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Yadvinder-Singh Bijay-Singh Jagdish K. Ladha Jaswinder S. Bains Rajeev K. Gupta Jagmohan-Singh V. Balasubramanian 《Nutrient Cycling in Agroecosystems》2007,78(2):167-176
Nitrogen use efficiency (NUE) in rice is low due to the inefficient management of fertilizer N by farmers. We evaluated a
leaf color chart (LCC) as a simple tool for improving the time and rate of N fertilizer use in farmers’ fields for 4 years
(2000–2003) in irrigated rice in northwestern India. Application of N fertilizer whenever leaf greenness was less than shade
4 on the LCC (the critical LCC value) produced rice grain yields on a par with blanket recommendation of applying 120 kg N ha−1 in three equal splits in different years, but it resulted in an average saving of 26% fertilizer N across villages and seasons.
In most situations, there was no significant advantage of applying 20 kg N ha−1 as basal N at transplanting on grain yield and NUE of rice compared with no basal N. Use efficiencies of fertilizer N were
higher when N was applied using LCC with a critical value of 4 than the recommended practice of applying 120 kg N ha−1 in three equal split doses on all sites and in all years. The LCC with a critical value of 4 for real-time N management can
be efficiently used to increase NUE in all types of inbred rice cultivars presently popular with the farmers of the Indian
Punjab. The LCC is a cheap and easy-to-use tool that allows real-time N management by farmers on a large area leading to improved
fertilizer N use efficiency, and reduced risks associated with fertilizer N application. 相似文献
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Yadvinder-Singh R. K. Gupta Gurpreet-Singh Jagmohan-Singh H. S. Sidhu Bijay-Singh 《Nutrient Cycling in Agroecosystems》2009,84(2):141-154
Development of a sustainable and environment friendly crop production system depends on identifying effective strategies for
the management of tillage and postharvest crop residues. Three-year (2004–2007) field study was initiated on two soil types
to evaluate the effect of straw management (burning, incorporation and surface mulch) and tillage (conventional tillage and
zero tillage) before sowing wheat and four nitrogen rates (0, 90, 120 and 150 kg N ha−1) on crop yields, N use efficiency, and soil fertility in the northwestern India. Effect of tillage and straw management on
nitrogen transformation in soils was investigated in a laboratory incubation study. In sandy loam, grain yield of wheat with
straw mulch-zero-till (ZT) was 7% higher compared to when residues were burnt-ZT but it was similar to straw burnt-conventional
till (CT), averaged across 3 years. In silt loam, grain yield of wheat with straw mulch-ZT was 4.4% higher compared to straw
incorporated-CT, but it was similar to straw burnt-CT. Response to N application was generally observed up to 150 kg N ha−1 except in 2004–2005 on sandy loam where N response was observed up to 120 kg N ha−1, irrespective of straw and tillage treatments. In sandy loam, RE was lower (49%) for straw burnt-ZT than in other treatments
(54–56%). In silt loam, RE was higher in straw mulch-ZT compared with straw incorporation-CT (65 vs. 58%). In sandy loam,
AE was higher in straw burnt-CT and straw mulch-ZT compared with the other treatments (19.2 vs. 16.9 kg grain kg−1 N applied). In silt loam, AE was lower in straw incorporation-CT than in other treatments (16.0 vs. 17.6 kg grain kg−1 N applied). Rice yield and N uptake were not influenced by straw and tillage management treatments applied to the preceding
wheat. Recycling of rice residue (incorporation and surface mulch) compared with straw burning increased soil organic carbon
and the availability of soil P and K. There was more carbon sequestration in rice straw mulch with zero tillage (25%) than
in straw incorporation with conventional tillage (17%). Soil N mineralization at 45 days after incubation was 15–25% higher
in straw retention plots compared with on straw burnt plots. 相似文献
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Yadvinder-Singh R. K. Gupta Jagmohan-Singh Gurpreet-Singh Gobinder-Singh J. K. Ladha 《Nutrient Cycling in Agroecosystems》2010,88(3):471-480
Crop residues are important sources of organic matter and plant nutrients and known to affect soil quality. Tillage affects
residue decomposition and nutrient cycling processes. A 2 year field study was aimed to investigate the decomposition and
nutrient dynamics from surface-placed and incorporated rice (Oryza sativa L.) residue on two soil types using the nylon mesh bag technique over wheat cropping cycle in rice–wheat system in northwestern
India. A single-pool first-order exponential decay function showed R
2 larger than 0.9. Over the wheat growing cycle about 20% of buried rice residue and 50% of surface-placed residue remained
undecomposed. Nitrogen exponential decay models were significant at P < 0.01. At wheat boot stage (1,100 growing degree days, DGD) 12 kg N ha−1 (27% of the initial N) was released from the buried residue losing 60–65% of its N at the end of decomposition cycle. Nitrogen
in surface rice residue increased throughout the decomposition cycle due to microbiological immobilization. The change in
P with time (DGD) was small and weakly defined by the exponential function. Nutrient dynamics of rice residue indicate that
it is not a potential source of N and P for wheat over short-term. The change in K concentration was well described by exponential
function (R
2 0.73–0.86). Potassium in rice residue decreased at a fast rate during the initial 20 days (400 DGD) and >80% was released
by 40 days (680 DGD). 相似文献
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