Leach, D.

Malhi, S.S.

Nyborg, M.

English

eCommons@USASK

Influence of long-term applications of N and S fertilizers (1980-2005) on dry matter yield of grass and soil properties in a Dark Gray Chernozem in north-central Saskatchewan

University of Saskatchewan Research Archive

Influence of Long-Term Applications of N and S Fertilizers (1980-2005) on Dry Matter Yield of Grass and Soil Properties in a Dark Gray Chernozem in North-Central Saskatchewan    S. S. Malhi1, M. Nyborg2 and D. Leach1 1Agriculture and Agri-Food Canada, P.O. Box 1240, Melfort, Saskatchewan, Canada S0E 1A0  (Phone: 306-752-2776 Ext. 230; Fax: 306-752-4911; E-mail: malhis@agr.gc.ca) 2Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada T6G 2E3   Background  In the Prairie Provinces of Canada, most soils are deficient in plant-available N.  In the Parkland region, many soils also contain insufficient amounts of plant-available S for high crop yields.  When soils are lacking in one or more nutrients, plant growth is reduced, resulting in low crop yields. So, application of fertilizers is essential to obtain high sustainable yield.  Application of N, S and other fertilizers to soils lacking in these nutrients can increase forage dry matter yield and improve soil quality.  Objective To determine the effects of long-term annual applications of N, S and K fertilizers to grass from 1980 to 2005 on forage dry matter yield (DMY), and soil pH, total organic C (TOC), total N (TN), light fraction organic C (LFOC) and light fraction organic N (LFN). Materials and Methods • Field experiment was conducted on a Dark Gray Chernozem (Boralfic Haploboroll) loam soil at Canwood in north-central Saskatchewan (mean annual precipitation 425 mm). • The site had been cultivated for several years in 1920’s or early 1930’s, and then allowed to revert to grassland. • The dominant grasses on the experimental site were bromegrass (Bromus inermis Leyss), Kentucky bluegrass (Poa pratensis L.) and rough hair grass (Agrostic scabra Wild). • Experiment was established in 1980 with annual applications of:   o no fertilizer (Nil);    o Ammonium nitrate at 112 kg N ha-1 (N);   o 112 kg N + sodium sulphate to supply 11 kg S ha-1 (NS); and  o 112 kg N + 11 kg S + potassium   chloride to supply 40 kg K ha-1 (NSK).  • Fertilizers were broadcast on the surface every year in May from 1980 to 2005.  • There was one strip (0.91 m wide x 62 m long) for each treatment, and each strip was divided into 10 replications (6.2 m long x 0.91 m wide).  • The strips were separated by 1 m wide x 62 m long pathways.  • Grass was usually harvested once in each growing season for DMY.  • Soil samples in Nil, N, NS and NSK treatments were obtained from the 0-5, 5-10 and 10-15 cm depths in spring 2007.  • Soil samples after air-drying and grinding were analyzed for pH, TOC, TN, LFOC and LFN. • In 1994, grass species composition in cut 1 and cut 2, and ground cover were estimated.  Summary of Results  • There was no increase in DMY with N alone application compared to the unfertilized control. Forage DMY increased considerably when both N and S fertilizers were applied together (i.e., NS treatment), and DMY further improved when K fertilizer was also applied in combination with NS (i.e., NSK treatment).  • Composition of plant species changed markedly in various treatments after long-term fertilization. In Nil treatment, land was covered with bromegrass, fine grasses and herbs (dogwood). In N only treatment, there was virtually no bromegrass in the stands. In treatments with combined applications of NS or NSK, vegetation was predominantly bromegrass, which is a high yielding grass species.  • Root mass (0-15 cm) usually maximized when N, S or K fertilizers were applied together. Root mass in the Nil, N, NS and NSK treatments was 19.5, 17.6, 32.8 and 41.2 Mg ha-1, respectively. • Soil pH declined with annual applications of N and S fertilizers mainly in the 0-5 cm and 5-10  layers. • TOC and N increased with NS application mainly in the 0-5 cm soil layer, while LFOC and LFN also increased in the 5-10 cm soil layer. • There is a close relationship between DMY improvement and increase in C sequestration in soil from proper fertilization.  Conclusion • The findings suggest that application of balanced fertilization by alleviating all nutrient deficiencies is an appropriate strategy for sustaining high forage yield, while also improving soil quality by increasing organic C and N storage in soil.  Acknowledgements The authors thank K. Fidyk, K. Hemstad-Falk, C. Nielsen and D. Schick for technical help; and Erin Cadieu for printing the poster.              Figure 1. Effect of long-term applications of N, S and K fertilizers (from 1980 to 2005 - 26 annual applications) to grass on dry matter yield (DMY - averaged over 26 years) on a Dark Gray Chernozem soil at Canwood, Saskatchewan (Experiment 1).               Figure 2. Effect of long-term applications of N, S and K fertilizers (from 1980 to 2005 - 26 annual applications) to grass on soil pH in a Dark Gray Chernozem soil at Canwood, Saskatchewan (Experiment 1). 0123456NiL N NS NKSMean DMY (Mg ha-1)0123456780-5 cm 5-10 cm 10-15 cmpHNiL N NS NKS             Figure 3. Effect of long-term applications of N, S and K fertilizers (from 1980 to 2005 - 26 annual applications) to grass on soil total organic C (TOC) and total N (TN) in a Dark Gray Chernozem soil at Canwood, Saskatchewan, Canada (Experiment 1).                Figure 4. Effect of long-term applications of N, S and K fertilizers (from 1980 to 2005 - 26 annual applications) to grass on soil light fraction organic C (LFOC) and N (LFN) in a Dark Gray Chernozem soil at Canwood, Saskatchewan, Canada (Experiment 1). 01020304050600-5 cm 5-10 cm 0-10 cmTOC (Mg ha-1)NiL N NS NKS0.01.02.03.04.05.06.00-5 cm 5-10 cm 0-10 cmTN (Mg ha-1)NiL N NS NKSTOC (Mg ha-1)TN (Mg ha-1)01234567891011121314150-5 cm 5-10 cm 0-10 cmLFOC (Mg ha-1)NiL N NS NKS0.00.10.20.30.40.50.60.70.80.91.00-5 cm 5-10 cm 0-10 cmLFN (Mg ha-1)NiL N NS NKS Table 1. Effect of long-term annual applications of N, S and K fertilizers on vegetation composition in cut 1 and cut 2 in 1994, and estimated ground cover of various grass species on a Dark Gray Chernozem soil at Canwood, Saskatchewan, unlimed plots (Experiment 1 – established in 1980) Treatment  Nil N NS NSK aLSD0.05  Vegetation composition in cut 1 (%) Bromegrass  29 2 92 92 11*** Vetch  2 0 0 0 2** Fine grasses  12 70 7 6 10*** Herbs  57 28 1 2 13***         Vegetation composition in cut 2 (%) Bromegrass  43 5 83 89 15*** Vetch  0 0 0 0 0ns Fine grasses  19 88 16 7 12*** Herbs  38 7 1 2 11***        Estimated ground cover (%) Bromegrass  33 2 72 75 10*** Vetch  14 4 5 3 4*** Fine grasses  19 55 12 15 11*** Herbs  22 23 11 7 6*** Bluegrass  12 16 0 0 3*** ans indicates that the difference between the treatments is not significant;  **, and *** indicate that the difference is significant at P < 0.01 and P < 0.001, respectively.  

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Influence of long-term applications of N and S fertilizers (1980-2005) on dry matter yield of grass and soil properties in a Dark Gray Chernozem in north-central Saskatchewan

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