Bio-Enriched Rice-Based Spent Mushroom Substrate(BIOSMS) soil conditioner

Abstract

BIOSMS is an effective soil conditioner using rice-based Spent Mushroom Substrate (SMS) from oyster mushroom (Pleurotus sp. ) combined with liquid organic plant supplements namely indigenous microorganisms (IMO) and oriental herbal nutrient (OHN) for vegetable crops. The SMS contained 70% rice straw and 30% sawdust. Together with chicken manure (CM), the materials were analyzed for % Carbon and % Nitrogen content. Indigenous Microorganisms (IMO) and Oriental Herbal Nutrient (OHN) were prepared in accordance with existing protocol and sprinkled to the SMS / CM mixture at 60% moisture. Soil conditioner quality was monitored including microbial population, pH and temperature. The rice-based SMS (carbon-rich) is mixed with CM (nitrogen-rich) to attain the ideal CN ratio of 30:1 for further decomposition. The ideal mass ratio of both substrates was determined by analyzing its total carbon and total nitrogen and computing its C:N ratio thru trial and error following the formula: Our findings showed that the ideal mass ratio of rice-based SMS to CM is 4.5:1 to attain the 30:1 ideal C: N as shown in Table 3. Table 3. Calculation of the ideal C / N ratio of rice-based SMS and CM (BSWM,2019) The specifications of organic soil conditioners were identified in the Philippine National Standard / Bureau of Agriculture and Fisheries Standards (PNS / BAFS 183:2020) as follows: Total N-P2O5-K2O (2.5-5%), Organic Matter (> 20%), C:N (10:1-20:1), Actual MC (<35%), Odor (No foul odor i.e. ammonia, rotting, or fermentation, Lead (50 ppm), Chromium (150 ppm), and Cadmium (5 ppm). Our results (Table 4) showed that Total nitrogen, phosphorus and potassium (NP2O5-K2O) was highest in T1- SMS+CM (SMS1) (3.33%). This was comparable to T2- SMS+CM+IMO (SMS2) (3.03%) and T3- SMS+CM+OHN (SMS3) (3.11%). T4SMS+CM+IMO+OHN (SMS4) was significantly lower than T1, T2, and T3. Meanwhile T5- SMS Alone attained the lowest (1.52%). T1- SMS+CM (SMS1), T2SMS+CM+IMO (SMS2), T3-SMS+CM+OHN (SMS3), and T4-SMS+CM+IMO+OHN (SMS4) passed the PNS / BAFS 183:2020 for Total N-P2O5-K2O while T5 SMS alone did not qualify to the standard value. The heavy metal content of all the rice-based spent mushroom substrate conforms to the allowable limit set by the Philippine National Standards for Organic Soil Amendments. Results showed that lead content of all the formulated rice-based SMS ranged from 0.004 (SMS Alone) to 7.8 (SMS+CM) which was way below the allowable limit of 50 ppm. Chromium content ranged from 25.0 (SMS Alone) to 77.8 (SMS+CM). This is way below the allowable limit of 150 ppm. Meanwhile, the cadmium content was 0.0001 ppm across all the formulated rice-based SMS as compared to the allowable limit of 5 ppm. Table 4. Quality of the Formulated Rice-Based SMS Soil Conditioners. BSWM 2021. The quality, efficacy and effect on soil chemical properties of SMS+CM were statistically comparable with the rice-based SMS combined with IMO and OHN. All rice-based SMS soil conditioners passed (PNS / BAFS) 183:2020 and have potential in increasing yield and improving soil health.