Soil potassium effects on cotton (Gossypium Hirsutum) growth, yield and quality in the texas high plains

Date

2018-03-30

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Abstract

When comparing soil potassium (K) levels common in west Texas to the current Mehlich III-K critical level for cotton (Gossypium hirsutum L.), applications of fertilizer K are not often recommended. However, when K is applied to soil, positive responses in yield of cotton have been reported. The objectives of this research were to: 1) Evaluate the effect of different application methods and rates of K fertilizer on cotton growth, lint yield, and fiber quality; 2) Evaluate the effect of K fertilization on lint yield and fiber quality components within specific node zones; and, 3) Determine the effect of K fertilizer rates within irrigation levels on lint yield and boll distribution. In Lamesa muriate of potash (KCl) was applied using two methods, knife injected (0-0-15) and broadcast (0-0-60), and at New Deal KCl was applied using the knife injected method. Rates of K application included 0, 45, 90, 135, and 180 kg ha-1 with high and low irrigation levels. At Lamesa in 2016 lint yield was greater when 90 kg K ha-1 was applied broadcast under high irrigation (2,153 kg ha-1 lint) compared to the 180 kg ha-1 treatment under high irrigation and all K treatments under low irrigation. There were no differences in 2017 for yield at Lamesa. It can be concluded from this experiment that K rates affected bulk lint yield when applied by broadcasting compared to the injection application method in 2016 at the Lamesa, TX, location. At New Deal lint yield differences were not identified for K application rate, while a difference in irrigation was observed, where the high irrigation level increased machine harvested yield on average by 940 kg ha-1 in 2016 and 425 kg ha-1 in 2017. Similar to previous research, irrigation had an effect on boll distribution. At New Deal total bolls in 2016 under the low irrigation resulted in an 175,000 boll ha-1 increase at 135 kg K ha-1 over 45 and 90 kg K ha-1. Differences did not exist in 2016 for box picking yield between K treatments in New Deal. When 180 kg K ha-1 was applied total bolls and box picking yield under low irrigation increased in the early and middle node zones and total nodes over all other K application rates at New Deal in 2017. Based on box picking results from 2017, 180 kg K ha-1 significantly increased yield under the low irrigation in New Deal. In 2016, 135 kg K ha-1 and in 2017, 180 kg K ha-1 tended to have more bolls in the early node zone under the low irrigation and the middle node zone across both irrigation levels. Box picking helped determine that the early and middle node zones were able to utilize the K within the plant due to the increase in bolls and yield compared to the late and vegetative node zones. Our results in the overall bulk lint yield suggest further research is needed to better understand the dynamics of K and cotton production and the effects on lint yield between irrigation levels and application methods.

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Keywords

Potassium, Soil, Cotton

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