Sources of growth in wheat yields in Pakistan's Punjab, 1965-2000: is there a sustainability issue?

Byerlee, D. and Siddiq, A. (1990) Sources of growth in wheat yields in Pakistan's Punjab, 1965-2000: is there a sustainability issue? Working Paper. CIMMYT, Mexico.

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Abstract

Wheat yields rose rapidly in the Punjab of Pakistanduring the Green Revolution decade, 1966-76, but the rate of growth has been significantly slower in the decade that followed. A simple model is used to disaggregate the effects on yields of three factors: 1) the conversion of rainfed land to irrigated land, 2) the adoption of high-yieldingvarieties (HYVs), and 3) the increasing yields of HYVs resulting from the release of newer HYVs and increased fertilizer application. Applying the model to the period 1971-73 to 1984-86 indicates that, given the change in inputs, irrigated wheat yields should have incresed by at least 725 kg/ha.Yields in fact increased by only 375 kg/ha, reflecting the presence of long-term negative influences on yields. The stagnation in yields of HYVs in the 1970s and 1980s is contrary to earlier projections based on extensive on-farm experimentation. The results suggest that important sustainabilityissues must be resolved if wheat yields in Pakistan's Punjab are to be maintained. The issues appear to relate to 1) increased cropping intensity, which leads to delayed planting of wheat, 2) use of poor quality tubewell water, 3) increased weed and disease problems, and 4) low efficiency offertilizer use. Many of these factors are not well understood or quantified. Projections of wheat supply and demand to the year 2000 suggest that Pakistan needs to reformulate its stratagy of increasing yields by adding more inputs and focus instead on increasing the efficiency of use of inputs andarresting the tendincy for yields to decline over the long term

Item Type:	Monograph (Working Paper)
Uncontrolled Keywords:	Triticum aestivum; Crop yield; Yield increases; Pakistan; Punjab; Farm inputs; High yielding varieties; Irrigation, RP6840
Author Affiliation:	CIMMYT, Mexico
Subjects:	Crop Improvement
Divisions:	Other Crops
Depositing User:	Mr Daneti Raju
Date Deposited:	15 Mar 2014 15:21
Last Modified:	15 Mar 2014 15:21
URI:	http://eprints.icrisat.ac.in/id/eprint/12569

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