A 2-year trial was conducted at Dakahlia Province near Manzala Lake in Northern Egypt, comparing the potential of Amshot to reclaim saline soils with the conventional methods, ponding and gypsum. Average annual rainfall at the site is 67 mm. The soils are highly saline-sodic and heavy in texture (61% clay).
An area of 273 m2 was divided into 12 plots, with four replications of three treatments. Water was ponded on all plots for the duration of the trial to a depth of 5-10 cm. In the second treatment, gypsum was broadcast as dry granules just before planting at a rate of 10 tons/feddan (1 feddan=4200m2). In the third treatment, Amshot was cultivated by vegetative cuttings at a density of 80,000 plants per feddan.
Soil samples were collected at 15 cm intervals from 0 to 105 cm depth. These were taken before the experiment started, and at the end of the first and second year. Samples were analyzed for soluble and exchangeable Na, Ca and Mg as well as the relative electrical conductivity (REC) of the saturation extract, and the soluble absorption rate (SAR). Another measure of salinity, the exchangeable sodium percent (ESP) is the proportion of absorbed sodium as a percentage of total absorbed cations. It is one of the most important indicators of soil physical characteristics. The ESP and SAR were measured at the surface layer (0-15 cm) at sampling. Fresh and dry weight of the Amshot yield was recorded for the first year.
Amshot was superior to both gypsum and ponding in causing ESP reduction during both years, and gypsum surpassed ponding. Gypsum reduced the ESP to 14.1 after two years, just below the alkalinity limit (ESP 15), but Amshot reduced it until it became non-sodic, to ESP 10.1.
Overall, Amshot showed a higher reduction in SAR values. Gypsum was more effective in reducing the SAR in the top 15 cm, whereas Amshot was more effective in the lower layers. This could be attributed to the distribution of roots under the surface. Below 45 cm, gypsum and Amshot were about equally effective.
The effect of Amshot on reducing soil alkalinity was accompanied by a reduction in total salt content. The REC did not change significantly during the first year in the three treatments in the upper 30 cm. REC changes became apparent below 30 cm. Amshot was the most successful treatment at reducing salt content, particularly below 30 cm.
Amshot also shows promise as fodder. Fresh weigh of three cuts of Amshot averaged 4.3 tons per feddan, compared to clover (Trifolium alexandrinum) which produce less than 2 tons per feddan fresh weight. Amshot also grows year round whereas the growing season for clover is late January to early May.