HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (25) Citing Articles via Google Scholar Google Scholar Articles by Regmi, A. P. Articles by Pandey, S. P. Search for Related Content PubMed Articles by Regmi, A. P. Articles by Pandey, S. P. Agricola Articles by Regmi, A. P. Articles by Pandey, S. P. Related Collections Nutrient Management Soil Fertility and Productivity

DIVISION S-4—SOIL FERTILITY & PLANT NUTRITION

Yield and Soil Fertility Trends in a 20-Year Rice–Rice–Wheat Experiment in Nepal

^a Social Sciences Division, International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines
^b CIMMYT, P.O. Box 5186, Kathmandu, Nepal
^c Central Soil Science Division, NARC, Khumaltar, Nepal

* Corresponding author (J.K.LADHA{at}cgiar.org)

The rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system occupies about 13.5 million ha in South Asia and is important for the region's food security. We examined the long-term yield trends, changes in soil nutrient fractions (both total and available), and nutrient balances in a 20-yr rice–rice–wheat experiment conducted in the Indo-Gangetic plain of Nepal. The yield of first rice crop fertilized with recommended NPK fertilizer or farmyard manure (FYM) declined an average of 0.09 or 0.07 Mg ha^-1 yr^-1, respectively. These 20-yr trends explained only 20 to 21% of the variability in yield, and inexplicable shorter-term yield trends were observed. Likewise, wheat yield declined at 0.05 Mg ha^-1 yr^-1 (with both NPK and FYM) over the 20 yr. However, the yield of second rice crop did not decline over that period. The total and available N and P, and total and labile C contents of soil from Year 10 to 20 were either maintained or increased, but total K and available K declined. The apparent K balance showed net losses of 62.3 and 15.2 kg K ha^-1 yr^-1 with NPK and FYM treatments, respectively. Depletion of soil K and inadequate K fertilization seems to be the primary reasons of limited and declining yield of first rice and wheat crop. In addition, the yield of wheat declined because of a delay in sowing, which was estimated to be 0.04 Mg ha^-1 for each day delay in sowing. The study showed that the current local fertilizer recommendations, particularly for K, for the rice–rice–wheat system are inadequate.

Abbreviations: DAS, days after sowing • DAT, days after transplanting • EC, electrical conductivity • FYM, farmyard manure • IRRI, International Rice Research Institute • LTE, long-term experiment • PMN, potentially mineralizable N • TC, total C • TK, total K • TN, total N • TP, total P • WSC, water-soluble C

This article has been cited by other articles:

				K. Girma, S. L. Holtz, D. B. Arnall, B. S. Tubana, and W. R. Raun The Magruder Plots: Untangling the Puzzle: Previously Published in Agron. J. 99:1191-1198 (2007) Agron. J., May 7, 2008; 100(Supplement_3): S-11 - S-18. [Abstract] [Full Text] [PDF]

				K. Girma, S. L. Holtz, D. B. Arnall, B. S. Tubana, and W. R. Raun The Magruder Plots: Untangling the Puzzle Agron. J., August 10, 2007; 99(5): 1191 - 1198. [Abstract] [Full Text] [PDF]

				H. Pathak, C. Li, R. Wassmann, and J. K. Ladha Simulation of Nitrogen Balance in Rice-Wheat Systems of the Indo-Gangetic Plains Soil Sci. Soc. Am. J., August 3, 2006; 70(5): 1612 - 1622. [Abstract] [Full Text] [PDF]

				M. C. Manna, A. Swarup, R. H. Wanjari, Y. V. Singh, P. K. Ghosh, K. N. Singh, A. K. Tripathi, and M. N. Saha Soil Organic Matter in a West Bengal Inceptisol after 30 Years of Multiple Cropping and Fertilization Soil Sci. Soc. Am. J., December 2, 2005; 70(1): 121 - 129. [Abstract] [Full Text] [PDF]

				T. Fan, B. A. Stewart, W. A. Payne, W. Yong, J. Luo, and Y. Gao Long-Term Fertilizer and Water Availability Effects on Cereal Yield and Soil Chemical Properties in Northwest China Soil Sci. Soc. Am. J., May 6, 2005; 69(3): 842 - 855. [Abstract] [Full Text] [PDF]

				Yadvinder-Singh, Bijay-Singh, J. K. Ladha, C. S. Khind, R. K. Gupta, O. P. Meelu, and E. Pasuquin Long-Term Effects of Organic Inputs on Yield and Soil Fertility in the Rice-Wheat Rotation Soil Sci. Soc. Am. J., May 1, 2004; 68(3): 845 - 853. [Abstract] [Full Text] [PDF]