Potassium and Phosphorus

Abstract

Using K‐rich plants as biological K fertilizer is an innovation in physiological ecology of plant nutrition and a possible solution to the problem of K deficiency in soils and crops in China and other developing countries.

Since 1978, over 70 water plants, herbs and a few crops have been tested, of which 20 had a higher K content (>2.5% DM) than rice straw (1.67–2.5% DM). They were defined as K‐rich plants. Alligator alternanthera [Alternanthera philoxeroides (Mart.) Griseb] contains as much as 9.75% K on a dry matter basis. The results of pot cultures and field trials carried out in 1982–1984 showed that the application of dried Alligator alternanthera at the rate of 1500 kg/ha increased rice yields by 17.4% and was equally effective as or even more effective than KCl or rice straw. It should be noted that biological K fertilizers are superior to chemical ones in improving crop yield and quality because K‐rich plants not only supply crops with K but also with other nutrients and organic matter. Furthermore, biological K fertilizers can reduce pollution while chemical K fertilizers may increase pollution.

Key words:

• Alligator alternanthera
• biological potassium fertilizer
• potassium‐rich plants