Soil fertility changes and crop yields from the first 4 years of the Mandela trials.

2020 ◽  
pp. 303-324
Author(s):  
M. Swanepoel ◽  
R. Auerbach ◽  
N. J. Mashele
Keyword(s):  
Soil Fertility ◽  
Crop Yields

Plantation Agriculture in the Tropics

2005 ◽  
Vol 34 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Alfred E. Hartemink
Keyword(s):  
Carbon Sequestration ◽  
Soil Erosion ◽  
Soil Fertility ◽  
Cover Crops ◽  
Fertility Decline ◽  
Crop Yields ◽  
Perennial Crops ◽  
Tropical Countries ◽  
Plantation Agriculture ◽  
National Economies

Plantation agriculture is more than 400 years old and contributes to the regional and national economies in many tropical countries. This paper reviews some of the main environmental issues related to plantation agriculture with perennial crops, including soil erosion, soil fertility decline, pollution, carbon sequestration and biodiversity. Soil erosion and soil fertility decline are of concern in some areas, but in most plantations these are being checked by cover crops and inorganic fertilizer applications. Few studies have been conducted on the issue of carbon sequestration under perennial plantation cropping. Reductions in deforestation yield much greater benefits for a reduction in CO2 emissions than expanding plantation agriculture. The biggest threat to biodiversity is the loss of habitat through expansion of the plantation area. Despite the environmental problems and concerns, this review has shown that crop yields of most perennial crops have increased over time due to improved crop husbandry including high-yielding cultivars and improved soil management. It is likely that more attention will be given to the environmental aspects of plantation cropping due to the increasing environmental awareness in tropical countries.

scholarly journals Can Organic Sources of Nutrients Increase Crop Yields to Meet Global Food Demand?

Agronomy ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 214 ◽  
Author(s):  
Jagadish Timsina
Keyword(s):  
Climate Change ◽  
Soil Fertility ◽  
Organic Farming ◽  
Crop Yields ◽  
Food Demand ◽  
Conventional Farming ◽  
Chemical Fertilizers ◽  
Organic Nutrients ◽  
On Farm ◽  
Global Food

Meeting global demand of safe and healthy food for the ever-increasing population now and into the future is currently a crucial challenge. Increasing crop production by preserving environment and mitigating climate change should thus be the main goal of today’s agriculture. Conventional farming is characterized by use of high-yielding varieties, irrigation water, chemical fertilizers and synthetic pesticides to increase yields. However, due to either over- or misuse of chemical fertilizers or pesticides in many agro-ecosystems, such farming is often blamed for land degradation and environmental pollution and for adversely affecting the health of humans, plants, animals and aquatic ecosystems. Of all inputs required for increased agricultural production, nutrients are considered to be the most important ones. Organic farming, with use of organic sources of nutrients, is proposed as a sustainable strategy for producing safe, healthy and cheaper food and for restoring soil fertility and mitigating climate change. However, there are several myths and controversies surrounding the use of organic versus inorganic sources of nutrients. The objectives of this paper are: (i) to clarify some of the myths or misconceptions about organic versus inorganic sources of nutrients and (ii) to propose alternative solutions to increase on-farm biomass production for use as organic inputs for improving soil fertility and increasing crop yields. Common myths identified by this review include that organic materials/fertilizers can: (i) supply all required macro- and micro-nutrients for plants; (ii) improve physical, chemical and microbiological properties of soils; (iii) be applied universally on all soils; (iv) always produce quality products; (v) be cheaper and affordable; and (vi) build-up of large amount of soil organic matter. Other related myths are: “legumes can use entire amount of N2 fixed from atmosphere” and “bio-fertilizers increase nutrient content of soil.” Common myths regarding chemical fertilizers are that they: (i) are not easily available and affordable, (ii) degrade land, (iii) pollute environment and (iv) adversely affect health of humans, animals and agro-ecosystems. The review reveals that, except in some cases where higher yields (and higher profits) can be found from organic farming, their yields are generally 20–50% lower than that from conventional farming. The paper demonstrates that considering the current organic sources of nutrients in the developing countries, organic nutrients alone are not enough to increase crop yields to meet global food demand and that nutrients from inorganic and organic sources should preferably be applied at 75:25 ratio. The review identifies a new and alternative concept of Evergreen Agriculture (an extension of Agroforestry System), which has potential to supply organic nutrients in much higher amounts, improve on-farm soil fertility and meet nutrient demand of high-yielding crops, sequester carbon and mitigate greenhouse gas emissions, provide fodder for livestock and fuelwood for farmers and has potential to meet global food demand. Evergreen Agriculture has been widely adapted by tens of millions of farmers in several African countries and the review proposes for evaluation and scaling-up of such technology in Asian and Latin American countries too.

scholarly journals Crop Yield and Soil Fertility Status of Long-Term Rice-Rice-Wheat Cropping Systems

2017 ◽  
Vol 5 (1) ◽  
pp. 42-50
Author(s):  
Nabin Rawal ◽  
Rajan Ghimire ◽  
Devraj Chalise
Keyword(s):  
Soil Fertility ◽  
Crop Yield ◽  
Management Practices ◽  
Crop Yields ◽  
Oryza Sativa L ◽  
Farmyard Manure ◽  
Wheat Yield ◽  
Nutrient Supply ◽  
Available Phosphorus

Balanced nutrient supply is important for the sustainable crop production. We evaluated the effects of nutrient management practices on soil properties and crop yields in rice (Oryza sativa L.) - rice - wheat (Triticum aestivum L.) system in a long-term experiment established at National Wheat Research Program (NWRP), Bhairahawa, Nepal. The experiment was designed as a randomized complete block experiment with nine treatments and three replications. Treatments were applied as: T1- no nutrients added, T2- N added; T3- N and P added; T4- N and K added; T5- NPK added at recommended rate for all crops. Similarly, T6- only N added in rice and NPK in wheat at recommended rate; T7- half N; T8- half NP of recommended rate for both crops; and T9- farmyard manure (FYM) @10 Mg ha-1 for all crops in rotation. Results of the study revealed that rice and wheat yields were significantly greater under FYM than all other treatments. Treatments that did not receive P (T2, T3, T7, T8) and K (T2, T4) had considerably low wheat yield than treatments that received NPK (T5) and FYM (T9). The FYM lowered soil pH and improved soil organic matter (SOM), total nitrogen (TN), available phosphorus (P), and exchangeable potassium (K) contents than other treatments. Management practices that ensure nutrient supply can increase crop yield and improve soil fertility status.Int. J. Appl. Sci. Biotechnol. Vol 5(1): 42-50

scholarly journals Application of Chemical Fertilizers in Cocoa-Based (Theobroma cacao) Agroforestry Systems; Impact on Yields and Policy Ramifications: Empirical Evidence from Cameroon

2020 ◽  
pp. 38-49
Author(s):  
Azembouh Roshinus Tsufac ◽  
Nyong Princely Awazi ◽  
Bernard Palmer Kfuban Yerima ◽  
Roger Kogge Enang
Keyword(s):  
Soil Fertility ◽  
Causal Relationship ◽  
Crop Yields ◽  
Household Survey ◽  
Agroforestry Systems ◽  
Chemical Fertilizer ◽  
Farm Size ◽  
Chemical Fertilizers ◽  
Cocoa Farmers ◽  
Cocoa Yield

Soil fertility decline has pushed farmers across the world to resort to chemical fertilizers in order to improve soil fertility and enhance crop yields. In agroforestry systems, the application of chemical fertilizers is a call for concern considering that agroforestry systems are supposedly agro-ecological, environmentally friendly and sustainable systems. It was within this context that this study sought to assess the application of chemical fertilizers in cocoa-based agroforestry systems and its policy ramifications. Data was collected through a household survey of 300 cocoa farmers in Cameroon, and analyzed on SPSS 17.0 employing descriptive and analytical techniques. It was found that the most commonly used chemical fertilizers by cocoa farmers in cocoa-based agroforestry systems were NPK 20:10:10 (60%), NPK 15:20:15 (50%), and Urea (40%). It was also noticed that a majority of the cocoa farmers sampled used no chemical fertilizer (35%), very small quantity (15%), small quantity (20%), and moderate quantity (20%). With respect to frequency of use, most cocoa farmers never used chemical fertilizer (35%), used it rarely (30%), or used it occasionally (15%). However, some cocoa farmers used chemical fertilizers frequently (5%) and very frequently (5%) in their cocoa agroforests. Coefficients of correlation and regression showed the existence of a statistically significant (p<0.05) direct and inverse non-causal and causal relationship between different explanatory variables (income level, availability of chemical fertilizers, access to information, membership in farming group and access to extension services) and cocoa farmers’ use of chemical fertilizers; while farm size and number of farms had a statistically significant inverse relationship. Correlation and regression coefficients showed the existence of a statistically significant (p<0.05) direct non-causal and causal relationship between different levels of cocoa yields (very high cocoa yield, high cocoa yield, average cocoa yield, low cocoa yield, very low cocoa yield, no change in cocoa yields) and the application of chemical fertilizers in cocoa-based agroforestry systems. On the basis of the study’s findings, it is recommended that measures be taken to limit the use of chemical fertilizers in cocoa-based agroforestry systems in order to enhance the sustainability of these systems.

CORRELATION OF MICROBIOLOGICAL AND CHEMICAL SOIL DATA WITH CROP YIELDS OF THE JORDAN SOIL FERTILITY PLOTS

Soil Science ◽  
1949 ◽  
Vol 67 (4) ◽  
pp. 279-286 ◽  
Author(s):  
J. W. WHITE ◽  
F. J. HOLBEN ◽  
C. D. JEFFRIES ◽  
A. C. RICHER
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Chemical Soil

scholarly journals Impact of land management system on crop yields and soil fertility in Cameroon

Solid Earth ◽  
2015 ◽  
Vol 6 (3) ◽  
pp. 1087-1101 ◽  
Author(s):  
D. Tsozué ◽  
J. P. Nghonda ◽  
D. L. Mekem
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Cropping Systems ◽  
Control Sample ◽  
Cropping System ◽  
Field Work ◽  
Exchange Capacity ◽  
Direct Seeding ◽  
Ph Values ◽  
The Impact

Abstract. The impact of direct-seeding mulch-based cropping systems (DMC), direct seeding (DS) and tillage seeding (TS) on Sorghum yields, soil fertility and the rehabilitation of degraded soils was evaluated in northern Cameroon. Field work consisted of visual examination, soil sampling, yield and rainfall data collection. Three fertilization rates (F1: 100 kg ha−1 NPK + 25 kg ha−1 of urea in DMC, F2: 200 kg ha−1 NPK + 50 kg ha−1 of urea in DMC and F3: 300 kg ha−1 NPK + 100 kg ha−1 of urea in DMC) were applied to each cropping system (DS, TS and DMC), resulting in nine experimental plots. Two types of chemical fertilizer were used (NPK 22.10.15 and urea) and applied each year from 2002 to 2012. Average Sorghum yields were 1239, 863 and 960 kg ha−1 in DMC, DS and TS, respectively, at F1, 1658, 1139 and 1192 kg ha−1 in DMC, DS and TS, respectively, at F2, and 2270, 2138 and 1780 kg ha−1 in DMC, DS and TS, respectively, at F3. pH values were 5.2–5.7 under DMC, 4.9–5.3 under DS and TS and 5.6 in the control sample. High values of cation exchange capacity were recorded in the control sample, TS system and F1 of DMC. Base saturation rates, total nitrogen and organic matter contents were higher in the control sample and DMC than in the other systems. All studied soils were permanently not suitable for Sorghum due to the high percentage of nodules. F1 and F2 of the DS were currently not suitable, while F1 and F3 of DMC, F3 of DS and F1, F2 and F3 of TS were marginally suitable for Sorghum due to low pH values.

scholarly journals Agricultural diversification promotes multiple ecosystem services without compromising yield

2020 ◽  
Vol 6 (45) ◽  
pp. eaba1715 ◽  
Author(s):  
Giovanni Tamburini ◽  
Riccardo Bommarco ◽  
Thomas Cherico Wanger ◽  
Claire Kremen ◽  
Marcel G. A. van der Heijden ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Nutrient Cycling ◽  
Soil Fertility ◽  
Pest Control ◽  
Crop Yields ◽  
Cropping Systems ◽  
Context Dependency ◽  
Water Regulation ◽  
Trade Offs ◽  
The Impact

Enhancing biodiversity in cropping systems is suggested to promote ecosystem services, thereby reducing dependency on agronomic inputs while maintaining high crop yields. We assess the impact of several diversification practices in cropping systems on above- and belowground biodiversity and ecosystem services by reviewing 98 meta-analyses and performing a second-order meta-analysis based on 5160 original studies comprising 41,946 comparisons between diversified and simplified practices. Overall, diversification enhances biodiversity, pollination, pest control, nutrient cycling, soil fertility, and water regulation without compromising crop yields. Practices targeting aboveground biodiversity boosted pest control and water regulation, while those targeting belowground biodiversity enhanced nutrient cycling, soil fertility, and water regulation. Most often, diversification practices resulted in win-win support of services and crop yields. Variability in responses and occurrence of trade-offs highlight the context dependency of outcomes. Widespread adoption of diversification practices shows promise to contribute to biodiversity conservation and food security from local to global scales.

Effects of lupin-wheat rotations on soil fertility, crop disease and crop yields

1984 ◽  
Vol 24 (127) ◽  
pp. 595 ◽  
Author(s):  
TG Reeves ◽  
A Ellington ◽  
HD Brooke
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Disease Incidence ◽  
Mineral Nitrogen ◽  
Gaeumannomyces Graminis ◽  
Wheat Crop ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Nitrogen Levels ◽  
Crop Diseases

Three experiments, begun in successive years, were conducted between 1974 and 1979 in north-eastern Victoria to investigate the effects of rotating wheat (cv. Olympic) and 'sweet' lupins (Lupinus angustifolius cv. Uniharvest) on crop yields, soil fertility and crop diseases. The grain yield of continuous wheat was 2.58 t/ha and of continuous lupins 0.66 t/ha (P<0.05). Wheat, grown after a lupin crop, yielded 750 kg/ha more than wheat after wheat, and a second wheat crop, after lupins, yielded 420 kg/ha more than a third successive wheat crop. Lupins, grown after wheat, yielded 50-165% more than lupins after lupins. Grain nitrogen of wheat was significantly increased after lupins (P<0.01). Differences in soil mineral nitrogen were apparent ten weeks after sowing, with mean nitrogen levels of 37 and 55 kg/ha under wheat and lupins, respectively. Soil mineral nitrogen (0-20 cm) was consistently greater after lupins than after wheat (P<0.01) when measured just before seeding the succeeding crop. Overall, mean accretion of mineral nitrogen under lupins was 4 1 kg/ha.year. Residual nitrogen from lupins, after one succeeding wheat crop had been grown, was also evident (mean 23 kg/ha). Crop rotation influenced the incidence of crop diseases in wheat and lupins. Lupins after lupins suffered severely from brown leaf spot (Pleiochaeta setosa), up to 63% of plants being infected compared with only 18% after wheat. Disease incidence (mainly Gaeumannomyces graminis) in wheat increased from less than 1% in the first year of cropping, to 36% infection in year 3. When wheat was grown after lupins, disease incidence was negligible.

SEQUENCING INTEGRATED SOIL FERTILITY MANAGEMENT OPTIONS FOR SUSTAINABLE CROP INTENSIFICATION BY DIFFERENT CATEGORIES OF SMALLHOLDER FARMERS IN ZIMBABWE

2014 ◽  
Vol 51 (1) ◽  
pp. 17-41 ◽  
Author(s):  
H. NEZOMBA ◽  
F. MTAMBANENGWE ◽  
R. CHIKOWO ◽  
P. MAPFUMO
Keyword(s):  
Soil Fertility ◽  
Crop Yields ◽  
Smallholder Farmers ◽  
Mineral Fertilizers ◽  
Soil Productivity ◽  
Soil Fertility Management ◽  
Management Options ◽  
Integrated Soil Fertility Management ◽  
Fertility Management ◽  
Maize Grain

SUMMARYResearch has proved that integrated soil fertility management (ISFM) can increase crop yields at the field and farm scales. However, its uptake by smallholder farmers in Africa is often constrained by lack of technical guidelines on effective starting points and how the different ISFM options can be combined to increase crop productivity on a sustainable basis. A 4-year study was conducted on sandy soils (<10% clay) on smallholder farms in eastern Zimbabwe to assess how sequencing of different ISFM options may lead to incremental gains in soil productivity, enhanced efficiency of resource use, and increase crop yields at field scale. The sequences were primarily based on low-quality organic resources, nitrogen-fixing green manure and grain legumes, and mineral fertilizers. To enable comparison of legume and maize grain yields among treatments, yields were converted to energy (kilocalories) and protein (kg) equivalents. In the first year, ‘Manure-start’, a cattle manure-based sequence, yielded 3.4 t ha−1of maize grain compared with 2.5 and 0.4 t ha−1under a woodland litter-based sequence (‘Litter-start’) and continuous unfertilized maize control, respectively. The ‘Manure-start’ produced 12 × 106kilocalories (kcal); significantly (p< 0.05) out-yielding ‘Litter start’ and a fertilizer-based sequence (‘Fertilizer-start’) by 50%. A soyabean-based sequence, ‘Soya-start’, gave the highest protein production of 720 kg against <450 kg for the other sequencing treatments. In the second year, the sequences yielded an average of 5.7 t ha−1of maize grain, producing over 19 × 106kcal and 400 kg of protein. Consequently, the sequences significantly out-performed farmers’ designated poor fields by ~ fivefold. In the third year, ‘Soya-start’ gave the highest maize grain yield of 3.7 t ha−1; translating to 1.5 and 3 times more calories than under farmers’ designated rich and poor fields, respectively. In the fourth year, ‘Fertilizer-start’ produced the highest calories and protein of 14 × 106kcal and 340 kg, respectively. Cumulatively over 4 years, ‘Manure-start’ and ‘Soya-start’ gave the highest calories and protein, out-performing farmers’ designated rich and poor fields. Sunnhemp (Crotalaria junceaL.)-based sequences, ‘Green-start’ and ‘Fertilizer-start’, recorded the highest gains in plant available soil P of ~ 4 mg kg−1over the 4-year period. Assessment of P agronomic efficiencies showed significantly more benefits under the ISFM-based sequences than under farmers’ designated rich and poor fields. Based on costs of seed, nutrients and labour, ‘Soya-start’ gave the best net present value over the 4 years, while ‘Fertilizer-start’ was financially the least attractive. Overall, the ISFM-based sequences were more profitable than fields designated as rich and poor by farmers. We concluded that ISFM-based sequences can provide options for farm-level intensification by different categories of smallholder farmers in Southern Africa.

Sign in / Sign up

Export Citation Format

Share Document