Comparison of salt tolerance among various species of forage grasses in salt-affected land พรพิมล สุริยาจันทราทอง 1., วรพงษ์ สุริยาจันทราทอง 2., สุมนทิพย์ บุนนาค 1.,
บุปผา โตภาคงาม 3., วัชรินทร์ บุญภักดิ์ 4 และชาญชัย มณีดุลย์ 5
| Two field trials were conducted at Chiang Yun Forage Station Mahasarakarm Province,
to compare various forage species in salt-affected land. An experimental plot of non-saline soil
ws also included as a control. Salt tolerance of grasses in the saline soil was determined
by their persistency and productivity compared with those grown in non-saline soil. Fertilizer
responses of grasses in both saline and non-saline were also compared.
Six different grass varieties were used in each trial in which three varieties were introduced (exotic)
grasses and the other three native varieties. The introduced grasses used in both trial were Guinea
grass (Panicum maximum cv. Hamil), Ruzi grass (
Brachiaria ruziziensis) and Rhode grass ( Chloris gyana
cv. Common). The native grass used in the first trial were Paspalum distichum,
Panicum repens and Dactyloctenium aegytium.
In the second trial, Dactyloctenium aegyptium was replaced by
Cynodon dactylon.
In the first trial, it was found that although the electrical conductivity (EC) value of the designated
salt-affected land was relatively low and similar to that of the non-saline soil (approximately 0.2 mmho/cm),
the dry matter yields, especially of the introduced grasses, were markedly decreased. However,
grasses grown on the saline soil tended to show a greater response to fertilizer than those of the
non-saline soil. Application of fertilizer resulted in an average increase in dry matter yield of grasses
of approximately 150% in the saline soil, compared with only 50% increase in yield in non-saline
soil.
In the second trial, it was observed that the degree of salinity as measured by the EC value varied
greatly between sub-plots or even within the sub-plots themselves. Furthermore, it also varied with
seasonal changes, with the EC value being higher in the dry season than in the rainy season.
Because of the variation in the EC of soil found in the second trial, the sub-plots were classified
into two groups according to the EC value of the soil. The low EC plots had the EC value about 3
to 6 mmho/cm, and the high EC plots had EC values in excess of 10 mmho/cm, as measured
during the dry season.
The results showed that grasses, especially the introduced species, had poorer persistency and
productivity in the high EC plots than in the low EC plots. Althought, the introduced grasses can tolerate
a low EC, their dry matter yields were reduce to almost the same level as the native varieties.
Among the introduced grasses, Rhode grass seemed to show greater tolerance of soil salinity
than Guinea and Ruzi grass, as it produced a higher dry matter yield than the other species.
Native grassess were much more resistant to the high soil salinity than the introduced species.
Both Panicum repens and Cynodon
dactylon were able to persist in the high EC plots even during the dry season, but
the dry matter yield of Panicum repens was higher than that
of Cynodon dactylon
The chemical composition, including crude protein (CP), neutral detergent fiber (NDF) and acid
detergent fiber (ADF) of grasses showed little difference between the saline and non-saline soils during
the rainy season. However, in the dry season, grasses grown on saline soil had a higher CP
and lower NDF and ADF concentrations than those grown in non-saline soil.
The content of K, Na and Cl in the grasses were different between the saline and non-saline soils.
Grasses grown in saline soil had lower K but high Na and Cl concentrations than grasses grown
in non-saline soils. The results in both trials showed that in the saline soil the K concentration
of grasses was approximately half of that in non-saline soil. In the case of Na and Cl, it was found
in the second trial that the concentrartions were about 4-5 fold higher in grasses grown in saline soil.
In addition, the concentration of K, Na and Cl of grasses tended to increase with increasing
salinity or EC of the soil. The CA concentration of grasses in both saline and non-saline soil were
relatively low, but a little higher in non-saline than saline soils.
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* ได้รับทุนจากองค์การบริหารเทศกิจแห่งสหรัฐอเมริกา (USAID) และสถาบันวิจัยและพัฒนา มหาวิทยาลัยขอนแก่น ปี 2528-2531 1. ภาควิชาชีววิทยา คณะวิทยาศาสตร์ มหาวิทยาลัยขอนแก่น 2. ภาควิชาสัตวศาสตร์ คณะเกษตรศาสตร์ มหาวิทยาลัยขอนแก่น 3. ภาควิชาปฐพีศาสตร์ คณะเกษตรศาสตร์ มหาวิทยาลัยขอนแก่น 4. ศูนย์วิจัยอาหารสัตว์ขอนแก่น กองอาหารสัตว์ กรมปศุสัตว์ 5. กองอาหารสัตว์ กรมปศุสัตว์ |
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