The effects of potassium and magnesium fertilizers on yield and composition of successive crops of ryegrass, clover, sugar beet, potatoes, kale and barley on sandy soil at Woburn

Abstract

SUMMARYIn an 8-year field experiment, potassium sulphate and to a lesser extent magnesium sulphate increased yields of all crops both when applied alone and together. Although K/Mg interactions did not affect yields they considerably affected the ratio of concentrations of these elements in the dry matter of the crops. Sodium chloride increased yields of kale but not of barley harvested at ear-emergence.Percentage yield response to potasium followed the orderPotatoes (218%) < clover = barley < sugar beet < kato; < ryegress (17%).Magnesium increased yields from 3 to 10%, most with potatoes.Changes in exchangeable magnesium in the soil reflected differences between applied magnesium and crop uptakes. Changes in exchangeable potassium were less than expected, probably because non-exchangeable potassium was released on plots without added potassium and ‘fixed’ in non-exchangeable forms on plots where much fertilizer potassium had been given.Increase in the incidence of magnesium deficiency symptoms reported recently in South. East England are attributed to the local liming materials containing only small amounts of magnesium and to less F.V.M being applied to crops than previously.

The longevity of sodium, potassium and magnesium fertilizer residual effects on the yield and composition of ryegrass grown on a sandy soil

“…However, when data from the previous crops (1960-7) are included (Bolton & Penny, 1968), the K balance over a 15-year period shows releases of 565, 276 and -14 kg/ha of non-exchangeable K from the K o , Kj and K 2 plots. This suggests that some of the K residues were in a non-exchangeable form in 1967.…”

“…Full details of the treatments and their effects on a sequence of crops and soil composition in 1967 were given in a previous paper (Bolton & Penny, 1968).…”

“…Such effects have therefore been studied in cattle, particularly lactating cows, and the using an experiment where different amounts of intake in fodder and drinking water is often K, Mg and Na were given to a succession of 8 years supplemented by using salt licks. In some areas of of arable crops (Bolton & Penny, 1968). Ryegrass England, farmers apply sodium chloride to pastures was chosen as the test crop because (a) it can remove because they believe palatability is improved.…”

Changes in magnesium and calcium in soils of the Broadbalk wheat experiment at Rothamsted from 1865 to 1966

“…This situation is unlikely to change on parts of the field which continue to grow wheat. However, some crops remove more Mg and some respond to more Mg fertilizer than cereals (Bolton & Penny, 1968). Potatoes grown on…”

Data presentation, interpretation, and communication

“…Although K fertilization can strongly diminish Ca and Mg uptake of plants, this quite rarely leads to Ca or Mg deficiency in crops. Plant K-Ca-Mg interactions can be affected by various factors, such as the availability of the particular cation and the presence or absence of other cations in the growth medium (Epstein, 1972); the plant species and varieties (Bolton andPenny, 1968, Lombin andMustafa, 1981); the age of plants (Gahaller et al, 1975), the water supply (Jenne et al, 1958), etc. Potassium application resulting in biomass or yield increases can also affect plant K-Ca-Mg interactions due to the dilution effect (Dibb and Thompson, 1985).…”