Long-term influence of cropping systems, tillage methods, and N sources on nitrate leaching

1995 ◽  
Vol 75 (4) ◽  
pp. 497-505 ◽  
Author(s):  
R. C. Izaurralde ◽  
Y. Feng ◽  
J. A. Robertson ◽  
W. B. McGill ◽  
N. G. Juma ◽  
...  

The extent of nitrate leaching in cultivated soils of Alberta is unknown. We studied how long- and short-term agricultural practices influenced nitrate leaching in a cryoboreal subhumid soil-climate of north-central Alberta. The study used plots from three crop rotation-tillage studies at Breton on an Orthic Gray Luvisol, and from one at Ellerslie on an Orthic Black Chernozem. Soil samples were taken in the fall of 1993 from selected treatments as well as native forest sites in 0.3-m depth increments from 0 to 3.9 m and analyzed for NO3-N. No NO3− were found under native forest vegetation. NO3-N accumulated below 0.9-m depth of agricultural ecosystems cultivated for as long as 64 yr ranged from 0 to 67 kg N ha−1. At Breton, fallow-wheat rotation plots receiving fertilizer N and manure contained eight times more NO3-N below 0.9 m depth than non-fertilized plots. NO3-N levels in an 8-yr legume-based rotation and in continuous-barley plots were similar but greater than in continuous-forage plots. Eighty-seven percent of NO3− found under continuous barley occurred below the root zone compared with only 35% in the 8-yr rotation. At Ellerslie, NO3-N mass was related to fertilizer N and mineralization of soil organic matter. Increased efforts should be directed towards better synchronizing N release from or addition to soils with plant uptake. Evidence of greater nitrate leaching under zero tillage than under conventional warrants further confirmation. Key words: Nitrogen loss, fallow, Hordeum vulgare L., Triticum aestivum L., manure, legumes, synthetic fertilizer

1993 ◽  
Vol 73 (4) ◽  
pp. 387-397 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
O. O. Akinremi

The possibility of nitrates being leached into groundwater supplies from improper use of fertilizers is a concern to society. Two experiments were conducted on a loam soil in the Brown soil zone at Swift Current, Saskatchewan. In the first experiment, continuous wheat (Triticum aestivum L.), grown under various fertilizer-N management systems and with and without cereal trap strips (tall stubble, 0.4–0.6 m) to capture snow and enhance soil-moisture storage, was compared with short stubble cut at the standard height (0.15–0.2 m). Prior to seeding in spring 1991, tall stubble had stored 14.7 ha-cm of soil moisture at 0–1.2-m depth compared with 10.9 ha-cm under short-stubble treatment. Because growing-season precipitation in 1991 was much higher than normal (302 mm from 1 May to 31 My), considerable NO3-N was leached below the rooting zone of wheat (1.2 m), particularly in the tall-stubble treatment. Leaching patterns were as expected in short stubble, with major leaching occurring only at the highest N rate (125 kg ha−1), where yield and N-uptake response had levelled off. However, in tall stubble, the amount of NO3-N leached beyond the root zone under the 0 and 25 kg N ha−1 rates was similar to that under the 125 kg N ha−1 rate. This result was attributed to poor tillering obtained at low N rates, which contributed to lower evapotranspiration, thereby permitting more moisture to be leached and enhancing N mineralization. When we used a leaching model (NLEAP) to simulate our results, it gave lower estimates of NO3 leached and did not reveal the interaction of NO3-N leaching with N rates that was observed under tall stubble. The second experiment measured soil NO3-N distribution to 2.4 m under two fallow–wheat–wheat systems after a 24-yr period. One system received only N, the other, N + P fertilizer. The results corroborated those obtained under tall stubble in the first experiment: the poorly fertilized system had the most NO3-N below the root zone. The results of this study suggest that the key to reducing nitrate leaching is the adoption of proper fertilization practices, since too little fertilization may potentially be as detrimental to groundwater pollution as too much. Key words: Fertilizer N, N uptake, snow management, crop rotations, NO3 leaching


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1571
Author(s):  
Nicolò Colombani ◽  
Micòl Mastrocicco ◽  
Fabio Vincenzi ◽  
Giuseppe Castaldelli

Nitrate is a major groundwater inorganic contaminant that is mainly due to fertilizer leaching. Compost amendment can increase soils’ organic substances and thus promote denitrification in intensively cultivated soils. In this study, two agricultural plots located in the Padana plain (Ferrara, Italy) were monitored and modeled for a period of 2.7 years. One plot was initially amended with 30 t/ha of compost, not tilled, and amended with standard fertilization practices, while the other one was run with standard fertilization and tillage practices. Monitoring was performed continuously via soil water probes (matric potential) and discontinuously via auger core profiles (major nitrogen species) before and after each cropping season. A HYDRUS-1D numerical model was calibrated and validated versus observed matric potential and nitrate, ammonium, and bromide (used as tracers). Model performance was judged satisfactory and the results provided insights on water and nitrogen balances for the two different agricultural practices tested here. While water balance and retention time in the vadose zone were similar in the two plots, nitrate leaching was less pronounced in the plot amended with compost due to a higher denitrification rate. This study provides clear evidence that compost addition and no-tillage (conservation agriculture) can diminish nitrate leaching to groundwater, with respect to standard agricultural practices.


1987 ◽  
Vol 67 (1) ◽  
pp. 103-116 ◽  
Author(s):  
J. P. SINGH ◽  
J. W. B. STEWART ◽  
R. E. KARAMANOS

Current criteria for predicting zinc (Zn) deficiency in Saskatchewan soils are based on DTPA-extractable Zn values. DTPA-extractable Zn levels in 12% of 1200 samples taken across Saskatchewan contained less than 0.5 mg Zn kg−1 soil and would be classified as potentially Zn deficient. However, 23 field trials in 1982, 1983 and 1984 with spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), lentils (Lens esculenta Moench.), peas (Pisum sativum L.), alfalfa (Medicago sativa L.), corn (Zea mays L.) and flax (Linum usitatissimum L.) produced only one significant response to Zn fertilization. No yield benefits due to either annual or residual application of Zn fertilizer were obtained even on high lime soils or those containing DTPA-extractable Zn levels below 0.5 mg kg−1 soil. Hence, current soil criteria to identify Zn deficiencies under the prevailing cropping systems must be revised to reflect these findings. Key words: DTPA-extractable Zn, crop response, critical level


2004 ◽  
Vol 84 (1) ◽  
pp. 187-194 ◽  
Author(s):  
D. McCartney ◽  
L. Townley-Smith ◽  
A. Vaage ◽  
J. Pearen

Herbage production for silage and pasture production of annual species was investigated near Melfort in northeastern Saskatchewan. Barley (Hordeum vulgare L.) and oats (Avena sativa L.) were seeded as spring monocrops (SMC) and in binary intercrop (IC) mixtures with fall species including winter wheat (Triticum aestivum L.), fall rye (Secale cereale L.), winter triticale (X Triticosecale Wittmack L.), biennial Italian ryegrass (Lolium multiflorum Lam.) and annual Westerwolds ryegrass (Lolium multiflorum Lam.). Fall species were also seeded as monocrops (FMC). Silage Spring harvest occurred when barley (early-silage cut) and oats (late-silage cut) reached soft dough stage and again late in the autumn. An additional deferred grazing (DG) treatment containing each one fall species was harvested once in the autumn. Mean ranking of spring herbage silage yield was Oat-SMC (100%) > Oat-IC (91%) > Barley-SMC (83%) = Barley-IC (78%) > late-cut FMC (53%) > early-cut FMC (42%) (P ≤ 0.001). SilageSpring herbage yield of IC combinations was similar, but FMCs containing annual ryegrass were 26% to 34% (P ≤ .01) greater than other treatments. Crude protein content (g kg-1) was 14 to 35% higher (P ≤ 0.001) in IC systems than the corresponding SMC. Neutraleutral detergent fibre (NDF) and acid detergent fibre (ADF) content (g kg-1) of barley based systems was 15 and 22% lower (P ≤ 0.001) than those with oats. Ranking and relative productivity for fall pasture was DG (100%) > early-cut FMC (67%) > late-cut FMC (49%) > Barley-IC (30%) > Oat-IC (24%) = Barley-SMC (14%) (P ≤ 0.001). Cropping systems that contained no spring cereal produced 2.37-fold higher (P ≤ 0.001) fall pasture yield than those with spring cereals. Among FMCs, ICs and DG systems, mean yield of ryegrass treatments were generally higher (P ≤ 0.05) than that of fall cereals. Key words: Annual forage, deferred grazing, intercrop, monocrop


Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 302-306 ◽  
Author(s):  
W. F. Schillinger ◽  
T. C. Paulitz

Rhizoctonia bare patch caused by Rhizoctonia solani AG-8 is a major fungal root disease in no-till cropping systems. In an 8-year experiment comparing various dryland no-till cropping systems near Ritzville, WA, Rhizoctonia bare patch first appeared in year 3 and continued unabated through year 8. Crop rotation had no effect on bare patch during the first 5 years. However, from years 6 to 8, both soft white and hard white classes of spring wheat (Triticum aestivum L.) grown in a 2-year rotation with spring barley (Hordeum vulgare L.) had an average of only 7% of total land area with bare patches compared with 15% in continuous annual soft white wheat or hard white wheat (i.e., monoculture wheat). In years 6 to 8, average grain yield of both soft white wheat and hard white wheat were greater (P < 0.001) when grown in rotation with barley than in monoculture. Although both classes of wheat had less bare patch area and greater grain yield when grown in rotation with barley, monoculture hard white wheat was more severely affected by Rhizoctonia than soft white wheat. Soil water levels were higher in bare patches, indicating that roots of healthy cereals did not grow into or underneath bare patch areas. This is the first documentation of suppression of Rhizoctonia bare patch disease in low-disturbance no-till systems with rotation of cereal crops.


1978 ◽  
Vol 58 (2) ◽  
pp. 421-426 ◽  
Author(s):  
H. W. JOHNSTON ◽  
J. B. SANDERSON ◽  
J. A. MACLEOD

The influence of cultivating field peas (Pisum sativum L.) with barley (Hordeum vulgare L.), oats (Avena sativa L.) or wheat (Triticum aestivum L.), on pea disease severity, total seed, and protein yields was determined in a 2-yr study. Pea disease severity was reduced in mixed cropping systems in direct proportion to the amount of peas in the stands. Larger pea seed was produced with decreasing pea plant populations in mixtures. Higher concentrations of protein in the companion cereal and higher proportions of peas in the harvest mixtures resulted in increased protein yields with increasing percentages of peas seeded. Total seed and protein yields were equalled or increased in mixed crops over that of pure stands of the respective cultivars. Mixed cropping of field peas and cereals is offered as an alternate method of protein production for on-farm use.


1982 ◽  
Vol 62 (4) ◽  
pp. 995-1001
Author(s):  
P. A. O’SULLIVAN ◽  
P. N. P. CHOW ◽  
J. H. HUNTER ◽  
K. J. KIRKLAND

Control of green foxtail (Setaria viridis (L.) Beauv.) with AC 206,784 (2-chloro-N-isopropyl-2′,3′-acetoxylidide) was evaluated at four locations in western Canada. With soil applications, control was good at Lacombe in 1978 but poor at Lacombe and Regina during 1979. Control was good at Brandon and Scott in 1979. At two locations in 1979, soil surface (PE) applications were less effective for control of green foxtail than preplant-incorporated (PPI) treatments. PPI treatments to a depth of 5 cm were more effective than PPI to 10 cm. Soil applications of AC 206,784 did not control wild oats (Avena fatua L.) or injure wheat (Triticum aestivum L.) under field conditions but did provide suppression of these species under greenhouse conditions. Barley (Hordeum vulgare L.) tolerance to AC 206,784 was good. Treating the soil zone containing the emerging coleoptiles of green foxtail and wheat caused more injury that treating the root zone. Application of AC 206,784 as a tank-mixture with triallate did not affect its activity on green foxtail or influence triallate activity on wild oats. In field and greenhouse experiments, control of green foxtail with AC 206,784 applied at the two-leaf stage was variable; at the four-leaf stage it was poor.


1992 ◽  
Vol 72 (4) ◽  
pp. 1091-1107 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
V. O. Biederbeck ◽  
A. J. Leyshon

Low commodity prices and a desire by producers on the Canadian Prairies to reduce fertilizer-N inputs have resulted in a marked increase in grain lentil (Lens culinaris medikus) production. Many producers grow lentil in rotation with spring wheat (Triticum aestivum L.). A 12-yr study carried out at Swift Current, Saskatchewan, on an Orthic Brown Chernozemic silt loam was used to compare the N economy of four monoculture wheat rotations, of various rotation lengths and levels of N fertilization, with that of a wheat–lentil (W–Len) rotation. Except for continuous wheat (Cont W) receiving mainly P fertilizer, all systems received N and P on the basis of soil tests. Neither grain nor straw yield of the associated wheat crop was influenced by lentil in the rotation; but grain- and straw-N concentrations of the wheat in W–Len were increased compared with those of monoculture wheat. Average N content of straw was greatest for grain lentil and for wheat grown on fallow (F) (14.2 kg ha−1 yr−1), followed by wheat in W–Len (11.8 kg ha−1 yr−1) and by stubble-wheat of well-fertilized monoculture systems (F–W–W and Cont W (9.5 kg ha−1 yr−1)), and lowest for Cont W receiving mainly P (5.7 kg ha−1 yr−1). Nitrate N in the root zone (0–90 cm) in spring and at harvest was greatest under F–W, followed by W–Len and then by F–W–W and Cont W receiving N and P, and lowest for Cont W receiving mainly P. In the last 5 or 6 yr of study, there was a marked increase in the amount of soil-NO3 N found in the root zone under the W–Len rotation. This was accompanied by a similar increase in the apparent net N mineralized (estimated by N balance) during the growing season. Concomitantly, there was a gradual reduction in the fertilizer-N requirement for W–Len, indicating a cumulative enhancement of the N-supplying power of the soil, although estimates of the initial potential rate of N mineralization on samples taken in 1990 did not confirm this trend. We concluded that soil-testing laboratories may need to adjust fertilizer-N recommendations downward for producers that regularly use a 2-yr W–Len rotation. There was less NO3 N leached below the root zone of W–Len, probably because there was greater synchrony of N uptake in W–Len than in Cont W (N + P); this augurs well for the use of the W–Len rotation for sustainability.Key words: Crop rotations, pulse crops, N mineralization, N fixation, N leaching


1993 ◽  
Vol 73 (3) ◽  
pp. 703-712 ◽  
Author(s):  
V. S. Baron ◽  
A. C. Dick ◽  
H. G. Najda ◽  
D. F. Salmon

Annual crops are used routinely for pasture in many parts of the world, but in Alberta they are used primarily to offset feed shortages. Experiments were conducted during 1987 and 1988 at Lacombe, Alberta under dryland conditions and at Brooks, Alberta under irrigation to determine the feasibility of using spring-planted combinations of spring and winter cereals to extend the grazing season. Treatments for simulated grazing were spring oat (Avena sativa L.), and barley (Hordeum vulgare L.) monocrops (SMC), winter wheat (Triticum aestivum L.) and winter triticale (X Triticosecale Wittmack) monocrops (WMC), spring and winter cereal binary mixtures, seeded together in the spring (intercrop-IC) and the winter cereal seeded after one clipping of the spring cereal (double crop-DC). Clippings were initiated at the jointing stage of the spring cereals and were repeated at intervals of 4 wk. The SMC produced the highest yields during the first two cuts (mid-June and mid-July), but regrowth declined thereafter. The WMC generally had superior yields after mid-July. The IC yield was similar to the higher of the SMC or WMC at any cut with more uniform productivity over the growing season. The DC was inferior to the IC for late summer and fall production. Averaged over years the IC produced 92 and 87% as much DM in the fall as the WMC at Lacombe and Brooks, respectively. Yield totalled over all cuts resulted in the sequence IC > WMC > DC > SMC. The IC is a feasible season-long pasture system under irrigation in southern Alberta and under rain-fed conditions in central Alberta. Key words: Cereals, double-crop, intercrop, monocrop, pasture, yields


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