LTRAS -- "The World's Youngest 100-year Experiment"

Year 12 Assessment & Planning

Suggesting changes to cropping systems in the core long-term experiment

The following two tables list current cropping systems and corresponding proposed cropping systems. Except for systems 1-3, all other systems would be modified. Irrigated wheat/fallow systems would be dropped in favor of completely new systems, and the CWT, CCT, LCT, and OCT systems would be expanded to three-year systems with a fourth (horticultural) crop added in the wheat year. Input and ideas about system management, alternative horticultural or other crops and new, non-conforming systems is needed. This input can be provided under the cropping system headings included below.

Table 1. Current Cropping Systems

Cropping System	Even Years	Odd Years
1. Rain fed wheat control (RWC)	unfertilized rain fed wheat	fallow
2. Rain fed wheat/legume (RWL)	unfertilized rain fed wheat	rain fed legume cover crop
3. Rain fed wheat/fallow (RWF)	fertilized rain fed wheat	fallow
4. Irrigated wheat control (IWC)	unfertilized irrigated wheat	fallow
5. Irrigated wheat/legume (IWL)	unfertilized irrigated wheat	rain fed legume cover crop
6. Irrigated wheat/fallow (IWF)	fertilized irrigated wheat	fallow
7. Conventional wheat/tomato (CWT)	fertilized irrigated wheat	fertilized irrigated tomato
8. Conventional corn/tomato (CCT)	fertilized irrigated corn	fertilized irrigated tomato
9. Legume/corn/tomato (LCT)	winter legume then irrigated corn	fertilized irrigated tomato
10. Organic corn/tomato (OCT)	winter legume then irrigated corn with compost and no pesticides	winter legume then irrigated tomato with compost and no pesticides

There are 6 one-acre plots per system, 3 for each of the two phases. For example, there are also 3 plots in the RWC system that are fallow in even years and planted to wheat in odd years. All tomato/corn systems have been split in half and reduced tillage treatments are now compared to previous tillage treatments within each plot.

Table 2. Proposed Cropping Systems

Cropping system	Year 1	Year 2	Year 3
1. Rain fed wheat control (RWC)	unfertilized rain fed wheat	fallow	repeats and remains the same
2. Rain fed wheat/legume (RWL)	unfertilized rain fed wheat	rain fed legume cover crop	repeats and remains the same
3. Rain fed wheat/fallow (RWF)	fertilized rain fed wheat	fallow	repeats and remains the same
4. Bio-fuels system¹	irrigated wheat/corn	irrigated wheat/corn	irrigated wheat/corn
5. Alfalfa/corn²	irrigated alfalfa	irrigated alfalfa	irrigated corn/alfalfa
6. Irrigated perennial grass or woody crop (e.g. poplars) for cellulosic biomass³	irrigated perennial grass or woody perennial	irrigated perennial grass or woody perennial	irrigated perennial grass or woody perennial
7. Conventional wheat/tomato (CWT)	Plots become part of systems 8 and 9
8. Conventional corn/tomato (CCT)	fertilized irrigated wheat then horticultural crop⁴	fertilized irrigated tomato	fertilized irrigated corn
9. Legume/corn/tomato (LCT)	winter legume then irrigated wheat then horticultural crop	winter legume then fertilized irrigated tomato	fertilized irrigated corn
10. Organic corn/tomato (OCT)	winter legume then irrigated wheat with compost and no pesticides then manure then horticultural crop	winter legume then irrigated tomato with compost and no pesticides	winter legume then irrigated corn with compost and no pesticides

1. This new system would attempt to generate the largest amount of grain for ethanol production possible per year, within economic constraints. It will likely emphasize reduced tillage and be managed intensively. This suggestion is subject to elaboration and modification. Oilseeds might be included, or other alternative crops. See (Assessment Planning Process 1-4.pdf) for further discussion.

2. Alfalfa is a major crop in California and in Yolo County. It is important to California’s dairy industry and growing alfalfa has significant effects on soil quality and related farming systems properties associated with sustainability. Plots might be split with half managed similar to commercial hay systems, and the other similar to dairy systems. Corn in rotation would link the crop to the core rotation in systems 7-10.See (Assessment Planning Process 1-4.pdf) for further discussion.

3. Cellulosic biomass for ethanol production can be produced in large amounts. Growing a perennial grass or other cellulose source would have implications for soil quality and other properties associated with sustainability. See (Assessment Planning Process 1-4.pdf) for further discussion.

4. A short season horticultural crop like broccoli or melons would be grown following wheat harvest. Other crops are being considered and can be proposed. See (Assessment Planning Process 1-4.pdf) for further discussion.

5. The plots used for system 7 (CWT), become part of systems 8 and in this proposal.

A list of the ten cropping systems that constitute the core long-term experiment at LTRAS follow. The management of each is described and future plans for the system are included. There is room for comments and suggestions under each system. Some of the systems may be modified after this cropping season. Logically, any change should be an improvement, not simply change for its own sake. Changes should not be so radical that the possibility for inference and interpretation of long-term trends that require making use of the first twelve year’s results is undermined. Currently, for the most intensive management systems (IWF, CWT, CCT, OCT), farming practices are supposed to reflect the best management practices available. Other systems (RWC, RWL, RWF, IWC, IWL, LCT) were included primarily for research purposes to provide a range of irrigation-input treatments, from none to moderately intensive. This range allows for investigation and interpretation of long term trends in soil quality, crop productivity and related phenomena that are central to long-term research and to agricultural sustainabiltiy. This is the core design principle of the long-term experiment that should be taken into account when suggesting new systems to replace the irrigated wheat/fallow series. For example, if an annual, intensive biofuels system were to be added as some have suggested, besides providing information about biofuels production, we need to consider how would it contribute to the core objective of analyzing the effects of inputs and irrigation over time. For more background about the experimental and treatment designs of the LTRAS systems see LTRAS design 2005.pdf.

Changes to current systems:

There is room for comments about each system under the system heading. Plans are to expand the CWT, CCT, LCT, and OCT from two to three year systems by changing them all to C/W/T systems, and to add a horticultural crop following wheat. That crop has yet to be determined. The details of how best to manage each system are open for discussion and suggestions.

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Cropping system	(CCT): Conventional corn/tomato
Current management	Tomatoes : Haley 3155* transplanted in spring at 10,500 plants per acre. 45 lbs N-P-K per acre at planting, 100 lbs N per acre at side-dress. Herbicides and pesticides as needed. Corn: 7570RR at 32,500 plants per acre. 45 lb N-P-K per acre at planting, 165 lb N per acre as urea at side-dress. Use tillage and glyphosate and other herbicides and pesticides as needed.
Current plans	Convert from a two-year cropping systems to a three-year cropping system by adding wheat. Add a fourth (horticultural crop) following wheat (broccoli and melons have been suggested so far). Maintain or improve (?) other current crop management practices.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).
*in 2006, Haley 3155 will be replaced by Heinz 9780 due to losses to nematodes.

Cropping system	(LCT) Legume corn/tomato
Current management	*Tomatoes: Haley 3155 transplanted in spring at 10,500 plants per acre. 45 lbs N-P-K per acre at planting, 100 lbs N per acre at side-dress. Herbicides and pesticides as needed. Corn : 7570RR at 24,500 plants per acre. Incorporate winter legume cover crop (lana vetch and magnus pea) prior to planting. Use tillage and glyphosate and other herbicides and pesticides as needed.
Current plans	Convert from a two-year cropping systems to a three-year cropping system by adding wheat. Add a fourth (horticultural crop) following wheat (broccoli and melons have been suggested so far). Maintain or improve (?) other current crop management practices.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).
*in 2006, Haley 3155 will be replaced by Heinz 9780 due to losses to nematodes.

Cropping system	(OCT) Organic corn/tomato
Current management	*Tomatoes* : Haley 3155* transplanted in spring at 10,500 plants per acre. 45 lbs N-P-K per acre at planting, 100 lbs N per acre at side-dress. Herbicides and pesticides as needed. Corn : 7570 at 32,500 plants per acre. Incorporate winter legume cover crop (lana vetch and magnus pea) prior to planting. Prior to incorporation, add 4 t/ac wet weight composted poultry manure. Control weeds through tillage.
Current plans	Convert from a two-year cropping systems to a three-year cropping system by adding wheat. Add a fourth (horticultural crop) following wheat (broccoli and melons have been suggested so far). Maintain or improve (?) other current crop management practices.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).
*in 2006, Haley 3155 will be replaced by Heinz 9780 due to losses to nematodes.

Cropping system	(CWT) conventional wheat-tomato.
Current management	*Tomatoes* : Haley 3155* transplanted in spring at 10,500 plants per acre. 45 lbs N-P-K per acre at planting, 100 lbs N per acre at side-dress. Herbicides and pesticides as needed. *Wheat:* Summit planted at 120 lb/ac. 100 lb N per acre at planting using ammonium nitrate. 50 lb N per acre in spring as foliar urea solution. Use tillage, herbicides and pesticides as needed.
Current plans	Convert from a two-year cropping systems to a three-year cropping system by adding corn managed similarly to CCT above. Add a fourth (horticultural crop) following wheat (broccoli and melons have been suggested so far). Maintain or improve (?) other current crop management practices
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).
*in 2006, Haley 3155 will be replaced by Heinz 9780 due to losses to nematodes.

Cropping system	(IWC) Irrigated wheat/fallow, without fertilizer
Current management	*Wheat:*Summit planted at 120 lb/ac. Use tillage, herbicides and pesticides as needed.
Current plans	This system would be discontinued to allow for the creation of new, non-conforming systems requiring irrigation.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).

Cropping system	(IWF) Irrigated wheat fertilizer
Current management	*Wheat:* Summit planted at 120 lb/ac. 100 lb N per acre at planting using ammonium nitrate. 50 lb N per acre in spring as foliar urea solution. Use tillage, herbicides and pesticides as needed.
Current plans	This system would be discontinued to allow for the creation of new, non-conforming systems requiring irrigation.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).

Cropping system	(IWL) Irrigated wheat legume
Current management	*Wheat:* Summit planted at 120 lb/ac. Incorporate winter legume cover crop (lana vetch and magnus pea) grown during the “fallow” phase of the two year crop cycle the previous spring. Use tillage, herbicides and pesticides as needed.
Current plans	This system would be discontinued to allow for the creation of new, non-conforming systems requiring irrigation.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).

Cropping system	(RWC) Rainfed wheat/fallow, without fertilizer
Current management	*Wheat:* Summit planted at 120 lb/ac. Use tillage, herbicides and pesticides as needed.
Current plans	This system will continue. It might be converted to no-till or reduced tillage, and straw might be removed instead of incorporated to conform more closely to farm practice.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).

Cropping system	(RWF) Rainfed wheat/fallow, with fertilizer
Current management	*Wheat:* Summit planted at 120 lb/ac. 75 lb N per acre at planting using ammonium nitrate. 50 lb N per acre in spring as foliar urea solution. Use tillage, herbicides and pesticides as needed.
Current plans	This system will continue. It might be converted to no-till or reduced tillage, and straw might be removed instead of incorporated to conform more closely to farm practice.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).

Cropping system	(RWL) Rainfed wheat legume
Current management	*Wheat:* Summit planted at 120 lb/ac. Incorporate winter legume cover crop (lana vetch and magnus pea) grown during the “fallow” phase of the two year crop cycle the previous spring. Use tillage, herbicides and pesticides as needed.
Current plans	This system will continue. It might be converted to no-till or reduced tillage, and straw might be removed instead of incorporated to conform more closely to farm practice.
Comments: (please include what you would change, how it is an improvement, and how it would effect interpretation and use of previously collected data).

New systems:

In addition, plans are to end the irrigated what/fallow systems and replace them with non-conforming systems. By non-conforming we mean that they would not have to be three year systems and need not be constrained by the same rules of experimental design needed for the core experiment. Regression analysis based on inputs or other factors would allow cross system inference. Inference is strengthened, however, if new systems connect or intersect with the core experiment during some phase of the proposed system. For example, if a three or four year alfalfa/corn system (e.g., a-a-a-c) were added, the results from the corn phase could be analyzed along with corn results from the core experiment.

Comments regarding new systems:

General comments for LTRAS:

Year 12 Assessment page