Limited Water Supply Conditions Research Articles

Foliar Application of Glycinebetaine and Salicylic Acid Improves Growth, Yield and Water Productivity of Hybrid Sunflower Planted by Different Sowing Methods

Improved planting methods and foliar application of glycinebetaine (GB) and salicylic acid (SA) can improve the water productivity in field crops under limited water supply conditions. A 2-year field study was conducted to evaluate the possible role of different planting methods and foliar applications of GB and SA in improving the yield, quality and water productivity of hybrid sunflower (Helianthus annuus L.). The crop was planted by flat sowing (75 cm spaced rows) and ridge sowing (75 cm spaced ridges), with GB and SA applied exogenously at 100 and 0.724 mm, respectively, at both budding and flowering stages, while control plots received distilled water. Ridge sowing, rather than flat sowing, improved the biological yield, oil yield, leaf area index (LAI), crop growth rate (CGR), plant height, water-use efficiency and final achene yield during both the years. Foliar applications of GB and SA at both the stages improved the achene yield, although foliar application of GB at flowering was the most effective. Neither the planting methods nor the foliar application of GB and SA altered the achene oil contents during both the years. Foliar application of GB and SA increased the free proline content of the leaf and GB contents at flowering but reduced the achene protein contents, whereas planting method had no effect on these attributes across the years. Of the foliar applied chemicals, GB was more effective in improving sunflower growth and yield and water productivity than SA. To conclude, ridge sowing coupled with foliar application of GB at flowering stage could be beneficial for achieving maximum yields of hybrid sunflower under relatively water limited conditions in the field.

Involvement of the V2 Vasopressin Receptor in Adaptation to Limited Water Supply

Mammals adapted to a great variety of habitats with different accessibility to water. In addition to changes in kidney morphology, e.g. the length of the loops of Henle, several hormone systems are involved in adaptation to limited water supply, among them the renal-neurohypophysial vasopressin/vasopressin receptor system. Comparison of over 80 mammalian V2 vasopressin receptor (V2R) orthologs revealed high structural and functional conservation of this key component involved in renal water reabsorption. Although many mammalian species have unlimited access to water there is no evidence for complete loss of V2R function indicating an essential role of V2R activity for survival even of those species. In contrast, several marsupial V2R orthologs show a significant increase in basal receptor activity. An increased vasopressin-independent V2R activity can be interpreted as a shift in the set point of the renal-neurohypophysial hormone circuit to realize sufficient water reabsorption already at low hormone levels. As found in other desert mammals arid-adapted marsupials show high urine osmolalities. The gain of basal V2R function in several marsupials may contribute to the increased urine concentration abilities and, therefore, provide an advantage to maintain water and electrolyte homeostasis under limited water supply conditions.

Effects of Deficit Drip Irrigation Ratios on Cotton (Gossypium hirsutum L.) Yield and Fibre Quality

AbstractIncreasing irrigation costs and declining water availability compel producers to adapt irrigation strategies for maximum crop yield and water use efficiency. A field trial was conducted to observe the effects of various drip irrigation ratios (IR‐0, IR‐25, IR‐50, IR‐75 and IR‐100) on water use efficiency (WUE), the irrigation water use efficiency (IWUE), lint yield, yield components and fibre quality at two upland cotton varieties during 2004 and 2005. WUE was found to increase from 0.62 to 0.71 kg m−3 as the irrigation water applied was reduced from 100 % to 75 % of soil water depletion. Deficit irrigation of cotton with drip irrigation at 75 % treatment level (IR‐75) did not decrease seed cotton yield and yield components during 2 years, with the exception of the number of bolls in 2005. Among fibre quality parameters, no significant differences in fibre length, fineness, uniformity index and elongation were detected between the 100 % and 75 % irrigation levels in 2005. The results revealed that irrigation of cotton with a drip irrigation method at 75 % level had significant benefits in terms of saved irrigation water without reducing yield, and high WUE indicated a definitive advantage of employing deficit irrigation under limited water supply conditions.

Different drip irrigation regimes affect cotton yield, water use efficiency and fiber quality in western Turkey

Decreasing in water availability for cotton production has forced researchers to focus on increasing water use efficiency by improving either new drought-tolerant cotton varieties or water management. A field trial was conducted to observe the effects of different drip irrigation regimes on water use efficiencies (WUE) and fiber quality parameters produced from N-84 cotton variety in the Aegean region of Turkey during 2004 and 2005. Treatments were designated as full irrigation (T 100, which received 100% of the soil water depletion) and those that received 75, 50 and 25% of the amount received by treatment T 100 on the same day (treatments T 75; T 50 and T 25, respectively). The average seasonal water use values ranged from 265 to 753 mm and the average seed cotton yield varied from 2550 to 5760 kg ha −1. Largest average cotton yield was obtained from the full irrigation treatment (T 100). WUE ranged from 0.77 kg m −3 in the T 100 to 0.98 kg m −3 in the T 25 in 2004 growing season and ranged from 0.76 kg m −3 in the T 100 to 0.94 kg m −3 in the T 25 in 2005 growing season. The largest irrigation water use efficiency (IWUE) was observed in the T 25 (1.46 kg m −3), and the smallest IWUE was in the T 100 treatment (0.81 kg m −3) in the experimental years. A yield response factor ( k y) value of 0.78 was determined based on averages of two years. Leaf area index (LAI) and dry matter yields (DM) increased with increasing water use for treatments. Fiber qualities were influenced by drip irrigation levels in both years. The results revealed that well-irrigated treatments (T 100) could be used for the semi-arid climatic conditions under no water shortage. Moreover, the results also demonstrated that irrigation of cotton with drip irrigation method at 75% level (T 75) had significant benefits in terms of saved irrigation water and large WUE indicating a definitive advantage of deficit irrigation under limited water supply conditions. In an economic viewpoint, 25.0% saving in irrigation water (T 75) resulted in 34.0% reduction in the net income. However, the net income of the T 100 treatment is found to be reasonable in areas with no water shortage.

Effect of elevated CO2, temperature and limited water supply on antioxidant status during regrowth of nodulated alfalfa

Atmospheric CO2 is a major contributor to the greenhouse effect and is one of the main inducers of climate change. Previous studies with nodulated alfalfa plants have shown that elevated CO2 increased the growth of plants grown under well‐watered or limited water supply conditions. The beneficial effects of atmospheric CO2 enrichment included higher photosynthetic rates, growth and water‐use efficiency and an increase in the root/shoot ratio. However, at the moment, we do not have information on the possible implications of the beneficial effect of elevated CO2 as it may relate to a higher capacity of the violaxanthin–antheraxanthin–zeaxanthin (VAZ) cycle, the dissipation of excess radiation as heat and the effect on photooxidation, and to an improved leaf antioxidant system (Halliwell–Asada cycle). The aim of the present study was to determine the effects of the interaction between CO2 (ambient, around 350 vs 700 μmol mol−1), temperature (ambient vs ambient + 4°C) and water availability (well irrigated vs partially irrigated) on the leaf antioxidant status of nodulated alfalfa during regrowth. Parameters measured in this study included relative growth rate (RGR), H2O2 content, oxidative damage [measured as thiobarbituric acid‐reacting substances (TBARS)], leaf pigment composition (chlorophylls and xanthophylls), ascorbate (ASA) and glutathione pool levels and antioxidant enzymes. Our results revealed that during alfalfa regrowth, the effects of elevated CO2, limited water supply, temperature and their interactions on growth were not related to significant or general changes in leaf antioxidant capacity, H2O2 accumulation or oxidative stress (TBARS concentrations). The beneficial effects of CO2 enrichment in well‐watered and limited water‐subjected plants were not associated with an increase in the capacity of alfalfa leaves to dissipate excess radiation as heat through the VAZ cycle or with an increase in the antioxidant capacity, measured in terms of Halliwell–Asada cycle enzymes and antioxidant compounds. Furthermore, elevated CO2 did not affect RGRs during the last 15 days of regrowth and reduced the activity of several antioxidant enzymes (catalase, superoxide dismutase and glutathione reductase and ASA peroxidase in limited water‐subjected plants), suggesting a lower basal rate of oxygen activation and H2O2 formation, leading to a relaxation of the antioxidant system.

Water-nitrogen relationships for wheat growth and productivity in late sown conditions

Field experiments were conducted on a sandy loam soil (Typic Ustochrept) to study the water-nitrogen –yield relationships of late sown wheat under adequate and limited water supply conditions. The treatments comprised of four levels of irrigation (I 0 , no post-sown irrigation; I 1 , one irrigation at CRI stage; I 2 , two irrigations, each at CRI and flowering stages; I 3 , four irrigations each given at CRI, jointing, flowering and dough stages) in main plots and a combination of three N levels (0, 50 and 100 kg N/ha) and two levels of zinc as ZnSO 4 . 7H 2 O (0 and 5 kg Zn/ha) in sub-plots of a split plot design and were replicated three times. Progressive increase in irrigations from 0 to 4 and nitrogen levels from 0 to 100 kg/ha, increased the average LAI, CGR, RGR and NAR, yield attributes, wheat biomass and grain yield significantly (p ≤ 0.05) over the control (I 0 and N 0 ), in both the seasons, respectively. Analyses by multiple regression techniques reveled that LAI estimates with N uptake were much higher at 84% predictability than the estimate based on water use that could account for 75% of the variations only. Lower levels of water consumption by crop were seen to result in less leaf area therefore, resulting in lower biomass and grain yields at lower levels of irrigation. The highest rate of biomass gains of 53.1 kg/ha-mm was obtained during the 60–90 day period, a period that fell within the maximum growth phase of wheat, followed by 28.3 and 6.7 kg/ha-mm during 90-120 and 0-60 days after sowing (DAS) periods. The response of the above ground biomass to nitrogen uptake was higher (76.6 kg/ha-kg N uptake) during 60-90 DAS period than during the 0-60 DAS period (22.1 kg/ha-kg N uptake). Additive production functions therefore, took care of the stage sensitivity along with the complete water and nitrogen stresses as induced through different applications of water and nitrogen. The maximum growth rates in wheat were commensurate with highest levels of water use as well as nitrogen use observed during the 60-90 DAS period of growth. For this reasons, scheduling of water and nitrogen application ought to consider providing relatively less quantities of water during the 0-60 DAS period as compared to the 90-120 and 60-90 DAS periods respectively, in order to provide just sufficient amounts of water so as to enhance the uptake of available nitrogen required for optimum growth and development of wheat. Journal of Agriculture Science and Technology Vol. 7(1) 2005: 1-17

Water–nitrogen relationships for wheat growth and productivity in late sown conditions

Field experiments were conducted on a sandy loam soil (Typic Ustochrept) to study the water–nitrogen yield relationships of late sown wheat under adequate and limited water supply conditions. The treatments comprised of four levels of irrigation ( I 0, no post-sown irrigation; I 1, one irrigation at CRI stage; I 2, two irrigations, each at crown root initiation (CRI) and flowering stages; I 3, four irrigations each given at CRI, jointing, flowering and dough stages) in main plots and a combination of three N levels (0, 50 and 100 kg N/ha) and two levels of zinc as ZnSO 4·7H 2O (0 and 5 kg Zn/ha) in sub-plots of a split plot design and were replicated three times. Progressive increase in irrigations from 0 to 4 and nitrogen levels from 0 to 100 kg/ha, increased the average leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR), yield attributes, wheat biomass and grain yield significantly ( p ≤ 0.05) over the control ( I 0 and N 0), in both the seasons, respectively. Analyses by multiple regression techniques reveled that LAI estimates with N uptake were much higher at 84% predictability than the estimate based on water use that could account for 75% of the variations only. Lower levels of water consumption by crop were seen to result in less leaf area therefore, resulting in lower biomass and grain yields at lower levels of irrigation. The highest rate of biomass gains of 53.1 kg/ha-mm was obtained during the 60–90 day period, a period that fell within the maximum growth phase of wheat, followed by 28.3 and 6.7 kg/ha-mm during 90–120 and 0–60 days after sowing (DAS) periods. The response of the above ground biomass to nitrogen uptake was higher (76.6 kg/ha-kg N uptake) during 60–90 DAS period than during the 0–60 DAS period (22.1 kg/ha-kg N uptake). Additive production functions therefore, took care of the stage sensitivity along with the complete water and nitrogen stresses as induced through different applications of water and nitrogen. The maximum growth rates in wheat were commensurate with highest levels of water use as well as nitrogen use observed during the 60–90 DAS period of growth. For this reasons, scheduling of water and nitrogen application ought to consider providing relatively less quantities of water during the 0–60 DAS period as compared to the 90–120 and 60–90 DAS periods respectively, in order to provide just sufficient amounts of water so as to enhance the uptake of available nitrogen required for optimum growth and development of wheat.

Nutrient economy through land configuration and residue management in a greengram (Phaseolus radiatus L.)-wheat (Triticum aestivum L.) cropping sequence with limited water supplies

A field experiment on a greengram-wheat cropping sequence was carried out under limited water supply conditions in 1997-98 and 1998-99 at the farm of the Indian Agricultural Research Institute, New Delhi. The greengram was sown either on flat beds or on broad beds 2 m in width, divided by furrows, with 0, 30 and 60 kg P2O5/ha. After the harvest of greengram pods, wheat was grown in the same plots, either with the greengram stover removed or with the stover incorporated along with 0, 40, 80 and 120 kg N/ha applied to wheat. The grain yield of greengram was higher when sown on broad beds with furrows compared to flat bed sowing, and the application of 30 or 60 kg P2O5/ha resulted in significantly higher grain yields compared to no phosphorus application. The combination of broad bed and furrows with phosphorus fertilization was found to be ideal for achieving higher productivity in greengram. The land configuration treatments had no impact on the productivity of wheat. The application of phosphorus to the preceding crop had a significant residual effect on the grain yield of wheat. The incorporation of greengram stover also significantly increased the grain yield of wheat. The increasing levels of N increased the grain yield of wheat significantly up to 80 kg/ha. The combination of greengram stover incorporation and 80 kg N/ha applied to wheat significantly increased the grain yield. Further, there was a significant interaction effect between the phosphorus applied to the preceding crop and N levels given to wheat on the grain yield of wheat.

Root growth and soil water utilization of winter wheat in the North China Plain

AbstractWinter wheat (Triticum aestivum L.) is the major crop in the North China Plain (NCP). The monsoon climate in this region causes most rain to fall in the summer season, but during the winter‐wheat growing season (October–May) the rainfall is far less than the water requirements for the crop. The efficiency of soil water use by winter wheat needs to be improved to reduce the need for irrigation. In this paper, we report the results of two seasons' work on soil water utilization, root growth and distribution, root water uptake by the crop under different irrigation treatments, and possible ways to improve soil water‐use efficiency. The field experiments were carried out at Luancheng Station (37° 53′N, 114° 41′E) from 1996 to 1997 and 1998 to 1999, two growing seasons of winter wheat. Five treatments for each season: rain‐fed and irrigated winter wheat with different irrigation numbers from 1 up to 4, were set up in a randomized plot design. Soil available water‐holding capacity at the experimental site was about 454 mm for the top 2 m soil profile. Root sampling results showed that winter wheat had a prolific root system with an average maximum rooting depth of 2 m. Most of the root system was concentrated in the upper 40 cm of soil. Root length density in the top layer of soil (0–20 cm) was very high, with values over 5 cm cm−3. The distribution of water uptake from the soil profile under high soil moisture conditions was the same as the distribution of root length density. The roots in the top layer of soil played an important role in soil water uptake. When root length density was less than 0 · 8 cm cm−3, the root was the main factor limiting the complete utilization of soil water by crops. The scarcity of roots in the deep soil layers restricted the full utilization of soil water by the crops. Thus, at maturity, over 100 mm of available water remained in the root zone for the rain‐fed treatment, although the upper layers had already entered water deficit. The crop took up 80% of the total available soil water in the treatment without irrigation in a dry season. For irrigated wheat, from 40 to 50% of crop water uptake was from the stored soil water. Available stored soil water played an important role in the higher production of wheat crops in the NCP. Effective measures to increase the utilization of stored soil water could improve crop performance under conditions of limited water supply. Results showed that deep tillage to break the soil pan improved root growth in the deeper soil layers, and sowing the crop evenly also enhanced water uptake from the top soil layer to compete with soil evaporation. Copyright © 2004 John Wiley & Sons, Ltd.

A non-linear model for farm optimization with adequate and limited water supplies: Application to the South-east Anatolian Project (GAP) Region

This paper develops a non-linear optimization model for the determination of optimum cropping pattern, water amount and farm income under adequate and limited water supply conditions. The objective function of the model is based on crop water-benefit functions. The model is solved using Ms Excel Solver package for conditions existing in South-east Anatolian Region of Turkey. The model gives the optimal distribution of crop areas, irrigation water needs of crops and total profit for the farm under adequate and limited water supplies. The problem was also solved by a linear programming (LP) model, in order to indicate the difference between non-linear programming (NLP) and linear programming models. After the examination of NLP and LP model solutions, it can be seen that, the NLP model can give higher farm income values than the LP model under deficit irrigation conditions. Also, in some capacity levels, with the NLP model, instead of two different irrigation volume applications for one crop, the best irrigation volume ratio has been calculated.

Irrigation planning in cotton through simulation modeling

Experiments were undertaken at CCS Haryana Agricultural University Farm, Sirsa (India) to estimate the optimum irrigation schedule for cotton resulting in minimum percolation losses. The sprinkler line source technique was adopted for creating various irrigation regimes at different crop growth stages. The SWASALT (Simulation of Water And SALT) model after calibration and validation provided water balance components. The wa-ter management response indicators (WMRI's) such as transpiration efficiency Et/(Irr + P), relative transpiration Et/Etp, evapotranspiration efficiency ET/(Irr + P), soil moisture storage change ΔW/Wint (deficit/excess) and percolation loss Perc/(Irr. + P) were evaluated using water balance components as estimated by the simulation study. Under limited water supply conditions, the optimum irrigation depth was found to be 57 mm at crop growth stages with pre-sowing and 1st irrigation of 120 mm and 80 mm respectively for sandy clay loam underlain by sandy loam soil (Type I). The corresponding values of relative transpiration, transpiration efficiency and evapotranspiration efficiency were 0.65, 0.65 and 0.89 respectively. The crop yield varied linearly with increasing irrigation depth which was evident from increase in relative transpiration with increasing depth of water application. However, increased depth of irrigation resulted in less moisture utilisation from soil storage (20% depletion at 40 mm depth and 4.4% moisture built up at 100 mm depth). The extended simulation study for sandy soil underlain by loamy sand (Type II) indicated that two pre-sowing irrigations each 40 mm and subsequent irrigations of 40 mm at an interval of 20 days depending upon rainfall were optimum. This irrigation scenario resulted in zero percolation loss accompanied by 74% relative transpiration and 14 per cent soil moisture depletion.

WATER AND NITROGEN MANAGEMENT FOR LOWLAND TRANSPLANTED RICE UNDER LIMITED WATER SUPPLY

Under conditions of limited water supply, intermittent irrigation instead of continuous flooding is necessitated in rice cultivation. To assess the response of lowland transplanted rice to intermittent irrigation vis-a-vis continuous submergence, field experiments were conducted at the Agricultural College, Killikulam during rubi seasons (Oct-Feb) of 1990 and 1991. The effect of partial substitution of inorganic nitrogen through bio fertilizers-azolla and blue green algae (BGA) - was also evaluated. The results indicated that rice yield was reduced by 3 to 19 per cent by intermittent irrigation compared to continuous submergence. The practice of irrigation immediately after disapperance of ponded water was most suitable under limited water supply. With this practice, the yield reduction was only marginal (3-5%) but it helped to save about 28.7 per cent of irrigation water compared to continuous submergence. Substitution of 25 per cent of inorganic nitrogen through inoculation of azolla or BGA maintained the grain yield of rice on par with the application of 100 per cent of N through inorganic fertilizers.

Aspects of the Effect of ABA on the Water Status of Barley and Wheat Seedlings

AbstractThe effect of abscisic acid on plant growth and survival during water deprivation was studied in barley and wheat seedlings. Under conditions of both limited and ample water supply, treatment with abscisic acid greatly reduced transpiration and, in addition, suppressed root growth. In water‐deprived seedlings, abscisic acid increased the total dry matter, reflecting improved efficiency in water‐use. In addition, the growth period and survival of water‐deprived seedlings were markedly prolonged. In field trials, however, abscisic acid had no significant effect on waterdeprived seedlings. Possible reasons for this lack of response are discussed.

Effect of Planting Date on Water‐Use and Its Efficiency in Dryland Grain Sorghum1

AbstractIt has been postulated that water regime was the major operative factor responsible for different yield response of dryland grain sorghum [Sorghum bicolor (L.) Moench] to different planting dates. Our research was done in order to appraise this postulation.For four consecutive years, four grain sorghum hybrids were planted on two planting dates (March 20–24 and April 12–16) in Israel under conditions of limited water supply as determined by the amount of stored soil moisture prior to planting. Vegetative development, grain yield, and soil water extraction profiles were determined.Early planting, as compared with late planting, increased grain yield through increased tillering and greater weight per grain. During the period from emergence to 51 days, early planted sorghum used about half as much water as late‐planted sorghum. Early planted sorghum was less water stressed, as evidenced by lower leaf diffusive resistance prior to heading and smaller reduction in LAI (leaf desiccation) after heading, as compared with late‐planted sorghum. Lower water use in early planted sorghum, during the period prior to heading, was ascribed to lower potential evapotranspiration, smaller LAI, and possibly slower root development, as compared with the respective period in late‐planted sorghum. Total amount of water used at maturity did not differ between planting dates, apparently due to the longer period of growth and the larger amount of stover dry matter per plant in early planted sorghum, which served to offset the decreased water use during the earlier phase of growth.No appreciable differences were found between hybrids tested in terms of adaption to early planting or water use.

Field measurements of water use for irrigation control in Kenya coffee

The paper presents the results of 10 years of soil moisture studies in arabica coffee in high altitude tropical conditions. Very deep soils and contrasting wet and dry seasons give unusually favourable conditions for soil moisture measurements.Volumetric measurements on soil cores are reported for 10 ft. depth of soil, which is shown to include most of the root system of arabica coffee, and holds 48 in. of water under field conditions when active drainage has ceased. This is shown to correspond to a soil moisture tension of 1/3 atm. Of the 48 in. of water only 12 are available to plants. Wilting points determined by sunflower seedlings on soil samples to 15 ft. depth are shown to agree well with field sampling under wilting conditions in coffee plantations.A series of seasonal factors relating the water use of the coffee crop to the readings of an evaporation pan are presented, and their application over 6 years is shown to check with soil sampling data within the limits of sampling error. This method is proposed for control of supplementary irrigation under conditions of limited water supply, but a distillation-type radiation integrator can with advantage replace the evaporation pan.The balance of the hydrological equation for this crop is demonstrated in each of the 6 years.