Efficacy evaluation of farm inputs on nutrient dynamics

The pot experiment determined the nutrient release pattern in soil amended with different organic materials under green house conditions. NH4-N was released at 31 to 66 days after pot incubation (DAPI), the highest of which was from the combination of 0.6 t/ha CRH [carbonized rice hull] + 1 t/ha CM [chicken manure]. The lowest NH4-N was released from 0.5 t/ha COF. Flooding the soil increased the availability of soil P, released 6 to 31 DAPI. It declined at 48 DAPI and increased at 62 and 66 DAPI in all treatments. At 31 DAPI, 5 t/ha CRH had the highest release while 2.5 t/ha RSC gave the lowest. The slowest release was observed at 48 DAPI, possibly due to fixation of P in the soil surface or by microorganisms. A higher amount of exchangeable K was found in the treatments with 0.6 t.ha CRH+CM and 5 t/ha CRH, released from 21 to 66 DAPI. The combination of CRH + CM could have enhanced the mineralization of the organic materials, thus a comparable result was obtained as compared with the higher application of CRH at 5 t/ha. The highest soil K was observed in the combination of 0.6 t/ha CRH + 1t/ha CM at 20 and 31 DAPI, while the least was observed from 0.6 t/ha CRH alone at 62 DAPI. The trend of soil K continued to decline from 20 until 62 DAPI. Upon flooding, available S increased and almost leveled off at 21 DAPI. Its release declined at 20 to 31 DAPI and increased at 31 to 62 DAPI. The decline might be attributed to temporary fixation of S by microorganisms, while the increase could be due to higher amount of S released upon their death. At 62 DAPI, the highest S was from the soil with 2.5 t/ha RSC and the lowest from the untreated. Except for the soil applied with 2.5 t/ha RSC and 0.6 t/ha CRH, all other treatments increased microbial activity at 21 to 66 DAPI, with the combination of 0.6 t/ha CRH + 1 t/ha CM having the highest result followed by soil with 5 t/ha CRH. As the level of P in soil solution increased, less P leached. More K leached through time. The highest amount of K in water was observed in pots applied with 0.6 t/ha CRH + 1 t/ha CM. These results are being verified in a field experiment