international fertilizer correspondent
No 7
News from other sources
50 years promotion
- The early years
- Proven again and again
- Proven over time
- When more means no more and less, even less
- The way ahead for nutrient management
- 50 years recent events
- 50 years in print
Field Handbook on Oil Palm
by Ian Rankine and Thomas Fairhurst and issued
by PPI/PPIC with 4T Consultants Pty. Ltd, Australia. The area under oil
palm production has developed at breathtaking pace since 1970, from 3.2
million ha to 9.7 million ha, of which 54% is in Asia. Even more impressive
is the increase in production, from 15 million tons of oil palm fruit
in 1970 to 118.8 million tons today, of which 80% is produced in Asia.
However, in order to maintain sustainable high production, it is essential
to select the right variety and site, to adopt correct crop husbandry
practices and to supply adequate amounts of nutrients at the right time
and in the correct ratio. It is worth remembering that oil palm is a heavy
feeder on potassium and magnesium. The three Field Handbooks on Oil Palm
are a must for all successful planters and advisors. More information
can be obtained from tfairhurst@ppi-ppic.org
or from irankine@cpgi.co.m.au
Recent releases from the Potash Development Association (PDA) focus attention
on:
Profitable potash use for potatoes
(January 2002, leaflet No. 15). The justifications given for applying potash to the potato crop are:
- to achieve economic optimum yield response;
- to maintain soil K reserves, and
- to achieve quality requirements for marketing.
Under UK conditions, John Hollies (PDA) estimates a profit with potash of £381/ha from an input of potash of 344 kg/ha costing £69/ha, i.e. for each £ invested in potash, the grower gets a return of £5.50 through higher yields. Potash improves quality by raising specific gravity, improving fry colour, reducing tuber damage and internal blackening, and improving flavour.
Balancing biosolids
(February 2002, leaflet No. 20)
About half a million tons of dry solids are being applied to agricultural
land in the UK. The nutrients N and P2O5 that it contains represents
a value in the order of £6-7 million. The crucial point is that
whereas biosolids are a good source of N, P2O5 , S and Mg, they contain
only traces of potassium. Balancing biosolids with potash is indispensable
if high and economic yield levels are to be maintained.
Fodder beet – PDA leaflets 16 and 27
Fodder beet is a heavy, and often under-estimated feeder on K. In a long-term field trial sponsored by PDA in the UK it was found that fodder beet absorbs up to 5.9 kg K2O per ton of roots which is much more K than previously thought (1.7 kg/t, PDA October 1997). Also a European comparison shows fodder beets much more K hungry than sugar beets. A 60 t/ha crop should therefore receive some 265 kg/ha K2O according to PDA leaflet No. 27. More detailed information on the nutrient requirement of fodder beet is given in PDA leaflet 16.
Cereals – watch your P’s and K’s – PDA leaflets 7 and 11
It is tempting to believe that crops are performing satisfactorily if there are no signs of deficiency and yet yield losses often occur with no visible symptoms. K removal, when only grains are removed from the field, is moderate and might misguide the real demand but it should be remembered that cereals may take up more than 250 kg/ha of potash during vegetative growth and a daily uptake rate as high as 10 kg/ha is not uncommon. That is why a good soil K and P status is indispensable for a bumper yield. The PDA leaflets No. 7 and 11 discuss this matter.
Forage maize – PDA leaflet 17
An average 40 t/ha maize crop for silage absorbs about 360 kg/ha K2O until August, implying a daily rate of uptake of about 8 kg/ha K2O, says John Hollies in his PDA leaflet on forage maize. A good soil K status helps to meet the requirement of the crop.
Potash for grassland – PDA leaflet 14
Fertilization of grassland with potash is becoming an important issue. There is strong evidence that many farmers are not getting the best from their grassland because of potash deficiency. In contrast to precision farming of an arable crop where close yield monitoring is possible, such indicators are not available for grassland. Furthermore, yield decline due to hidden potash hunger is not easily seen through deficiency symptoms because potash works more discreetly. Farmers should reconsider how they fertilize grassland because increased yields more than pay back the investment. For example, 17 t/acre of silage can be obtained at 260 units/acre of N with no added potash but, when N is balanced with 360 units/acre of potash, 28 t/acre can be achieved.
Copies of all PDA leaflets can be obtained through john@pda.org.uk or by phone or fax +44.1994.427 443. More information is available at www.pda.org.uk
Plant nutrient use in North American agriculture
Publication
and CD-ROM available. A new publication available from the Potash &
Phosphate Institute (PPI) reviews current information on nutrient sources…
both organic and inorganic… as related to modern crop production
in the U.S. and Canada. Titled “Plant nutrient use in North American
agriculture”, PPI/PPIC/FAR Technical Bulletin 2002-1 discusses the
differences and similarities, advan-tages and disadvantages, relative
abundance or scarcity, and amounts of plant nutrients required to produce
today’s food demands. Estimated availability of organic and inorganic
fertilizers, management challenges of each source, potential effects on
the environment, and how that concern can be managed are also addressed.
The publication contains more than 100 pages in 10 chapters and appendices.
More information can be obtained at PPI, 655 Engineering Drive, Suite
110, Norcross, GA 30092-2837, USA, by fax +1 770 448 0439 or e-mail circulation@ppi-far.org