MSc

A field experiment was conducted at the Instructional Farm,
College of Agriculture, Vellayani, Thiruvananthapuram, Kerala state to
find out the nitrogen and phosphorus requirement for guinea grass
(Panicum maximum J.) under zero and 50 per cent shade levels.
The influence of shade levels, nitrogen and phosphorus
application on growth parameters, fodder yield, quality of produce,
physiological parameters, uptake of nutrients, chemical properties of soil
and economics was investigated.
Two levels of shade (0 and 50 per cent), three levels of nitrogen
(100, 200 and 300 kg ha") and three levels of phosphorus (25, 50 and 75
kg ha") were combined to form eighteen treatment combinations. The
experiment was laid out in split plot design with three replications.
Results of the experiment revealed that lower levels of shade as
well as higher- levels of nitrogen and phosphorus had significant positive
influence on improving the fodder production potential of guinea grass.
The lower levels of shade and higher doses of nitrogen and phosphorus
were found to increase significantly the growth parameters namely
number of tillers and leaf: stem ratio and physiological parameters like
leaf area index, CGR, RGR and NAR.
,
Lower levels of shade and higher doses of nitrogen and
phosphorus registered maximum green fodder yield in all the five
harvests. Total green fodder yield was also highest at open and at higher
levels of nitrogen and phosphorus. Similar results were obtained in the
case of dry fodder yield also.
Quality parameters of the forage significantly improved as shade
progresses. Higher levels of nitrogen and phosphorus registered higher
crude protein and chlorophyll contents and lower crude fibre content.

The nutrient content of plant showed a significant increase with
increasing levels of shade while the nutrient uptake showed a significant
increase with lower levels of shade. Application of nitrogen and
phosphorus significantly increased the content and uptake of nitrogen,
phosphorus and potassium.
There was a significant increase In available phosphorus and a
decrease in available potassium content of the soil with increase in shade
levels. Application of nitrogen significantly increased the nitrogen
content of the soil while reduced phosphorus and potassium content of
the soil after the experiment. Phosphorus levels also significantly
increased the nitrogen and phosphorus content but potassium content of
the soil after the experiment showed a parabolic type of response.
Lower levels of shade with higher dose of nitrogen and
phosphorus registered highest net returns and benefit cost ratio. But
economic yield was obtained in shade intensity upto 50 per cent.