Balanced fertilization for sustainable health and cropproduction

摘要

Observed results showed that appliction of optimal dose of NPK (100% NPK) through inorganic fertilizers along with 5.4 t ha FYM (Frm Yard Manure, dry weight basis) gave most sustainable yields of both rice and wheat and improved soil quality indicators. Balanced use of NPK fertilizers with correction by application of deficient nutrients gave nutrients gave more or less at par crop yields of both crops. The omission of P and K fertilizers showed most unstable crop yields. The application of potassimenhanced significantly the rice and wheat production in comparison to 100% N and NP treatments. Application of optimal (100% NPK) and super optimal (150% NPK) dose of NPK without Zn should remarkable reduction in crop yields and soil quality parameters.The maximum available N, P and K in soil was found by application of optimal dose of NPK (100% NPK) through inorganic fertilizers along with 5.4 t ha FYM. Organic carbon declined from 1.48 to 0.59% under the unfertilized control. Under fertilized treatments, it decreased up to 1.10% only but some other centre showed remakable increase in organic carbon content in soil with mineral fertilizers application to crops.Soli quality parameters viz; organic carbon, bulk density, hydraulic conductivity, mean weight diameter, microbial population and available nutrients improved remakably by applicable by application of 100% NPK fertilizers along with farm yard manure @ 5.41 ha~(-1) (dry wt basis) but these were deteriorated with alone application of chemical fertilizers. Indirect application of sulphur (through SSP) showed marginal response on crop yield over regular application of sulphur less fertilizers. It may be concluded that fertilizer application was the key input for increasing the crop yields in rice-wheat cropping system. Response of N and FYM was remakable in both crops since beginning whereas response to P, K, S and Zn was improved with the passage of timedue to continuous removal of these nutrients from soil by cropping. Combined use of either FYM or Zn along with optimal NPK produced higher crop yield of rice wheat-cowpea fodder. Pattern of rice yield in lst 20 years showed declining trend which later on stabilized whereas wheat yield were more or less stable. Zn was found to limit crop productivity when its availability in soil dropped below threshed hold value. Its application in soil @ 50 kg ZnSO_4 / ha was sufficient to meet Zn need for 4-5 years under intensive and high input cropping. Soil organic carbon declined to about one third from the initial status of 1.48% during a period of three decades without using any nutrient input however its original status was restored by conjoint use of organicand inorganic sources of nutrients in integrated manner.