عنوان مقاله [English]
Environmental stresses are one of the main causes of severe yield reductions. Drought is still a serious agronomic problem and also one of the most important factors contributing to crop yield loss in arid and semi-arid areas in the world. Filter Cake is a byproduct of sugarcane industry and experiments on corn showed that the use of 20 tons per hectare Filter Cake increases crop productivity, total amount of dry matter, protein and forage yield compared with the control.
Materials and methods
This experiment was conducted at the Research Station of the Ramin Agricultural University of Khuzestan in 2012. The experiment was done as a split plot based on randomized complete block design with three replications. Drought stress at the end of the growth period in three levels, non-stress, mild and severe drought stress, respectively irrigated after 25, 50 and 75% depletion of available water, and was considered as the main factor. Drought stress was applied in early stage of the male inflorescence of plants to maturity for 35 days, due to the critical stage of the plant in late spring. Soil moisture was determined by gravimetric method. Different doses of Filter Cake (0, 10, 20 and 30 tons per hectare) were considered as subplot factor and was added to the soil two days before the seeding. The final harvest as green corn was performed in the first phase of dough by hand in three times and two midfields of each subplot was considered as the margin of half a meter for each side. Finally, the data were analyzed using SAS 9.1 and means were compared by Duncan’s multiple range test at probability level of 5%.
Results and discussion
In non-stress conditions, Filter Cake is significantly increased plant height, So the amounts of 20 and 30 tons per hectare increased by 11.7% and 10.1% of the plant’s height, respectively, but the use of 10 tons of Filter Cake did not have a significant effect on it. In severe stress conditions, the use of different levels of Filter Cake significantly reduced the plant’s height. Although Mild stress did not have a significant effect on membrane stability index, severe drought stress reduced it about 17.5% compared with non-stress treatments. The osmotic potential in normal conditions was the highest, however, it was decreased with increasing stress. Therefore, in severe stress conditions and treatment without Filter Cake, osmotic potential was -1.71 MPa. Mild and severe drought stress significantly reduced soluble proteins of the leaf by 12.5% and 17.1%, respectively compared with the control. Application of 10 tons per hectare of Filter Cake had no significant effect on sodium ion concentration, but using 20 and 30 tons per hectare of Filter Cake increased the concentration by 39% and 44%, respectivelycompared with the control. The use of 10 tons of Filter Cake in non-stress conditions had no significant effect on Na, but using 20 and 30 tons per hectare of Filter Cake increased the amount of Na by 10% and 13.7%,, respectively compared with the control. In severe stress conditions, the use of 20 and 30 tons per hectare of Filter Cake decreased fresh weight yield by 9% and 14.5%,, respectively. Under non-stress conditions, the use of Filter Cake led to increased dry matter production. In severe stress conditions the use of 10 tons per hectare of Filter Cake did not have significant effects on biological yield, but application of 20 and 30 tons per hectare of Filter Cake decreased biological yield by19% and 23%, respectively compared with treatment without Filter Cake.
The results showed that: (1) Drought stress reduces the growth and yield of sweet corn and economic benefit in spring planting in Khuzestan province. (2) The use of Filter Cake through physical modification of the soil, causes uniformity of germination and early growth acceleration of product, and in non-stress conditions increases economic performance. (3) In drought stress conditions, the use of Filter Cake, due to high salinity and salt accumulation in the root zone, causes secondary oxidative stress and increases damage to cell membranes and reduces the economic benefit.
In order to investigate the effect of Filter Cake levels application on some morpho-physiological characteristics and ear yield of sweet corn (Zea mays var saccharata) under late drought stress condition, an experiment was conducted in Ramin Agriculture and Natural Resources University, Khuzestan, at 2012. The experiment was arranged in split-plots design in RCBD (Randomized Complete Block Design) with three replications. Treatments of experiment were drought stress (irrigation after 25, 50 and 75% depletion of available water content) in main plots and filter cake (0, 10, 20 and 30 ton.ha-1) arranged in sub-plots. Results showed that the effect of drought stress significant on more traits and led to decrease of plant height, leaf area index (LAI), membrane stability index(MSI), leaf osmotic potential, soluble protein contents, ear and biological yield while effect of drought stress on shoot sodium concentration was not significant. The intensive drought stress led to decrease 21.7 and 27.3% ear and biological yield compared to control respectively. Application of filter cake on non-stress led to increase height of plant and ear and biological yield. But high levels of filter cake in intensive stress led to increase salinity and damage to cell membranes and reduce LAI and MSI and thus reduce economic performance. It also the amount of 30 ton.ha-1 of filter cake in intensive stress condition has been decrease ear and biological yield 18.7 and 23.3% compared to non-filter cake application respectively.