Response of soybean stem termination types to water stress and supplemental irrigation

1983 ◽  
Author(s):  
Enrique Villalobos-Rodriguez
Author(s):  
Adnan Al-ghawry ◽  
Attila Yazar ◽  
Mustafa Unlu ◽  
Celaleddin Barutcular ◽  
Yeşim Bozkurt Çolak

Abstract A field experiment was carried out to evaluate the effect of different conventional and supplemental irrigation strategies on leaf stomatal conductance (gs) and chlorophyll content (SPAD) yield and irrigation water productivity (IWP) of wheat using sprinkler line source in 2014 and 2015 in the Mediterranean region. The irrigation strategies were, supplemental irrigation (SI) during flowering and grain filling (SIFG), SI during grain filling (SIG), SI during flowering (SIF) and conventional irrigation (CI). These strategies were conducted under four irrigation levels 25, 50, 75, 100% and a rain-fed as control. The results indicated that CI100 and CI75 produced the greater grain yield and IWP, respectively. CI100 resulted in the increased chlorophyll content by 8.8% over rain-fed. The results confirmed that the SPAD and stomatal conductance values were not equally sensitive to water stress during growth stages. The wheat crop suffered a greater SPAD and gs reductions when the water stress occurred during the grain filling stage (SIF strategy) compared to other strategies, which means that the grain filling stage is more sensitive and effective to decrease the yield of winter wheat. The higher grain yields were achieved when the seasonal mean gs reached 207.4 mmol/m2s in CI and 169.2 mmol/m2s in SI, and the stomatal closure responded well to low, moderate and severe drought treatments. The leaf stomatal conductance (gs) was correlated linearly with grain yield. These relations could be used as a physiological indicator to evaluate water stress effect on the growth and productivity of wheat.


2017 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Bariot Hafif

<p><em>One of the factors that affect the productivity of cacao plants is water availability. Water deficit will negatively affect the development of cacao flowers and beans. Water stress is reported as one of the causes of low productivity on plantation crops in Lampung Province. The study was aimed to analyze the characteristics of agroecology and supplemental irrigation required for growth and production of cacao in Lampung. The research was carried out in the District of Pesawaran, Tanggamus, East Lampung, and South Lampung, Lampung Province, from 2012 to 2015. The study was conducted with the survey method and literature study for the collection of the primary and secondary data, related to the characteristics of the land agroecology. Geographically, the main cacao growing areas in this region is divided into two regions, western region consist of Pesawaran and Tanggamus District and east region comprise of East Lampung and South Lampung District. Based on agroecological zones, the planting of cacao in both regions is in accordance with the recommendations of land use. However, land suitability analysis showed that some of the agroecological characteristics of land becomes a limiting factor for the growth and production of cacao, including soil pH &lt; 5.5, low cations exchange capacity (CEC) (&lt; 16 cmol(+)/kg), air humidity &gt; 75%, and in some areas there is an erosion hazard. Another obstacle is the water deficit that occurs during 140 days within 1 year of cacao growth cycle that occurred in July until mid-November. There are two factors that can be applied  to increase cacao productivity in Lampung province, i.e. (1)  an improvement of cacao cultivation technology that can address the characteristics of agroecology as a limiting factor of growth, and (2) an application of a supplemental irrigation technology to avoid cacao from water stress. The requirement of supplemental irrigation is 340.5 mm in western region and 209.7 mm in eastern region of Lampung.</em></p>


2018 ◽  
Vol 1 (2) ◽  
pp. p107
Author(s):  
M. H. Ali

Water stress is one of the limiting factors for rice production. Under rainfed condition with erratic rainfall, water stress becomes a serious threat for sustainable rice production. Drought tolerant cultivars along with appropriate management practices can solve the problem. Field and control condition studies were carried out to study the response of some rice cultivars to water-stress, and to develop appropriate on-farm management strategy for sustainable yield under drought condition. The results revealed that most of the cultivars produced good yield under drought condition compared to normal irrigated condition (under control condition and field study). Levee management strategy (of height of 20 cm) seems a viable option to alleviate the effect of drought under field condition. Levee management and life-support supplemental irrigation (when necessary) can facilitate good yield of most of the cultivars. These cultivars seemed to be appropriate for cultivation in drought-prone areas.


EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Claudia Paez ◽  
Jason A. Smith

Biscogniauxia canker or dieback (formerly called Hypoxylon canker or dieback) is a common contributor to poor health and decay in a wide range of tree species (Balbalian & Henn 2014). This disease is caused by several species of fungi in the genus Biscogniauxia (formerly Hypoxylon). B. atropunctata or B. mediterranea are usually the species found on Quercus spp. and other hosts in Florida, affecting trees growing in many different habitats, such as forests, parks, green spaces and urban areas (McBride & Appel, 2009).  Typically, species of Biscogniauxia are opportunistic pathogens that do not affect healthy and vigorous trees; some species are more virulent than others. However, once they infect trees under stress (water stress, root disease, soil compaction, construction damage etc.) they can quickly colonize the host. Once a tree is infected and fruiting structures of the fungus are evident, the tree is not likely to survive especially if the infection is in the tree's trunk (Anderson et al., 1995).


EDIS ◽  
2017 ◽  
Vol 2017 (5) ◽  
Author(s):  
Davie Mayeso Kadyampakeni ◽  
Kelly T. Morgan ◽  
Mongi Zekri ◽  
Rhuanito Ferrarezi ◽  
Arnold Schumann ◽  
...  

Water is a limiting factor in Florida citrus production during the majority of the year because of the low water holding capacity of sandy soils resulting from low clay and the non-uniform distribution of the rainfall. In Florida, the major portion of rainfall comes in June through September. However, rainfall is scarce during the dry period from February through May, which coincides with the critical stages of bloom, leaf expansion, fruit set, and fruit enlargement. Irrigation is practiced to provide water when rainfall is not sufficient or timely to meet water needs. Proper irrigation scheduling is the application of water to crops only when needed and only in the amounts needed; that is, determining when to irrigate and how much water to apply. With proper irrigation scheduling, yield will not be limited by water stress. With citrus greening (HLB), irrigation scheduling is becoming more important and critical and growers cannot afford water stress or water excess. Any degree of water stress or imbalance can produce a deleterious change in physiological activity of growth and production of citrus trees.  The number of fruit, fruit size, and tree canopy are reduced and premature fruit drop is increased with water stress.  Extension growth in shoots and roots and leaf expansion are all negatively impacted by water stress. Other benefits of proper irrigation scheduling include reduced loss of nutrients from leaching as a result of excess water applications and reduced pollution of groundwater or surface waters from the leaching of nutrients. Recent studies have shown that for HLB-affected trees, irrigation frequency should increase and irrigation amounts should decrease to minimize water stress from drought stress or water excess, while ensuring optimal water availability in the rootzone at all times.


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