PhD

Two field experiments were conducted at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram, to study the performance of intercrops in a mature coconut garden. The study was conducted for two years from June 1992 to May 1994. In the first experiment, the effect of nutrients, moisture and light on the productivity of intercrops, uptake of nutrients, quality of produce, soil properties and economics were studied. The effect of five cropping systems with two doses of fertilizers along with a control were tried in Randomised Block Design with three replications. In the second experiment, the interspecific root competition was studied using the radiotracer technique. The absorption of 32P by component crops in mono and mixed crop situation were investigated.
Plant characters such as height and leaf area of intercrops were not influenced by cropping systems and different doses of fertilizers applied to intercrops.
The results show that cassava can be raised along with banana, elephant foot yam and vegetable cowpea successfully under the partial shade of coconut.
Half the recommended dose of N and P and full dose of K was found sufficient to the intercrops grown in coconut garden.
The total dry matter production of economic produce of intercrops was not varying much by cropping systems and fertilizer doses probably because of the substitution effect.
The highest uptake of NPK by intercrops was recorded in cropping system, coconut+ cassava+ banana (C4) followed by coconut+ cassava+ banana+ elephant foot yam+ vegetable cowpea (C5).
The soil moisture status was not altered by raising different intercrops in coconut garden.
Cassava received only 75% of PAR in the cropping system compared to open and there was a corresponding decrease in tuber yield also.
Highest net income was obtained from coconut+ cassava+ banana+ elephant foot yam+ vegetable cowpea cropping system.
Radiotracer studies using 32P showed that, cassava can be raised as intercrop in coconut, without much competition for nutrients. Banana can be grown in association with coconut without any adverse effect on banana nutrition. Cassava+ banana, elephant foot yam+ banana and cassava+ elephant foot yam are ideal combinations of intercrops which can be raised in coconut garden without any competition for nutrients.
From the results, it can be concluded that cassava, banana, elephant foot yam and vegetable cowpea can be raised successfully and economically as intercrops in mature coconut garden applying half the recommended dose of N and P and full dose of K without much competition for nutrients, moisture and light.