Hi,
I have heard many times that :
With no-till, organic matter content tend to be higher than in conventional systems.
And that :
With no-till, mineralization rates are lower tend to be lower than in conventional systems.
From this point,
Has it been demonstrated that in no-till, a higher content of organic matter can compensate the diminished mineralization rates, thus leading to a higher availability of nutrients at the end of the day ?
(considering that we compare a field with the exact same settings, the only changing factor is ploughing).
Over time, soil organic matter tends to build up in no-till which may affect N mineralization rates. we have done a couple of studies attempting to find answers to your question. Unfortunately, there is not much in the literature to shed light on your question.
See the attached publications on our work.
No- till is believe to increase release of nutrients and their uptake by increasing soil organic matter content, biological activity, nutrient cycling and availability of plant nutrients. The attached files may provide you more information.
No till increase level of crop production by increasing nutrient uptake as compare to conventional tillage results of AICRP DLA, solapur also showed same results
Farmers are experiencing increase in soil nutrient through zero till, and increased nutrient uptake. But this requires more systematic scientific study.
You are absolutely right Dr. Murray. To get maximum benefit to no-till more systematic guidelines are needed. Specially it should be strict instructions on: do not burn stable from previous crops, allow livestock to graze on stubble, allow planting through surface residue into narrow slits in the soil, when the rains are late consider early dry sowing, control weeds before sowing, manage major soil problems according to best practice to optimize yields and use diverse crop rotation to better utilize soil nutrients and enrich them.
Soil organic carbon (C) has profound effects on soil physical, chemical and biological properties . Maintenance of soil organic C (SOC) in cropland is important, not only for improvement of agricultural productivity but also for reduction in C emission . However, short- and medium-term changes of SOC are difficult to detect because of its high temporal and spatial variability . On the contrary, soil labile organic C fractions (i.e., microbial biomass C (MBC), dissolved organic C (DOC), and easily oxidizable C (EOC)) that turn over quickly can respond to soil disturbance more rapidly than total organic C (TOC) . Therefore, these fractions have been suggested as early sensitive indicators of the effects of land use change on soil quality .Agricultural practices such as tillage methods are conventionally used for loosening soils to grow crops. But long-term soil disturbance by tillage is believed to be one of the major factors reducing SOC in agriculture. Frequent tillage may destroy soil organic matter (SOM) and speed up the movement of SOM to deep soil layers . As a consequence, agricultural practices that reduce soil degradation are essential to improve soil quality and agricultural sustainability. Crop residue plays an important role in SOC sequestration, increasing crop yield, improving soil organic matter, and reducing the greenhouse gas . As an important agricultural practice, straw return is often implemented with tillage in the production process. Although numerous studies have indicated that tillage methods combined with straw return had a significant effect on labile SOC fractions, the results varied under different soil/climate conditions. For example, both no-tillage and shallow tillage with residue cover had significantly higher SOC than conventional tillage without residue cover in Loess Plateau of China , while Wang et al. reported that the difference between the treatments of plowing with straw return and no-tillage with straw return on TOC in central China was not significant. Rajan et al. showed that in Chitwan Valley of Nepal, no-tillage with crop residue application at upper soil depth had distinctly higher SOC sequestration than conventional tillage with crop residue. The effects of tillage on soil labile organic C vary with regional climate , soil condition (, residue management practice, and crop rotation .
PLoS One. 2014; 9(2): e88900.Published online 2014 Feb 20. doi: 10.1371/journal.pone.0088900PMCID: PMC3930598
Effects of Different Tillage and Straw Return on Soil Organic Carbon in a Rice-Wheat Rotation System
Probably No till does not increase SOC, yes. you are reading right. Quantity of additional organic carbon in soil under no-till is relatively small: in large part apparent increases result from an altered depth distribution. The larger concentration near the surface in no-till is generally benefcial for soil properties that often, though not always, translate into improved crop growth. In many regions where no-till is practised it is common for soil to be cultivated conventionally every few years for a range of agronomic reasons, so any soil carbon beneft is then lost.
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