scholarly journals WAYS TO INCREASE THE EFFICIENCY OF LONG-TERM APPLICATION OF DIFFERENT FERTILIZER SYSTEMS IN SHORT-TERM CROP ROTATION

2019 ◽  
Vol 30 ◽  
pp. 39-45
Author(s):  
L. V. Potapenko ◽  
L. М. Skachok ◽  
N. I. Horbachenko
Keyword(s):  
Crop Rotation ◽  
Green Manure ◽  
Podzolic Soil ◽  
Mineral Fertilizer ◽  
Available Phosphorus ◽  
Winter Rye ◽  
Short Term ◽  
Fertilizer System ◽  
Nutrient Reserves

Objective. To evaluate the influence of different fertilizer systems in combination with microbial preparations on the change of nutritional regime of sod-podzolic soil and the yield of crops of short-term crop rotation in the Polissia region. Methods. Fields — stationary experiment, laboratory, mathematical and statistical. Results. On the basis of studies conducted in a long-term stationary experiment on sod-podzolic soil, analysis and determination of dependence between the content of available compounds of nitrogen, phosphorus, potassium on fertilizer systems and microbial preparations was performed. It was found that the highest nutrient reserves in the soil were in the organo-mineral fertilizer system “manure + green manure + NPK” in combination with microbial preparations: the content of mineral compounds of nitrogen — 82.32 kg/ha, available phosphorus — 223 mg/kg of soil, and exchangeable potassium — 122 mg/kg, which is 1.8, 1.4 and 1.6 times higher than the parameter of the mineral fertilizer system, respectively. At the same time, due to the inoculation of seeds nitrogen reserves in the soil can increase up to 26 %. The application of the fertilizer system “manure + green manure + NPK” provides an optimal level of root nutrition of crops of short-term crop rotation and, as a consequence, the highest productivity of crops, which amounted to: winter rye — 5.2 FU (fodder units), potatoes — 7.7 FU, oats — 3.3, lupine — 3.8 FU on background without inoculation and 5.7, 8.3, 3.9 and 4.4 FU, respectively, when microbial preparations were applied. The increase due to inoculation with this fertilizer system amounted to 0.5 fodder units (FU) for winter rye, 0.5 FU for potatoes, and 0.6 FU for oats, and 0.6 FU for lupine. Conclusion. The nutrient regime of sod-podzolic soil depends on the use of various fertilizer systems in combination with microbial preparations. Organic-mineral fertilizer system “manure + green manure + NPK” under the use of microbial preparations is most effective for growing crops on sod-podzolic soil in short-term crop rotation. This combined fertilizer system contributes to the greatest accumulation of nutrient reserves: nitrogen mineral compounds — 82.3 kg/ha, available phosphorus — 220 mg/kg of soil and exchangeable potassium — 122 mg/kg.

scholarly journals FORMATION OF CORN PRODUCTIVITY IN CROP ROTATION DEPENDING ON LONG-TERM FERTILIZATION AND LIMING

2021 ◽  
Vol 358 (57) ◽  
pp. 29-40
Author(s):  
Oleh STASIV ◽  
◽  
Yuriy OLIFIR ◽  
Keyword(s):  
Crop Rotation ◽  
Zea Mays L ◽  
Mineral Fertilizer ◽  
Forest Steppe ◽  
Joint Application ◽  
Aluminum Compounds ◽  
Corn Productivity ◽  
Fertilizer System ◽  
Hydrolytic Acidity

Corn (Zea mays L.) is one of the main source of feed and food resources. The importance of this culture in the world economy continues to grow. In Ukraine corn is an export-oriented crop of universal purpose and high potential. Based on the results of research in the ninth rotation of long-term stationary experiment, it was found that in the Western Forest-Steppe in four-field crop rotation on Albic Stagnic Luvisol the highest productivity of corn 73 t . ha–1 is formed by organo-mineral fertilizing system with systematic joint application of 10 t . ha–1 manure, N65Р68К68 on the background of periodic liming with 1.0 n CaCO3 by hydrolytic acidity. It is shown that long-term unilateral application of mineral fertilizer system (more than 50 years) on acidic soil along with the accumulation of nitrogen compounds increases the acidity and content of mobile aluminum compounds, leads to blocking the activity of enzyme systems, reducing absorption and transformation of nutrients and in consequence the formation of low-yield corn at the level of control without fertilizers.

scholarly journals Influence of ecological and agrochemical factors on the level of soybean yield

2019 ◽  
pp. 16-18
Author(s):  
V. T. Sinegovskaya ◽  
E. T. Naumchenko
Keyword(s):  
Crop Rotation ◽  
Active Ingredient ◽  
Ecological Factors ◽  
Mineral Fertilizer ◽  
Potential Yield ◽  
Soybean Yield ◽  
Organic Mineral ◽  
Annual Grasses ◽  
Fertilizer System

The article presents the results of studies on the effectiveness of the use of mineral and organic-mineral fertilizer systems in a long-term stationary 5-course soy-grain crop rotation depending on agro-ecological factors. The goal of research is to study the effect of long-term application of mineral (annually N42 P48 kg of active ingredient / ha of crop rotation area) and organic-mineral (annually N24 P30 kg of active ingredient + 4.8 t of manure per 1 ha of crop rotation area) fertilizer system on the productivity of soybean in crop rotation. The objects of research were mid-ripening and early-ripening soybean varieties, preceding crops - annual grasses (soy-oat mixture) and spring wheat. The preceding crops, variety and hydrothermal conditions under which soybean was grown from 1963 to 2017 were considered as agro-ecological factors. It was established that the highest yield of soybean was obtained when placing soybean crops after wheat, while by the number of years, the yield level of 1,8 – 2,0 t/ha was repeated 16 % more often than when growing soybean after annual grasses. The maximum increase in yield relative to the control (0, 17 t/ha) was formed by the long-term use of organic-mineral fertilizer system for soybean cultivated after wheat. In cold wet years, the use of organic-mineral fertilizer system ensured plant resistance to unfavorable weather conditions, stimulating an increase in the soybean yield relative to the control by 0,18 t/ha. The most responsive to fertilizer application were the mid-ripening soybean varieties: the increase in grain yield amounted to 0,03 – 0,20 t/ha relative to the control, and the realization of potential yield of the variety increased by 2–7 %.

scholarly journals 35 years after the Chernobyl accident – do we need rehabilitation measures on agricultural land?

2021 ◽  
Vol 30 (4) ◽  
pp. 131-142
Author(s):  
E.V. Prosyannikov ◽  
◽  
L.A. Zvereva ◽  
A.L. Silaev ◽  
◽  
...  
Keyword(s):  
Crop Rotation ◽  
Agricultural Land ◽  
Podzolic Soil ◽  
Arable Land ◽  
Mineral Fertilizer ◽  
Perennial Grasses ◽  
First Year ◽  
Winter Rye ◽  
Second Year ◽  
Rehabilitation Measures

The changes in the density of pollution Cs-137 of arable land, hayfields and pastures in the south-west of the Bryansk region are considered. It is noted that the cleansing process is slow, so reha-bilitation measures are the main way to reduce the specific activity of the radionuclide in crop and feed production. The paper presents algorithm of calculation. Economic efficiency of agrotech-nical and agrochemical rehabilitation of arable land is estimated on results of stationary field ex-periments. The most economically expedient rehabilitation measures for various soils and densi-ties of radioactive contamination are established: 1) soil sod-podzolic sand, contamination densi-ty 137Cs 871 kBq/m2 – in crop rotation barley, clover, corn, winter rye, oats application of lime flour in a dose of 2.1 t/ha + NPK; 2) sod-podzolic sandy loam soil, contamination density Cs-137 2516 kBq/m2 – in crop rotation winter rye, potatoes, barley + perennial grasses, clover + timofeevka of the first year of use, clover + timofeevka of the second year of use introduction of phosphorite flour in a dose of 288 kg/ha + NPK; 3) sod-podzolic soil light loamy, contamination density Cs-137 901 kBq/m2 – in crop rotation potatoes, barley, corn, oats + perennial grasses, clover + timofeev-ka of the first year of use, clover + timofeevka of the second year of use, winter rye application of one-and-a-half doses of phosphorus-potassium mineral fertilizer in combination with one dose of nitrogen mineral fertilizer (NP1,5K1,5); 4) sod-podzolic soil is light loamy, contamination density Cs-137 1224 kBq/m2 – in crop rotation potatoes, barley, corn, oats + perennial grasses, clover + timofeevka of the first year of use, clover + timofeevka of the second year of use, application of dolomite flour in a dose of 3 t/ha + manure 120 t/ha + K600. For natural meadows, where rehabili-tation measures are not used, an adaptive method of agroecological use is proposed. With a con-tamination density of Cs-137 of more than 185 kBq/m2, it is advisable to harvest a green mass of canary grass stands in the central parts of the floodpubs, which accumulate less radionuclide, grazing animals along the otava is prohibited in order to protect them from radioactive substanc-es that may enter their body with sod and shallow soil. In “near the river bed” and “near terrace” parts of the waterprays, where grass stands accumulate much more Cs-137, grazing of animals is prohibited.

scholarly journals Reduction of anthropogenic loading on an agroecosystem by increasing its energy efficiency

2018 ◽  
Vol 26 (2) ◽  
pp. 71-76
Author(s):  
T. Gnatiuk
Keyword(s):  
Energy Efficiency ◽  
Crop Rotation ◽  
Field Pea ◽  
Perennial Grasses ◽  
Crop Rotations ◽  
Winter Rye ◽  
Energy Costs ◽  
Short Term ◽  
Organic System ◽  
Fertilizer System

For full functioning , an artificially created agroecosystem should include qualitatively and quantitatively balanced components. This is possible if the anthropogenic burden on such a system is reduced and energy costs are balanced within it. In order to substantiate this statement, a production experiment was conducted in which short-term crop rotation was introduced on the land of an experimental field. Determination of energy efficiency of crop rotations and crop rotations in general was carried out by calculating technological maps of cultivating the corresponding crops. The higher the energy efficiency, the less the energy spent on cultivating crops and the less the cost of obtaining a unit of production from the corresponding area. After three years of research, we have determined that the most energy-intensive crop in short-term rotation is potatoes, less energy is spent on the cultivation of field pea-oat mixture, rye, oats with sowings of clover, and clover alone. The most energy-efficient was the organic fertilizer system (manure) for growing winter rye with a coefficient of energy efficiency of 5.10. For cultivation of field pea with oats for the same fertilizer system, the cultivation efficiency was 5.70. Growing oats with sowings of clover and using an organic system (manure) had an energy utility of 4.11. After application of the organic system (siderate) for the cultivation of winter rye, the coefficient of energy efficiency was 5.03 and for potatoes 2.21. After using the organoleptic system 50 : 50 to grow perennial grasses, this ratio was 33.05, and after the use of the mineral system for growing potatoes, 2.13. However for the cultivation of perennial grasses, we used the aftereffects of fertilizers introduced under the clover of the first year, and in the second year, under the perennial grasses, fertilizers were not applied at all, but for the cultivation of clover in crop rotation it is expedient to use an organomineral system of 50 : 50. Adhering to the basic principles of biological agriculture, namely the introduction of a scientifically grounded alternation of crops, rejecting the use of chemical plant protection products, avoiding the replacement of organic fertilizers (manure and siderate) by mineral fertilizers, it is possible to reduce energy costs for growing crops of crop rotation and crop rotation in general as a consequence, and thus to reduce the anthropogenic load on the whole agroecosystem .

ОтзывчивостькартофелянаудобрениеипотериурожаяотфитофторозавусловияхСеверо-ЗападаРоссии

2019 ◽  
Author(s):  
A.I. Ivanov ◽  
Zh.A. Ivanova ◽  
O.I. Yakusheva ◽  
P.A. Filippov
Keyword(s):  
Late Blight ◽  
Humus Content ◽  
Mineral Fertilizer ◽  
Fertilizer Application ◽  
Organic Fertilizers ◽  
Winter Rye ◽  
Soil Cultivation ◽  
Weather And Climate ◽  
Fertilizer System ◽  
Comprehensive Study

Целью комплексного исследования, выполненного в Меньковском филиале АФИ в 20122017 годах была оценка вредоносности возбудителя фитофтороза в зависимости от почвенноагрохимических и погодноклиматических условий. Методической основой исследования служил длительный полевой опыт агрофизический стационар в системе полевого и овощекормового севооборотов, в которых картофель возделывали по обороту пласта многолетних трав после озимой ржи и после ячменя. Объектами исследования служили: картофель раннеспелого сорта Ломоносовский среднеустойчивого к возбудителю фитофтороза по клубням и слабоустойчивого по ботве дерновоподзолистая почва средней, хорошей и высокой степени окультуренности и системы удобрения культуры. Супесчаная почва опыта характеризовалась рНКСl 5,26,3, содержанием гумуса 2,13,7, подвижных соединений P2О5 195676 мг/кг и К2О 97298 мг/кг. На хорошо окультуренной и высокоокультуренной почвах их поддерживали применением под картофель 35 и 70 т/га органических удобрений соответственно. Факторы исследования: степень окультуренности почвы (варианты: средняя, хорошая и высокая) и уровень применения минеральных удобрений в расчете на заданный КПД (коэффициент полезного действия фотосинтетически активной радиации) (варианты: КПД ФАР, 13 без удобрений КПД ФАР, 24 N80P20K100 КПД ФАР, 35 N120P30K150). В ходе комплексного исследования установлены параметры поражения возбудителем фитофтороза и уровень потерь урожая картофеля в зависимости от агроклиматических и почвенноагрохимических условий. Агрономическая эффективность изученных вариантов системы удобрения на культуре картофеля высокая. Уровень прибавок урожайности клубней и окупаемость 1 кг д.в. удобрений достигли 3358 и 8,311,6 з.ед. (зерновых единиц) на минеральной, 2545 и 3,98,0 з.ед. на органической и 3379 и 3,86,7 з.ед. на органоминеральной системе удобрения. В неэпифитотийных условиях (2 из 3 лет наблюдений) на фоне низких и умеренных показателей поражения общие потери урожая составляют 5, а окультуривание почвы и применение органических и минеральных удобрений снижают их на 3080. На эпифитотийном фоне, повторяющемся 1 раз в 3 года, пораженность ботвы и клубней картофеля возрастает в 4,3 и 6,1, интенсивность поражения в 2,8 и 3 и развитие в 12 и 17,5 раза соответственно. В эпифитотийные годы потери урожая возрастают в 5,2 раза (до 26), а минеральная система удобрения сокращает их только на среднеокультуренной почве. На этом фоне повышение степени окультуренности почвы и доз органических удобрений до высокого уровня неэффективно.Late blight is one of the most harmful potato diseases in the NorthWest of Russia. Today, its negative effects are aggravated by weather and climate changes. The goal of a comprehensive study carried out in the Menkovsky branch of the Agrophysical Institute in 2012 2017 was an assessment of the harmfulness of the late blight pathogen depending on soilagrochemical, weather and climate conditions. The methodical basis of the research was a prolonged field agrophysical stationary experiment in the system of field and vegetablefeed crop rotations, where potato was cultivated after winter rye and after barley, which, in turn, were grown after perennial grasses. The objects of the study were potato Lomonosovsky, sodpodzolic soil with different degree of cultivation and fertilizer systems for the culture. Potato Lomonosovsky is early ripening variety, its tubers are medium resistant to the late blight agent, and its tops are weakly resistant to it. The sodpodzolic soil had average, good and high cultivation degree. Sandy loam soil in the experiment had the value of pHKCl of 5.2 6.3, the humus content of 2.1 3.7, the content of mobile P2O5 and K2O compounds of 195 676, 97 298 mg/kg, respectively. In well and highly cultivated soils, these parameters were maintained by the application of 35 and 70 t/ha of organic fertilizers for potato, respectively. The experimental factors were the degree of soil cultivation (average, good and high) and the level of mineral fertilizer application for a given efficiency of photosynthetically active radiation (PAR efficiency of 1 3, without fertilizers PAR efficiency of 2 4, N80P20K100 PAR efficiency of 3 5, N120P30K150). In the course of the comprehensive study, the parameters of potato damage by late blight and the level of crop losses were established depending on the agroclimatic soilagrochemical conditions. Agronomic efficiency of the studied variants of the fertilizer system for potato was high. The level of tuber yield increase and payback of 1 kg of fertilizers active substances reached 33 58 and 8.3 11.6 cereal units (CU) for the mineral system, 25 45 and 3.9 8.0 CU for the organic one, and 33 79 and 3.8 6.7 CU for the organic and mineral fertilizer system. Under nonepiphytotic conditions (2 of 3 years of the observation), against the background of low and moderate damage rates, the total yield loss was 5, and the soil improvement and organic and mineral fertilizer application reduced them by 30 80. Against an epiphytotic background, repeated 1 time in 3 years, the damage of tops and potato tubers increases by a factor of 4.3 and 6.1, the intensity of the damage grew 2.8 and 3 times, and the development increases by a factor of 12 and 17.5 times, respectively. In the epiphytotic years, yield losses increased 5.2 times (up to 26), and the mineral fertilizer system reduced them only in medium cultured soil. Against this background, increasing the soil cultivation degree and organic fertilizer doses to a high level is ineffective.

FERTILIZATION SYSTEM AS A WAY OF SOIL FERTILITY AND STABILIZATION OF FIELD CROP ROTATION PRODUCTIVENESS

1970 ◽  
pp. 38-41
Author(s):  
V. T. Sinegovskaya ◽  
E. T. Naumchenko
Keyword(s):  
Soil Fertility ◽  
Crop Rotation ◽  
C:N Ratio ◽  
Mineral Fertilizer ◽  
Organic Fertilizers ◽  
Nitrogen And Phosphorus ◽  
Rotation System ◽  
Mobile Phosphorus ◽  
Crop Rotation System ◽  
Fertilizer System

The article presents the results of comparative evaluation of the efficiency of the long-term application of mineral and organic fertilizers in the crop rotation system. It was found that the application of the mineral fertilizer system increased the value of hydrolytic acidity of the soil from 4,30 to 5,29 mg-eq per 100 g of soil, the indicator of metabolic acidity decreased from 5,2 to 4,9 pH units. By the end of the 11th rotation for both fertilizer systems, the content of mobile phosphorus increased by more than 4 times relative to the initial value, its mobility indicator – by 2,2-3,2 times compared with the control. The use of the organo-mineral system was accompanied by an increase in the content of humus by 0,35 % and a decrease in the C:N ratio from 11,2 to 8,9. The increased productivity of wheat was revealed when applying nitrogen and nitrogen-phosphorus fertilizers against the background of prolonged use of the mineral and organo-mineral fertilizer system. The change in wheat productivity by 56 % depended on the content of mineral nitrogen, mobile phosphorus, humus in the topsoil, and on the phosphate ion mobility. Soybean productivity depended on soil fertility indicators only by 24 %: the relationship between soybean productivity and the mineral forms of nitrogen and phosphorus is weak and direct, between productivity and P2O5 mobility - weak and inverse, with humus - moderate and direct.

scholarly journals THE BUCKWHEAT ROLE IN CROP ROTATION AND WEED CONTROL IN THIS SOWINGS IN LONG TERM TRIAL

2015 ◽  
Vol 1 ◽  
pp. 141
Author(s):  
Andris Lejiņš ◽  
Biruta Lejiņa
Keyword(s):  
Weed Control ◽  
Crop Rotation ◽  
Crop Rotations ◽  
Winter Rye ◽  
Term Trial ◽  
Experimental Plots ◽  
Yield Decrease ◽  
Research Institute

Buckwheat research has been carried out within the long-term crop rotation stationary that was established in 1969 as a part of the Research institute of Agriculture. Buckwheat proportion within the partcular crop rotations went up to 22%. The highest buckwheat yields were obtained from the buckwheat variants that where cultivated after winter rye, and within the buckwheat monoculture experimental plots. A considerable yield decrease was observed when cultivating buckwheat after potatoes. Weeds in the buckwheat sowing were effectively brought under control by the herbicide Butisane 400 (1.5 l ha-1), applied immediately after sowing and Betanal AM 2.5 l ha-1 after seedling in 2-3 leaves stage.

scholarly journals Effectiveness of various elements of grain cultivation technology

2021 ◽  
Vol 36 ◽  
pp. 07001
Author(s):  
Fedor A. Popov ◽  
Evgeniya N. Noskova ◽  
Lyudmila M. Kozlova
Keyword(s):  
Crop Rotation ◽  
Spring Wheat ◽  
Streptomyces Hygroscopicus ◽  
Winter Rye ◽  
Field Crop ◽  
Loamy Soil ◽  
Grain Crops ◽  
Cultivation Technology ◽  
Three Factor

The article presents the results of a long-term stationary three-factor experiment on sod-podzolic loamy soil to identify the effectiveness of various methods of basic and pre-sowing treatment of soil, the use of biological preparations in the technology of cultivating grain crops in six-field crop rotation. It was established that the most profitable elements of the technology in energy and economic terms will be: surface-cut treatment with KPS-4 cultivator and introduction of Azotovit and Phosphatovit biologics into the tillering stage of oat in a vetch-oat mixture for green feed; surface-cut treatment with KBM-4,2 cultivator or with pre-sowing treatment with a APPN-2,1 combined aggregate and introduction of Azotovite and Phosphatovite biological preparations into the soil before sowing winter rye for grain; ploughing with pre-sowing treatment with APPN-2,1 combined aggregate for spring wheat; surface-cut treatment with pre-sowing treatment with APPN-2,1 combined aggregate and introduction of biologic preparation based on strain Streptomyces hygroscopicus A4 at tillering stage of oat in pea-oat mixture for grain-hay; ploughing with KPS-4 cultivator and introduction of Pseudobacterin-2 biopreparation at barley tillering stage; ploughing with pre-sowing treatment with APPN-2,1 combined aggregate and introduction of biologic preparation based on strain Streptomyces hygroscopicus A4 at oat tillering stage.

scholarly journals Crop Rotation Compared with Continuous Rye Cropping for Weed Biodiversity and Rye Yield. A Case Study of a Long-Term Experiment in Poland

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 644 ◽  
Author(s):  
Jastrzębska ◽  
Kostrzewska ◽  
Marks ◽  
Jastrzębski ◽  
Treder ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Functional Diversity ◽  
Plant Protection ◽  
Winter Rye ◽  
Herbicide Application ◽  
Weed Species ◽  
Long Term Experiment ◽  
Effect On Yield

In recent years, sustainable agriculture has revitalized interest in crop rotations and their effects on crop performance and agroecosystem biodiversity, including weeds. This article used winter rye as an example and focused on the crop rotation (CR) impact on species, taxonomic and functional diversity of weed communities and analysed the contribution of crop rotation to protecting yield and regulating weed abundance. Long-term continuous rye cropping (CC) provided a background for comparison. Two variants of plant protection were also adopted: herbicide application (H+) and no plant protection (H−). The data from the 10th, 30th and 50th years of the experiment were included in the analysis. Diversified crop rotation with no chemical protection resulted in a satisfactory rye yield and reduced weed abundance—especially problem species—without a decrease in weed species diversity or functional diversity. When rye was grown under crop rotation, the herbicide application had no effect on yield protection, but it was harmful to weed biodiversity. The rye yield correlated negatively with weed biomass, but did not show a link with weed biodiversity. Continuation of long-term experiments as a research basis for contemporary and future scientific challenges is necessary.

Quantifying short-term effects of crop rotations on soil organic carbon in southwestern Saskatchewan

2000 ◽  
Vol 80 (1) ◽  
pp. 193-202 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
V. O. Biederbeck ◽  
B. G. McConkey ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Green Manure ◽  
Harvest Index ◽  
Crop Residue ◽  
Weather Conditions ◽  
Order Kinetic ◽  
Short Term ◽  
Crested Wheatgrass ◽  
Crop Residue Decomposition ◽  
Legume Green Manure

Crop management practices can have a major influence on soil fertility and soil organic C (SOC) sequestration. We need to accurately measure and estimate changes in SOC in the short term (<20 yr). A 10-yr crop rotation experiment, conducted on a medium-textured Orthic Brown Chernozem at Swift Current, in southwestern Saskatchewan, was sampled in 1990 (3 yr after initiation of the study) and in 1993 and 1996, to measure SOC changes under nine crop rotation treatments. Minimum tillage practices were used. The stubble was cut high to enhance snow trap and N and P fertilizer applied based on soil tests. Grain and straw yields of the cereals, and hay yields of the crested wheatgrass (CWG) [Agropyron cristatum (L.) Gaeertn.] were measured annually. An empirical equation which uses two simultaneous first order kinetic expressions, one to estimate crop residue decomposition and the other to estimate soil humus C mineralization was used, together with crop residue (straw and estimated root) C inputs, to estimate SOC changes over the 1987 to 1996 period. The estimated SOC values for the 1990 to 1996 period were generally similar to the measured values (r2 = 0.64, P < 0.0001). Significant (P < 0.10) changes in SOC were not observed below 15 cm depth, perhaps because shallow tillage (10- to 12.5-cm depth) is practiced. A change from cropland to CWG did not increase SOC, and this treatment, chemical fallow-winter wheat (Triticum aestivum L.)-spring wheat (F-WW-W), and F-high-yielding (Hy) Canada Prairie Spring (CPS) wheat-Hy (F-Hy-Hy) rotations, had the lowest SOC gains among the rotations. The CPS wheat had a higher harvest index (0.46) than hard red spring (HRS) wheat (0.39), but it increased SOC less than the comparable HRS wheat rotation between 1990 and 1996 indicating that higher grain yields do not always equate to higher SOC. Weather conditions were favourable for cereals from 1990 to 1996 and we measured significant increases in SOC (up to 5.5 Mg ha−1 in 6 yr). This is encouraging for producers who may be contemplating participating in "C trading", although this also suggests that periods of less favourable weather will limit gains in SOC. Summerfallowing once in 4 yr in this semiarid environment did not reduce SOC gains compared to continuous wheat (Cont W). For example, a F-W-W-W rotation gained 4.88 Mg C ha−1 in 6 yr while continuous wheat gained 5 Mg ha−1. Growing Indianhead lentil (Lens culinaris Medikus) as a legume green manure crop (GM) with wheat in a GM-W-W rotation did not increase SOC more than F-W-W. The efficiencies of conversion of residue C to SOC were high, ranging between 9% for frequently fallowed systems to 29% for continuously cropped systems, likely due to the favourable weather conditions experienced. Key words: Carbon sequestration, legume green manure, crested wheatgrass, harvest index effect, C conversion efficiencies

Sign in / Sign up

Export Citation Format

Share Document