The Experts below are selected from a list of 3717 Experts worldwide ranked by ideXlab platform
Huafeng Shao - One of the best experts on this subject based on the ideXlab platform.
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towards development of eco agriculture of rainwater harvesting for Supplemental Irrigation in the semi arid loess plateau of china
Journal of Agronomy and Crop Science, 2009Co-Authors: X N Zhao, Huyuan Feng, Yanbin Wang, Huafeng ShaoAbstract:The semi-arid Loess Plateau is a central zone of Chinese rain-fed farming. Drought and soil erosion are the two major obstacles to restrict economic development in this semi-arid Loess Plateau. The traditional conservation agriculture and runoff agriculture have been developed for several decades, which have reduced water and soil loss and improved rainwater utilization efficiency to a certain extent. However, its regulative role in rainwater is very much limited, and problems of agriculture production, such as severe seasonal drought and water shortage, low agriculture productivity, fragile ecological environment, and low yield-invest ratio, are still going on. Supplemental Irrigation of harvested rainwater is an important form of rainfall regulation and utilization on the basis of sophisticated technologies and theories of conservation agriculture and runoff agriculture, which not only promotes fulfilling rainfall harvesting in spatial location like the conservation agriculture and runoff agriculture measure but also gets at true rainfall harvesting in time distribution by principle of superposition and also decreases invalid evaporation for rainfall runoff. Agriculture productivity will be highly increased by using rainwater harvesting for Supplemental Irrigation. It not only brings about the integration of ecological reconstruction with economic development, but also provides a new approach to the agriculture sustainable development and overcomes two of the biggest obstacles (drought and soil erosion). It is suggested that this technology will become a strategic measure and comprehensive development model in semi-arid Loess Plateau of China.
Johan Rockström - One of the best experts on this subject based on the ideXlab platform.
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rainfed agriculture unlocking the potential
Research Papers in Economics, 2009Co-Authors: S P Wani, Johan Rockström, Theib OweisAbstract:1. Rainfed Agriculture - Past Trends and Future Prospects 2. Zooming in on the Global Hotspots of Rainfed Agriculture in Water Constrained Environments 3. Water Resource Implications of Upgrading Rainfed Agriculture - Focus on Green and Blue Water Trade-offs 4. Tectonics-climate Linked Natural Soil Degradation and its Impact in Rainfed Agriculture: Indian Experience 5. Determinants of Crop Growth and Yield in a Changing Climate 6. Yield Gap Analysis: Modeling of Achievable Yields at Farm Level 7. Can Rainfed Agriculture Feed the World? - An Assessment of Potentials and Risk 8. Opportunities for Improving Crop-water Productivity Through Genetic Enhancement of Dryland Crops 9. Water Harvesting for Improved Rainfed Agriculture in the Dry Environments 10. Supplemental Irrigation for Improved Rainfed Agriculture: In WANA Region 11. Opportunities for Water Harvesting and Supplemental Irrigation for Improving Rainfed Agriculture in Semi-arid Areas 12. Integrated Farm Management Practices and Up Scaling the Impact for Increased Productivity of Rainfed Systems 13. Challenges of Adoption and Adaptation of Land and Water Management Options in Smallholder Agriculture: Synthesis of Lessons and Experiences 14. Scaling-out Community Watershed Management for Multiple Benefits in Rainfed Areas.
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agro hydrological evaluation of on farm rainwater storage systems for Supplemental Irrigation in laikipia district kenya
Agricultural Water Management, 2005Co-Authors: S N Ngigi, Johan Rockström, H H G Savenije, Josephine N Thome, F Penning W T De VriesAbstract:Abstract Semi-arid agro-ecosystems are characterized by erratic rainfall and high evaporation rates leading to unreliable agricultural production. Total seasonal rainfall may be enough to sustain crop production, but its distribution and occurrence of intra-season dry spells (ISDS) and off-season dry spells (ODS) affect crop production. Rainwater harvesting (RWH) and management, especially on-farm storage ponds for Supplemental Irrigation offers an opportunity to mitigate the recurrent dry spells. Farm ponds are small runoff storage structures of capacities ranging from 30 to 100 m3 used mainly for Supplemental Irrigation of kitchen gardens, and sometimes for domestic and livestock water supply. The main objective of the study was to evaluate the hydrological and economic performance of farm ponds with the view of assessing their contributions to water and food security in semi-arid agro-systems of Kenya. Agro-hydrological evaluation of on-farm runoff storage systems entailed field survey, monitoring of water losses, analysis of rainy seasons and dry spell occurrence, soil moisture and water balance, estimation of Supplemental Irrigation requirement (SIR) and farm-level cost-benefit analysis of cabbage production using low-head drip Irrigation system. Significant water losses through seepage and evaporation, which accounted on average for 30–50% of the stored runoff, is one of the factors that affect the adoption and up-scaling of on-farm water storage systems. Frequency analysis of rainfall revealed that there is 80% probability of occurrence of dry spells exceeding 10 and 12 days during the long rains and short rains, respectively. The occurrence of off-season (after rainfall cessation) dry spells was more pronounced than intra-seasonal (within the rainy season) dry spells. The length of intra-seasonal (10–15 days) was less than off-season dry spells (20–30 days). The occurrence of off-season dry spells coincides with the critical crop growth stage, in particular flowering and yield formation stages. A 50 m3 farm pond with a drip system Irrigation system was found adequate to meet Supplemental Irrigation requirement for a kitchen garden of 300–600 m2 planted with a 90 days growing period cabbages. The cost-benefit analysis showed that farm ponds are feasible solutions to persistent crop failures in semi-arid areas which dominant most countries in Sub-Saharan Africa (SSA).
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risk analysis and economic viability of water harvesting for Supplemental Irrigation in semi arid burkina faso and kenya
Agricultural Systems, 2005Co-Authors: Johan Rockström, Jennie BarronAbstract:Food insecurity affects a large portion of the population in sub-Saharan Africa (SSA). To meet future food requirements current rainfed farming systems need to upgrade yield output. One way is to i ...
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Supplemental Irrigation for dry spell mitigation of rainfed agriculture in the sahel
Agricultural Water Management, 2003Co-Authors: Paul J Fox, Johan RockströmAbstract:Abstract Unreliable and erratic rainfall combined with inherent low soil fertility in crust prone soils affect crop growth in the Sahel. Past efforts of agricultural water management have primarily focused on maximising rainfall infiltration through soil and water conservation. The challenge of how to cope with dry-spells, short periods of water stress during crop growth, remains largely unsolved. Small-scale water harvesting (WH) for Supplemental Irrigation may be a tool for small-holder farmers to stabilise crop water supply and thereby increase yields and create incentives for increased investments in fertilisation. Results are presented on the effects on Sorghum (Sorghum Bicolor (L.)) yields under Supplemental Irrigation and soil nutrient application in an on-farm experiment in northern Burkina Faso. Focus is on dry-spell bridging and water and nutrient interactions on biomass productivity. The water harvesting system consisted of a low-cost manually dug farm pond with a storage volume of 150 m3, collecting surface runoff as rill and small gully flow from a 1.8 ha catchment area. The on-farm experiment involved five repetitions of two levels of nutrient application (non-fertilised and fertilised) and two levels of Supplemental Irrigation (non-irrigated and irrigated) including: farmers’ traditional practices (TC), Supplemental Irrigation (I), fertiliser application (F) and Supplemental Irrigation combined with fertilisation (IF). This paper presents field results from three rainy seasons (1998–2000), receiving a cumulative seasonal rainfall ranging from 418 to 667 mm. Supplemental Irrigation ranging from 60 to 90 mm per season was applied based on actual occurrence of dry-spell induced crop water stress. Supplemental Irrigation had a significant effect on grain yield over the three crop seasons (∗∗P
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resilience building and water demand management for drought mitigation
Physics and Chemistry of The Earth, 2003Co-Authors: Johan RockströmAbstract:Abstract Doughts resulting in complete crop failure are common in Eastern and Southern Africa. We are at present experiencing a regional crisis, where crop failures related to drought are threatening the lives of millions of people in several countries in Southern Africa. A major challenge is to seek ways of mitigating and coping with droughts in small-holder farming systems, particularly in semi-arid regions which are most hardly hit by the effects of drought. An entry-point for drought mitigation is to build water resilience of present rainfed farming systems. The water balance is a good starting point to assess the options. As has been argued for decades, the term drought is very debated, and the boundaries between droughts being politically and biophysically defined is not sharp. Often crop failures and social suffering are blamed on drought, while in reality the causes are more complex than only a decline in rainfall. A challenge is to find management strategies to deal with the unreliable and extremely variable rainfall in savannah environments. In this paper examples of small-scale management practices to mitigate drought in semi-arid rainfed farming are presented. Focus is on water harvesting systems for Supplemental Irrigation. It is shown that with relatively simple and cheap means it is possible to build resilience to deal with water scarcity in semi-arid farming systems. If such measures are combined with efforts of maximising plant water availability and plant water uptake capacity, there are good chances of mitigating certain droughts. Conservation tillage systems have proven to maximise rainfall infiltration and storage of water in the soil, enabling even crops lacking Supplemental Irrigation to bridge severe dry spells. Interestingly, building resilience in rainfed farming systems is also a means of water demand management. More crop is produced per drop of water in resilient farming systems, which reduces the amount of water needed to produce food. Despite the opportunities to build resilience to mitigate droughts, it is impossible to escape from the severe drought years. This is where coping mechanisms are required, which involve social, economic and institutional preparedness to cope with the social effects of climatic droughts.
Theib Oweis - One of the best experts on this subject based on the ideXlab platform.
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Supplemental Irrigation a highly efficient water use practice
2012Co-Authors: Theib OweisAbstract:Supplemental Irrigation: a highly efficient water use practice , Supplemental Irrigation: a highly efficient water use practice , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
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rainfed agriculture unlocking the potential
Research Papers in Economics, 2009Co-Authors: S P Wani, Johan Rockström, Theib OweisAbstract:1. Rainfed Agriculture - Past Trends and Future Prospects 2. Zooming in on the Global Hotspots of Rainfed Agriculture in Water Constrained Environments 3. Water Resource Implications of Upgrading Rainfed Agriculture - Focus on Green and Blue Water Trade-offs 4. Tectonics-climate Linked Natural Soil Degradation and its Impact in Rainfed Agriculture: Indian Experience 5. Determinants of Crop Growth and Yield in a Changing Climate 6. Yield Gap Analysis: Modeling of Achievable Yields at Farm Level 7. Can Rainfed Agriculture Feed the World? - An Assessment of Potentials and Risk 8. Opportunities for Improving Crop-water Productivity Through Genetic Enhancement of Dryland Crops 9. Water Harvesting for Improved Rainfed Agriculture in the Dry Environments 10. Supplemental Irrigation for Improved Rainfed Agriculture: In WANA Region 11. Opportunities for Water Harvesting and Supplemental Irrigation for Improving Rainfed Agriculture in Semi-arid Areas 12. Integrated Farm Management Practices and Up Scaling the Impact for Increased Productivity of Rainfed Systems 13. Challenges of Adoption and Adaptation of Land and Water Management Options in Smallholder Agriculture: Synthesis of Lessons and Experiences 14. Scaling-out Community Watershed Management for Multiple Benefits in Rainfed Areas.
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assessment of winter wheat production under early sowing with Supplemental Irrigation in a cold highland environment using cropsyst simulation model
Agricultural Water Management, 2007Co-Authors: Bogachan Benli, Claudio O Stockle, Mustafa Pala, Theib OweisAbstract:Abstract The most important question in Supplemental Irrigation management is when and how much water to apply. It is a laborious and expensive task to develop Supplemental Irrigation schedules solely by conventional field experimentation. A cropping system simulation model (CropSyst) was evaluated for its ability to simulate growth, biomass, grain yield and evapotranspiration (ET) of wheat sown early with Supplemental Irrigation (SI). This was computed under rainfed conditions in a semiarid climate with cold winters in the highlands of Turkey. Experimental data from three growing seasons (1998–2001) were used. The experimental design incorporates Bezostia bread wheat cultivar tested under two main treatments: no Irrigation at sowing (rainfed-A1) and Irrigation at sowing with 50 mm of water (A2); and two sub treatments: rainfed (B1) and spring Supplemental Irrigation to replenish the total water requirement at 0–90 cm soil profile (B2) at the Ankara Research Institute of Rural Services. Crop input parameters were selected from the model documentation and experimental data. A few cultivar-specific parameters were adjusted within a narrow range of typical fluctuations by model calibration. Results showed that CropSyst was able to simulate yield, biomass and evapotranspiration as observed in the field experiments. Overall, the Willmott Index of agreement between simulated and observed values of grain yield, biomass and ET were 0.98, 0.76 and 0.91, respectively. CropSyst model predicted better the seasonal evapotranspiration under full Supplemental irrigated conditions (A2B2) than under rainfed conditions (A1B1), with values of the Willmott index of agreement being 0.97 and 0.89, respectively. The model was run for 20 years (1982–2001) including the 4-year experimental period. Data showed that wheat grain yield could be improved by 15, 19 and 25% with applying only 50 mm of water at the sowing time of 15 October, 1 October and 15 September, respectively. In 80% of the cases, the respective SI applications would give 2.75, 2.7 and 2.95 t ha−1, of the long-term average rainfed yield of 2.1 t ha−1, respectively.
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water harvesting and Supplemental Irrigation for improved water productivity of dry farming systems in west asia and north africa
Agricultural Water Management, 2006Co-Authors: Theib Oweis, Ahmed HachumAbstract:In the dry areas, water, not land, is the most limiting resource for improved agricultural production. Maximizing water productivity, and not yield per unit of land, is therefore a better strategy for dry farming systems. Under such conditions, more efficient water management techniques must be adopted. Supplemental Irrigation (SI) is a highly efficient practice with great potential for increasing agricultural production and improving livelihoods in the dry rainfed areas. In the drier environments, most of the rainwater is lost by evaporation; therefore the rainwater productivity is extremely low. Water harvesting can improve agriculture by directing and concentrating rainwater through runoff to the plants and other beneficial uses. It was found that over 50% of lost water can be recovered at a very little cost. However, socioeconomic and environmental benefits of this practice are far more important than increasing agricultural water productivity. This paper highlights the major research findings regarding improving water productivity in the dry rainfed region of West Asia and North Africa. It shows that substantial and sustainable improvements in water productivity can only be achieved through integrated farm resources management. On-farm water-productive techniques if coupled with improved Irrigation management options, better crop selection and appropriate cultural practices, improved genetic make-up, and timely socioeconomic interventions will help to achieve this objective. Conventional water management guidelines should be revised to ensure maximum water productivity instead of land productivity.
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water use efficiency and transpiration efficiency of wheat under rain fed conditions and Supplemental Irrigation in a mediterranean type environment
Plant and Soil, 1998Co-Authors: Heping Zhang, Theib Oweis, S Garabet, Mustafa PalaAbstract:Growth and water use were measured in wheat (Triticum aestivum L.) grown in northern Syria in a typical Mediterranean climate over five seasons 1991/92–1995/96. Water use was partitioned into transpiration (T) and soil evaporation (Es) using Ritchie's model, and water-use efficiency (WUE) and transpiration efficiency (TE) were calculated. The aim of the study was to examine the influence of Irrigation and nitrogen on water use, WUE and TE. By addition of 100 kg N ha-1, Es was reduced from 120 mm to 101 mm under rain-fed conditions and from 143 mm to 110 mm under irrigated conditions, and T was increased from 153 mm to 193 mm under rain-fed conditions and from 215 mm to 310 mm under irrigated conditions. Under rain-fed conditions, about 35% of evapotranspiration (ET) may be lost from the soil surface for the fertilized crops and 44% of ET for the unfertilized crops. Transpiration accounted for 65% of ET for the fertilized crops and 56% for the unfertilized crops under rain-fed. As a result of this, WUE was increased by 44% for dry matter and 29% for grain yield under rain-fed conditions, and by 60% for dry matter and 57% for grain yield under irrigated conditions. Transpiration efficiency for the fertilized crops was 43.8 kg ha-1 mm-1 for dry matter and 15 kg ha-1 mm-1 for grain yield, while TE for the unfertilized crops was 33.6 kg ha-1 mm-1 and 12.2 kg ha-1 mm-1 for dry matter and grain yield, respectively. Supplemental Irrigation significantly increased post-anthesis water use, transpiration, dry matter and grain yield. Water-use efficiency for grain yield was increased from 9.7 to 11.0 kg ha-1 mm-1 by Supplemental Irrigation, although WUE for dry matter was not affected by it. Irrigation did not affect transpiration efficiency for grain yield, but decreased transpiration efficiency for dry matter by 16%. This was associated with higher harvest index as a result of good water supply in the post-anthesis period and increased transpiration under irrigated conditions.
Yajun Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of rainfall harvesting and mulching technologies on water use efficiency and crop yield in the semi arid loess plateau china
Agricultural Water Management, 2009Co-Authors: Yajun Wang, S S Malhi, Cecil Vera, Yubao Zhang, Jinniu WangAbstract:In semi-arid areas, crop growth is greatly limited by water. Amount of available water in soil can be increased by surface mulching and other soil management practices. Field experiments were conducted in 2005 and 2006 at Gaolan, Gansu, China, to determine the influence of ridge and furrow rainfall harvesting system (RFRHS), surface mulching and supplementary Irrigation (SI) in various combinations on rainwater harvesting, amount of moisture in soil, water use efficiency (WUE), biomass yield of sweet sorghum (Sorghum bicolour L.) and seed yield of maize (Zea mays L.). In conventional fields without RFRHS, gravel-sand mulching produced higher biomass yield than plastic-mulching or straw-mulching. In plastic-mulched fields, an increasing amount of Supplemental Irrigation was needed to improve crop yield. There was no effect of RFRHS without plastic-covered ridge on rainwater harvesting when natural precipitation was less than 5 mm per event. This was due to little runoff of rainwater from frequent low precipitation showers, and most of the harvested rainwater gathered at the soil surface is lost to evaporation. In the RFRHS, crop yield and WUE were higher with plastic-covered ridges than bare ridges, and also higher with gravel-sand-mulched furrows than bare furrows in most cases, or straw-mulched furrows in some cases. This was most likely due to decreased evaporation with plastic or gravel-sand mulch. In the RFRHS with plastic-covered ridges and gravel-sand-mulched furrows, application of 30 mm Supplemental Irrigation produced the highest yield and WUE for sweet sorghum and maize in most cases. In conclusion, the findings suggested the integrated use of RFRHS, mulching and supplementary Irrigation to improve rainwater availability for high sustainable crop yield. However, the high additional costs of Supplemental Irrigation and construction of RFRHS for rainwater harvesting need to be considered before using these practices on a commercial scale.
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the effect of Supplemental Irrigation on watermelon citrullus lanatus production in gravel and sand mulched fields in the loess plateau of northwest china
Agricultural Water Management, 2004Co-Authors: Yajun Wang, Zhongkui Xie, Zhishan ZhangAbstract:Abstract Trials were conducted to examine the effects and economic feasibility of Supplemental drip Irrigation on watermelon (Citrullus lanatus) production in fields with and without surface mulch consisting of a mixture of gravel and sand in the Loess Plateau of northwest China in 2001 and 2002.The trial involved four levels of drip Irrigation: 0, 23, 45 and 68 mm of water to both mulched and non-mulched fields (control). Both treatments were randomized with four replications. There was a significant difference in rainfall amounts between the two experimental years. Rainfall during the watermelon growth period was 126 mm in 2001 and 223 mm in 2002. In 2001, 45 mm of Irrigation increased yields by about 36% and 68 mm increased yields by about 46%. Drip-Irrigation, with 68 mm had the highest water use efficiency (WUE), 24.7 kg m−3, which was 29.3% more than the non-irrigated treatments. In the wet year, 2002, Supplemental Irrigation decreased WUE for the mulched fields but did not significantly increase yields. However it did increase yields in the non-mulched fields: 23, 45, and 68 mm of Irrigation increased yields by 21, 26 and 38%, respectively. In 2002, the average yield increase for the mulched treatments as compared to the non-mulched treatments was 25.4%, or 11,400 kg ha−1, with a corresponding average increase in WUE of 25.3%, or 3.7 kg m−3. There were no significant differences in the soluble solid content of the melons among the Irrigation treatments for the mulched treatments. However, for the control treatments, the soluble solid content of the 45 and 68 mm Irrigation treatments was significantly lower than for the 0 and 23 mm Irrigation treatments. The net seasonal income was estimated to be highest at US$ 6012 ha−1 for the 0 mm Irrigation treatment in mulched fields in 2002, the wet year, followed by US$ 4938 ha−1 for the mulched with 68 mm of Irrigation in 2001, the dry year. The net profit per mm of water used was the highest (US$ 20.8 mm−1) for the mulched, 68 mm Irrigation treatment in 2001. Supplemental drip Irrigation of mulched fields in dry year definitely increases watermelon yields.
Dong Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of Supplemental Irrigation at the jointing stage on population dynamics grain yield and water use efficiency of two different spike type wheat cultivars
PLOS ONE, 2020Co-Authors: Yunqiu Shang, Xiang Lin, Keyi Lei, Sen Wang, Panpan Zhao, Dong WangAbstract:To solve the problems of yield reduction and low water-use efficiency (WUE) of winter wheat (Triticum aestivum L.) caused by winter and spring drought, a 2-year field experiment (2017–2019) was performed under movable shelter conditions with the large- and multispike cultivars Shannong 23 and 29, respectively, to explore the optimal Supplemental Irrigation regime. Three wetting layers were used for Irrigation at the jointing stage: 0–10 cm (T2), 0–20 cm (T3) and 0–30 cm (T4). No Irrigation at the jointing stage (T1) served as the control. Within a given cultivar, the soil water content in the 0–80 cm soil layers increased after Irrigation, and the rate of tiller mortality decreased with increasing depth of the wetting layer used for Irrigation at jointing. No significant differences were found between the T3 and T4 treatments in the photosynthetic rate (Pn) of the apical leaf of the main stem (O), the first primary tiller (I) and the fourth tiller (IV) after jointing. However, compared with the T3 treatment, the T4 treatment had a significantly higher transpiration rate (Tr) and lower instantaneous water-use efficiency (WUEleaf) of the apical leaf of the O and tillers I and IV. This eventually led to a decreasing WUE, although there was no significant change in the spike number or grain yield. These results indicated that moderate Irrigation at jointing can effectively reduce the tiller mortality, improve the leaf Pn of the tillers, and increase the spike number and grain yield. However, excessive Irrigation can significantly increase the leaf Tr of the tillers, lead to inefficient water consumption and significantly reduce the WUEleaf of the tillers and the WUE. Irrigation at the jointing stage brought the soil water content in the 0–20 cm profile to 100% of field capacity, making it the most suitable Supplemental Irrigation regime for both the large- and multispike cultivars in the North China Plain.
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effects of Supplemental Irrigation on the accumulation distribution and transportation of 13c photosynthate yield and water use efficiency of winter wheat
Agricultural Water Management, 2019Co-Authors: Hongbo Zhang, Kun Han, Dong WangAbstract:Abstract Water resources are increasingly scarce, and droughts are frequent in the Huang-Huai-Hai Plain of China. There is an urgent need for developing water-saving technologies for winter wheat production in this region. Field experiments were carried out in silty loam soil from 2012 to 2014. Based on the same water condition in seeding period and the normal emergence of winter wheat, five Supplemental Irrigation (SI) regimes differing in the timing of SI were established. Crop development was categorized using the Zadoks scale. T1: no Irrigation after emergence; T2: SI at jointing (4th node detectable, Z34); T3: SI at pre-wintering (average daily temperature drops to about 2 ° and the wheat plant basically stops growing) and jointing; T4: SI at jointing and anthesis complete (Z69); T5: SI at pre-wintering, jointing and anthesis complete. The results showed that SI brought the soil water content in the 0–20 cm profile to 100% field capacity at the pre-wintering, jointing and anthesis complete stages of winter wheat, mainly improving the water supply condition in the 0–40 cm soil layer. Compared with no Irrigation after emergence, SI at jointing and anthesis complete significantly increased grain yield by increasing the spike number, kernel number and grain weight. SI at the pre-wintering stage can improve grain number and yield under the condition of no SI at anthesis complete (comparing T3 with T2), but had no significant effect on grain yield when SI was supplied at jointing and anthesis complete (comparing T5 with T4), and even worse, the Irrigation water use efficiency decreased. The decrease of water supply before anthesis complete significantly reduced the dry matter accumulation and photosynthetic rate at anthesis but promoted the translocation of photosynthates to the plant ear. SI at anthesis complete is advantageous for the assimilation of carbohydrates in the middle and late grain filling stage and for the distribution of those carbohydrates from vegetative organs to grain. These results indicated that SI at jointing and anthesis complete was conducive to coordinating the relationship between photosynthesis and photosynthates retranslocated after anthesis, and may improve the harvest index, grain yield and water use efficiency.
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effect of Supplemental Irrigation on the relationships between leaf aba concentrations tiller development and photosynthate accumulation and remobilization in winter wheat
Plant Growth Regulation, 2016Co-Authors: Xiang Lin, Dong Wang, Philip J White, Kun Han, Jie Zhou, Shipeng JinAbstract:Drought after the jointing stage restricted the growth and yield formation in wheat. Supplemental Irrigation (SI) at Z31 (Zadoks Stage 31) reduced the ABA concentrations in the leaves of the inferior tillers (T3 and T10) and improved the survival rate of the tillers. Additional SI at Z60 reduced the ABA concentrations in the flag leaves of ear-bearing stems after anthesis and increased the assimilate accumulation and the 1000-grain weight. These two SIs increased the yield by 16.7–32.2 % compared with a rainfed control (W0). Delaying the first SI from Z31 to Z34 or Z39 reduced the ABA concentrations in the leaves of the main stem and superior tillers (T1 and T2) but increased the ABA concentrations in the leaves of the inferior tillers at Z45 and reduced the survival rate of the tillers. Delaying SI from Z31 and Z60 (W1) to Z34 and Z69 (W2) increased the partitioning of the recent (14C-labelled) assimilate to the stems plus sheaths and stalk plus glume at anthesis and the grains at maturity and increased the 1000-grain weight and the grain yield significantly. However, if SI was applied too late, i.e., at Z39 and Z77 (W3), the redistribution of the recent assimilate from the vegetative organs to the grain after anthesis and the grain yield at maturity were reduced. These data suggested that: (1) a lower soil moisture at the early jointing stage elevated the ABA concentrations in the inferior tillers and inhibited their growth; (2) if SI was applied too late (W3) senescence of the inferior tillers could not be halted; and (3) low ABA concentrations in the leaves during the later grain filling following the late SI (W3) were correlated with a reduced transfer of assimilates from the vegetative organs to the grain, leading to a significant reduction in the grain weight at maturity.
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the effect of Supplemental Irrigation after jointing on leaf senescence and grain filling in wheat
Field Crops Research, 2013Co-Authors: Dong Wang, Philip J WhiteAbstract:Abstract Food security in the Huang-Huai-Hai Plain of China is threatened by water shortages and the early senescence of wheat induced by water deficit. However, effective water-saving Irrigation techniques based on the consideration of precipitation, soil water storage and crop requirements are rudimentary. Information on the responses of transpiration, photosynthesis and plant senescence to Supplemental Irrigation (SI) at different stages of crop development is urgently required. Field experiments were performed in 2007–2008 and 2008–2009 to provide this information. Four Irrigation treatments were tested: rainfed (W0), SI at Zadoks stage 31 (Z31) and Z60 (W1), SI at Z34 and Z69 (W2), and SI at Z39 and Z77 (W3). The SI brought soil water content in the 0–140 cm profile to 75% field capacity. Supplemental Irrigation increased grain yields and the scheduling of SI affected yield components. Delaying SI from Z31 and Z60 (W1) to Z34 and Z69 (W2) decreased the number of spikes, but increased the number of grains per spike, 1000-grain weight and crop yield. Activities of superoxide dismutase (SOD) and catalase (CAT) in flag leaves of plants from the W2 treatment were greater, and malondialdehyde (MDA) concentrations in flag leaves were lower, than those from the W3 treatment until 24 days after anthesis and those from the W1 and W0 treatments throughout anthesis. Although SI increased both photosynthetic rate (Pn) and transpiration rate ( E ), the net effect was greater instantaneous water use efficiency (WUE leaf = Pn/ E ). Supplemental Irrigation also increased agronomic Water Use Efficiency (grain yield/crop evapotranspiration). Delaying SI decreased the grain filling rate at the beginning of grain filling in 2007–2008, but increased the grain filling rate later in grain filling in both 2007–2008 and 2008–2009. An appropriate delay in SI (W2) increased grain yield substantially, but if SI was applied too late (W3), there was less effect on grain yield, probably because of an inhibition of assimilate remobilization to the grain due to delayed senescence.