Effect of different rice based cropping systems on soil health under organic management

Deterioration of soil fertility is the main drawback of monocropping of rice where the system is highly nutrient exhaustive and thus, has depleted inherent soil fertility, causing deficiency of several nutrients. Crop diversification, especially under organic management is an alternative to restore the fertility in the soil and sustain it. The present investigation was conducted during May 2015 to May 2017 at Department of Agronomy, College of Horticulture, Thrissur to study the effect of crop diversification to sustain the soil health under organic management. The experiment was laid out in completely randomized block design and practiced under three replication. Rice was grown under four different cropping systems with and without foliar spray of liquid organic manures (LOMs) along with traditional cropping system (rice-rice-fallow) keeping as control. The rotations followed were rice-rice-njavara rice, rice-rice-salad cucumber, rice-rice-vegetable cowpea, rice-rice-amaranthus and rice-rice-fallow. The management practices were followed as per the Package of Practices Recommendations: (Ad hoc) for organic farming: Crops of the Kerala Agricultural University. Jeevamrurtham, Panchagavyam, green leaf extract and fish amino acid were the liquid organic manures sprayed at fifteen days intervals after planting/ transplanting. The results further indicated that introduction of leguminous crop in the existing rice-rice-rice/ fallow not only increased the system yield but also improved the physical, chemical and biological properties of the soil. It improved the physical characters like bulk density, porosity and water holding capacity, decreased pH, increased organic carbon, available NPK and total microbial biomass.