Principal Component Interactions in Silvopastoral Systems

Abstract

Two silvopastoral systems involving Acacia tortilis and Leucaena leucocephala as tree component with understorey crops of Cenchrus ciliaris and Panicum maximum were established in two spacings (4x4 m and 4x3 m) during 1982 at Central Research Farm of Indian Grassland and Fodder Research Institute, Jhansi. The observations related to principal bio-physical factors viz., photosynthetically active radiation (PAR), soil moisture, soil temperature and tree root weight, and understorey grass production were recorded during 1996 and 1997.

 Stepwise procedure of regression analysis was employed to examine the effect of different factors in influencing the understorey crop production. The pooled analysis of results indicated that at wider spacing (4x4 m), the below ground factors like soil moisture, soil temperature and root biomass of tree influenced the understorey grass production significantly. The relationship, dry grass yield (g/m²)=EXP (7.1351-0.1963** ST(10-20) + 0.1220* SM (0-10)), showed soil temperature (ST) at 10-20cm depths and soil moisture at 0-10cm depths, explained 85.82% variation in understorey grass production of C. ciliaris under A. tortilis. Whereas, the relationship, dry grass yield =EXP (4.7084-0.1094** ST(20-30) + 0.2739**SM(10-20)) evolved for prediction of P maximum under L. leucocephala explained 29.62% variation.