Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Conservation of the natural land resources of the Mekong delta

27.11.2002


Physical fertility of typical Mekong delta soils (Vietnam) and land suitability assessment for alternative crops with rice cultivation



Most of the soils in the Mekong delta, Vietnam are formed and developed during the Holocene period. The first Viet people came to reclaim and exploit this plain at the beginning of the 17th century. As a result, in the middle of the 19th century, the Mekong delta had become the largest region of agricultural production, essentially rice produce for marketing purposes. Around 1980 three rice crops in a year were applied. That system continued to increase with time within the recent past 10 years. This land use system has mainly enlarged on the areas along Hau and Tien river.

Nowadays, in the Mekong delta, rice yield and production in the developing and well developed alluvial soil groups tend to be stable. However, there is a tendency to gradual decrease year to year, although chemical fertilizers and other amendments were intensively applied. This study is carried out in order to conserve the natural land resources of the Mekong delta. The study focuses and evaluates mainly physical soil characteristics which are related to physical soil degradation of the selected major soil groups in the area of mono and intensive rice cultivation as Chau Thanh (Tra Vinh province), Vung Liem (Vinh Long province), Cai Lay (Tien Giang province), Cao Lanh (Dong Thap province), Tan An (Long An province), Phung Hiep (Can Tho province), Vinh Chau (Soc Trang province), O Mon (Can Tho province), Tinh Bien (An Giang province), and Moc Hoa (Long An province).


A quantitative land evaluation is carried out for some alternative crops (soybean, mungbean, maize and cotton) in order to change and develop a new land utilization type for sustainable agricultural production. Results show that soil compaction, the so-called “plow pan” has already existed between 20-40 cm soil depth and its thickness varies from 35-50 cm in the intensive rice cult!ivation area. Soil resistance penetration tends to increase from 40 cm to 100 cm in the soil profile and its value varies in the range of 0.8-1.2 MPa. Infiltration rate is low in the topsoil (average 0.8 cm/hr) and very low in the subsoils. Surface hardsetting and subsoil plinthization exist in the Degraded Grey Soils and sodification is found in the area of saline intrusion. Soil aggregate stability over 10 study locations is low and it is strongly influenced by soil organic matter and soil texture. The value of pF2-pF2.5 is approximately representing the matric head at field capacity. The volumetric water content at wilting point is 0.05 cm_/cm_ and 0.25 cm_/cm_ for loamy sand and heavy clay textured soils respectively. About 62 % of the cases, in rice intensive area, show a cumulative available soil water storage between 100-120 mm water at 0-50 cm soil depth, and it will be mainly lost by evaporation. Due to the intensive rice cultivation, local farmers usually irrigate the fields year around. In combination with a shallow low water table level (50-80 cm from soil surface) in the rice area, the soil water storage in the subsoils is not depleted to the wilting point even in the dry season and that happens on most of the study locations.

Muscovite is a dominant clay mineral in recent alluvial soils and kaolinite is a main soil mineral in old alluvial soils and soils derived from hard rock of the mountainous area. Soil compaction, soil hardsetting, plinthization, nutrient depletion, sodification and acidification (from oxidation of pyrite) are the main soil degradation types found in the different study locations. Soil compaction tends to increase in the existing mono-rice cultivation and it is a main soil constraint influencing to the crop yield and soil productivity in future.Soybean represents the best perspective crop to be alternated in the area of intensive rice cultivation and also suitable for the other areas of the study locations. However, few soil constraints need to be reclaimed and improved, the crop yield can reach more than 2 tons/ha. Cotton and maize can be planted in saline and alkaline soils. Organic matter, balanced mineral fertilization, soil preparation under the proper moisture condition and alternative land use application are the necessary activities to be done to conserve soil resources, to improve the rice yield and to develop a sustainable agricultural production in the Mekong delta.


The obtained results will help and support to the local farmers and even local government, specially the department of agriculture and rural development, in the Mekong delta, Vietnam to select and to develop the adapted land utilization types and the proper soil management packages for sustainable agricultural production at the present time and in future.

Khoa Le Van | alfa

More articles from Agricultural and Forestry Science:

nachricht Kakao in Monokultur verträgt Trockenheit besser als Kakao in Mischsystemen
18.09.2017 | Georg-August-Universität Göttingen

nachricht Ultrasound sensors make forage harvesters more reliable
28.08.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>