Effects of Foliar Applied Potassium on Cotton in the San Joaquin Valley of California

ABSTRACT
Foliar fertilization of cotton, Gossypium hirsutum and G. barbadense, has been a subject of researchers since 1992 in California. The practice has expanded from its limited beginnings to widespread use for supplying supplemental nitrogen and potassium. Yield and economic advantages have been realized by researchers, and growers alike. Replicated field tests were conducted annually from 1992 to 1997 to evaluate the effects of foliar N and K on cotton yields and quality. K2SO4, KNO3, and KTS (Potassium Thiosulphate) were applied at various timings beginning at first bloom, in single and multiple applications. Rates of K2O were kept constant at 5.0 Kg/ha for each application. All three materials, K2SO4, KNO3, and KTS resulted in increased lint yields when compared to an untreated control. Maximum positive benefits occurred when applications were made between one and three weeks after first bloom. Increases in lint yields have generally been up to 100 Kg/ha.

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Nitrogen Fertilization of Cotton Based on Inorganic Nitrogen Analysis of the Soil

ABSTRACT
Cotton is produced on widely differing soils under irrigated or rainfed conditions in South Africa. Under these circumstances seed cotton yields can vary greatly and so do their nitrogen demands. This model was the culmination of nitrogen field trials carried out over three seasons at four locations scattered over South Africa. In these trials, six levels of nitrogen were applied, with four replications at each site. Pre-plant soil samples were taken at 0-300mm, 300-600mm and 600-900mm. These samples were analysed immediately for inorganic nitrogen. For assessment of the amount of nitrogen that can be mineralised, these samples were incubated at 15/26C over a 14-week period. Petiole samples were taken for analysis at one and three weeks after the appearance of the first flower. The higher the initial nitrogen plus mineralised complement in the soil, the lower the percentage of nitrogen utilized by the cotton crop. A utilization factor of 66.7% seems to be a good average. The same results were obtained with applied nitrogen, where a utilization factor of 80% seems to be a good average. The nitrogen required to achieve a certain target cotton yield is taken as the point of departure in this model. Subtract from this 66.7% of the total inorganic N-content of the top 900mm soil plus the amount of nitrogen mineralised during the growth period. This leaves the amount of nitrogen to be applied for production of the target yield. The Nitrogen content of the irrigation water should be taken into account but it was negligibly low during these trials. Working with a utilization factor of 80% for the applied nitrogen, the actual amount can be calculated. Tests of the calculated nitrogen requirement against actual yields achieved in this and other trials gave a very good correlation of r2 = 0.977 between calculated and actual nitrogen needs.

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Influence of Nitrogen Nutrition on the Yield and Quality of Cotton

ABSTRACT
Nitrogen plays an important role in the growth and yield of cotton. In rigid genetical conditions, growth and development of different cotton cultivars react differently to nitrogen fertilizers. The changes in parameters of cotton fibers of different cotton cultivars that react to the application of increasing doses of nitrogen fertilizers were studied. Results show that some cultivars are more responsive to applied nitrogen than other. Apparently this is related to the differences in the absorption of nitrogen from soil resources and from the applied fertilizers. These cultivars had improved fiber quality after the application of nitrogen fertilizers in comparison to the control cultivar.

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The Effects of the Nitrogen Fertilizer Rates on the Uptake and Yield of Cotton on Calcareous Soil

ABSTRACT
Excessive nitrogen fertilizer rates in Upland cotton (Gossypium hirsutum L.) produces high levels of nitrates in calcareous soils. The experiments were conducted in the Experimental Station of Vardates in central Greece, during the seasons 1992 and 1993. The objectives were to examine the effects of variable nitrogen rates on the nitrogen uptake and the yield of cotton in calcareous soils. The experiments were conducted in complete, randomized blocks, using the nitrogen rates of 0, 60, 90, 120, 150, and 180 kg.ha-1, while phosphorus and potassium were kept constant at 80 kg.ha-1. The dry matter content (grams per plant) and nitrogen uptake, as well as the concentration of NO3- (ppm) in soil depth of 0-30 cm, differed for the applied nitrogen rates and stages of plant growth. Cotton plants appeared to have a higher dry matter content and nitrogen uptake at the ‘blooming’ stage while the lowest value of concentration of NO3- (ppm) in soil appeared at the ‘squares’ stage. The yield of seed cotton of 4400 – 4500 kg.ha-1 was not significantly affected by the high nitrogen rates of 120 – 180 kg.ha-1, (r2 = 0.4). The yield of seed cotton (4733 kg. ha-1) and the dry matter content ( 100 g.plant-1), were positively affected by the rates of 60 kg N. ha-1, 80 kg P2O5. ha-1 and 80 kg K2O. ha-1 (r2 = 0.75 ).

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The Effect of Potassium Fertilizer Plus Higher Nitrogen Rates on Growth and Yield of Cotton

ABSTRACT
Two field experiments were carried out in two locations of Beni-Suef Governorate in middle Egypt, on Giza 75 cotton cultivar (Gossypium barbadense L.) to increase cotton yield by increasing nitrogen rates, while enhanced by potassium. The treatments were 112.5, 150, 187.5 kg N/ha and 187.5, 225.5 kg N plus 60kg K/ha. Results revealed that previous treatments had little effect on plant growth and boll weight. Without K, the yield components and yield of seed cotton increased insignificantly by increasing nitrogen rate up to 150kg/ha but decreased significantly with the rate 187.5kgN/ha. Applying K fertilizer plus higher N rates, reversed the negative effect of nitrogen increases and raised the yield of seed cott

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Effects of Organic and Inorganic Nitrogen Fertilizer Applications on Cotton Yield, Quality and Soil Properties in Gezira, Sudan

ABSTRACT
A factorial field trial investigating the effects of farm yard-manure (FYM) and urea application on cotton yield, quality and soil properties was conducted on a Vertisolic soil, low in organic matter, using cultivar Acala 93-H, for 3 consecutive seasons (1995-98) at the Gezira Research Station in Sudan. The FYM was given at 3 levels (0, 10, and 20 t/ha), while urea was at the rates (0, 21.5, 43.0, 64.5 and 86.0 kg N/ha). Both FYM and urea application significantly increased cotton fiber yield. Application of 20t FYM+43 kg N/ha gave the optimum cotton fiber yield (908 kg/ha) and outyielded the standard control (86 kg N/ha) by 10.1%. Urea and FYM application had no significant effects on most of the fiber properties. FYM reduced bulk density, and increased the hydraulic conductivity, total nitrogen and organic carbon of the top 30 cm of soil. The proposed practice (20t FYM+43kg N urea/ha) has definitely reduced the cost of inorganic nitrogen fertilizer and improved the soil conditions.

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Yield and Quality Properties of Cotton as Affected by Potassium Fertilization

ABSTRACT
A four year field test was initiated in 1997 to evaluate potassium as a soil treatment on yield and fiber quality of cotton in Adana. Four rates of potassium as K2SO4 (0, 80, 160 and 240 kg/ha) were applied to C.1518 cotton in two splits with half the K applied at planting and half when the crop reached the first bloom stage. Yield, plant growth and development and High Volume Instrument quality evaluation were measured for each treatment. Averaged over all treatments, adding K produced significant seed-cotton and lint yield responses (P=0.01) compared with the untreated control. K treatments produced a significantly higher boll weight than the control. HVI lint quality values were not affected by any treatment.

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Foliar Fertilization in Cotton

ABSTRACT
The supply of nutrients through the soil can be restricted by different factors such as soil compactness, extreme conditions of soil/water regime, pH of the soil solution, etc. Excessive N application to the soil might lead to environmental hazards. Foliar fertilization, when correctly applied provides solutions to many of these cases and helps to optimize nutrient management as supplement to soil application of nutrients.

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KTS-Potassium Thiosulphate – A Liquid Potassium and Sulphur Fertilizer for Cotton Production

ABSTRACT
KTS is a clear liquid fertilizer product containing 25% K20 and 17% sulphur. This product was developed in the early 1990’s and currently is being manufactured in the US and distributed throughout the cotton growing regions of North and South America, Australia and the Middle East. KTS can be used as a source of potassium and sulphur for starter fertilizers, sidedress placement, through irrigation water and for foliar applications. The product has been accepted by many cotton production managers to enhance growth and boll development.

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Tillage, Cover Crop and N Effects on Cotton Grown in 19 cm Row Widths

ABSTRACT
In areas of the USA where cotton (Gossypium hirsutum L.) is traditionally harvested with a spindle picker, there is widespread interest in producing cotton in narrow rows and harvesting with a stripper harvester. Optimum management practices with this system are not well-defined. This study was conducted to determine the effects of residue management and nitrogen fertilization on cotton grown in 19-cm-row widths. Similar experiments were conducted in Florence, SC and Auburn, AL, USA, over two growing seasons. Treatments at both locations were tillage system (conventional vs. conservation), winter cover crops (cereal, legume, or none), and N fertilizer rates (0, 45, 90, 135 kg N/ha). Tillage system had only a small effect on yield and fiber properties. The availability of N (either through fertilizer or cover crop) had the greatest impact on the cotton crop. At both locations, optimum N rate for cotton following either no cover crop or following the winter cereal was between 45 and 90 kg/ha. Following the legumes, N rate had a small effect on yield. Overall, there was an average of 2 to 3 bolls per plant. Short fiber length at Florence in 1997 (2.57 cm) and low micronaire at Auburn both years (3.0 micronaire units) suggest that environment during boll development may play a more important role in determining fiber properties in narrow-row systems than in wide-row systems.

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