Simulating Long-Term Effects of Nitrogen Fertilizer Application Rates on Corn Yield and Nitrogen Dynamics

2007 ◽  
Vol 50 (4) ◽  
pp. 1287-1303 ◽  
Author(s):  
K. R. Thorp ◽  
R. W. Malone ◽  
D. B. Jaynes
Keyword(s):  
Nitrogen Fertilizer ◽  
Fertilizer Application ◽  
Nitrogen Dynamics ◽  
Corn Yield ◽  
Long Term Effects ◽  
Application Rates

scholarly journals LONG-TERM EFFECTS OF GRAIN LEGUMES ON RAINY-SEASON SORGHUM PRODUCTIVITY IN A SEMI-ARID TROPICAL VERTISOL

2000 ◽  
Vol 36 (2) ◽  
pp. 205-221 ◽  
Author(s):  
T. J. REGO ◽  
V. NAGESWARA RAO
Keyword(s):  
Grain Yield ◽  
Rainy Season ◽  
Central India ◽  
Fertilizer Application ◽  
Carthamus Tinctorius ◽  
Grain Legumes ◽  
Long Term Effects ◽  
Total N ◽  
Sorghum Grain

In southern and central India, farmers crop Vertisols only in the post-rainy season, to avoid land management problems in the rainy season. In 1983 ICRISAT established a long-term trial seeking to intensify cropping. The trial included intercrops, sequential crops and appropriate Vertisol management technology to allow consecutive rainy-season and post-rainy season crops to be grown. Benefits provided by legumes to succeeding rainy-season sorghum (Sorghum bicolor) were analysed in relation to a non-legume system of sorghum + safflower (Carthamus tinctorius). Rainy-season sorghum grain yield production was sustained at about 2.7 t ha−1 over 12 years within a continuous sorghum–pigeonpea (Cajanus cajan) intercrop system. With a cowpea–pigeonpea intercrop system, succeeding sorghum benefitted each year by about 40 kg N ha−1 (fertilizer nitrogen (N) equivalent). Without N fertilizer application the sorghum grain yield was around 3.3 t ha−1. Legume benefits were less marked in the chickpea (Cicer arietinum)-based rotation than in the pigeonpea system, in which a 12-year build up of soil total N (about 125 μg g−1) was observed. Although sorghum benefitted from this system, pigeonpea yields declined over time due to soil-borne fungi and nematodes. Wider rotations of crops with pigeonpea may help to overcome these problems, while sustaining sorghum production.

LONG-TERM EFFECTS OF ROW SPACING AND FERTILIZER ON THE PRODUCTIVITY OF RUSSIAN WILD RYEGRASS

1968 ◽  
Vol 48 (1) ◽  
pp. 75-84 ◽  
Author(s):  
T. Lawrence ◽  
D. H. Heinrichs
Keyword(s):  
Ammonium Phosphate ◽  
Phosphate Fertilizer ◽  
Fertilizer Application ◽  
Forage Yield ◽  
Row Spacing ◽  
Long Term Effects ◽  
Forage Production ◽  
Bare Ground ◽  
Drought Period

A study was conducted from 1947 to 1966 to determine the long-term effects of row spacings and applications of ammonium phosphate fertilizer (16–20–0) on the productivity and persistence of Russian wild ryegrass, Elymus junceus Fisch.The optimum row spacing for highest seed production was 0.9 m, whereas for highest forage production it was 0.6 m. The 280-kg/ha rate of fertilizer significantly increased the seed and forage yield over the 151-kg/ha rate, which in turn significantly increased the yield over the zero fertilizer treatment.Increases in precipitation in August and September increased the seed yield of Russian wild ryegrass the following year. Significant positive correlations were found between forage yields and precipitation during March, April, May, and the previous September for practically all treatments.Width of row increased with age of stand. During the 19-year period there was still bare ground between the grass rows seeded 0.9 and 1.2 m apart. These areas of bare ground were slightly narrower when fertilizer was used, indicating that fertilizer application tended to accelerate row-width development.Russian wild ryegrass was found to have excellent cold tolerance, drought tolerance and persistence. It survived through a long drought period and resisted invasion by weeds and volunteer grass seedlings after the third crop year.

THE LONG-TERM EFFECTS OF FERTILIZER APPLICATION AND THREE ROTATIONS ON WEED COMMUNITIES IN WHEAT (AFTER 21–22 YEARS AT INDIAN HEAD, SASKATCHEWAN)

1982 ◽  
Vol 62 (3) ◽  
pp. 741-750 ◽  
Author(s):  
LARRY HUME
Keyword(s):  
Species Composition ◽  
Fertilizer Application ◽  
Continuous Cropping ◽  
Long Term Effects ◽  
Canada Thistle ◽  
Short Term ◽  
Weed Communities ◽  
Green Foxtail ◽  
Lamb’S Quarters

The effect of fertilizer application and three rotations (continuous cropping, fallow-wheat, and fallow-wheat-wheat rotations) on the species composition of the weed community was examined using rotations that had been running for 21–22 yr at Indian Head, Saskatchewan. Before spring seeding, stinkweed and lamb’s-quarters were more abundant on wheat after fallow than they were on either wheat following wheat after fallow or on continuous cropping. After seeding, continuous cropping produced the largest weed densities of green foxtail, thyme-leaved spurge, and vetch. In most instances, Canada thistle was most abundant on continuously cropped and nonfertilized plots. After spring seeding, green foxtail was the only species with a larger density on fertilized plots. Interactions between fertilizer application and rotation, and among species, influenced species composition in the weed community. Fertilizer application tended to reduce community differences between continuous cropping and short-term wheat-fallow rotations. Allelopathic effects of Canada thistle may have reduced green foxtail and redroot pigweed densities. With the use of 2-or 3-yr wheat-fallow rotations and herbicide application, weed problems can be minimized in southeastern Saskatchewan.

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