Plant-water status and grain yield of sorghum (sorghum bico1or (l.) moench) in relation to soil water status at Morogoro, Tanzania.
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Date
1987
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Publisher
Sokoine University of Agriculture
Abstract
ABSTRACT
A field experiment was conducted at the Sokoine University of Agriculture experimental Farm to study plant-water status and grain yield of sorghum (Sorghum bicolor (L.) Moench) in relation to soil-water status.The treatments consisted of two soils, one having high water holding capacity (soil 1), the other with a low water holding capacity (soil 2); and two sorghum cultivars namely, Serena (improved) and Mbangala (local) under two moisture regimes of limited irrigation and rainfed conditions. Leaf water potential (kj'O and weighted soil-matric potential were measured to assess the water status for the plant and soils, respectively. Other observa-tions made were plant height, stem diameter, number of leaves, leaf area index (LAI), root length density, dry matter (DM) and grain yields as well as total water use efficiency (TWUE) and irrigation water use (IWUE).Plants growing in soil 1 showed higher than those in soil 2 throughout the measurement period.Mbangala maintained a higher than Serena with values of -5.42 and -7.51 bars respectively.plants had higher
The irrigated than those under rainfed conditions.The weighted matric potential,soil 2 than in soil 1.
The averages for the entire was lower in season were -0.29 and -0.38 bars for soils 1 and 2,respectively.The plots planted with Mbangala showed a lower l’pthan those with Serena their values being -0.34 and -0.33 bar^ , respectively.The weighted soil matric potential was lower under
irrigated thanu.nc[er rainfed conditions.The differences under rainfed and irrigated conditions were larger in soil 1 than in soil 2.Soils did not show any significant difference in stem diameter at 56 days after planting (dap) despite the consistent trend observed whereby soil 1 produced plants
with greater diameter than soil 2.significantly (P Serena. Mbangala showed 0.05) greater stem diameter than While stem diameter of Serena averaged 1.88cm, that of Mbangala was 2.10cm.
Moisture regime had no effect on stem diameter. Soil 1 produced significantly (P ^_0.05) taller
plants than soil 2.Plant height in soil 1 exceeded that in soil 2 by 24.5cm.Cultivar and moisture regimes as well as their interactions were non-significant..However, the interaction between soil X cultivar was highly significant (P ,0.01) .Both cultivars were taller (although not significantly so) in soil 1 than in soil 2. On the other hand, both cultivars showed consistently greater plant height under irrigated than rainfed conditions although the differences were non
significant.Plants growing in soil 1 were observed to have a significantly (P.</p.Ol) higher number of leaves at 56 d.a.p. than those growing in soil 2.Serena produced a significantly (P^O.Ol) higher number of leaves than Mbangala at 56 d.a.p.leaf number.Moisture regime had no effect on The interaction of cultivar X moisture regime significantly (P^0.05) affected the number of leaves.
0.05) higher values of LAI were produced by plants growing in soil 1 compared to those
growing in soil 2.At 56 d.a.p. LAI in soil 1 were higher by a factor of 0.9 than those in soil 2.
The other factor viz; cultivar, moisture and their inter actions were non-significant.At 76 d.a.p. soils showed no significant effect on LAI.Mbangala produced significantly (P^O.Ol) higher LAI than Serena, the former exceeding the latter by 2.2.Moisture regimes were highly significantAll other interactions 0.01).except soil X cultivar were significant (P^0.05).Significantly (P<^0.05) higher DM was produced by plants growing in soil 1 than those in soil 2 at 56 d.a.p. Soil 1 plants exceeded those in soil 2 by 2700kg DM per hectare.Dry matter yield was significantly (pZ.0.01) higher for Serena than for Mbagala at 56 d.a.p. Moisture regimes and the interactions between the factors were non-significant.At 76 d.a.p. 0.05) higher DM than in soil 1 produced significantly those for soil 2,
the former exceeding the latter by about 1700kg DM per hectare.Plants in Mbangala produced signi-ficantly p.01) higher DM exceeding Serena by about 5200kg of DM per hectare.The irrigated plots produced 14% more DM than the rainfed plots.Soil 1 showed higher root length density than soil 2. Mbangala showed better root development than Serena showing the following trend:Irrigated Serena Irrigated Mbangala Rainfed Mbangala Rainfed Serena.Soils did not show any significant effect on grain Serena produced significantly (P^0.05) higher grain yield than Mbangala.Serena exceeded Mbangala by 286.6kg of grain per hectare.Moisture regimes showed a highly significant (P^O.Ol) effect on grain yield.Plants growing under irrigation outyielded those under rainfed conditions by 170kg per hectare.The interaction between Soil X Moisture regime was not significant while that of cultivar X Moisture regime on grain yield was significant (Pz^,O.O5).
Soil 1 showed higher TWUE than soil 2 in DM yield at 56 d.a.p.Soil 2 gave a TWUE value Of 233.5kg DM per hectare-cm of water while that of soil 1 was 108.6.Serena showed higher TWUE than Mbagala in terms of DM at 56 d.a.p. having values of 85.15 and 56.90kg DM per hectare-cm of water, respectively.Total water use efficiency was observed to be higher under irrigated than rainfed conditions.By irrigation, the TWUE was increased by 24.3% over the rainfed conditions.
In the case of grain yield, soil 1 showed higher TWUE than soil 2,the latter giving 17% less TWUE
compared to the former.Total water use efficiency of Serena was higher than that of Mbangala by 20.1kg grain per hectare-cm of water.With irrigation, TWUE was increased by 5.2% over the rainfed conditions.Irrigation water-use efficiency (IWUE) for soil 1appeared to be lower than that of soil 2.ponded well to irrigation than soil 1.higher IWUE in soil 2 than in soil 1.Soil 2 had res Serena.
Description
Dissertation
Keywords
Plant water stress, Grain yield