S. F. Mousavi, B. Mostafazadeh-Fard, A. Farkhondeh, M. Feizi,
Volume 11, Issue 4 (Number 4 - 2009)
Abstract
High groundwater salinity, a high water table and secondary soil salinization are dominant conditions in eastern Isfahan Province, Iran. This region has a low annual rainfall, high annual evaporation demand, saline soils and limited fresh water supplies. To investigate the effects of irrigation deficit and salinity on cantaloupe (Cucumis melo L. var. cantalupensis) production, a field experiment was performed at the Salinity and Drainage Research Station of Rudasht, 65 km East of Isfahan. Irrigation treatments were T65, T80 and T95 (irrigation after 65, 80 and 95 percent of cumulative evaporation from Class A pan, respectively), each having three replicates. EC of irrigation water was 5.25 dS m-1; irrigation water depth for the whole growing period was 300, 342 and 384 mm, for T65, T80 and T95 treatments, respectively. The results showed that T65 and T80 irrigation treatments significantly reduced fresh yield, number of fruit, fruit weight per plant and water use efficiency. Fresh-fruit yield was 31.73, 38.48 and 54.34 ton ha-1, and water use efficiency was 10.58, 11.25 and 14.16 kg m-3 in T65, T80 and T95 irrigation treatments, respectively. A second order polynomial equation was fitted (R2= 0.99) for production function (yield vs. irrigation water depth). The relationship between water use efficiency and irrigation water depth was also a second order polynomial equation (R2= 0.97). Nitrogen and potassium content of fruits in T65 treatment was higher than T80 and T95 treatments. Effect of irrigation regimes was not significant on P and Na content of fruits, but was significant on Cl- content (P< 0.05). Overall results showed that cantaloupe is a crop sensitive to soil moisture stress.
S. F. Mousavi, M. Moazzeni, B. Mostafazadeh-Fard, M. R. Yazdani,
Volume 14, Issue 5 (9-2012)
Abstract
The prevalent method of irrigation in paddy fields in Iran is continuous ponding, which changes to intermittent method at the time of water shortage. Soil cracks are the main problem in intermittent irrigation. In this study, effects of adding rice straw on some soil physical characteristics and cracks were studied in paddy soils of the Guilan Province of Iran. The experiment was performed as split-split plots based on a complete randomized blocks design. Treatments included four soil textures (silty clay, silty clay loam, clay loam, and sandy loam), seven rates of rice straw (0, 2, 3, 4, 5, 6 and 7% by weight), and three soil moisture stages of drying conditions [primary stage (T1), initial crack stage (T2), final crack stage (T3)]. Results revealed that soil texture, rice straw rate, crack treatments, and their interactions had significant (P< 0.01) effects on soil moisture content, bulk density, and time to crack formation. During the drying stage (from T1 to T3), moisture content decreased, however, bulk density and time to crack formation increased. In silty clay soil, addition of 2-3% rice straw expedited crack formation, and an addition of 4-7% straw delayed crack formation. In silty clay loam soil, addition of 3-5% straw enhanced crack formation, and addition of 6-7% delayed crack formation. The addition of rice straw in clay loam and sandy loam delayed crack formation. In general, addition of rice straw increased soil moisture content, decreased bulk density, and delayed crack formation.
