Increasing Soil Organic Matter Enhances Inherent Soil Productivity while Offsetting Fertilization Effect under a Rice Cropping System

Abstract

Understanding the role of soil organic matter (SOM) in soil quality and subsequent crop yield and input requirements is useful for agricultural sustainability. SOM is widely considered to affect a wide range of soil properties, however, great uncertainty still remains in identifying the relationships between SOM and crop yield due to the difficulty in separating the effect of SOM from other yield-limiting factors. Based on 543 on-farm experiments, where paired treatments with and without NPK fertilizer were conducted during 2005-2009, we quantified the inherent soil productivity, fertilization effect, and their contribution to rice yield and further evaluated their relationships with SOM contents under a rice cropping system in the Sichuan Basin of China. The inherent soil productivity assessed by rice grain yield under no fertilization (Y-CK) was 5.8 t/ha, on average, and contributed 70% to the 8.3 t/ha of rice yield under NPK fertilization (Y-NPK) while the other 30% was from the fertilization effect (FE). No significant correlation between SOM content and Y-NPK was observed, however, SOM content positively related to Y-CK and its contribution to Y-NPK but negatively to FE and its contribution to Y-NPK, indicating an increased soil contribution but a decreased fertilizer contribution to rice yield with increasing SOM. There were significantly positive relationships between SOM and soil available N, P, and K, indicating the potential contribution of SOM to inherent soil productivity by supplying nutrients from mineralization. As a result, approaches for SOM accumulation are practical to improve the inherent soil productivity and thereafter maintain a high crop productivity with less dependence on chemical fertilizers, while fertilization recommendations need to be adjusted with the temporal and spatial SOM variation.

Integrating environmental parameters and economic benefits to analyze the ecological agriculture (EA) application in the mountain rice paddy system of Chongqing, China

“…Our results are similar to the study by Irshad et al, in which rapeseed meal was applied to soil resulting in accumulation of phosphorus fractions up to 4.6-fold [34]. The possible reason for this phenomenon could be that rapeseed meal was used as organic amendments in this study, since the decomposition of organic amendments usually experiences longer time, while fertilizers are accumulated by plants and microorganisms rapidly or transported to the water body in the vicinity via runoff [35]. A relatively high amounts of AP and pore water DOC were observed from EA, revealing that organic amendments can extend the sustainability of paddy ecosystem and improve paddy soil properties [36].…”

Spatial Prediction of Soil Organic Matter Using a Hybrid Geostatistical Model of an Extreme Learning Machine and Ordinary Kriging

“…SOM directly affects the sustainability of soil quality such as soil nutrients and soil texture. It also indirectly impacts carbon emissions and, in turn, climate change, which limits the productive forces of food and the carrying capacity of the ecological environment [2][3][4]. That is, the sustainable connotation of SOM can be defined as: the SOM in the land unit meets the needs and aspirations of the food productivity of the present, which coordinates with the development of population growth and resource utilization without compromising the ability of future generations to meet their own food needs [5,6].…”

Carbon Organic Content under Organic and Conventional Paddy Field and its Effect on Biological Activities (A Case Study in Pati Regency, Indonesia)

“…An increase in rice production is needed to meet the demand for food from a rapidly developing population (Liu et al, 2016). Improving soil fertility, especially soil organic carbon (SOC) content (Pospíšilová et al, 2011), has an important role in maintaining a sustainable growth in rice yield (Zhao et al, 2016). Increasing SOC content mainly through organic amendments (such as green manure, manure and crop residues)  Received for publication September 19, 2019 Accepted after corrections January 17, 2020 can improve soil fertility and crop yields (Zhang et al, 2016).…”