scholarly journals Considerations for Unharvested Plant Potassium

2020 ◽  
pp. 147-162
Author(s):  
Ciro A. Rosolem ◽  
Antonio P. Mallarino ◽  
Thiago A. R. Nogueira
Keyword(s):  
Cover Crops ◽  
Crop Production ◽  
Organic Amendments ◽  
Crop Rotations ◽  
Exchangeable K ◽  
Rooting Zone ◽  
Weak Complexes ◽  
Fertilizer Recommendations ◽  
K Fertilizer

AbstractPotassium (K) is found in plants as a free ion or in weak complexes. It is easily released from living or decomposing tissues, and it should be considered in fertilization programs. Several factors affect K cycling in agroecosystems, including soil and fertilizer K contributions, plant K content and exports, mineralization rates from residues, soil chemical reactions, rainfall, and time. Soil K+ ions can be leached, remain as exchangeable K, or migrate to non-exchangeable forms. Crop rotations that include vigorous, deep-rooted cover crops capable of exploring non-exchangeable K in soil are an effective strategy for recycling K and can prevent leaching below the rooting zone in light-textured soils. The amount of K released by cover crops depends on biomass production. Potassium recycled with non-harvested components of crops also varies greatly. Research with maize, soybean, and wheat has shown that 50–60% of K accumulated in vegetative tissues is released within 40–45 days. A better understanding of K cycling would greatly improve the efficacy of K management for crop production. When studying K cycling in agricultural systems, it is important to consider: (1) K addition from fertilizers and organic amendments; (2) K left in residues; (3) K partitioning differences among species; (4) soil texture; (5) soil pools that act as temporary sources or sinks for K. In this chapter, the role of cash and cover crops and organic residues on K cycling are explored to better understand how these factors could be integrated into making K fertilizer recommendations.

Potassium supplying power of a Typic Ustochrept profile using quantity/intensity technique in a long-term fertilized plot

2001 ◽  
Vol 137 (2) ◽  
pp. 195-203 ◽  
Author(s):  
T. R. RUPA ◽  
S. SRIVASTAVA ◽  
A. SWARUP ◽  
D. SINGH
Keyword(s):  
Crop Production ◽  
Soil Depth ◽  
Farmyard Manure ◽  
Clay Fraction ◽  
Cropping System ◽  
Water Soluble ◽  
Continuous Cropping ◽  
Exchangeable K ◽  
K Fertilizer ◽  
Phosphorus And Potassium

The effect of 27 years of continuous cropping, fertilization and manuring on potassium (K) supplying capacity of a Typic Ustochrept soil profile from Delhi, India under a maize–wheat–cowpea (fodder) cropping system was investigated by employing the quantity/intensity (Q/I) approach. The predominant mineral suite of the <2 μm clay fraction was illite. The values of equilibrium activity ratio of K in solution in equilibrium with the soil (ARKE), labile pools of K (KL), immediately available K (ΔK0), K available with difficulty (KX) and water soluble+exchangeable K (1 M NH4OAc K) in different soil layers (0 to 105 cm) under different treatments were in the following order: 100% nitrogen, phosphorus and potassium (NPK)+farmyard manure (FYM) > 100% NPK > control (no fertilizer) > 100% N >100% NP. The ARKE value, a measure of availability or intensity of labile K in soil decreased with profile depth due to greater K fixation by specific sites in the lower layers. The quantity of specifically sorbed K (KX) and the potential buffering capacity of soil (PBCK) showed a increasing trend with soil depth. In soil without K fertilizer treatments (control, 100% N and 100% NP) about 100% of the total K uptake by crops was from non-exchangeable soil K reserve as compared to 49·5 and 32·2% when annually 84 kg K/ha and 84 kg K/ha+FYM at the rate of 15 t/ha were applied. The results showed the greatest depletion of non-exchangeable K reserves in the plots which did not receive K fertilization. To ensure sustained crop production under intensive cropping, application of recommended dose of NPK plus FYM is required.

Site specific impacts of climate change on crop rotations and their management in Brandenburg/Germany

2020 ◽  
Author(s):  
Kurt-Christian Kersebaum ◽  
Susanne Schulz ◽  
Evelyn Wallor
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Cover Crops ◽  
Crop Production ◽  
Capillary Rise ◽  
Crop Rotations ◽  
Climate Conditions ◽  
Soil Map ◽  
Digital Soil Map

&lt;p&gt;Climate change impact on crop production depends on the cultivated crop and its position within crop rotations and on site conditions, e.g. soils and hydrology, buffering adverse weather situations. We present a regional study across the federal state of Brandenburg/Germany based on gridded climate data and a digital soil map using the HERMES-to-Go model. The aim was to investigate defined crop rotations and common agricultural practices under current and future climate conditions regarding productivity and environmental effects. Two contrasting GCMs (HAD and MPI) were used to generate climate input for modelling for the RCPs 2.6 and 8.5.&lt;/p&gt;&lt;p&gt;5 different types of crop production were simulated by defining crop rotations over 4-5 years for soil quality rating groups. While one rotation is comprised by the most common crops, another rotation modifies the first one by introducing a legume followed by a more demanding crop. The third rotation intends to produce higher value crops, e.g. potatoes than the first one, while the fourth rotation has its focus on fodder grass and cereal production. Building on this the fifth rotation replaces the fodder grass by alfalfa. All rotations are simulated in shifted phases to ensure that each crop is simulated for each year.&lt;/p&gt;&lt;p&gt;Sowing, harvest and nitrogen fertilization were derived by algorithms based on soil and climate information to allow self-adaptation to changing climate conditions. The crop rotations are simulated under rainfed and irrigated conditions and with and without the implementation of cover crops to prevent winter fallow.&lt;/p&gt;&lt;p&gt;We used the digital soil map 1:300.000 for Brandenburg with 99 soil map units. Within the soil map unit, up to three dominant soil types were considered to achieve at least 65% coverage. 276 soil types are defined by their soil profiles including soil organic matter content and texture down to 2 meters. Groundwater levels are estimated using the depth of reduction horizons as constant values over the year, to consider capillary rise depending on soil texture and distance between the root zone and the groundwater table.&lt;/p&gt;&lt;p&gt;In total each climate scenario contains about 148.000 simulations of 30 years. Beside crop yields we analyse the outputs for trends in soil organic matter, groundwater recharge, nitrogen leaching and the effect on water and nitrogen management using algorithms for automatic management.&lt;/p&gt;&lt;p&gt;Results indicate that spring crops were more negatively affected by climate change than winter crops especially on soils with low water holding capacity. However, few areas with more loamy soils and potential contribution of capillary rise from a shallow groundwater even benefited from climate change. Irrigation in most cases improved crop yield especially for spring crops. However, further analysis is required to assess if irrigation gains an economic benefit for all crop rotations. Nitrogen leaching can be reduced by implementing winter cover crops. Soil organic matter is assessed to decline for most sites and rotations. Only the rotations with multiyear grass or alfalfa can keep the level, but not on all sites.&lt;/p&gt;

Cover Crops

2017 ◽  
pp. 257-281 ◽  
Author(s):  
Vladan Ugrenović ◽  
Vladimir Filipović
Keyword(s):  
Organic Matter ◽  
Organic Farming ◽  
Soil Quality ◽  
Cover Crops ◽  
Farming Systems ◽  
Crop Rotations ◽  
Multiple Role ◽  
Pests And Diseases ◽  
Organic Farming Systems

The use of cover crops is widespread practice in organic farming systems. Cover crops can be defined as crops that are usually not grown commercially, and can have a multiple role in crop rotations. The benefit of cover crops has been known since long. Legumes are used as biological fixer of nitrogen for the next crop, and are established during periods when the soil is without major crops in order to reduce erosion. In recent years, the role of cover crops has been extended to the biocontrol of weeds, pests and diseases, as well as to the overall improvement of soil quality by increasing organic matter, encouraging the circulation of nutrients and reducing soil compaction. At the same time, their use tends to reduce costs and even create new sources of income on the farm.

The role of crop rotations in determining soil structure and crop growth conditions

2005 ◽  
Vol 85 (5) ◽  
pp. 557-577 ◽  
Author(s):  
B. C. Ball ◽  
I. Bingham ◽  
R. M. Rees ◽  
C. A. Watson ◽  
A. Litterick
Keyword(s):  
Nutrient Cycling ◽  
Crop Production ◽  
Soil Structure ◽  
Crop Residues ◽  
Growth Conditions ◽  
Crop Growth ◽  
Crop Rotations ◽  
Disease Suppression ◽  
Growth And Yield

Increasing concern about the need to provide high-quality food with minimum environmental impact has led to a new interest in crop rotations as a tool to maintain sustainable crop production. We review the role of rotations in the development and preservation of soil structure. After first introducing the types of rotations in current practice and their impact on yield, we assess how soil and crop management in rotations determines soil structure, and in turn how soil structure influences crop growth and yield. We also briefly consider how soil structure might contribute to other beneficial effects of rotations, namely nutrient cycling and disease suppression. Emphasis is given to the influence of crop choice and, where relevant, interaction with tillage system and avoidance of compaction in the improvement and maintenance of soil structure. Crop rotations profoundly modify the soil environment. The sequence of crops in rotation not only influences the removal of nutrients from a soil, but also the return of crop residues, the development and distribution of biopores and the dynamics of microbial communities. These processes contribute to the development of soil structure. We have identified areas where further research is needed to enable the potential benefits of rotations in the management of soil structure to be fully exploited. These include: improved quantitative linkages between soil structure and crop growth, the consequences to soil structure and nutrient cycling of crop residue incorporation, developing natural disease suppression, amelioration of subsoils by crop roots, the fate of carbon deposited by plant roots in soil and the fate of organic nitrogen in soil. Key words: Organic farming, microbial activity, nutrient cycling, compaction, disease suppression, soil structure

scholarly journals RESPONSE OF FIVE LETTUCE TYPES TO K FERTILIZERS ON HISTOSOLS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 665b-665
Author(s):  
N.M. El-Hout ◽  
C.A. Sanchez ◽  
S. Swanson
Keyword(s):  
Crop Production ◽  
Field Studies ◽  
Organic Soils ◽  
Soil Test ◽  
Nutrient Element ◽  
Optimal Production ◽  
Fertilizer Recommendations ◽  
K Fertilizer ◽  
Southern Florida ◽  
K Fertilization

Potassium is often considered the nutrient element most limiting to crop production on organic soils. On Histosols in southern Florida, K2SO4, rather than KCl, is often used for lettuce (Lactuca sativa L.) production to minimize the risk of salt injury. However, recent soil-test calibration research suggests that current K fertilizer recommendations for lettuce may be too high. Four field studies were conducted from 1989 to 1991 to evaluate the response of five lettuce types to K rate and source. The five lettuce types evaluated were leaf, bibb, boston, romaine (cos), and crisphead. Two sources of fertilizer K (K2SO4 and KCl) were evaluated at rates ranging from 0 to 600 kg K ha-1. Lettuce showed a minimal or no response to K fertilization. Potassium chloride had detrimental effects on lettuce only when applied at rates in excess of those required for optimal production. These studies showed that K fertilizer recommendations for lettuce produced on Histosols in Florida can be reduced. Furthermore, KCl, a more economical source, is suitable when the K is applied at appropriate rates.

Responses of potato (Solanum tuberosum) to potassium fertilizers

2001 ◽  
Vol 136 (4) ◽  
pp. 407-426 ◽  
Author(s):  
M. F. ALLISON ◽  
J. H. FOWLER ◽  
E. J. ALLEN
Keyword(s):  
Dry Matter ◽  
Application Rate ◽  
Yield Response ◽  
Published Data ◽  
Fresh Weight ◽  
Exchangeable K ◽  
Weight Yield ◽  
Fertilizer Recommendations ◽  
Tuber Dry Matter ◽  
K Fertilizer

Between 1989 and 1999, 33 experiments tested the effects of potassium (K) fertilizer on the yield and quality of potatoes. The experiments were done on a range of soil types and used varieties and management conditions common to modern commercial production. The average yield in these experiments was 48 t/ha. Nearly half of the experiments were done on soils that had exchangeable K values < 120 mg/l (MAFF Indices 0–1) but use of K fertilizer resulted in statistically significant increases in fresh weight yield in only seven experiments. Generally, soil exchangeable K was a poor predictor of the probability of a yield response. Potassium fertilizer caused an increase in dry weight yield in only four experiments and these experiments were characterized by the absence of irrigation, soils with small amounts of exchangeable K and use of determinate varieties. Re-examination of published data supported the findings in the current work: potatoes are not particularly responsive to K fertilizer and the optimal K application rate is rarely > 170–210 kg K/ha. When applied at the optimal rate, the effects of K fertilizer on tuber dry matter concentration were nonsignificant. Exceeding the optimal K application rate caused occasional reductions in tuber dry matter concentrations particularly if potassium chloride (KCl) was used. In the two experiments where it was tested, application rate and form of K had no effect on crisp fry-colour. The effect of K fertilizer on tuber K concentration was measured in 21 experiments and on average each tonne of fresh weight yield was associated with 4·2 kg K. The range in values was large, 2·8–5·7 and related to soil exchangeable K.For fertilizer recommendations based solely on the probability of a significant yield response to K fertilizer it is suggested that no more than 210 kg K/ha be applied even on soils with < 120 mg exchangeable K/l. For fertilizer recommendations based on crop K removal, an uptake value of 4·8 kg K/t fresh weight (FW), as has been suggested, would be adequate, although errors in the estimation of yield may lead to over or under application of K. Since there was little evidence to support fertilizer policies that apply more K than is removed by the crop a fertilizer recommendation system based primarily on the probability of a yield response would be more than sufficient.

The effects of tillage systems and crop rotations on soil chemical properties of a Black Chernozemic soil

1994 ◽  
Vol 74 (3) ◽  
pp. 301-306 ◽  
Author(s):  
C. A. Grant ◽  
G. P. Lafond
Keyword(s):  
Winter Wheat ◽  
Crop Production ◽  
Chemical Properties ◽  
Soil Surface ◽  
Crop Rotations ◽  
Reduced Tillage ◽  
Nitrogen Accumulation ◽  
Tillage Systems ◽  
Rooting Zone ◽  
C And N

The effects of zero (ZT), minimum (MT) and conventional tillage (CT) systems and three 4-yr crop rotations on soil total C and N, mineralizable N, NO3-N, P, K and SO4-S accumulation and distribution in the soil profile were determined after one 4-yr cycle of crop production on Black Chernozemic Indian Head heavy clay soil. The distributions of available P and K in the profile were not affected by tillage or rotation. Total C and N in the 0–5 cm depth was higher in the reduced tillage systems than in CT, but differences in the 5–10 cm and 10–15 cm depths were not significant. Nitrate concentration was higher in the 15–30 cm and 30–60 cm depths under CT than under reduced tillage. Inclusion of fallow increased accumulation of NO3-N in the deeper soil depths, while inclusion of winter wheat in the rotation reduced deep movement of NO3-N. Nitrate-nitrogen accumulation after field pea production was comparable to that after winter wheat, but a greater proportion of the NO3-N was present near the soil surface after winter wheat, reducing the potential for leaching below the rooting zone. Potential for movement of NO3-N below the rooting zone may be increased by fallow and decreased by production of winter wheat and by reduced tillage systems. Key words: Tillage, rotations, nitrate, sulphate

scholarly journals Implication of O2 dynamics for both N2O and CH4 emissions from soil during biological soil disinfestation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chen Wang ◽  
Xuehong Ma ◽  
Gang Wang ◽  
Guitong Li ◽  
Kun Zhu
Keyword(s):  
Wheat Straw ◽  
Crop Residues ◽  
Management Practice ◽  
Organic Amendments ◽  
Soil Disinfestation ◽  
Hypoxic Area ◽  
Hypoxic Fraction ◽  
Biological Soil Disinfestation ◽  
Straw Incorporation

AbstractSoil O2 dynamics have significant influences on greenhouse gas emissions during soil management practice. In this study, we deployed O2-specific planar optodes to visualize spatiotemporal distribution of O2 in soils treated with biological soil disinfestation (BSD). This study aimed to reveal the role of anoxia development on emissions of N2O and CH4 from soil amended with crop residues during BSD period. The incorporation of crop residues includes wheat straw only, wheat straw with biochar and early straw incorporation. The anoxia in soil developed very fast within 3 days, while the O2 in headspace decreased much slower and it became anaerobic after 5 days, which was significantly affected by straw and biochar additions. The N2O emissions were positively correlated with soil hypoxic fraction. The CH4 emissions were not significant until the anoxia dominated in both soil and headspace. The co-application of biochar with straw delayed the anoxia development and extended the hypoxic area in soil, resulting in lower emissions of N2O and CH4. Those results highlight that the soil O2 dynamic was the key variable triggering the N2O and CH4 productions. Therefore, detailed information of soil O2 availability could be highly beneficial for optimizing the strategies of organic amendments incorporation in the BSD technique.

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