Growth and yield of barley in Mediterranean-type environments
1984
Shepherd, R.D.
The broad objective of this thesis is to examine how climate and crop management influenced barley growth and yield in Mediterranean-type environments. Detailed data on soils, climate and crops were collected during four growing seasons at several sites in different agro-ecological zones in north-west Syria. The relationships between the soil and climate information and barley development, growth and yield were analyzed, and their implications discussed in relation to the need for further research work and for the development of improved crop management practices. Plant phosphorus content during the early growth stages played a critical role in the development and growth of the crops. When plant P concentrations were low early in crop life both crop development and relative growth rates were slow. During the later stages of growth decreased nutrient availability associated with soil drying ('nutritional drought') was implicated as a major component of the damaging effects of drought on growth. Soil water deficits occurred earlier in the crop cycle at the drier sites and in the drier years, which gave good opportunity for adaptation to drought. Harvest index and kernel weight were found to be relatively stable components of yield between fertilizer treatments, sites and years. This stability appeared to be a result of transpiration control and the response to this of dry matter partitioning. The results confirm that substantial increases in yields above those presently attained by farmers on nutrient deficient soils are possible by judicious fertilizer application and good crop management, even in the lower rainfall zones
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