Potassium Response in some Malawi Soils

Abstract

Potassium (K) response curves were generated for some Malawi soils using four different rates of potassium fertilizer, with grass being used to estimate plant availability. The study was conducted to find the point of maximum response for potassium. The soils were characterized, limed and fertilized with equal amounts of nitrogen. Potassium was applied at four rates: 0.0, 0.1, 0.2 and 0.4 me K/100 cm 3 soil. The K treated soils were put in pots and cropped with grass. The grass was harvested six weeks after planting, dried and weighed. In general, addition of potassium resulted in increased growth of grass in all soils, with some soils showing better response than others. For montmorillonitic soils and soils with mixed mineralogy response was linear up to the highest rate of 0.4 me K/100 cm 3 . Apparently the 0.4 me K/100 cm 3 soil was not enough to give maximum yield for these potassium depleted soils. For the kaolinitic soils 0.4 me K/100 cm 3 soil was beyond point of maximum response. The variation of response to added potassium in the different soils calls for soil specific fertilizer additions. Smallholder farmers should move from blanket (crop specific) fertilizer recommendations currently being used to crop and soil specific fertilizer recommendations. Basal fertilizer dressings (starter packs) should always contain potassium. Correlation and calibration studies should be conducted to establish a potassium low optimum level for Malawi soils.

Effect of salicylic acid and potassium application on yield and grain nutritional quality of wheat under drought stress condition

“…An elevated level of K slightly increased crude protein under drought stress condition. Application of K improves plant N uptake and utilization, enzyme activity, and protein synthesis (Daniel et al 2016;Lakudzala 2013). In present study, application of SA and K 3 enhanced crude protein content in wheat under drought stress condition.…”

“…In present study combined application of SA and adequate amount of K improved plant growth and grain yield of wheat greater than when SA and K were applied separately. K plays a vital role in plant growth and productivity by regulating photosynthesis, stomatal opening, and transportation of assimilates from source to sink, enzyme activity and carbohydrate synthesis (Daniel et al 2016;Yawson et al 2011;Lakudzala 2013). SA is also essential for plant growth, physiological performance and crop productivity under abiotic stress conditions.…”

“…Potassium (K) can play effective roles in the physiological processes of photosynthesis, formation of carbohydrates and protein, transportation of water and nutrients, nitrogen (N) utilization, and stimulation of early growth in plants (Daniel et al 2016;Lakudzala 2013). It controls stomata opening and enhances enzyme activation in plants, therefore it improves crop productivity (Yawson et al 2011).…”

Potassium (K)-to-magnesium (Mg) ratio, its spatial variability and implications to potential Mg-induced K deficiency in Nitisols of Southern Ethiopia

“…Potassium (K + ) is an essential plant nutrient next to nitrogen (N) and phosphorous (P). It aids plants in the physiological processes such as transportation of water, nutrients and carbohydrates, photosynthesis, N utilization, stimulation of early growth, and in insect and disease resistance [1,2]. It also helps plants regulate the opening and closing of stomata [1,3] which is needed for efficient water use.…”

Salicylic acid and potassium nitrate promote flowering through modulating the hormonal levels and protein pattern of date palm Phoenix dactylifera ‘Sayer’ offshoot

“…Under the water shortage conditions, leaf stomata do not function actively in plants with potassium deficiency and, therefore, cause excessive water loss (Farooq et al, 2015). Potassium (K) plays a vitally role in the physiological processes of photosynthesis, in the formation of carbohydrates and proteins, the transfer of water and nutrients, in use of nitrogen (N), and the stimulation of early plant growth (Lakudzala, 2013). In plant tissues, the transport of water, nutrients, and carbohydrates is enhanced by potassium application (Safar-Noori et al, 2018).…”