ALBERT

Description: SUMMARYGrowth and water use of kabuli-type chickpea was measured during the 1982/83 and 1983/84 growing seasons in northern Syria under rainfed conditions. Winter-sown (November) and springsown (March) crops of cv. ILC 482 were grown in 1982/83 while in 1983/84 spring-sown crops of contrasting genotypes (ILC 482, ILC 1929 and ILC 3279) were compared.In 1982/83, shoot dry matter and seed yields of the winter-sown crop were almost twice those of the spring-sown crop although the water use of both crops was almost the same. Root growth of both crops was most rapid before flowering but continued until maturity (early June) in the winter-sown and until mid to late pod filling (also early June) in the spring-sown crop. Root dry weight (c. 45 g/m2) and length (c. 45 cm/cm2) were similar in both crops during pod filling.In 1983/84, shoot weight, root weight and root length were similar in all genotypes but the later maturity of ILC 3279 resulted in lower seed yield and hence harvest index, and greater water use.The root length density decreased approximately logarithmically with depth in the soil profile although comparison between seasons and with other published results showed that the relations could not be used predictively. Water use efficiency was poorer in the second, drier season and was almost doubled by winter sowing.

Description: In the Mediterranean region, chickpeas are traditionally spring-sown since humid winter conditions encourage the development of Aschochyta blight which often causes complete crop failure. Lines resistant to this blight have been selected at the International Centre for Agricultural Research in Dry Areas (ICARDA) and thus winter planting has become feasible. The best selection, ILC 482, was sown in both winter and spring at three locations in northern Syria with contrasting precipitation patterns. Crop growth and soil moisture analyses were undertaken on all treatments, and relevant meteorological data were collected at each location. At all locations maximum greenarea and dry-matter production of the winter-sown crop was nearly double that of the spring sowing. Large differences were also observed between sites, with green-area and dry-matter production decreasing with precipitation. Depth of profile recharge, amount of extractable moisture and crop evapotranspiration also decreased with precipitation, but only small differences in these moisture variables were observed between winter and spring sowing. Duration of green-area production, as determined by the onset of rapid leaf senescence, was closely related to the fraction of extractable moisture in the soil profile, rapid senescence occurring in all treatments when extractable moisture fell below 40% of its maximum value. Differences in the maximum rates of green-area production are discussed both in relation to the depth of profile recharge, hence the depth of rooting and moisture extraction and to the ambient evaporative demand. The differences observed in green-area and dry-matter production was clearly reflected in final seed yield. The components of yield, number of pods, percentage of empty pods and seed size are related to the variations in moisture stress experienced by the crop.

Description: SummaryAn analysis of chickpea experiments carried out in northern Syria during the 1980–1 and 1981–2 growing seasons showed that both intercepted solar radiation and its rate of conversion to dry matter were variable components of dry-matter production. Among the sources of variation in the experiments, the most important factor affecting both interception and utilization of solar radiation was site. Winter planting also led to increased solar radiation interception and utilization. Used in conjunction with chickpea lines resistant to blight, winter planting seems likely to lead to increased productivity. In higher rainfall areas, where the crop is usually grown, such an increase would be of commercial significance. In drier areas, winter planting would enable the cultivation of chickpea as a subsistence crop.

Description: SummaryRelations between yield, water use and pre-anthesis growth were analysed for cropsof barley grown for three seasons at several sites in northern Syria. The relations obtained were compared with those for other cereal crops grown in similar regions of Mediterranean climates.Phosphorus fertilizer application increased the rate of crop development from emergence to floral initiation and advanced anthesis by up to 11 days. Grain and total shoot dry-matter yields were increased by fertilizer (nitrogen + phosphorus) applications at all sites in all years, in most cases without increasing total evapotranspiration. The increased dry matter at anthesis was produced without having used a larger proportion of the total evapotranspiration in the whole season. Consequently, the ratio of grain yield to total above-ground dry-matter yield (harvest index) and kernel weight were also relatively stable between sites and years, despite some very low amounts of post-anthesis water use. Grain yield appeared to be largely determined by anthesis and there were strong linear relationships between grain yield or total dry-matter yield and number of kernels. Differences in water use efficiency of crops given fertilizer between sites and years were closely related to the differences in amounts of winter growth.Some responses differed from those predicted from models of growth, water use and yield developed in other regions with similar climates. It is concluded that agronomists and breeders should increase amounts of early growth thereby increasing grain and dry-matter yields. Future research emphasis should also be on the development of dynamic simulation models of pre-anthesis growth and water use.

Description: SUMMARYBarley (cv. Beecher) was grown at two sites (Jindiress and Breda) in northern Syria, chosen for their contrasting edaphic and climatic conditions. At both sites, three fertilizer treatments were applied zero (Z), 60 kg P2O5/ha (P), and 60 kg P2O5/ha with 60 kg N/ha (NP) and measurements made of shoot and root growth, and water use.The growth of crops not given fertilizer was similar at both sites and early growth was increased by the application of fertilizers. However, at maturity, yield was increased at Jindiress by giving N and P together, but not by P alone, while at Breda P alone increased yields but additional N produced no additional yield. There were marked effects of fertilizer on crop development at Jindiress; anthesis and maturity were about 14 days earlier in the NP treatment than in the Z treatment.Root growth was also affected by fertilizer applications and there were small but significant differences in growth between the sites. The proportion of root weight: total plant weight was greater than commonly observed in temperate cereals and there were substantial differences between the sites in the pattern of root distribution within the soil profile.The total amount of water used by the crops differed between the sites but was largely unaffected by fertilizer treatment at each site. Evapotranspiration during the winter when the soil was recharged with water was about 50% of the seasonal total. At Jindiress, the pattern of water extraction from the profile and the root distribution were similar before flowering but at Breda, there was no correspondence. Rates of water inflow varied with both site and time.Crop characteristics that may be associated with increased yields are discussed. Deeper, more extensive rooting is unlikely to be useful in such regions but rapid early growth of both shoots and roots may allow water to be used more efficiently.