TITLE:

Peanut Planting Pattern Study at AG-CARES. Lamesa, Texas 2000.

AUTHORS:

Mike Schubert and Brett Jungman

METHODS AND MATERIALS:

Planting Date: May 2, 2000, Single row.

May 9, 2000, Double Row and Ultra Narrow Row

Variety: FlavorRunner 458

Insecticide     : None.

Rhizobium    : Nitragin “Lift” applied in seed drill.

Irrigation       : 75% ET Low Energy Precision Application in every furrow (LEPA-EF)

75% ET Low Energy Precision Application in alternate furrows (LEPA-AF)

75% ET Low Elevation Spray Application at 80-inch drop spacing (LESA)

Fertilizer: 20 lb N/acre preplant.

Harvest Date: Dug November 11. Threshed November 28.

Several years ago, the interest in ultra narrow row (UNR) cotton led to speculation that peanuts grown under UNR patterns might have higher yields, earlier maturity, or improvements in some aspects of quality. These speculations quickly turned to the belief that UNR peanut production would indeed lead to earlier maturity, without research to study the question in a controlled fashion. In 1998, we addressed our concerns that widespread adoption of this practice might subject producers to unknown risks, by conducting tests at AG-CARES that included both Single Row (SR) and Triple Row (to simulate UNR). The planting patterns were watered by LEPA-AF at 75% ET. This did not work well and led to the question of how to water UNR peanuts most effectively. In 1999 and 2000, we conducted tests to compare single row (SR), double row (DR), and UNR planting patterns under three irrigation application schemes: Alternate Furrow (80″ spacing) Low Energy Precision Application (LEPA-AF), Every Furrow (40″ spacing) LEPA (LEPA-EF), and Low Elevation Spray Application (80″ spaced spray) (LESA). The inclusion of DR also allowed us to examine its usefulness in this region. Double-row planting has generally been found to increase yields in the warmer, more humid peanut growing regions of south Texas and the southeastern US peanut growing states–particularly where Tomato Spotted Wilt Virus is a problem.

We followed the basic irrigation strategy that has been successful at this location: (1) pre-irrigation if needed to begin the season with a full profile; (2) application of approximately 0.50 inches of water immediately after planting; (3) supplying 0.50 to 0.75 inches of moisture during early vegetative growth until about July 1; (4) provision of sufficient water to replace 0.75 of calculated cotton evapotranspiration (ET) at 2.5 to 3.5-day intervals (usually 1.50 to 1.75 inches of moisture per week) throughout the rapid fruit development period from about July 1 through at least mid-September; and (5) then reduced water supply of approximately 0.50 to 0.75 inches per week until harvest with perhaps 0.25 inches of water the day before digging if needed.

Seeding rates in 1999 for the DR and UNR treatments were chosen from those providing favorable results in field trials conducted by the late Dr. A. L. Harrison in South Texas during the late 1950’s and early 1960’s. Single row plots were planted normally, DR plots were planted by offsetting planter boxes about 4 inches and double planting with each pass in opposite directions; UNRs were planted with a vacuum planter with seven drills spaced 10 inches apart on flattened 80-inch beds. In 2000, we returned to using a triple-row UNR pattern, planting by offsetting boxes and planting in each direction to obtain three seed drills approximately 10 inches apart on each 40-inch bed. There were essentially three experiments in the 1999 and 2000 tests, each watered by the methods described above. Each water application area was divided into three replications with planting patterns randomized within each replication.

Plots were dug using a 2-row KMC digger/inverter with modifications of the length and angle of the left blade for the UNR plots. In 1999, yield data was collected using a 2-row Lilliston 1500 peanut combine modified to allow direct sacking of the peanuts from the measured plot length. In 2000, yield data was collected using a 4-row KMC combine to thresh measured plot length with peanuts from each yield plot collected in a sacking trailer.

This report covers results from all three years. Year-to-year variation requires two or three years of field testing in order to have confidence in the results.

RESULTS AND DISCUSSION:

In all three years, plants in the UNR plots quickly covered the soil. These plots showed up as distinctly different to the other planting patterns, especially the SR pattern, in aerial infrared photographs. They were visibly more water stressed from late June throughout the remainder of the season compared to the other planting patterns. This was most obvious in the LEPA-AF plots, but was also noted with LESA and LEPA-EF. The surface of the UNR plots was much drier than the other planting patterns throughout much of the season and required extra water for digging without significant losses in 1999. The cold wet conditions of the 2000 harvest caused significant plant deterioration and harvest losses in all planting patterns.

The particular UNR arrangement used in 1999 presented two other problems, as well:

(1) Using seven drills spaced 10 inches apart placed the outside drills too close to the edge of the digger, so that plants sometimes rode around the outside of the digger rather than going over the shaker bars and sometimes accumulated and drug on the sides. This also required the driver to be more accurately positioned over the rows than with the single or DR patterns.

(2) The plants in the center seed drill were difficult to dig. With the help of personnel at Sam Stevens Co., we changed the angle of the left digger blade and lengthened the blade somewhat to allow it to run slightly in front of the right digger blade and dig the center row. While this generally undercut the center drill, the narrow space between the blade tips contributed to accumulation of vines and dragging.

In 2000, we attempted to use six 10″ seed drills, to reduce crowding of the outside of the digger and to eliminate the center drill. The vacuum planter on loan to the cotton researchers conducting UNR research could not be adjusted without major alterations, so we went back to offsetting our regular planter to obtain the desired planting patterns.

In 1998, UNR (triple row) yielded significantly less than did SR (Table 1), but grades were equal for both planting patterns. When peanut yields were compared for planting patterns within each irrigation scheme (Table 2), yields were significantly reduced with UNR in both the LEPA-AF and LESA in 1999, but were statistically equal for all patterns in 2000. Only in the LEPA-EF was the UNR yield statistically equal to those of the SR and DR patterns, and its average yield among the replications (5,935 lb/ac) was numerically smaller than that of the other patterns (6,256 lb/ac) in 1999. UNR yields were reduced the most under LEPA-AF irrigation, 3,855 lb/ac compared to 5,886 for SR and 5,238 for DR.

When 1999 yields were compared among planting patterns without regard for irrigation scheme (Table 3), the UNR yielded 4,806 lb/ac, which was significantly less than the SR (6,020) and DR (6,002) yields. Across planting patterns, LEPA-EF and LESA had the highest yields with 6,149 and 5,686 lb/ac, respectively, with LEPA-AF significantly lower with 4,993 lb/ac. There were no significant differences in among planting patterns in 2000.

Despite speculation that UNR might produce more mature peanuts, the summary in Table 4 shows that grades were significantly lower and other (small) kernels were significantly higher in UNR than in SR or DR planting patterns. Grade data are incomplete for 2000.

Under the conditions at AG-CARES in 1998-2000, UNR peanuts did not increase yields over those of single or double row peanuts. Yields were significantly reduced under some irrigation schemes. Likewise, a comparison of grade data in 1999 indicates that the UNR peanuts may have been less mature (certainly smaller) than peanuts from the other planting patterns. Even when UNR yields were equal to the other patterns under LEPA-EF, increased seed costs were not recovered, and there was nothing to offset the need for specialized planting equipment and increased complexity of harvest. Likewise, double row planting patterns did not pay for increased seed costs in this trial.

This experiment allowed us to gain insight into past results in irrigation research. The superiority of LEPA-AF irrigation has been puzzling in light of our knowledge that peanut fruit must be surrounded by moist soil to develop properly. When we began our research in 1995, we were certain that LEPA-AF would not work on peanuts. Throughout the years, we have learned that except in rare occasions this irrigation scheme outperforms LEPA-EF and LESA (spray mode). In 2000 at the Western Peanut Growers Research Farm near Denver City, LEPA-AF produced the highest yields compared to two other LESA applicators, but yielded the same as bubblers. We have speculated that the reason LEPA-AF works in West Texas is that even with runner peanuts, we make exceptionally high yields despite the fact that our plants are smaller and that their peanuts are more concentrated around the crown of the plant with few pods toward the ends of the vines, when compared to traditional growing areas. Field observations confirm that LEPA does, in deed, keep the pod development zone of our runner plants moist although the soil in the non-watered furrow can get extremely dry. This irrigation scheme probably will not work as well where significant pod development occurs in a wider band in relation to the center of the row. In 1999, we saw that yields were reduced on both double row and ultra narrow row peanuts. It was apparent that at least part of the pod zone of plants located further away from the wet furrow was too dry for proper fruit development. All yields were low and statistically equal at AG-CARES in 2000.

From the research in 1999 and 2000 and observations of triple row peanuts at AG-CARES in 1998, we are not encouraged in the belief that ultra narrow row peanuts have any advantage over conventional planting patterns. We do not intend to repeat this type of research in the future.

NOTE: We want to acknowledge the support of Lamesa Cotton Growers, Western Peanut Growers, Texas Peanut Producers Board, The Peanut Foundation, and the High Plains Precision Agriculture Initiative in this and other peanut research at AG-CARES

Table 1. Planting Pattern Effects on Peanut Yield and Grade. Planting Pattern Experiment. AG-CARES. 1998. Lamesa, Texas.
	Pod Yield	Grade
	(pounds per acre)
Single Row (SR)	3,342 a1	79 a
Double Row (DR)	2,640 b	79 a
1 Means in each column followed by the same letter are not statistically different at P = 5%.

Table 2. Planting Pattern Effects on Yield Within Each Irrigation Method. Planting Pattern–Irrigation Method Experiment. AG-CARES. 1999 & 2000. Lamesa, Texas.
	SR	DR	UNR		SR	DR	UNR
Irrigation Method	Pod Yield (pounds per acre)
	1999				2000
LEPA, Alternate Furrow	5,886 a1	5,238 a	3,855 b		1,629 a	1,882 a	1,586 a
LEPA, Every Furrow	6,256 A	6,256 A	5,935 A		1,812 A	1,943 A	1,734 A
LESA, 80″ Spacing	5,919 a	6,512 a	4,628 b		1,952 a	1,960 a	1,542 a
1 Means in each row for each year followed by the same letter are statistically equal at P=5%.

Table 3. Planting Pattern and Irrigation Method Effects on Yield. AG-CARES. 1999 & 2000. Lamesa, Texas.
	Pod Yield (lb/ac)		Irrigation Method	Pod Yield (lb/ac)
Planting Pattern	1999	2000		1999	2000
Single Row	6,020 a1	1,798 a	LEPA, Every Furrow	6,149 a	1,830 a
Double Row	6,002 a	1,928 a	LESA, 80″ Spacing	5,686 a	1,818 a
Ultra Narrow Row	4,806 b	1,621 a	LEPA, Alternate Furrow	4,993 b	1,699 a
1 Means in each column followed by the same letter are not statistically different at P = 5%.

Table 4. Grade Response to Planting Pattern and Irrigation Method. Planting Pattern–Irrigation Method Experiment. AG-CARES. 1999. Lamesa, Texas.
Planting Pattern	Grade	OK	Irrigation Method	Grade	OK
Single Row	76.9 a1	2.0 b	LEPA-EF	76.4 a	2.2 a
Double Row	76.9 a	2.1 b	LESA	75.7 a	3.4 a
Ultra-Narrow Row	73.7 b	4.2 a	LEPA-AF	75.3 a	2.7 a
1 Means in each column followed by the same letter are not statistically different at P = 5%.