ISSN:
1573-0867
Keywords:
fertilizer nitrogen use efficiency
;
intercropping
;
N budget
;
pigeonpea
;
sorghum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Cropping systems and fertilizer management strategies that effectively use applied nitrogen (N) are important in reducing costs of N inputs. We examined the effect of time of N application on dry matter (DM) and grain yield (GY), N accumulation, the N budget in crop from soil, fertilizer and atmosphere, and the fertilizer N use efficiency (estimated by the conventional difference method, and the direct 15N recovery by the crops), in a sorghum/pigeonpea intercropping system on an Alfisol (Ferric Luvisols (FAO); or Udic Rhodustalf (USDA) in India. Fertilizer N was applied at planting (basal) and at 40 days after sowing (delayed). Nitrogen was applied only to the sorghum rows in the intercropping treatment. Nitrogen derived from air (Ndfa) was estimated by the15 N natural abundance method, and N derived from fertilizer (Ndff) was estimated by the 15N isotope dilution method. Delaying N fertilization till 40 days after sowing (DAS), rather than applying at sowing increased DM and GY of the sorghum, but not of pigeonpea. Delaying N fertilization to sorghum for 40 days significantly (p〈0.001) increased 15N recovery in shoot from 15 to 32% in sole crop, and from 10 to 32% in intercrop. Similarly, there was a significant (p〈0.001) increase in N recovery (by the difference method) from 43 to 59% in sole crop and from 28 to 71 % in intercrop sorghum. Fertilizer N recovery by sole crop pigeonpea (14%) was higher than intercrop pigeonpea (2–4%). Pigeonpea fixed between 120–170 kg ha-1 of atmospheric N throughout the cropping season. Although there was a marked difference in nitrate-N (N03-N) concentrations between basal and delayed treatments at planting, no difference was observed in N03-N concentrations in soil solution between the treatments at 40 DAS. Our data on N accumulation by plants showed that the rate of N depletion or disappearance from the soil solution was 2–3 times faster than N accumulation by plants, suggesting that an appreciable amount of N03-N would disappear from soil solution in the top soil without being utilized by crops during the initial growth stage.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009788818738
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