Physiological characteristics of corn, under Conservation Agriculture Practice Systems (CAPS) in sloping oxisol

Conservation Agriculture Practice Systems (CAPS) is an agronomic innovation that espouses the simultaneous implementation of three major pillars, namely: 1) continuous crop rotation, 2) minimal tillage and 3) continuous ground cover, respectively. In local agro-ecosystems it is still untested. Hence this study was conducted to test its viability using physiological parameters in corn as key indicators of agronomic efficiency under a sloping upland in Northern Mindanao. A one year study (November 2011-November 2012) was conducted to determine and evaluate parameters such as net assimilation ratio (NAR), crop growth rate (CGR), partitioning coefficient (PC), harvest index (HI), dry matter (DM) and yield components, respectively. Five cropping systems (CS); CS1-(corn + Arachis pintoi - corn + Arachis pintoi), CS2-(corn + Stylosanthes guianensis - corn + Stylosanthes guianensis), CS3 - (corn + cowpea - upland rice -corn + cowpea) CS4 - (corn + rice bean - corn + rice bean), and CS5 - (corn-corn) were implemented. Parameters were measured at 30, 65 and 85 days after planting (DAP). H1 and yield components were determined during harvest. Differences in NAR were observed at 30-60 and 60-85 DAP across treatments and seasons. CS5 influenced CGR at 60-85 DAP, meanwhile PC was influenced by the interaction effects of CS5 and growing seasons at 65 and 85 DAP. Among CS5, CS2 and CS4 showed peculiar trend of DM partitioning. Corn with S. guianensis had more DM partitioned to the stem at vegetative stage (30 DAP) and had the second highest PC to the ear at 85 DAP. In CS4, more assimilates is directed towards the leaf organ at early stage (30 DAP), while higher allocation to the ear at 85 DAP. HI of 0.43 was obtained in CS1 which is significantly higher than the rest (CS2-CS5) having values of 0.3-0.33, respectively. Higher grain yields were obtained under CAPS compared to the conventional (CS5).