Soil water extraction pattern of coconut (Cococs nucifera L.) in relation to soil compaction

Effect of soil compaction on the gowth and activity of coconut roots in two soil series, namely, Andigama series (gravelly soil) and Madampe series (sandy loam soil) was studied. The effective root zone of coconut in relation to water sbsorption process under natural soil compaction were also investigated. Soil compactin and soil moisture absorption ability was determined using cone penetrometer and neutron scattering methods, respectively. Coconut root distributution in Andigama and Madampe series showed that 75%-80% of roots of adult coconut palms were localised in a depth ranging from 20 cm to 100 cm. About 5% of the roots were located beyond the 100 cm depth and 15% -20% was confined to the top layer (0-20 cm) of soil. Root growth of coconut in the two series did not show any significant differences. However, the root activity in the Madampe series, with respect to moisture absorption was higher that that of the Andigama series due to low compaction of the former. Results also showed that soil compaction higher than 250N/cm restricted the activity of coconut roots in the Andigama series for moisture absorption up to a distance of 2m away horizontally from the base of the tree and the highest moisture extraction was observed at m distance. High moisture extraction by coconut roots was confined to a depth ranging of 20 to 120 cm and of 20 to 250 cm in soils of Andigama and Madampe series, respectively, due to differences in soil compaction levels. It was condluded that soil compaction limits the water absorption ability of coconut roots vertically from the base of the tree, rather than coconut root growth and penetration

Effect of Potassium on Growth, Fruit Quality Improvements and Resistance to Anthracnose in Field Grown Capsicum (Capsicum Annum L. Cv. ‘Hungarian Yellow Wax’)

Postharvest losses of capsicum crop accounts for 30-40% of total crop production. It has been shown that postharvest losses of capsicums can be reduced significantly with the application of potassium due to improvements in disease resistance and fruit quality. The objective of this study was to investigate the effect of higher doses of potassium (K) on plant growth, yield and fruit quality parameters and resistance to anthracnose disease of capsicum cv. ‘Hungarian Yellow wax’. Three different levels of potassium, Department of Agriculture (DOA) recommended level [180g per bed (control)], double the level (360g per bed) and three times of the level (540g per bed) were applied to the soil in a Randomized Complete Block design. The same experiment was repeated in three farmer fields of Naula Grama Niladhari (GN) division in Dambulla Divisional Secretariat of Matale district of the central province of Sri Lanka. Plant growth parameters were measured at two week intervals, and fruit quality parameters (TSS, Ph, %TA), fruit physical parameters (length, width, pericarp thickness, fresh weight, firmness and cell wall thickness) were recorded. Finally the resistance to diseases of capsicum fruits was also tested by inoculation of Colletotrichum capsici to the fruits. This study concludes that application of higher doses of potassium improves some plant growth parameters (height and plant diameter at base), fruit physical parameters (fruit length, width , fresh weight, firmness and cell wall thickness). The tripled and doubled the dose of potassium application reduced anthracnose disease by over 75% and 95% respectively indicating that higher level of K could have a significant impact in reducing postharvest losses of capsicum in local conditions KEYWORDS: Potassium application, capsicum anthracnose, fruit qualit