ISSUE 9   July 9, 2009

CROP WATER USE

According to the USDA Crop-Weather Report of last week, only 10% of the crop land in the state was short of moisture. Nevertheless, with the warm and mostly rain-free weather of the past week to ten days, it will not be long before "not enough moisture" will be the talk of the day. Water is typically the most limiting factor to non-irrigated crop production in North Dakota. Water availability within a given season is dependent on rainfall and stored soil moisture. Moreover, the rate of water use by crops is dependent on the weather, growth stage and availability of water. From the time that the leaves of crops completely cover the soilís surface until they start to loose their color before harvest, crop water use will depend mostly on the weather, as water use under full canopy is highly correlated to the amount of potential evapo-transpiration (water lost through evaporation from an open pan of water) during this period.

Water is essential for numerous chemical reactions in the crop plant and provides structure to cells and tissues. The vast majority of the water that the crop uses, however, is for transpiration. When moisture supplies are adequate, transpiration stream brings nutrients and water from the soil via the roots to all parts of the plant, cools the plant, and allows stomata to remain open and CO2 to enter the leaves. When soil moisture is limiting, stomata close, reducing the availability for C02, increasing the temperature of the leaf tissue, reducing photosynthesis, and thereby slowing plant growth (but in some cases hastening plant development). Drought stress can reduce crop yields even before the plant begins to wilt, the first visible symptom of water stress.

Table 1. Approximate yield, water use and water use efficiency of some crops commonly grown in the northern Great Plains.

CROP

Average Yield/A

Average Water Use, Inches

Water Use Eff Yield/A/inch H2O

Alfalfa
Grain Corn
Potatoes
Sugarbeets
Soybeans
Spring Wheat
Sunflower

5 tons
120 bu
400 cwt
3.2 tons
35 bu
40 bu
1500 lb.

24
21
20
19
16
15
14

0.2 ton
6 bu.
20 cwt
0.2 ton
2.2 bu.
2.7 bu.
110 lb.

Flax
Pinto Beans
Barley

25 bu.
2200 lb.
55 bu

12
12
11

1.7 bu.
180 lb.
5 bu.

Source: J. W. Bauder and M. J. Ennen, NDSU Soil Science Dept.

Crops differ significantly in their water requirements, drought tolerance and water use efficiency. Crop selection can be one way of matching water availability with crop requirement, though predicting the amount of moisture that is likely to be available in a given season is more guesswork than science.

Strictly defining the water use by a crop is difficult as water use is affected by the amount and timing that water is available. For example, a crop like corn is water use efficient (produces more dry matter per inch of water), but also has a relatively high water requirement as it has a higher yield potential than most crops. Furthermore, crops differ in how water stress might affect them. Corn, for example is very sensitive to drought during the flowering process. Wheat on the other hand, is sensitive during several weeks proceeding flowering. A crop that is stressed early in its growth cycle may not be able to recover to the extent that it will be able to use the water that is available, even though rainfall during the latter stages of development is plentiful. Remember, it is difficult to precisely define the water use and water use efficiency of a crop. In Tables 1 and 2, crops are categorized as to their water requirements and water use efficiency is how much additional rainfall will be needed to augment the amount of moisture in the soil and to minimize moisture stress in the crop this season.

The difference in water use estimates between Tables 1 and 2 can partially be explained by the fact that the data in Table two were collected on crops that were mildly to severely water-stressed during the growing season, and therefore were limited in growth and water use by water availability. These numbers more accurately predict crop water use in the dryer parts of the state and in drought years.

Table 2. Water use (inches) by selected crops in experiments
conducted 1999-2000 and 2002-2004 in Mandan, ND.

Crop

1999-2000

2002-2004

Barley

12.0

--

Buckwheat

--

13.2

Canola

12.8

13.4

Chickpea

--

12.8

Corn

--

14.5

Crambe

11.8

--

Dry Bean

12.6

--

Dry Pea

11.4

11.7

Flax

12.6

--

Lentil

--

11.7

Millet

--

13.3

Safflower

14.2

--

Sorghum

--

13.8

Soybean

13.5

--

Spring Wheat

12.5

13.7

Sunflower

15.0

14.9

Source: Crop Sequence Calculator, USDA-ARS Mandan.

Joel Ransom
Extension Agronomist for Cereal Crops
Joel.ransom@ndsu.edu

 

DRY BEAN OBSERVATIONS

The 2008 Dry Bean Grower Survey was just released (for complete report see the reference at the bottom of this article). This was the 19th Annual Survey of varieties grown, pest problems, pesticide use and grower practices of the Northarvest Bean Growers Association, an association of dry edible bean growers in Minnesota and North Dakota. The survey was mailed to all Northarvest Bean Growers, however, not all growers returned the survey. Table 1 provides a short summary of practices reported by North Dakota growers in 2008 compared with answers provided during the 2007 survey.

Table: Selected information about dry bean management practices
reported by North Dakota farmers in the 2007 and 2008 annual dry bean grower survey.

   

2007

 

2008

Market Class

% of respondents' acres

Pink

 

1

 

0.5

Kidney

0.3

0.0

Black

 

6.8

 

13.1

Navy

 

15.3

 

13.4

Pinto

 

71.9

 

71.3

Other

 

4.7

 

1.7

Pinto varieties

% of respondents' acres

Maverick

 

63.4

 

46.0

La Paz

 

17.0

 

26.9

Windbreaker

--

 

10.1

Buster

 

7.2

 

4.0

ND307

 

--

 

2.6

Lariat

 

--

 

1.6

GTS 900

3.0

0.8

Stampede

 

--

 

0.7

Other

 

9.4

 

7.3

Soil test

 

% of Respondents

Soil test used

71.9

 

78.0

Soil test not used

28.1

 

22.0

Fertilizer use

% of Respondents

Nitrogen

 

69.6

 

76.6

Phosphate

66.7

 

73.9

Potash

 

20.3

 

17.1

Zinc

 

39.1

 

56.8

Other

 

4.3

 

5.4

Fungicide Treatment

% of Respondents

Treatment used

48.1

 

48.7

Treatment not used

51.9

 

51.3

Rizobium inoculant

% of Respondents

Inoculant used

25.5

16.1

Inoculant not used

74.5

83.9

Respondents

128

100

The main marketing class grown in ND is Pinto bean followed by Navy bean. The most popular variety in 2007 and 2008 was Maverick, but we see a gradual shift away from Maverick to newer varieties. The majority of producers use soil test information to design their fertilizer program. There was an increase in the used of Zinc. Producers used N, P, and K fertilizer with 76.6% (2008) of the respondents reporting use of Nitrogen. Only 16.1 percent of the producers used Rhizobium inoculant. Although we did not cross tabulate we make the assumption that producers either selected Rizobium inoculant or provided fertilizer N to the dry bean crop. Availability of Nitrogen to the plant will reduce the size and number of nodules on the dry bean plant. About half of the producers used fungicide treatments on the dry been seed. It is suggested that producers and crop consultants evaluate if the fertilization, seed treatment, and inoculation programs for the farm are performing as anticipated and that future management decisions are based on the response of dry bean to these management strategies.

References:

2007 Dry Bean Grower Survey
http://www.ag.ndsu.edu/pubs/plantsci/rowcrops/pp1392.pdf

2008 Dry Bean Grower Survey
http://www.ag.ndsu.edu/pubs/plantsci/rowcrops/e1421.pdf

Fertilizing Pinto, Navy and Other Dry Edible beans
http://www.ag.ndsu.edu/pubs/plantsci/soilfert/sf720w.htm  

Hans Kandel
NDSU Extension Agronomist, Broadleaf crops
hans.kandel@ndsu.edu


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