EFFECTS OF WATER AVAILABILITY AND VINE HARVESTING FREQUENCY ON THE PRODUCTIVITY OF SWEET POTATO IN SOUTHERN MOZAMBIQUE. II. CROP WATER USE

2003 ◽  
Vol 39 (1) ◽  
pp. 39-54 ◽  
Author(s):  
F. GOMES ◽  
M. K. V. CARR
Keyword(s):  
Sweet Potato ◽  
Water Use ◽  
Water Availability ◽  
Rainy Season ◽  
Ipomoea Batatas ◽  
Root Zone ◽  
Sandy Loam ◽  
Dry Season ◽  
Crop Water ◽  
Crop Water Use

In Mozambique, the sweet potato (Ipomoea batatas) is grown in the dry season in areas with a high water table, or as an irrigated crop. It is also grown in the rainy season when short-term droughts can occur. This paper reports the results of experiments designed to evaluate the effects of water availability and vine-harvesting practices on actual crop water use (cv. TIS 2534), during two contrasting seasons in the south of the country. Rain-fed crops extracted water to soil depths (variable sandy loam) of 0.75 m, with most (90%) taken from the top 0.25 m. Well-irrigated crops apparently obtained some (10%) water from below 0.75 m, but most (75%) came from the upper 0.25 m. Total water use from well-watered crops was about 800 mm during the rains, and 550 mm during the dry season. The corresponding values for rain-fed crops were 360 and 180 mm respectively. Peak rates of water use averaged 8 mm d−1 in the rainy season, and 5–6 mm d−1 in the dry season. Water use was not modified by the frequency of vine harvests. Actual rates of evapotranspiration fell below maximum values when the soil water deficit exceeded only 20 mm. By comparison, the maximum depth of extractable water in the root zone was 80–90 mm. The crop coefficients (Kc) for each stage of growth were consistent over both seasons and estimated to be: 0.55–0.7 (crop establishment), 1.1–1.2 (mid-season), and 0.8 (end-season).

EFFECTS OF WATER AVAILABILITY AND VINE HARVESTING FREQUENCY ON THE PRODUCTIVITY OF SWEET POTATO IN SOUTHERN MOZAMBIQUE. III. CROP YIELD/WATER-USE RESPONSE FUNCTIONS

2003 ◽  
Vol 39 (4) ◽  
pp. 409-421 ◽  
Author(s):  
F. GOMES ◽  
M. K. V. CARR
Keyword(s):  
Sweet Potato ◽  
Water Use ◽  
Crop Yield ◽  
Water Availability ◽  
Rainy Season ◽  
Dry Season ◽  
Yield Response ◽  
Root Production ◽  
Total Production ◽  
Storage Roots

In Mozambique the sweet potato (Ipomoea batatas) is grown as both a leafy vegetable, the terminal shoots or vines being progressively harvested during the season, and as a root crop. This paper reports the development of crop yield/water-use production functions using data from two irrigation experiments designed to evaluate the effects of water availability and vine harvesting practices on the productivity and water use (ETc) of sweet potato (cv. TIS 2534) during two contrasting seasons in the south of the country. As the frequency of vine harvesting increased, the water-use efficiency (WUE-ETc) for vine production (dry mass) increased from 1–2 to 4–5 kg ha−1 mm−1 during the rainy season, and from 1 to 9 kg ha−1 mm−1 during the dry season. By contrast, there was a corresponding reduction in the WUE-ETc for storage root production from 14 to 8–9 kg ha−1 mm−1 during the rainy season, and from 23 to 15–17 kg ha−1 mm−1 during the dry season. For the total yields (vines plus storage roots) the WUE-ETc during both seasons were independent of the vine harvesting treatment. Separate lines represented each season, the slopes of which were 13 kg ha−1 mm−1 in the rains, and 24 kg ha−1 mm−1 in the dry season. When, however, crop water-use was normalised using either the seasonal mean daily total of incoming solar radiation, or reference crop evapotranspiration (ETo), but not the saturation deficit of the air, a single common, linear relationship with yield resulted. Possible explanations for this are considered. Plotting relative yields against relative rates of water-use, also gave consistent results that could have general application for predicting the effects of water availability on productivity. Vine yields, when harvested frequently, were less sensitive to drought (yield response factor, Ky=0.7–0.9) than storage roots (Ky=1.2). For total production (vines plus roots), the sensitivity to water stress (Ky) increased, from 0.9–1.0 to 1.2, as the interval between vine harvests increased. Farmers in southern Mozambique trying to maximize total yield during the season, under conditions of water uncertainty, should harvest vines at intervals of not more than 14 days.

EFFECTS OF WATER AVAILABILITY AND VINE HARVESTING FREQUENCY ON THE PRODUCTIVITY OF SWEET POTATO IN SOUTHERN MOZAMBIQUE. I. STORAGE ROOT AND VINE YIELDS

2001 ◽  
Vol 37 (4) ◽  
pp. 523-537 ◽  
Author(s):  
F. Gomes ◽  
M. K. V. Carr
Keyword(s):  
Sweet Potato ◽  
Water Use ◽  
Water Availability ◽  
Dry Weight ◽  
Dry Season ◽  
Storage Root ◽  
Fresh Weight ◽  
Supplementary Irrigation ◽  
Dry Seasons ◽  
Water Use Efficiencies

In Mozambique the sweet potato (Ipomoea batatas) is often grown as both a leafy vegetable, the terminal shoots or vines being progressively harvested during the season, and as a root crop. This paper reports the results of experiments designed to evaluate the effects of drought and vine harvesting frequency on the productivity of both yield components (cv. TIS 2534). Experiments were conducted during the rainy and dry seasons, with supplementary irrigation treatments superimposed. As the frequency of vine harvesting (equivalent to the number of harvests) increased, the total fresh weight of vines increased. There was a corresponding reduction in the yield of storage roots, however, particularly under well-watered conditions. As a result, the total harvested yield (vines plus roots) was remarkably stable in both wet and dry seasons (43–45 t ha−1 fresh weight). The cumulative dry weight of harvested vines increased with the number of harvests at constant rates, depending on water availability (from +150 to +250 when rain-fed, up to +340 to +440 kg ha−1 harvest−1 when irrigated). The corresponding rates of reduction in storage root yields varied from −3 to −130 (rain-fed) down to 310 to 400 kg ha−1 harvest−1 (irrigated). Total dry weight yields under well-watered conditions were constant at about 11 to 13 t ha−1, or double this on an annual basis. Irrigation water-use efficiencies (by dry weight of harvested crop) were generally higher in the dry season than in the rains. For vine production they increased with the number of harvests from 1.6 to 3.5 (rains) up to 0.9 to 6.7 kg ha−1 mm−1 (dry season). The corresponding values for root production were 7.5 to 13.1 (rains) and 12.2 to 19.1 kg ha−1 mm−1 (dry season). For the combined dry weight yields the water-use efficiencies were, with one exception, independent of harvesting frequency at 11.2 (rains) and 19.0 kg ha−1 mm−1 (dry season). Irrigated plants harvested at weekly intervals yielded vine dry weights of about 0.5–0.6 t ha−1 week−1. Compensatory vine growth (reported elsewhere) was observed in previously droughted plants following a rainfall event. The practical implications of these results are discussed. Future papers describe in more detail the physiological aspects of the observed yield responses.

scholarly journals Assessment Improving of Rainwater Retention on Crop Yield and Crop Water Use Efficiency for Winter Wheat

2020 ◽  
Vol 26 (3) ◽  
pp. 46-54 ◽  
Author(s):  
Ali H. Abdullah ◽  
Sabah Anwer Almasraf
Keyword(s):  
Winter Wheat ◽  
Water Use Efficiency ◽  
Water Use ◽  
Crop Yield ◽  
Root Zone ◽  
Plant Production ◽  
Subsurface Water ◽  
Crop Water ◽  
Crop Water Use ◽  
Use Efficiency

Storage of rainwater within the root depth zone is one of the modern ways to increase plant production. Subsurface water retention technology was applied to assess improving values of crop yield and crop water use efficiency, applying a membrane made of low-density polyethylene trough installed below the crop root zone. The goal of this paper is to assess that the retention of rainwater above the membrane can improve the crop yield and crop water use efficiency values for winter wheat. The experiment was conducted in open field, within Joeybeh Township, located in east of the Ramadi City, in Anbar Province, in winter growing season 2018-2019. Two plots T1 (with membrane trough) and T2 (without membrane) were used for the comparison and cultivated with winter wheat, where the rainwater was only the source of irrigation. At the end of the harvest stage the obtained results of crop yield and crop water use efficiency for plots T1 and T2 were; 0.35 kg/m2 and 1.66 kg/m3, and 0.28 kg/m2 and 1.28 kg/m3, respectively. The increasing value of crop yield and crop water use efficiency in plot T1 was about 25 % and 30 %, respectively more than plot T2. Benefits of the installation of membrane trough are to keep soil moisture for longer times, prevent the cracks of the soil surface and reduce the deep percolation losses.

scholarly journals Seasonal Variation of Rainy and Dry Season Per Capita Water Consumption in Freetown City Sierra Leone

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 499
Author(s):  
Salmatta Ibrahim A ◽  
Fayyaz Ali Memon ◽  
David Butler
Keyword(s):  
Seasonal Variation ◽  
Water Use ◽  
Water Consumption ◽  
Low Income ◽  
Rainy Season ◽  
Predictor Variable ◽  
Dry Season ◽  
Data Set ◽  
Per Capita ◽  
End Use

Ensuring a sustainable urban water supply for developing/low-income countries requires an understanding of the factors affecting water consumption and technical evidence of individual consumption which can be used to design an improved water demand projection. This paper compared dry and rainy season water sources available for consumption and the end-use volume by each person in the different income groups. The study used a questionnaire survey to gather household data for a total of 398 households, which was analysed to develop the relationship between per capita water consumption characteristics: Socio-economic status, demographics, water use behaviour around indoor and outdoor water use activities. In the per capita water consumption patterns of Freetown, a seasonal variation was found: In the rainy season, per capita water consumption was found to be about 7% higher than the consumption for the full sample, whilst in the dry season, per capita water consumption was almost 14% lower than the full survey. The statistical analysis of the data shows that the average per capita water consumption for both households increases with income for informal slum-, low-, middle- and high-income households without piped connection (73, 78, 94 and 112 L/capita/day) and with connection (91, 97, 113 and 133 L/capita/day), respectively. The collected data have been used to develop 20 statistical models using the multiple linear stepwise regression method for selecting the best predictor variable from the data set. It can be seen from the values that the strongest significant relationships of per capita consumption are with the number of occupants (R = −0.728) in the household and time spent to fetch water for use (R = −0.711). Furthermore, the results reveal that the highest fraction of end use is showering (18%), then bathing (16%), followed by toilet use (14%). This is not in agreement with many developing countries where toilet use represents the largest component of indoor end use.

A parametric crop water use model

1981 ◽  
Vol 17 (4) ◽  
pp. 1095-1108 ◽  
Author(s):  
J. E. Burt ◽  
J. T. Hayes ◽  
P. A. O'Rourke ◽  
W. H. Terjung ◽  
P. E. Todhunter
Keyword(s):  
Water Use ◽  
Crop Water ◽  
Crop Water Use

Response of four grain legumes to water stress in south-eastern Queensland. IV. Interaction with sowing arrangement

1983 ◽  
Vol 34 (6) ◽  
pp. 661 ◽  
Author(s):  
RJ Lawn
Keyword(s):  
Water Stress ◽  
Population Density ◽  
Water Use ◽  
Spatial Arrangement ◽  
Crop Growth ◽  
Yield Response ◽  
Crop Water ◽  
Area Index ◽  
Crop Water Use ◽  
South Eastern

The effect of spatial arrangement and population density on growth, dry matter production, yield and water use of black gram (Vigna mungo cv. Regur), green gram (V. radiata cv. Berken), cowpea (V. unguiculata CPI 28215) and soybean (Glycine rnax CP126671), under irrigated, rain-fed fallowed and rain-fed double-cropped culture was evaluated at Dalby in south-eastern Queensland. Equidistant spacings increased initial rates of leaf area index (LAI) development and crop water use compared with 1-m rows at the same population densities. In the irrigated and rain-fed fallowed treatments, where more water was available for crop growth, both seed yields and total crop water use were higher in the equidistant spacings. However, in the double-cropped treatment, where water availability was limited, there was no yield difference between rows and equidistant spacings, primarily because initially faster growth in the latter was offset by more severe water stress later in the season. Higher population density also increased initial crop growth rate and water use, particularly in the equidistant spacings. However, there was no significant yield response to density, presumably because subsequent competition for light/ water offset initial effects on growth. Although absolute yield differences existed between legume cultivars within cultural treatments, there were no significant differential responses to either spatial arrangement or population density among these four cultivars.

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