Two field experiments were preformed at the Experimental Farm of Sids Agricultural Reseasrch Station, ARC, Beni-Suef Governorate, Egypt to study the possibility of using feldspar as potassium source along with some bio-stimulants namely, silicate dissolving bacteria (SDB), humic acids and farmyard manure and its effect on cotton productivity and soil properties after harvest. The results indicate that added 400 kg feldspar/feddan, 10 kg humic acid or 10 m 3 FYM/feddan improved plant height, number of fruiting branches/plant, number of open bolls/plant, boll weight, seed cotton yield, earliness%, seed index and leaf chemical contents, i.e.; N, P and K%, chlorophyll A and/or B as well as soil available N and K. Feldspar increased the soil available N and K, while FYM or humic acid improved soil pH, O.M, soil available N, P and K. On the other hand, soil salinity was increased as FYM application. The results of the interaction between treatments show that the best results were found when cotton plants were treated with 400 kg feldspar/feddan + 10 m 3 FYM/feddan or 10 kg humic acid/feddan in combined with silicate dissolving bacteria. Furthermore, the effect of SDB on cotton productivity is more pronounced when combined with feldspar, FYM or humic acids

seasons to study the response of cotton to potassium fertilization (12, 24, 36 and 48kg K 2 O) as soil application as well as 5kg K 2 O/ fad as foliar spraying three times at squaring, beginning of flowering and top of flowering) under different irrigation intervals at recommended irrigation interval (every 12 days), every 15 days, every 18 days and every 21 days). The results show that increasing potassium fertilization up to 36kg or 48kg K 2 O/fad as soil application as well as decreasing irrigation interval to 12 days exhibited the highest values of plant height, number of fruiting branches/ plant, number of open polls/plant, seed cotton yield, earliness % and seed index as well as leaf content of N, K, chlorophyll A and B and carotenoids. On the other hand, lint percentage and fiber properties did not respond to either potassium or irrigation treatments, while P content increased as increasing water irrigation. Increasing both potassium levels and the irrigation intervals improved water use efficiency and water utilization efficiency. The results of the interaction between potassium and irrigation treatments reveal that irrigation cotton plants every 15 days when fertilized with 48kg K 2 O/fad as soil application produced highest growth, yield and its components and chemical content of cotton leaf equal to these irrigated every 12 days and supplied water 36 or 48kg K 2 O/fad.

The current study was conducted to evaluate the effect of different sources levels of potassium fertilizer on the performance of cotton plants under the drought stress. Particularly cotton water applied efficiency, chemical and pigments content, vegetative growth, and yield characteristics were evaluated and compared among different sources levels of potassiumtreated and non-treated drought-stressed plants to test the potential of this fertilizer as a tool for alleviating drought stress.

Two field experiments were carried out at Sids Agricultural Research Station, Beni-Suef Governorate Middle Egypt, during 2012 and 2013 seasons to study the effect of applications ethyleneon growth, yield components, fiber properties and chemical constituents of the Egyptian cotton hybrid [G83 (G75 X G5844)] X G80 (Gossypiumbarbadense L.,). Cotton plants were treated with ethylene at start or at maximum of flowering. The experimental design was a randomized complete blocks with four replications.Results obtained could be summarized as follows:  The application of ethylene 20 ppm. at peak of floweringincreased significantly, no.of open bolls/plant, boll weight, seed cotton yield/fed., earliness % and lint % in two seasons.  When ethylene applied at both stages, no. fruiting branches/plant and seed indexwere insignificantly affected.  On the other hand, spraying cotton plants with ethylene at 20 ppm at peak of floweringtended to increase micronaire reading while fiber strength was not affected in both seasons.  Application of ethylene at 20 ppm at peak of floweringtended to increase chemical contents in cotton leaves i.e. chlorophyll a, total chlorophyll, carotene, total soluble sugar and polyphenols. It could be concluded that spraying ethylene 20 ppm. at peak of flowering could be recommended production of this new cotton hybrid [G83 (G75 X G5844)] X G80 under Middle Egypt location .

The present work was aimed to investigate using of potassium fertilizer as well as nano chitosan -NPK to alleviate the negative effect of water stress and its effect on cotton plant and some water relations. Two field experiments were conducted to study the possibility of using potassium fertilizer and nano chitosan -NPK to eliminate the negative impacts of water stress. The design of the experiment was split design plot, where number of irrigation treatments (6 and 9) were arranged in main plots, while potassium fertilization, i.e., K 1 = 96 kg K/ha as potassium sulphate, K 2 = 96 kg K/ha + twice foliar application of 2% potassium sulphate, K 3 = 96 kg K/ha + twice foliar application with 2% nano chitosan-NPK, K 4 = four times of foliar application with 2% potassium sulphate, and K 5 = four times of foliar application with 2% nano chitosan-NPK. The results obtained indicated that K 3 followed by K 2 which achieved the favourable values of plant height, first fruiting node, number of fruiting branches/plant, number of open bolls/plant, boll weight, seed index, lint percentage, seed cotton yield. Neither potassium fertilization nor irrigation number altered fiber properties. The data of the interaction showed the combined 96 kg K/ha as potassium sulphate + twice foliar application with 2% nano chitosan-NPK can diminish the negative effect of drought stress under deficit conditions, with higher seed cotton yield nearly equal to those obtained under full irrigation. It could be concluded that potassium fertilization and nano chitosan-NPK can improve cotton plant tolerance to water stress and enhance cotton productivity.