Northup ◽  
Alexandre C. Rocateli

AbstractThe aim of this study was to compare the effects of cowpea green manure and inorganic nitrogen (N) fertilizers on yields of winter wheat and soil emissions of nitrous oxide (N2O). The comparisons included cowpea grown solely as green manure where all biomass was terminated at maturity by tillage, summer fallow treatments with 90 kg N ha−1 as urea (90-N), and no fertilization (control) at planting of winter wheat. Fluxes of N2O were measured by closed chamber methods after soil incorporation of cowpea in autumn (October–November) and harvesting of winter wheat in summer (June–August). Growth and yields of winter wheat and N concentrations in grain and straw were also measured. Cowpea produced 9.5 Mg ha−1 shoot biomass with 253 kg N ha−1 at termination. Although soil moisture was favorable for denitrification after soil incorporation of cowpea biomass, low concentrations of soil mineral N restricted emissions of N2O from cowpea treatment. However, increased concentrations of soil mineral N and large rainfall-induced emissions were recorded from the cowpea treatment during summer. Growth of winter wheat, yield, and grain N concentrations were lowest in response to cowpea treatment and highest in 90-N treatment. In conclusion, late terminated cowpea may reduce yield of winter wheat and increase emissions of N2O outside of wheat growing seasons due to poor synchronization of N mineralization from cowpea biomass with N-demand of winter wheat.


1987 ◽  
Vol 109 (1) ◽  
pp. 141-157 ◽  
Author(s):  
T. M. Addiscott ◽  
A. P. Whitmore

summaryThe computer model described simulates changes in soil mineral nitrogen and crop uptake of nitrogen by computing on a daily basis the amounts of N leached, mineralized, nitrified and taken up by the crop. Denitrification is not included at present. The leaching submodel divides the soil into layers, each of which contains mobile and immobile water. It needs points from the soil moisture characteristic, measured directly or derived from soil survey data; it also needs daily rainfall and evaporation. The mineralization and nitrification submodel assumes pseudo-zero order kinetics and depends on the net mineralization rate in the topsoil and the daily soil temperature and moisture content, the latter being computed in the leaching submodel. The crop N uptake and dry-matter production submodel is a simple function driven by degree days of soil temperature and needs in addition only the sowing date and the date the soil returns to field capacity, the latter again being computed in the leaching submodel. A sensitivity analysis was made, showing the effects of 30% changes in the input variables on the simulated amounts of soil mineral N and crop N present in spring when decisions on N fertilizer rates have to be made. Soil mineral N was influenced most by changes in rainfall, soil water content, mineralization rate and soil temperature, whilst crop N was affected most by changes in soil temperature, rainfall and sowing date. The model has so far been applied only to winter wheat growing through autumn, winter and spring but it should be adaptable to other crops and to a full season.The model was validated by comparing its simulations with measurements of soil mineral N, dry matter and the amounts of N taken up by winter wheat in experiments made at seven sites during 5 years. The simulations were assessed graphically and with the aid of several statistical summaries of the goodness of fit. The agreement was generally very good; over all years 72% of all simulations of soil mineral N to 90 cm depth were within 20 kg N/ha of the soil measurements; also 78% of the simulations of crop nitrogen uptake were within 15 kg N/ha and 63% of the simulated yields of dry matter were within 25 g/m2 of the amounts measured. All correlation coefficients were large, positive, and highly significant, and on average no statistically significant differences were found between simulation and measurement either for soil mineral N or for crop N uptake.


2008 ◽  
Vol 23 (03) ◽  
pp. 250-259 ◽  
Author(s):  
Derek H. Lynch ◽  
Zhiming Zheng ◽  
Bernie J. Zebarth ◽  
Ralph C. Martin

AbstractThe market for certified organic potatoes in Canada is growing rapidly, but the productivity and dynamics of soil N under commercial organic potato systems remain largely unknown. This study examined, at two sites in Atlantic Canada (Winslow, PEI, and Brookside, NS), the impacts of organic amendments on Shepody potato yield, quality and soil mineral nitrogen dynamics under organic management. Treatments included a commercial hog manure–sawdust compost (CP) and pelletized poultry manure (NW) applied at 300 and 600 kg total N ha−1, plus an un-amended control (CT). Wireworm damage reduced plant stands at Brookside in 2003 and those results are not presented. Relatively high tuber yields (~30 Mg ha−1) and crop N uptake (112 kg N ha−1) were achieved for un-amended soil in those site-years (Winslow 2003 and 2004) when soil moisture was non-limiting. Compost resulted in higher total yields than CT in one of three site-years. Apparent recovery of N from CP was negligible; therefore CP yield benefits were attributed to factors other than N availability. At Winslow, NW300, but not NW600, significantly increased total and marketable yields by an average of 5.8 and 7.0 Mg ha−1. Plant available N averaged 39 and 33% for NW300 and NW600, respectively. Soil (0–30 cm) NO3−-N at harvest was low (&lt;25 kg N ha−1) for CT and CP, but increased substantially both in season and at harvest (61–141 kg N ha−1) when NW was applied. Most leaching losses of NO3−-N occur between seasons and excessive levels of residual soil NO3-N at harvest, as obtained for NW600, must be avoided. Given current premiums for certified organic potatoes, improving yields through application of amendments supplying moderate rates of N or organic matter appears warranted.


1989 ◽  
Vol 37 (2) ◽  
pp. 129-141 ◽  
Author(s):  
J.J. Neeteson ◽  
H.J.C. Zwetsloot

A statistical analysis was performed to investigate if, and to what extent, the response of sugarbeet and potatoes to fertilizer N depended on the amount of mineral N already present in the soil, soil type, and prior application of organic manures. For this purpose the results of 150 field trials with sugarbeet and 98 with potatoes were used. The analysis was focussed on the within-block stratum of variation in yield, where regression models were fitted to describe the response to N. For both sugarbeet and potatoes the best fit was obtained when not only fertilizer N was taken into account, but also soil mineral N, soil type and prior application of organic manures. The response to fertilizer N was weaker as the amount of soil mineral N was larger. The optimum amount of fertilizer N plus soil mineral N required was larger on sandy soils than on loam and clay soils. The difference was about 20 kg N/ha for sugarbeet and 100 kg N/ha for potatoes. When organic manures were applied prior to the application of fertilizer N, the optimum for both sugarbeet and potatoes was 15-50 N/ha lower than without application of organic manures. (Abstract retrieved from CAB Abstracts by CABI’s permission)


1986 ◽  
Vol 26 (3) ◽  
pp. 347 ◽  
Author(s):  
WM Strong ◽  
J Harbison ◽  
RGH Nielsen ◽  
BD Hall ◽  
EK Best

Available soil mineral nitrogen (N) was determined in a Darling Downs clay at intervals of 4-6 weeks throughout summer and autumn after harvest of two cereals (wheat and oats), two oilseeds (rapeseed and linseed), and four grain legumes (chickpea, fieldpea, lupin and lathyrus). Soil mineral N (0-1.2 m) at 40,68, 107, 150 and 185 days after harvest was affected (P < 0.05) by the prior crop. At 40 days it was generally higher following grain legumes (34-76 kg/ha N) than following oilseeds or cereals (16-30 kg/ha N). Net increase during the next 145 days was in the order of cereals (2 1-27 kg/ha N) < oilseeds (40 kg/ha N) <grain legumes (53-85 kg/ha N). These differences are partly accounted for by differences in the quantities of N removed in the grain of these crops. However, a large quantity of mineral N accumulated following lupin even though a large quantity (80 kg/ha) was removed in the grain.


1997 ◽  
Vol 128 (3) ◽  
pp. 251-262 ◽  
Author(s):  
J. P. GRYLLS ◽  
J. WEBB ◽  
C. J. DYER

From 1985 to 1987, 20 experiments were carried out on shallow chalk soils, in which soil N reserves were expected to be small, to assess seasonal variations in the response of winter cereals to applied fertilizer N, and to relate these responses to measurements of soil mineral N (SMN), temperature and soil moisture deficits (SMD).Soil mineral N measured in autumn varied from 21 kg/ha (1986) to 73 kg/ha (1985), while SMN in spring ranged from 19 kg/ha (1987) to 91 kg/ha (1985), these values were typical of soils in long-term arable rotations. Estimates of apparent net N mineralization (AM) during the growing season were small at c. 26 kg/ha and suggested large seasonal variation. The small AM is considered to be due to the shallow topsoil drying out during the growing season. Whole crop N offtake without fertilizer N was only c. 40kg/ha. Crop N offtake, grain yield without fertilizer N and AFR (apparent recovery of fertilizer N) could not be reliably predicted by regression on SMN in autumn, SMN in spring or AM. Little or none of the variation in crop yield could be accounted for by regression on accumulated temperature over winter, maximum SMD in April to July or mean temperature in April to July.Despite optimum grain yields being only moderate at 6·59 t/ha for winter wheat and 6·78 t/ha for winter barley, response to applied fertilizer N was large, between 3·77 and 5·38 t/ha. In consequence the requirement for fertilizer N (c. 240–250 kg/ha) was also large, but differed little between seasons. This large requirement is concluded to be a result of limited fertilizer recovery and mineralization of soil N during the growing season.


1996 ◽  
Vol 36 (5) ◽  
pp. 581 ◽  
Author(s):  
J Evans ◽  
NA Fettell ◽  
GE O'Connor

Grain legume-cereal rotations are unsustainable on acid soils because they promote acidification of surface soil through nitrate leaching. Two field experiments were conducted on red, clay-loams in the cropping zone of central western New South Wales to determine whether soil mineral N concentrations during crop growth are higher under pea than barley, and whether the nitrate concentration under pea crops can be decreased by ammending soil with cereal straw before sowing.Significantly higher mineral N, particularly nitrate, was found under pea than under barley, as early as 6 weeks following autumn sowing, and also in spring. The pea effect represented an increase of up to 23 kg N/ha of mineral N (0-30 cm). It is proposed that the source of higher nitrate concentration under pea may be residual soil nitrate not utilised by pea, or nitrate derived from the mineralisation of pea roots or exudate. The increase in soil nitrate during pea growth contributes to greater postharvest soil mineral N and higher wheat yields after pea, but also increases the risk of soil acidification. Soil ammendment with cereal straw was partially effective in reducing nitrate concentration under pea, but a more effective treatment is required.


2005 ◽  
Vol 85 (3) ◽  
pp. 377-386 ◽  
Author(s):  
B J Zebarth ◽  
Y. Leclerc ◽  
G. Moreau ◽  
J B Sanderson ◽  
W J Arsenault ◽  
...  

Soil N supply is an important contributor of N to crop production; however, there is a lack of practical methods for routine estimation of soil N supply under field conditions. This study evaluated sampling just prior to topkill of whole potato plants that received no fertilizer N as a field bioassay of soil N supply. Three experiments were performed. In exp. 1, field trials were conducted to test if P and K fertilization, with no N fertilization, influenced plant biomass and N accumulation at topkill. In exp. 2, plant N accumulation at topkill in unfertilized plots was compared with mineral N accumulation in vegetation-free plots. In exp. 3, estimates of soil N supply were obtained from 56 sites from 1999 to 2003 using a survey approach where plant N accumulation at topkill, and soil mineral N content to 30-cm depth at planting and at tuber harvest were measured. Application of P and K fertilizer had no significant effect on plant N accumulation in two trials, and resulted in a small increase in plant N accumulation in a third trial. Zero fertilizer plots, which can be more readily established in commercial potato fields, can therefore be used instead of zero fertilizer N plots to estimate soil N supply. In exp. 2, estimates of soil N supply were generally comparable between plant N accumulation at topkill and maximum soil NO3-N accumulation in vegetation-free plots; therefore, the plant bioassay approach is a valid means of estimation of plant available soil N supply. Plant N accumulation at topkill in exp. 3 averaged 86 kg N ha-1, and ranged from 26 to 162 kg N ha-1. Plant N accumulation was higher for sites with a preceding forage crop compared with a preceding cereal or potato crop. Plant N accumulation was generally higher in years with warmer growing season temperatures. Soil NO3-N content at harvest in exp. 3 was less than 20 kg N ha-1, indicating that residual soil mineral N content was low at the time of plant N accumulation measurement. Soil NO3-N content at planting was generally small relative to plant N accumulation, indicating that soil N supply in this region is controlled primarily by growing season soil N mineralization. Use of a plant bioassay approach provides a practical means to quantify climate, soil and management effects on plant available soil N supply in potato production. Key words: Solanum tuberosum, nitrate, ammonium, N mineralization, plant N accumulation


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