Tillage effect on agronomic efficiency of nitrogen under rainfed conditions of Tanzania.

2022 ◽  
pp. 246-255
Author(s):  
Leonard Rusinamhodzi ◽  
James Njeru ◽  
John E. Sariah ◽  
Rama Ngatoluwa ◽  
Phlorentin P. Lagwen

Abstract Nitrogen (N) deficiency is a common feature in soils managed by smallholder farmers in Africa. Crop residue retention, in combination with no-till (NT), may be a pathway to improve agronomic use efficiency of applied N for small-scale farmers under the predominant rainfed conditions. This chapter reports on the results of a study carried out over two cropping seasons in the long rains of 2014 and 2015 on two sites: (i) on-farm (Mandela); and (ii) a research station (SARI) in eastern Tanzania. The experiment consisted of two tillage systems, conventional tillage (CT) and Conservation Agriculture (CA), with a minimum of 2.5 t ha-1 crop residue cover maintained in the plots during the experiment. CT consisted of soil inversion through tillage and removal of crop residues. In the on-farm experiment, maize was grown in plots with four rates of N application: 0, 27, 54 and 108 kg N ha-1. In the on-station trial, five rates were used: 0, 20, 40, 60 and 100 kg N ha-1. Maize yield and agronomic efficiency (AE) of N were used to assess and compare the productivity of the tested treatments. The results showed that tillage, soil type and rate of N application influenced crop productivity. In the clay soils, the differences between tillage practices were small. Under CT, AE ranged between 21.6 and 53.9 kg/kg N, and it was 20.4-60.6 kg/kg N under CA. The lowest fertilizer application rate of 27 kg ha-1 often had the largest AE across the soil types and tillage practices. In the on-station trials at SARI, the largest AE of 24.6 kg/kg N was recorded under CA with 40 kg N ha-1. As in the on-farm trials, the highest N application rate on-station did not lead to the largest AE. In the CT, AE ranged between 11.5 and 16.8 kg/kg N compared with a range of 15.1 to 24.6 kg/kg N for the CA treatment. Overall, crop residue retention, in combination with NT, is important to improve soil moisture and use efficiency of applied nutrients. Additionally, the initial soil fertility status is also important in determining the magnitude of short-term crop response to applied nutrients. Innovative pathways are needed to achieve the multiple objectives played by maize crop residues for results reported here to be sustainable. However, efficiency of nutrient use needs to be assessed, together with returns on investments, as small yields may mean high nutrient use efficiency but not necessarily significant increased returns at the farm level.

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 464 ◽  
Author(s):  
Santosh Shiwakoti ◽  
Valtcho D. Zheljazkov ◽  
Hero T. Gollany ◽  
Markus Kleber ◽  
Baoshan Xing ◽  
...  

Crop residues are an important source of plant nutrients. However, information on the various methods of residue management on micronutrients in soil and wheat (Triticum aestivum L.) over time is limited. A long-term (84-year) agroecosystem experiment was assessed to determine the impact of fertilizer type and methods of crop residue management on micronutrients over time under dryland winter wheat-fallow rotation. The treatments were: no N application with residue burning in fall (FB), spring (SB), and no residue burn (NB); 45 kg N ha−1 with SB and NB; 90 kg N ha−1 with SB and NB; pea vines; and farmyard manure (FYM) and a nearby undisturbed grass pasture (GP). Wheat grain, straw, and soil samples from 1995, 2005, and 2015 were used to determine tissue total and soil Mehlich III extractable Mn, Cu, B, Fe, and Zn, and soil pH. After 84 years, extractable Mn and B in the top 10 cm of soil decreased in all plots, except for B in FYM and SB. The FYM plots had the highest extractable Mn (114 mg kg−1) in the top 10 cm soil; however, it declined by 33% compared to the GP (171 mg kg−1). Extractable Zn in the top 10 cm of soil increased with FYM while it decreased with inorganic N application in 2015; however, total Zn in grain increased by 7% with inorganic N (90 kg ha−1) application compared to FYM application. The results suggest that residue management had similar impact on soil micronutrients. Inorganic N and FYM application can be integrated to reduce micronutrient losses from cultivation.


1997 ◽  
Vol 129 (1) ◽  
pp. 1-12 ◽  
Author(s):  
A. BHOGAL ◽  
S. D. YOUNG ◽  
R. SYLVESTER-BRADLEY ◽  
F. M. O'DONNELL ◽  
R. L. RALPH

In 1977, a four-course rotation was set up at Ropsley (UK) to study crop response to eight rates of nitrogen application (35–265 kg ha−1). This rotation continued until 1990 when continuous winter wheat was introduced. Results from 1978 to 1990 provide an opportunity to study the initial phase of cumulative effects from different rates of N fertilizer application on the recovery of N by cereals and the retention of N in the soil.From 1978 to 1990, considerable variation in the recovery of nitrogen by winter wheat was observed. Neither rainfall nor drainage, as indicators of possible denitrification or leaching losses, provided a useful explanation for this, possibly because of the relatively dry conditions prevailing after spring fertilizer application. There was no evidence of increased soil N fertility, beyond single year residues, as a result of large N applications over the 13-year period.In order to achieve the economic optimum grain yield, it was necessary to use N applications which produced inefficient recovery of N. Thus, greater return of N in crop residues and immobilization at relatively large N applications (>150 kg ha−1) contributed to an observed build-up in soil organic N over the period of study. Plots receiving, on average, 265 kg ha−1 appeared to gain c. 250 kg ha−1 N over control plots (35 kg ha−1) after 13 years of N application. Reducing the N application rate from the economic optimum to a more biologically efficient N rate (156 kg ha−1) was calculated to result in an average yield loss of 0·305 t ha−1 and cause an estimated £17 ha−1 loss in profit.


Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 727 ◽  
Author(s):  
S. K. Dong ◽  
Y. Jiang ◽  
M. J. Wei ◽  
R. J. Long ◽  
Z. Z. Hu ◽  
...  

To illustrate the effect of nitrogen (N) application on soil physical and chemical characteristics, herbage yield and quality, and nitrogen and water use efficiency in the alpine region of Qinghai-Tibetan Plateau, a 3-year experiment was conducted on 3 mixtures of 4 perennial grasses commonly cultivated on the Plateau, Bromus inermis (BI) + Elymus nutans (EN), BI + E. sibricus (ES) + Agropyron cristatum (AC), and BI + ES + EN + AC by applying 4 levels of N fertiliser, 0, 115, 230, and 345 kg/ha from 1998 to 2000 in a randomised design. At harvesting time, soil pH and soil dry bulk density at 0–30 cm depth did not vary with N application rate. Soil organic carbon at 0–30 cm was not significantly variable under different N rates. Total soil N at 0–30 cm increased with N application rate and application year. After 3 years’ consecutive N treatment, total soil N reached 13 g/kg at an N application rate of 345 kg/ha. Soluble soil N at 0–30 cm increased with application rate but decreased with application year. At 345 kg N/ha application rate, soluble soil N was >100 mg/kg in 1998, but decreased to around 80 mg/kg in 2000. Herbage DM yields increased linearly with the N application rate. Compared with no fertiliser, 1.5 times more DM yield in 1998 and nearly double the DM yield in 1999 and 2000 were harvested for all grass mixtures at 345 kg N/ha. N concentrations in the herbages were significantly improved by N application. Each N fertiliser rate increased N contents in grass herbages by ≈3 g organic matter/kg. Apparent nitrogen recovery (ANR) decreased with N application rate in the establishment year of 1998, but increased with N application rate in 1999 and 2000. N use efficiency (NUE) decreased with N application throughout the experiment. Precipitation use efficiency (PUE) was significantly improved by N application for each grass mixture. Positive residual N-fertiliser effects were observed on herbage DM yield, ANR, NUE, and PUE in this study. BI + ES + AC showed higher DM yields, ANR, NUE, and PUE than the other 2 grass mixtures, and thus was proposed for N-input grassland systems in the alpine region of the Qinghai-Tibetan Plateau.


Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3415
Author(s):  
Jinsai Chen ◽  
Guangshuai Wang ◽  
Abdoul Kader Mounkaila Hamani ◽  
Abubakar Sunusi Amin ◽  
Weihao Sun ◽  
...  

Long−term excessive nitrogen fertilizer input has resulted in several environmental problems, including an increase in N2O emissions and the aggravation of nitrate leaching; monitoring nitrogen fertilizer is crucial for maize with high yield. This study aimed to optimize the amount of nitrogen applied to maize by Climate−Smart Agriculture (CSA) so as to continuously improve agricultural productivity and reduce or eliminate N2O emissions as much as possible. Field experiments with a completely randomized design were conducted to examine the effects of six nitrogen treatments (N application levels of 0, 120, 180, 240, 300, 360 kg·ha−1, respectively) on N2O emissions, residual concentration of nitrate and ammonium nitrogen, maize yield, and nitrogen utilization efficiency in 2018 and 2019. The results indicated that the residual concentration of nitrate nitrogen (NO3-−N) in the two seasons significantly increased; N2O emissions significantly increased, and the nitrogen fertilizer agronomic efficiency and partial productivity of maize fell dramatically as the nitrogen application rate increased. The maize grain yield rose when the N application amount was raised (N application amount <300 kg·ha−1) but decreased when the N application amount > 300 kg·ha−1. An increase in the nitrogen application rate can decrease nitrogen use efficiency, increase soil NO3-−N residual, and N2O emissions. Reasonable nitrogen application can increase maize yield and reduce N2O emissions and be conducive to improving nitrogen use efficiency. By considering summer maize yield, nitrogen use efficiency, and farmland ecological environment, 173.94~178.34 kg N kg·ha−1 could be utilized as the nitrogen threshold for summer maize in the North China Plain.


2019 ◽  
Vol 56 (4) ◽  
pp. 388-395
Author(s):  
B Gangaiah

A nutrient omission plot technique (NOPT) study in RCBD with 8 treatments (omission (-) of N, P, K, NP, NK, PK and no nutrient omission)and 3 replicates per treatment was made on rice at Port Blair, Andaman and Nicobar Islands during kharif 2015 to ascertain yield response and find out the most crucial nutrient for fertilization.The results revealed that yield response to fertilizers (NPK) was 2.63 t / ha (60.74%). The yield response of P (23.3 %) got multiplied by 2.16 and 2.60 times when combined with N and K applications as compared to their individual effects. Indigenous N, P and K supply capacity of the soil was estimated as 70.6, 10.0 and 80.0 kg/ha. Agronomic efficiency (kg grain / kg nutrient applied) was severely limited by P omission (10.13). The economics(Rs/ha) of rice cultivation indicates that omission of NPK & NP fertilizers results in losses. The highest profits realized with no omission (+NPK) were reduced by 52.3% with P omission. Omission of K followed by N and NK has less impact on profits. Rice crop duration got prolonged and shortened under P and N omission while K omission has no such effect.


1999 ◽  
Vol 79 (2) ◽  
pp. 389-394 ◽  
Author(s):  
Y. K. Soon

Cereal straw has many potential on-farm and off-farm uses. If straw is to be removed from land, the practice should not adversely impact long-term crop production and soil quality. A 10-yr experiment was conducted on a Dark Grey Solod near Beaverlodge, Alberta (55°13′N, 119°20′W) to determine the effects of fertilizer and straw management on the yield of, and nutrient (N and P) use by, continuous barley (Hordeum vulgare L.). Four straw management treatments: (i) straw removal; (ii) straw ploughed in; (iii) straw disked in; and (iv) straw disked in plus a red clover (Trifoleum pratense L.) green manure disked in every fifth year, were superimposed on four fertilizer treatments. The fertilizer treatments were application of N and P: (i) banded at soil-test recommended rates (ST,b); (ii) broadcast and incorporated at soil-test recommended rates (ST,bi); (iii) banded at soil-test rates of N+ 25 kg ha−1 and P+ 10 kg ha−1 (ST+,b); and (iv) as in (iii) but broadcast-applied and incorporated (ST+,bi). The straw ploughed-in treatment tended to produce lower annual barley yield and N uptake (by 9 and 13%, respectively) than the other three residue treatments. Barley yield and utilization of N and P were unaffected by straw removal as compared to disking-in straw. Barley yield and N uptake were higher (by 12 and 17%, respectively) with N and P application at the higher rate. At the recommended rate, broadcast-and-incorporated application of fertilizers resulted in lower yields and nutrient use than banded-in application. Treatment effects on P uptake tended to be small. The green-manured treatment used less fertilizer N, resulted in less total barley grain production, and did not increase the amount of crop residues incorporated. It is concluded that grain yield and nutrient (N and P) use of a continuous barley cropping system, fertilized at recommended rates of N and P, were unaffected by straw removal. Key words: Crop residue management, continuous barley production, fertilizer N and P


Author(s):  
Dalal H. Sary ◽  
Rama T. Rashad

Aims: A study was carried out in the field aims to study the response of a calcareous soil cultivated by soybean to the application of K-silicate (K-Si), K-humate (K-H), and compost at application rates 50% and 100% of the recommended dose. Study Design: Complete randomized block design with three replicates. Place and Duration of Study: At El-Nubaryia Agricultural Research Station (latitude of 30° 30°N longitude of 30° 20°E) Agricultural Research Center (ARC), Nubaryia, Egypt (Summer seasons of 2018 and 2019). Methodology: Compost was mixed with surface soil a week before cultivation at application rates 3.75 and 7.5 kg plot-1 (3.91 and 7.81 t ha-1, respectively). Powder K-H was spread on soil at application rates 7.5 and 15 g plot-1 while aqueous solutions of K-Si; 8 and 16 mL L-1 for plot was sprayed on soil 30, 60, and 90 days after cultivation. Results: Results showed that soil moisture(SM, %) was increased by the 100% application rate in the order compost (20.6%) > K-Si (19.3%) > K-H (19.1%). A significant increase was found in the seed yield (kg ha-1) by 129.5%, 84.8% and 70.6% by compost, K-H and K-Si, respectively. Compost at 100% application rate showed the most significant increase in the available nitrogen N (mg kg-1) in soil by 104.4% followed by K-H (by 81.8%) then K-Si by 23.4%. Compost also showed the most significant increase in the N uptake from soil (kg ha-1 soil) by seeds and straw followed by K-H then K-Si. The nutrient use efficiency (NUE, %) and agronomic efficiency (AE) values decreased in the order K-H > K-Si > compost at 50% and 100% application rates. Conclusion: The quite smaller dose and ease of field application by spraying may make the K-H more agronomically efficient than K-Si and compost.


Sign in / Sign up

Export Citation Format

Share Document