Showing 3 results for Regimes
Gh. Khajouei Nejad, H. Kazemi, H. Alyari, A. Javanshir, M. J. Arvin,
Volume 9, Issue 4 (1-2006)
Abstract
This study was conducted to evaluate the effects of four levels of irrigation (irrigation of plants after I1 = 40, I2 =60, I3 = 80 , and I4 = 100mm of evaporation from class A pan) and four plant densities(D1 = 30, D2 = 40, D3 = 50 and D4 = 60 plants/m2) on the seed yield and seed quality in three soybean cultivars(V1=Hobit, V2=Williams and V3=Hill) in a split factorial design, based on the completely randomized blocks, with three replication for two years(2001 and 2002). The Irrigation treatments were assigned to the main plots, and the plant densities and cultivars to the sub plots. Results indicated that soybean seed yield was influenced by the different irrigation and plant density levels in the both years. Irrigation levels I2 produced the highest and I4 the lowest seed yield. It was also revealed that the plant density D3 produced the highest and D1 the lowest seed yields. Among the cultivars under investigation, V2 produced the highest and V3 the lowest seed yield . Seed oil and its protein contents both were affected significantly by the irrigation levels, plant densities and cultivars in both years. The plants receiving I1 treatment had the highest and those having I4, the lowest percentages of seed oil. Changes in the plant densities also affected seed oil and protein content. The plant density of D1 caused the seeds to have the highest oil and lowest protein percentages. However, D4 decreased oil and increased protein percentages. The highest water use efficiency was obtained from I3 and that of the lowest value from I1. The results also indicated that D4 had the highest and D1 the lowest water use efficiencies. Therefore, it could be concluded that the water use efficiency can be increased by increasing the plant density per unit area. The highest efficiency for biological and grain yield belonged to V2 and V1 respectively where as the lowest efficiency for those two mentioned characters belonged to V1 and V3, respectively. However, the treatment I2V2D2 is recommended for higer the seed yield production per unit area.
Z Amiri, J Asghari, Kh Penahi Kord Aghari,
Volume 12, Issue 46 (1-2009)
Abstract
In order to determine the potato cultivars responses to irrigation regimes and fertilizer combinations, an experiment was conducted on Fereidan Research Farm, Isfahan Province in 2003. The trial was designed as split-split plot based on randomized complete block design with three replications. The cultivars (Arinda and Navita) were planted as main plots, and irrigated after 70, 140, 210 mm water evaporation from standard A pan surface that provided optimal watering, mild drought, and severe drought, respectively, as sub plots. Fertilizer combinations including of NPK + Zn, NPK+ Mn, NPK +Zn + Mn and NPK+ Manure were used as sub-sub plots. Results showed that the cultivar Arinda produced higher yield, mean tuber weight and total tuber number. By decreasing the amount of irrigation, the total yield and mean tuber weight were decreased. The highest amount of seed tubers (35-55 mm diameter) and marketable tuber sizes (diameter>35mm) and lowest amount of small size tuber numbers (diameter <35) were obtained in moderate drought. The use of NPK + Zn + Mn and NPK+ Manure produced the highest yield and mean tuber weight. Planting the cultivar Arinda with efficient irrigation is suggested in Isfahan province. Moderate drought is recommended for production of higher amount of seedy tubers. A combination of manure, Mn and Zn fertilizers are also suggested for potato farms of this district.
N. Ghorbani Ghahfarokhi, Z. Kiani Salmi, F. Raiesi, Sh. Ghorbani Dashtaki,
Volume 17, Issue 63 (6-2013)
Abstract
Free and uncontrolled pasture grazing by animals may decrease soil aggregate stability through reductions in plant cover and subsequent soil organic C, and trampling. This could expose the soil surface layer to degradation and erosion. The objective of this study was to determine the influence of pasture management (free grazing, controlled grazing and long-term non-grazing regimes) on aggregate-size distribution and aggregation parameters by wet and dry sieving methods in two native pastures, protected areas in Chaharmahal va Bakhtiari province. The studied pastures were 1) SabzKouh pastures protected from grazing for 20 years, and 2) Boroujen pastures protected from grazing for 25 years. Soil samples were collected from 0-15 cm depth during the grazing season in summer 2008. Samples (finer than 2 mm) were analyzed for aggregate-size distribution and aggregation parameters by wet and dry sieving methods. Results showed that pasture management had a significant influence on aggregate-size distribution and aggregation parameters in the two areas. The two methods indicated that macro-aggregates in non-grazing and controlled grazing regimes were higher than those in free grazing regime, whereas in free grazing management micro-aggregates showed an opposite trend, and were greater compared with the other grazing regimes. Similarly, soil aggregate stability indices (i.e. mean weight diameter, aggregate geometric and ratio mean diameter) were all improved by non-grazing regimes, suggesting that animal grazing and trampling break down large soil aggregates due largely to compaction and reduced plant coverage. However, the extent to which grazing affects soil aggregation depends in large part on grazing intensity and duration, and the area involved.
