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Effects of Sulfate of Potash Fertilization on Wheat Production PDF Print E-mail

Wheat represents one of the major staple crops around the world with most of its production used for human consumption. It represents an important source of energy, protein, vitamins, and minerals that are important for human health. Research shows the importance of potassium (K) fertilizer management to improve wheat yield and grain quality.

    Wheat (Triticum aestivum L.) is the most cultivated cereal in the world with more than 713 million tonnes produced during 2013. The European Union, China, and India are the leading producers. It is the most important staple crop in temperate regions. Although it is also produced in elevated regions in the humid tropics and subtropics. Wheat constitutes an important source of energy and protein for human diets with about two thirds of its total production destined to human consumption (Ranhotra, 1994). The crop was one of the first domesticated cereals and played an essential role in civilization development in areas like Europe, Asia, and Africa. Besides the energy and protein content, wheat grains are an important source of vitamin B, fiber, iron, and zinc among other micronutrients.
    Wheat production requires large amounts of K, which could be as high as 2 kg/ha per day during its maximum absorption point (Beaton and Sekhon, 1985). In general, K fertilizer will be applied in 1:1 ratio with nitrogen (N). Deficiencies of K are first observed in older leaves as chlorosis in leaf tips, which may develop into necrotic tissues, reduced canopies and root growth, as well as weaker straws and increased lodging. Because K uptake is directly related to plant water balance, deficient plants will be more susceptible to drought stress and have higher risk of disease incidence. Additionally, K application helps to alleviate the effects of saline soil conditions, helping to maintain osmotic water balance in plant tissue. With regards to grain quality, K fertilizer management improves grain protein content, which is an important property for baking purposes.
    An experiment was conducted by Lu et al. (2014) to study the effects of SOP (as the K source) split application and placement methods on wheat yields and grain quality. The experimental site was a semi-humid continental temperate monsoonal climate with sandy loam soil of pH 6.5 and <1.5% organic matter. Four winter wheat cultivars were selected for the experiment. Treatments were as follows: a) no SOP fertilizer application (control), b) basal placement, and c) 50% basal application + 50% topdressing application at jointing. Fertilizer treatments were applied using 120 kg/ha of K. Yield and grain quality parameters were collected at maturity.
    Results from the 2011 season showed significant effects of the growing season, cultivar, and SOP placements methods on yields and grain quality (Table 1). Cultivar response was significantly different, with ‘Jimai 20’ showing the highest grain yield during both seasons. Moreover, SOP placement resulted on significant differences, where the highest grain resulted from the basal + topdressing SOP application, which was 13% higher than the control. With regards to spike number, the highest values were observed during 2012. Finally, spike number increased significantly with K fertilizer addition, showing 9% higher spike number than the control.

Table 1. Effects of split SOP fertilizer applications on four wheat cultivar yield variables for 2010-11 and 2011-12 seasons (From Lu et al., 2014).

Variable

Grain yield
(kg/ha)

Spike no.
(x104/ha)

Year

 

 

2011

7584 a*1

 577 b

2012

 6668 b

606 a

Cultivar

   

‘Jimai 20’

 8056 a

 598 ab

‘Gaocheng 8901’

 6827 b

   556 c

‘Yannong 19’

 6612 b

582 bc

‘Jinan 17’

7010 b

 630 a

SOP fertilization

 

 

No SOP fertilization

6582 c

558 b

Basal (120 kg/ha K)

7218 b

608 a

Basal + topdressing (120 kg/ha K)

7626 a

614 a

* Significant at P ≤ 0.05 level. 1 Values followed by the same letter represent non-significant differences at 0.05 level.

    With regards to grain quality parameters, wet gluten content was significantly improved with SOP fertilization (Table 2). Furthermore, wet gluten content showed the same response, regardless of SOP placement. Moreover, dough development and stability time were significantly higher during 2012 season, which indicates an environmental effect on grain quality. Finally, SOP placement showed significant differences in dough development, stability, and loaf volume, indicating the positive effects of K fertilizer in the flour baking process. These results showed the importance of SOP fertilization in wheat and how critical is to locate the fertilizer properly to maximize return of investments.

Table 2. Effects of split SOP fertilizer applications on four wheat cultivar grain quality variables for 2010-11 and 2011-12 seasons (From Lu et al., 2014).

Variable

Grain yield
(kg/ha)

Dough development time (min)

Dough stability time (min)

Loaf volume (ml)

Year

 

 

 

 

2011

36.6 b*1

7.6 a

11.4 a

712 a

2012

38.4 a

5.9 b

9.2 b

697 a

Cultivar

       

‘Jimai 20’

36.6 b

6.5 ab

10.3 a

718 ab

‘Gaocheng 8901’

38.6 a

8.0 a

11.6 a

750 a

‘Yannong 19’

37.3 ab

62 b

9.6 a

674 b

‘Jinan 17’

37.4 ab

6.4 b

9.7 a

676 b

SOP fertilization

       

No SOP fertilization

37.0 a

5.9 c

8.9 c

662 c

Basal (120 kg/ha K)

37.6 a

6.7 b

10.0 b

704 b

Basal + topdressing (120 kg/ha K)

37.8 a

7.6 a

11.7 a

740 a

*Significativo al P≤0.05. 1Los valores seguidos por la misma letra representan diferencias no significativas al 0.05.

    Full articles:

Beaton, J.D. and Sekhon, G.S. (1985). Potassium nutrition of wheat and small Grains. In: Potassium in Agriculture (Munson, R.D. ed.), pp. 702-752. ASA/CSSA/SSSA, Madison, WI.

Lu, Q., Jia, D., Zhang, Y., Dai, X., and He, M. (2014). Split application of potassium improves yield and end-use quality of winter wheat. Agronomy Journal 106, 1411-1419.

Ranhotra, G. S. (1994). Wheat: contribution to world food supply and human nutrition. In Wheat, Springer, pp. 12-24.

 
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