Traditional Chinese medicine residue act as a better fertilizer for improving soil aggregation and crop yields than manure

Abstract

Manure application is widely considered to be an effective strategy for enhancing soil fertility and crop yields. However, concerns have been raised regarding the sustainability of these fertilizers due to the detrimental effects of salinity and toxic metals in animal manure on soil quality, especially in arid regions. The objective of this study was to determine the effects of applying sheep manure (SM) and traditional Chinese medicine residue (TCMR) on soil quality and crop in the agricultural practices of Loess Plateau, China. TCMR and SM treatments both decelerated the soil pH decreases and enhanced soil cation exchange capacity (CEC). Application of TCMR significantly increased the large macro-aggregate fraction of the soil and improved soil aggregation compared to SM (p < 0.05), by decreasing the accumulation of Na＋ and K＋ as dispersing agents and increasing the content of soil organic matter (SOM) as a binding agent. Applying TCMR to the soil increased the SOM, TN, and NaOH-N content by 6.82%–8.74%, 3.65%–3.72%, and 6.02%–9.49%, respectively, compared to SM. The physiological parameters and grain yields of maize (Zea mays L.) under TCMR treatments were higher than those in SM treatments, and the soil heavy metal content and pollution load index were lower. Thus, TCMR obtained better results in terms of improving soil nutrients, enhancing soil aggregation, decreasing heavy metal content, and increasing maize grain yields than SM. Applying TCMR in the field could be a judicious strategy for sustainable agriculture on the Loess Plateau and could also be extended to the similar agricultural regions.