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Questions related from Nguyen Hue
It has been recognized that a combination of wood-based biochar and mature compost, when thoroughly mixed with soil, would improve soil quality and crop growth. However, for perennial crops, such...
03 October 2017 3,101 6 View
It has been reported that organic P can be as high as 70% of the total P in soils. And if we fertilize with animal manure or compost, we add a lot of organic P. How can we estimate how fast and...
28 April 2017 8,662 19 View
We know that arsenate (H2AsO4 and HAsO4) can compete with phosphate, and arsenite As(OH)3 can be taken up similar to soluble silica (Si(OH)4). However, can silicate (normally Si(OH)4 at pH 3-9)...
02 March 2016 2,451 3 View
Biochars are thought of as 'inert' carbon materials, yet their reported CEC are relative high (over 20 centimole of charge per kg). Are these values correct? or the methods of measurement are not...
13 October 2015 8,936 5 View
How important is the constancy of ionic strength in measuring potassium by an ion selective electrode? In what cases that the ionic strength can be allowed to fluctuate? What is the chemical...
11 August 2015 1,065 2 View
In layer silicates of clay minerals, there are a lot of isomorphic substitutions in 2:1 minerals, both in the tetrahedral and octahedral layers (e.g., montmorillonite, hectorite, nontronite,...
07 February 2015 341 3 View
One of cultural practices in organic farming is to spray vegetable crops with compost tea. It is believed that compost tea would provide plant nutrients, stimulate growth (via growth hormones in...
03 February 2015 6,508 8 View
Green sand (K feldspar?) is considered a natural source of potassium (K) and is acceptable to organic farming. However, its K ( about 5 - 6%) is released very slowly. Are there any...
28 January 2015 3,508 3 View
Aluminum (Al) in water or soil solution can complex with many anions, such as SO4(2-), HPO4(2-), CO3(2-), F(-), citrate, malate, etc. While Al-citrate or Al-F is virtually non-toxic, Al-SO4 is not...
20 January 2015 4,282 3 View
Rice husk is abundant in many tropical countries, especially in South and Southeast Asia. It can be used as fuel for energy production or be made into biochar. How useful is rice-husk biochar as a...
20 January 2015 1,779 7 View
Aluminum (Al) toxicity is a serious constraint to crop production in many regions around the world. The first step in correcting this problem is to identify it. Should we use exchangeable...
29 November 2014 893 18 View
In organic farming and for high-K demanding crops, K could be a problem. N source can come from compost, or animal manure; P can be supplied by bone meal or rock phosphate, but K is hard to find....
13 November 2014 2,785 12 View
Soil quality can be many things to different people. However,should certain metrics (e.g., soil CEC, microbial population and diversity/activity, soil aeration, bulk density) be included as core...
31 October 2014 757 9 View
Organic matter can be estimated quickly and rather easily by burning a soil sample at 300 oC in a furnace for 4-6 hours. How well correlated is such a value with soil organic carbon as measured by...
17 September 2014 8,004 6 View
It has been reported that N2O production from agriculture contributes significantly to greenhouse gases and global warming. How can we control the N2O release from farming?
12 September 2014 3,431 8 View
As we know, As and P can compete with each other for soil adsorption as well as for plant uptake. How can we predict As phyto-availability upon fertilization with a P source?
09 September 2014 796 3 View
Water soluble nitrate sometimes can be measured quickly as absorbance at 206 and/or 250 nm wavelengths. However, other organic molecules, especially those with double bonds also absorb radiation...
09 September 2014 1,459 7 View
In organic/sustainable farming, compost is a good (major?) source of N and micro-nutrients for crops. How to predict/synchronize N release from compost and N need by a crop is important to a...
06 September 2014 2,794 4 View
As most agronomists and soil scientists know, Al and As are considered toxic to nearly all crops. Yet, at very low concentrations (part per billion in soil solution) could these two elements...
02 September 2014 1,376 3 View
Biochars are thought to be a very stable form of carbon, yet normal CEC measurement (e.g., Neutral 1 M ammonium acetate) would yield very high CEC values (ranging from 15 - 40 cmolc/kg). Where are...
31 August 2014 3,242 13 View
Arsenic is detrimental to human health and the quality of the environment.
11 March 2014 5,219 4 View
