Plant-water status and grain yield of maize (zea mays l) in relation to soil water status at Morogoro, Tanzania.
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Date
1987
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
Analysis was made of reference crop evapotranspiration (Eto) and rainfall (R) data on a 10-day basis over a 10-year period (1973/74 - 1982/83).On the average, ETo exceeds R during the entire short rain season thus making production of crops other than those tolerant to water stress a risky undertaking.The effects of soil water holding capacity (WHC), cultivars,and water regimes on soil ~ and plant - water status, growth, grain yield and yield components of maize (Zea mays L) were identified.The study was conducted during short rains on two soils (both Ferralsols) one x<rith high and the other with lox; WHC. Katuwani and Ilonga Composite maize cultivars with different maturation periods were grown under rainfed condition and under limited irrigation.High values of weighted soil matric potential (Ip m) were associated with high WHC of soil. In all treatments, (p m values declined near tasselling stage due to high demand for water and increased x$ith the approach of physiological maturity.Averaged over the entire season, leaf water potential (V 1) was 2.22 bars
higher in soil 1 (high WHC) than in soil 2 (low WHC). On the average, Katumani had Ip 1 values 3 bars higher than Ilonga Composite. Plants had Pl 4.0 bars higher under limited irrigation than under rainfed conditions on the average. Plant height, stem diameter, number of leaves/plant, leaf area/leaf and leaf area index were significantly affected by cultivars.Plants of Ilonga Composite were 16.4% taller, had stems 25.4% thicker and had 2 more leaves which were 55.9% larger than those of Katumani on the average. Leaf area index was signifi-cantly increased by irrigation and was 79% higher for Ilonga Composite compared to Katumani. In 0-90 cm depth root length density (RLD) was 42% higher in soil 1 than in soil 2 with Ilonga Composite having RLD 10% higher than that for Katumani. Ilonga Composite outyielded Katumani in dry matter (DM) production at 54 and 74 days from planting (DFP) by a factor of about 2, a difference attributed to bigger plants, more and larger
leaves by the former than the latter cultivar. At 54 DFP, irrigation significantly increased DM yield by 92 and 46% for Ilonga Composite and Katumani, respectively as compared to DM yield under rainfod conditions. Ilonga Composite had barren plants in all treatments.However,there were fewer barren plants (3 to 11%) under limited irrigation than under rainfed (26 to 35%) conditions.
Katumani had barren plants (4%) only in soil 2 and under rainfed conditions.Under similar conditions, percentage of barren plants was highest (35%) for Ilonga Composite.Cultivars, water regimes and their interaction had significant effect on the number of kernels set per cob.
Over-all, Ilonga Composite (because of bigger cobs) set about 295 kemels/cob, 27% more than the number set by Katumani. Irrigation led to a nonĀ significant 7 and a significant 98% increase in the number of kemels/cob for Katumani and Ilonga Composite, respectively.Cultivars and water regimes had significant affect on a thousand kernel weight.A thousand kernels of Ilonga Composite
weighted 313.7 g, 23% heavier than those of Katumani.Irrigation increased the weight of a thousand kernels by 43% from 234.2 g under rainfed to 335.5 g under irrigated conditions.All factors studied had significant effect on grain yield. In soil 1, grain yield was 1322.1 kg/ha, 18% more than that in soil 2 on the average. Ilonga Composite gave 1410.9 kg/ha of grain, 37% more than the average yield for Katumani. This was accounted for by bigger cobs and heavier grains for Ilonga Composite as opposed to Katumani. Overall, irrigation increased grain yield by 67% from
915.5 kg/ha under rainfed to 1527.1 kg/ha under limited irrigation.However, the increase was a non-signifleant 7% and a significant 138% for Katumani and Ilonga Composite, respectively.The amount of irrigation water varied with the WHO of soils. It was 40 and 50 ram in soil 1 while in soil 2 it was 50 and 80 mm for Katumani and Ilonga Composite, respectively. Ilonga Composite
took longer to mature and thus it received more rain as well as irrigation water than Katumani.
Total water use efficiency (TWUE) values for both DM and grain yield were higher in soil 1 than in soil 2 on account of WHC. ilonga Composite had TWUE (DM) values ranging from 1.3 to over 2.0
times greater than those for Katumani in the two water regimes.This was accounted for by bigger plants, more and larger leaves for Ilonga Composite than for Katumani.Irrigation increased TWUE (DM)for both cultivars. However, with respect to grain yield. Katumani had 'nigher THUE values than Hongs Composite under rainfed conditions and vice versa under limited irrigation.High values of irrigation water use efficiency (IWUE) both for iJil and grain yield were associated with a soil having high WHC and for Ilonga Composite.Comparison of the two cultivars grown shoved Katurcani to produce more grain weight/ha than Ilonga Composite under rainfed conditions
(short rains) and vice versa under irrigation.Thus, Katumani was drought tolerant while Ilonga composite was not.
Description
Dissertation
Keywords
Plant growth, Maize cultivars, Planting, Irrigation water