Assessing yield and fertilizer response in heterogeneous smallholder fields with UAVs and satellites

Economics of Fertilizer Application to Wheat Crop: The Results of a Survey in Lyallpur District (Notes and Comments)

The Pakistan Development Review ◽

10.30541/v10i1pp.88-99 ◽

1970 ◽

Vol 10 (1) ◽

pp. 88-99

Author(s):

Barkat Ali Quraishi ◽

Muhammad Jameel Khan

Keyword(s):

Agricultural Production ◽

Agricultural Research ◽

Fertilizer Application ◽

Wheat Crop ◽

Fertilizer Response ◽

Fertilizer Use ◽

Reliable Knowledge

Reliable knowledge about the contribution of various factors responsible for increasing agricultural production is indispensable for planning. This holds particularly for the fertilizer use, which has been recognized as one of the quickest and, perhaps, the cheapest means for increasing agricultural produc¬tion. In Pakistan the emphasis on planned development is gaining momentum and for this purpose more data and fuller information on fertilizer response are becoming increasingly essential. The Agricultural Research Stations in the country have been conducting experiments with a view to determining the extent to which the cropped yield may increase due to the application of fertilizer. But such experiments, because of their somewhat controlled nature in respect of certain factors, obviously can¬not tell us with a desired measure of accuracy as to what is actually happening at millions of private farms throughout the country. And, as such, the planning in this regard is apt to be wrong.

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Preliminary DRIS norms for coastal Douglas-fir soils in Washington and Oregon

Canadian Journal of Forest Research ◽

10.1139/x95-025 ◽

1995 ◽

Vol 25 (2) ◽

pp. 208-214 ◽

Cited By ~ 2

Author(s):

J.S. Shumway ◽

H.N. Chappell

Keyword(s):

Basal Area ◽

Site Index ◽

Douglas Fir ◽

Integrated System ◽

N Fertilizer ◽

Soil Test ◽

Fertilizer Response ◽

Response Data ◽

Limiting Nutrient ◽

Diagnostic Work

The Diagnosis and Recommendation Integrated System (DRIS) has been used successfully in agricultural crops and holds promise for use in forest stands. This study used soil tests to develop DRIS norms and evaluate their effectiveness in coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forests. DRIS norms for nitrogen, phosphorus, potassium, and calcium were developed using soil test and site index data from 72 soil series that commonly support Douglas-fir in western Washington. The norms were tested using soil test and stand basal area growth response data from 20 thinned and 30 unthinned N fertilizer test sites in coastal Washington and Oregon. Response to urea fertilizer in thinned stands averaged 34% and 43% for 224 and 448 kg N•ha−1, respectively, when N was identified as the most limiting nutrient. When N was not the most limiting nutrient, N response averaged 8% and 10% for 224 and 448 kg N•ha−1, respectively. Results were similar in unthinned stands and thinned stands, although response to fertilizer appeared to be slightly less in unthinned stands when N was the most limiting nutrient. DRIS correctly classified 25 of the 33 sites (76%) where N fertilizer increased growth by more than 15%. More importantly, 13 of the 17 (76%) sites that responded by less than 15% were correctly identified by DRIS. The results clearly indicate that N fertilizer response is dependent on the interactions (balance) between soil nutrients at a given site. Future soil diagnostic work needs to focus on techniques, like DRIS, that provide an assessment of these interactions.

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Transformed Inverse Model at Quadratic Variable in fertilizer Response

Asian Journal of Agricultural Research ◽

10.3923/ajar.2007.80.85 ◽

2007 ◽

Vol 1 (2) ◽

pp. 80-85

Author(s):

I.S. Salawu

Keyword(s):

Inverse Model ◽

Fertilizer Response

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Relationship of soil phosphorus fractions to phosphorus soil tests and fertilizer response

Canadian Journal of Soil Science ◽

10.4141/s02-079 ◽

2003 ◽

Vol 83 (4) ◽

pp. 443-449 ◽

Cited By ~ 6

Author(s):

R. H. McKenzie ◽

E. Bremer

Keyword(s):

Available P ◽

Soil Test ◽

Strongly Correlated ◽

P Fractions ◽

Soil Tests ◽

Fertilizer Response ◽

Inorganic P ◽

Soil P ◽

P Fertilizer ◽

Soil Test P

Soil tests for available P may not be accurate because they do not measure the appropriate P fraction in soil. A sequential extraction technique (modified Hedley method) was used to determine if soil test P methods were accurately assessing available pools and if predictions of fertilizer response could be improved by the inclusion of other soil P fractions. A total of 145 soils were analyzed from field P fertilizer experiments conducted across Alberta from 1991 to 1993. Inorganic P (Pi) removed by extraction with an anion-exchange resin (resin P) was highly correlated with the Olsen and Kelowna-type soil test P methods and had a similar relationship with P fertilizer response. No appreciable improvement in the fit of available P with P fertilizer response was achieved by including any of the less available P fractions in the regression of P fertilizer response with available P. Little Pi was extractable in alkaline solutions (bicarbonate and NaOH), particularly in soils from the Brown and Dark Brown soil zones. Alkaline fractions were the most closely related to resin P, but the relationship depended on soil zone. Inorganic P extractable in dilute HCl was most strongly correlated with soil pH, reflecting accumulation in calcareous soils, while Pi extractable in concentrated acids (HCl and H2SO4) was most strongly correlated with clay concentration. A positive but weak relationship as observed between these fractions and resin P. Complete fractionation of soil P confirmed that soil test P methods were assessing exchangeable, plant-available P. Key words: Hedley phosphorus fractionation, resin, Olsen, Kelowna

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The Estimation of Nitrogen Uptake and Utilization Efficiency in Cotton by the Fertilizer-Response Model

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha47411672 ◽

2019 ◽

Vol 47 (4) ◽

pp. 1400-1408

Author(s):

Lulu MA ◽

Qiang ZHANG ◽

Jiao LIN ◽

Wei SU ◽

Caixia YIN ◽

...

Keyword(s):

Growth Habit ◽

Dry Mass ◽

N Fertilizer ◽

Utilization Efficiency ◽

Digital Object Identifier ◽

Fertilizer Treatment ◽

Response Model ◽

Fertilizer Response ◽

Indeterminate Growth Habit ◽

N Status

Due to the indeterminate growth habit of cotton crops, a better understanding of N status at the rational fertilizer regime is important to promote lint yield. The fertilizer-response model was employed to evaluate N status by analyzing data of shoot dry mass, N content and N concentration at different growing stages. A field study was conducted on drip-irrigated cotton plants with N fertilizer addition in total amounts of 0 (N0), 120 (N1), 240 (N2), 360 (N3) and 480 (N4) kg ha-1 in Xinjiang, China in 2016. Thirty percent of total fertilizers were applied at planting and the rest 70% were applied over six applications. The N fertilizer treatment at the accumulative rate of 70 kg ha-1 was enough to induce the N status of steady state accumulation 60 days after germination. Since 90 days the treatments that delivered the N amount between 120 and 240 kg ha-1 was deficient for cotton demand, higher rates from 360 and 480 kg ha-1 induced inherent N reserve and resulted in the highest level of yield. With regard to the practical meaning, the N fertilizer dose of 360 kg ha-1 can be used for cotton growth. The N fertilizer dose of 120 kg ha-1 can be recommended when the yield of 5,840 kg ha-1 lint can meet the goal of cotton culture. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

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