Some Observations During the 2012 Drought

Although we have received significant rains in the last 10 days, much damage has occurred and many fields will not recover. County agents have estimated that about 20 to 30 percent of the fields in the southern tier of Wisconsin counties are barren. For stressed fields that have only partially pollinated, it becomes increasingly difficult to predict how plants react to increasing stress and the best management recommendations.

One observation that many farmers have noticed is lack of brace roots. Roots will not grow into dry soils. Since most of southern Wisconsin did not received any rainfall from June 1 until July 20, right during brace root formation, many plants have not developed brace roots. Some fields have lodged and most of those fields have recovered and are vertical. Brace root formation can still occur, but will slow as grain-filling proceeds.

Pollination at Arlington has progressed well (Table 1). Kernels per ear have ranged from 437 to 599 kernels per ear. During most years we produce about 400 to 600 kernels per ear, which at 30,000 ears/A and 280 mg per kernel will yield 140 to 200 bu/A.

Table 1. Pollination progress of Pioneer 35F48AM1 in a planting date study during 2012 at Arlington, WI.
Planting date	Silking date	Sampling date	Kernel rows	Kernels per row	Kernels per ear	Percent pollinated
March 26	July 9	July 18	16.0	30.8	492	79
		July 24	16.3	31.3	599	83
		July 31	15.8	27.8	437	76
May 8	July 15	July 18	16.5	27.3	450	73
		July 24	16.8	35.8	599	88
		July 31	16.3	31.4	510	82
May 21	July 21	July 24	16.3	29.1	473	68
		July 31	15.8	35.4	557	88

Rock River Labs (Watertown, WI) reports that corn silage samples from IA IL, IN, MI, SD, and WI have been averaging 74.6% moisture (Table 2). Forage moisture is too wet for all ensiling structures. Nitrate-N levels have been low and averaged 706 ppm with only one sample above 4000 ppm. Remember to freeze your corn silage sample before sending to a forage lab for Nitrate-N testing.

Table 2. Corn silage moisture and Nitrate-N levels from Rock River Labs during July 2-27 (Watertown, WI).
Parameter	Mean	Standard deviation	Min	Max
Moisture (%)	74.6	9.0	13.9	87.6
Nitrate-N (ppm)	706	720	0	4330