Page 147 - Ilmu Tanah

134 The Chemistry and Fertility of Soils under Tropical Weeds

but there was an increase instead. The increase was obviously originated from the
release of soil mineral structural K.
However, the effectiveness of Arachis pintoi is not consistent. Lestari (2018)
studied the effect of Arachis pintoi in several fertile and infertile soils of Lampung
as compared to that of Penissetum purpureum as shown in Table 7.13. Soil
samples were taken from 9 sites in Lampung. After drying and sieving to 2 mm, soil
samples were planted with these weed species for 4 weeks after which the soils
were analized for the pH 7.00 N NH 4 OAc extracted K.

Table 13. The pH 7.0 N NH 4 OAc extracted K from several soils of Lampung planted
with two different species of weeds*.

-1
Available K (mg kg )
Soil Samples Control
A. Pintoi P. purpureum
(No Weed)
Gedongmeneng 2.18 A 2.20 A 2.21 B
(a) (a) (a)
Sidosari 1.97 B 1.91 E 1.91 C
(a) (b) (b)
Tanjung Bintang 1.97 B 1.87 F 1.80 D
(a) (b) (c)
Sekampung Udik 2.20 A 2.20 A 2.25 A
(a) (a) (a)
Gisting 2.19 A 2.14 B 1.92 C
(a) (a) (b)
Hulu Sungkai 2.01 B 2.01 C 1.95 C
(a) (a) (b)
Kotabumi 2.02 B 1.99 CD 1.94 C
(a) (ab) (b)
Abung Selatan 2.01 B 1.95 DE 1.96 C
(a) (b) (b)
Liwa 2.19 A 2.21 A 2.18 B
(a) (a) (a)
Rataaan 2.08 2.05 2.01

LSD 5% 0.05
*Lestari (2018)

Abdul Kadir Salam and Nanik Sriyani – 2019