Natural farming needs manure augmentation to optimize soil quality and crop productivity

While assuming natural farming (NF) superior over conventional farming in improving physical, chemical and biological attributes, we hypothesized that the inclusion of farmyard manure (FYM) in addition to NF components would further enhance the soil quality and productivity. The objectives of the study were to assess the efficacy of NF in maize-blackgram intercropping, evaluating effect on soil quality of FYM-integrated NF, and to identify key soil quality indicators under rainfed agroecosystem. Over a 2 years span, the factorial experiment employed Jeevamrit concentrations (J1: 5% and J2: 10%), application intervals (I1: 15 days and I2: 30 days) and FYM levels (F1: 0 t FYM ha-1, F2: 5 t FYM ha-1 and F3: 10 t FYM ha-1) as factors, resulting in 12 combinations arranged in a randomized block design under maize intercropped blackgram. An additional recommended dose of fertilizers (RDF) enabled an orthogonal contrast to compare effects of conventional farming and bio-farming. The results revealed that yield and soil attributes of maize, intercropped with blackgram, were significantly improved with FYM-augmented NF system. The combined application of 10 t FYM ha-1 and 10% Jeevamrit with 15 days application interval significantly improved the bulk density (1.43 Mg m-3), mean weight diameter of soil aggregates (1.12 mm), saturated hydraulic conductivity (8.13 cm h-1) and plant available water (14.2 cm m-1) over rest of the treatments. The study yielded no evidence supporting the efficacy of NF on its own, as it failed to demonstrate any considerable impact on soil physical, chemical and nutrient attributes from their initial status. However, NF treatments substantially enhanced the biological activity (microbial biomass carbon by 3.88% and dehydrogenase by 21.95%) over treatment receiving RDF. The conventional farming reduced the soil organic carbon content (5.58 g kg-1), along with lower levels of available nitrogen (286 kg ha-1), phosphorus (19.2 kg ha-1) and sulphur (18.4 mg kg-1) when compared to bio-farming. Application of 10% Jeevamrit at 15-day span +10 t FYM ha-1 increased the maize grain equivalent yield by 8.65% over conventional farming. Soil quality index measured 0.68 under conventional farming system, 0.73 under NF that further improved to 0.90 with 10 t FYM ha-1 addition. The study demonstrates the potential synergy between FYM and the NF approach, leading to improved soil quality and agricultural productivity.