Improve Crop Nutrient Research Articles

Key crop nutrient management issues in the Western Australia grains industry: a review

In the present paper, we review 4 topics that were identified through extensive consultation with stakeholders as issues of high impact and influence for the grains industry: improving soil testing and interpretation; role of fluid fertilisers in the Western Australian (WA) grains industry; using spatial and temporal information to improve crop nutrient management, particularly for nitrogen; and developing recommendations for managing emerging nutrient deficiencies. The key findings are summarised below. To further improve soil testing and interpretation, the review suggests that future research should focus on addressing soil sampling and interpretation questions, as they are important factors affecting the accuracy of fertiliser recommendations with changing cropping practices. There have been several studies to compare fluid with granular forms of P in WA, but the responses have not, so far, been consistent. More work may be needed to understand different crop response to fluid P fertiliser additions, particularly on low pH soils in WA. An understanding of the long-term performance of fluid P will also require an assessment of the residual value of fluid P compared with granular P under field conditions. Precision agriculture (PA) technology has potential to improve crop nutrient management and farm profitability in WA. The review indicates that understanding both spatial and temporal yield variation is critical for the successful adoption of PA technology by growers. The review also suggests that in WA, there is a need to explore the use of different layers of spatial information for determining management zones. In response to wide adoption of no-till and stubble retention cropping systems, increased use of fluid fertilisers together with advanced application technologies, and increased interest in cropping in the high rainfall zone, there is need to better understand growers’ practices and attitudes to crop nitrogen (N) management, and thus to better position research and extension activities. The review also suggests the need to evaluate new fertiliser products and site-specific N management concepts and develop N management practices for waterlogging-prone soils for improved N use efficiency in cereal production systems in WA. The negative balance of magnesium (Mg) observed in WA cropping systems, together with the information reviewed on factors affecting soil Mg content and crop response to Mg application across Australia, suggests that there is a need to evaluate the risk and impact of Mg deficiency on acidic sandy soils of WA.

Growth and nutrient response of flax and durum wheat to phosphorus and zinc fertilizers

Flax (Linum usitatissimum L.) and durum wheat (Triticum turgidum L.) are important agricultural crops that enter the human food chain. Effective nutrient management considering nutrient interactions is important in order to increase crop yield and improve crop nutrient concentration. The objective of this study was to investigate the effect of P and Zn fertilizers on the yield and nutritional value of flax and durum wheat. A pot culture experiment conducted in a growth chamber using a calcareous clay-loam soil showed that P fertilizers can restrict flax growth due to an antagonistic effect of Zn fertilizer but can increase the seed yield of both crops by enhanced dry matter translocation to the seed/grain. Among the P sources, commercial monoammonium phosphate (CMAP) and commercial triple superphosphate (CTSP) had similar effects on growth and yield, but different impacts on the nutrient concentrations of both crops, indicating the importance of selecting P source to improve crop quality. Zinc addition with reagent grade P decreased the concentrations of P, K, Ca, Mg and Cu in flax but not in durum wheat. We conclude that proper combination of P and Zn fertilizers is necessary to optimize crop yields, but that P had a proportionally greater effect in promoting yield in durum wheat than in flax. In contrast, Zn had a greater impact on mineral composition in flax than in durum wheat, which can affect the nutritional quality of the crop as a component of the human diet. Key words: Flax, durum wheat, P and Zn fertilizers, nutrient, essential trace elements

Phosphorus Losses in Simulated Rainfall Runoff from Manured Soils of Alberta

Manure applied to agricultural land at rates that exceed annual crop nutrient requirements can be a source of phosphorus in runoff. Manure incorporation is often recommended to reduce phosphorus losses in runoff. A small plot rainfall simulation study was conducted at three sites in Alberta to evaluate the effects of manure rate and incorporation on phosphorus losses. Treatments consisted of three solid beef cattle manure application rates (50, 100, and 200 kg ha(-1) total phosphorus), an unmanured control, and two incorporation methods (nonincorporated and incorporated with one pass of a double disk). Simulated rain was applied to soils with freshly applied and residual (1 yr after application) manure at 70 mm h(-1) to produce 30 min of runoff. Soil test phosphorus (STP), total phosphorus (TP), and dissolved reactive phosphorus (DRP) concentrations in runoff increased with manure rate for fresh and residual manure. Initial abstraction and runoff volumes did not change with manure rate. Initial abstraction, runoff volumes, and phosphorus concentrations did not change with manure incorporation at Lacombe and Wilson, but initial abstraction volumes increased and runoff volumes and phosphorus concentrations decreased with incorporation of fresh manure at Beaverlodge. Phosphorus losses in runoff were directly related to phosphorus additions. Extraction coefficients (slopes of the regression lines) for the linear relationships between residual manure STP and phosphorus in runoff were 0.007 to 0.015 for runoff TP and 0.006 to 0.013 for runoff DRP. While incorporation of manure with a double disk had no significant effect on phosphorus losses in runoff from manure-amended soils 1 yr after application, incorporation of manure is still recommended to control nitrogen losses, improve crop nutrient uptake, and potentially reduce odor concerns.

Assessment of N, P and K management by nutrient balances and flows on peri-urban smallholder farms in southern Vietnam

There has recently been a strong tendency for agricultural production in peri-urban areas in southern Vietnam to move away from low input rice production to more intensive fruit and vegetable production, often in combination with pig production. The access to a market has led to increased availability of fertilisers and livestock feed in these areas, which has resulted in a dramatic increase in nutrient inputs. The objective of this study was to describe nutrient management on smallholder farming systems in a peri-urban area outside Ho Chi Minh City in southern Vietnam. Nutrient management was assessed by nutrient balances and flows and the data were gathered through interviews with local farmers, and measurement of inputs and outputs. Nine farms were selected containing one or more of the following production units: pig, crops, and fish. Feedstuffs and fertilisers were important sources of input of N, P and K on the livestock farms. On the farms without pig production, ash constituted on average 77% of all K input, but for N and P, fertilisers were the dominant forms of input. Farm-gate balances for N, P and K were positive on all farms and were in the range 31–868 kg N ha −1 per year, 23–644 kg P ha −1 per year and 9–770 kg K ha −1 per year. The different production units were poorly integrated as nutrient output from one unit seldom matched nutrient demand, as estimated by nutrient output, in the next unit. All pig production units showed similar nutrient use efficiencies, but there were large differences between the crop units, varying greatly both among different crops, and for the same crop, among the farms. The crop units were characterised by large nutrient surpluses and low nutrient efficiencies, indicating a high risk for nutrient losses to the wider environment. The results highlight the farmers' need for better tools to optimise farm nutrient management, both through better integration of the production units, but especially also by improving crop nutrient use efficiency.