A field experiment with rain-fed winter wheat investigated the nutritional aspects of paper-mill sludge as a mulch and incorporated into the topsoil. Treatments with chemical fertilizers were also used as controls. Paper-mill sludge used as mulch with high rate (100 MG ha−1) and also the combined N and K mineral fertilizer treatments increased yield when a low potassium otherwise caused potassium deficiency in wheat with high specific surface soil. High soil Ca : K molar ratio by incorporation lowered potassium uptake and yield, with visual symptoms of potassium deficiency. A very high Gapon selectivity coefficient (KG) for K exchange against Ca + Mg (16.58 (L/mole)0.5) produced a nonlinear normalized exchange isotherm in favor of potassium with these soils containing high illite. Ca and K which are released by sludge decomposition are diverged in soil when mobilized by rain infiltration, lowering Ca : K molar ratio. Low soil Ca : K molar ratio may be expected by surface sludge application relative to incorporation, due to greater rain infiltration through upper soil layers and their effluent pore volumes per unit depth. Ca from triple superphosphate by the P, N, and K mineral fertilizers combined also reduced potassium uptake and yield relative to N and K combined.

Physical aspects of paper mill sludge application for wheat production, their relative significance and interactions were investigated in a slow swelling-shrinking soil in a temperate climate by a field experiment. Other treatments were mineral fertilizers to gauge nutritional aspects. Treatment with N and K mineral fertilizers combined and the high rate sludge application as mulch, both increased yield when low potassium kinetics otherwise caused potassium deficiency in wheat. High specific surface may increase mechanical resistance to root growth and lower nutrient uptake (K). There are two potential apposing physical aspects of sludge application on swelling-shrinkage rate and K diffusion, also root growth (low mechanical impedance) and nutrient uptake; a positive interaction by increasing soil water content in root zone versus a negative interaction by decreasing diurnal soil temperatures to suboptimal values especially before wheat heading. Low soil temperatures under sludge may become critical for shoot propagation and head density at sub-optimal temperatures of cold years for wheat growth.

Bioreactors provide suitable conditions for the growth of cells and production of secondary metabolites by regulating physical and chemical factors. In this study, rst, sucrose, 2-(N-morpholino) ethanesulfonic acid (MES) as a buffering agent and medium pH was optimized in the Erlenmeyer ask. This aim was then pursued in a stirred bioreactor through aeration and pH medium adjustment. Results of the rst step showed that Schenk and Hildebrandt (SH) basal medium with naphthalene acetic acid (2 mg.l -1 ) and 6benzylaminopurine (1 mg.l -1 ) supplemented with 2.5 mM of MES and gradually increment of sucrose from 3 to 6% caused to catch the highest cell biomass and crocin production. The spectrophotometry measurement showed that the highest crocin content of the cells was 0.8 mg/g after ve weeks. The results of the second part revealed that in the stirred bioreactor, constant pH (5.8) during the growth period is a limited factor for the cell growth and crocin production. Although aeration initially found to be an inhibited factor for the production of crocin, results showed that, if the evaporated volume of water caused by aeration is constituted, it can be an effective factor to increase cell growth rate around 2 folds.In addition, total crocin content of the cells, based on the HPLC could be raised up to 2 mg/g. Based on this study, it can be concluded that MES and gradual increment of sucrose could increasing the cell growth and crocin production. Aeration in bioreactor can increase cell biomass, if the medium volume will be kept constant. Key MessageSaffron, the most expensive spice contains valuable compounds like crocin. Corm derived-cell containing crocin can be produced in higher scales and cheaper price by using cell culture in stirred bioreactor.

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