Differential Efficacy of Farmyard Manure and Cow Manure in Ameliorating Salinity Stress: Integrated Assessment of Spinach Growth, Soil Health, and Enzymatic Recovery

Abstract

Soil salinity is one of the major threats to food security in the world because it drastically reduces the growth of crops and interferes with the major processes in soil. This study compared the relative performance of two organic amendments that are readily available, namely farmyard manure (FYM) and cow manure in alleviating salinity stress on spinach (Spinacia oleracea L.) planted in the pot. This involved a thorough evaluation, which incorporated the measurements of the growth of plants, the carbon cycle in the soil and several important enzymatic functions. A comparison between four treatments was done: none as control, saline, which had EC greater than 4.0 dS/m, and saline manure treatment in the form of cow manure or FYM at 5% (w/w). Findings revealed that spinach growth was severely inhibited by salinity as the root length, shoot length, fresh and dry weight were found to be 38-63% lower than the non-saline control. Both organic amendments significantly alleviated salinity stress but FYM consistently outperformed cow manure in all parameters. FYM increased root length by 162% and dry matter accumulation to be on par with the non-saline control. The soil health indicators also exhibited impressive recovery: the soil organic carbon, the dissolved organic carbon and the microbial biomass carbon improved by 175, 128 and 45% in FYM-amended soil in comparison to the saline control. Enzyme activity, including urease, phosphatase, b-glucosidase and catalase, was restored at 78-100% of normal by FYM as opposed to 61-80% by cow manure. The Multivariate analysis showed that the parameters of plant growth, especially root and shoot length, were the major causes of separation of treatments. FYM has enhanced performance owing to its stabilized and humified organic matter that offers sustained amelioration in the soil structure, supplies nutrients, and offer microbial habitation. The conclusion of this paper is that FYM is a more efficient and sustainable amendment to restore saline soils providing a viable and environmentally friendly measure to increase the output and renew the soil biomass Capacity.