UAN a better way to apply N to crops?

Transcription

1 144 UAN a better way t apply N t crps? N prduct cmparisn Liquid N applicatin Liquid N cmpatibility with pesticides The aim f this trial was t investigate whether liquid N as UAN is a better and mre reliable surce f N cmpared t using granular Urea. The trials included an N prduct cmparisn; a liquid N applicatin trial (nzzle set up); and an investigatin f liquid N cmpatibility with herbicides and fungicides. Summary Liquid N (UAN as Easy N) was a majr fcus fr trial wrk n wheat at Birchip and Laen. UAN was cmpared t granular N prducts (urea and ammnium nitrate) and n differences in yield r prtein were fund between the varius prducts tested, r the timing during the seasn when the prducts were applied. The dry seasnal cnditins and high sil N cntributed t the lack f respnse frm N fertilisers at bth sites. UAN applied with flat fan r streaming nzzles shwed n difference in leaf scrch r yield. Cnditins at the time f applicatin were relative humid (higher than 50%) which may have had an affect. In additin, UAN was applied in a mix with water (59L UAN and 41L f water) this may have resulted in less crp damage than has been bserved in ther trial wrk. UAN mixed with herbicides r fungicides applied at mid tillering (GS15) r flag leaf emergence (GS39) caused n crp damage and there were n yield differences bserved. This may have been because the UAN was mixed with water. UAN did nt mix easily with 2,4D Amine and this herbicide needs t be mixed with water befre UAN is added. The BCG will cntinue with UAN trial wrk because we cnsider this prduct t have mre benefits than spreading urea in crp. Backgrund Urea has been the nitrgen fertiliser prduct f chice fr farmers in the Wimmera and Mallee. It has been the cheapest frm f N fertiliser and has been cmmnly predrilled prir t seeding. Pre-drilling urea has becme less ppular in the recent run f dry seasns. Due t the dry cnditins applying N pre-seeding has nt been required (n return n investment) r in sme cases, has resulted in haying-ff. Haying-ff is a duble negative because the csts are the urea applied pre-seeding and the lwer yield when the crp grew t quickly and ran ut f water in spring. T reduce the risk f N fertiliser nt being required r the crp haying ff, farmers have been tpdressing their crps during the seasn as the crp has required it. The prblem with using urea fr tpdressing is that urea vlatilises rapidly when applied

2 145 t highly alkaline sils if it des nt rain sufficiently t wash the prduct int the sil. Estimates frm CSIRO (Jeff Baldck) have shwn that n ur sil types with a ph abve 8.0, 35% f the N applied as urea can be lst if it des nt rain within 8 days f applicatin. A better way needs t be fund t apply N fertiliser in-crp. If there is t be an alternative t using urea it has t be mre reliable in relatin t uptake (ie. higher N efficiency) and it has t be cheap and cnvenient. Farmers in Western Australia have fund a slutin by using UAN (Urea Ammnium Nitrate) which is a liquid frmulatin f N, cntaining 42% N. Many WA farmers apply UAN when they spray their crps with herbicides r fungicides and apply the amunt as needed fr the ptential f the crp. UAN is marketed by Incitec-Pivt in Victria as Easy N. UAN is taken up by the crp bth thrugh the leaves and thrugh the sil after rain has washed the prduct int the sil. It is the uptake thrugh the leaves which may make this prduct mre efficient t use cmpared t tpdressing urea n ur highly alkaline sils. Leaf uptake f UAN has been estimated t be as high as 60% (Ian Fillery, CSIRO). In this trial we cmpared hw efficient UAN is as an N surce cmpared t the granular prducts urea and ammnium nitrate. We als investigated the cmpatibility f UAN with herbicides and fungicides because ultimately it is the in-crp applicatin that may be mst cnvenient and efficient. The cncern f UAN in cmbinatin with different herbicides and fungicides scrching the crp was als investigated. Methds Three trials were undertaken: UAN prduct cmparisn t granular urea and ammnium nitrate; applied preseeding and in-crp UAN applied in-crp using flat fan and streaming nzzles (t cmpare crp damage frm ptential crp scrching when the prduct is applied with a flat fan nzzle r streaming nzzle) UAN bilgical cmpatibility with herbicides and fungicides (t determine whether it is safe t use UAN in cmbinatin with herbicides r fungicides) The trials were cnducted using fully replicated (x4) randmised blck designs at Birchip and Laen. Yitpi wheat was swn at 175 plants/m 2 at bth sites. The trials were n swn n May 6 th at Birchip and June 22 nd at Laen. Available N in the tp 70cm f sil at seeding was - Birchip 65 kg and Laen 101 kg N/ha. Trial 1. N prduct cmparisn Three surces f N fertiliser (granular Urea 46% N; Ammnium Nitrate 27% N; and liquid UAN (as Easy N) 42% N) were applied at 25kg N/ha at three stages: predrilled; five leaf stage (GS15) and end f tillering (GS30). UAN was applied at the same rate f N as the ther N prducts (59L/ha f Easy N) and was mixed with water t a ttal vlume f 100L/ha, and applied with XR11002 flat fan nzzles. Trial 2. UAN applicatin flat fan vs. streaming nzzles

3 146 UAN (as Easy N) was applied at 25kg f N (59L/ha f Easy N) and mixed with water t a ttal vlume f 100L/ha. The prduct was applied using tw types f nzzles: XR11002 flat fan and a SJ3-04VP Streamjet nzzle. The prduct was applied at bth the five leaf stage (GS15) and end f tillering (GS30). Trial 3. UAN cmpatibility with herbicides and fungicides UAN (59L f Easy N) was mixed with water (41L) t make a ttal vlume f 100L/ha t which a range f herbicides and fungicides were added. Treatments were applied pre-seeding; in crp at the five leaf stage (GS15) and at full flag leaf emergence (GS39), using XR11002 nzzles. The UAN / pesticide mixes include the mst cmmnly used herbicides and fungicides see the results fr a list f prducts used. Weather cnditins at the time f spraying and immediately after were recrded. The level f scrching was assessed 5 days after applicatin. Weather cnditins at the time f spraying the UAN (Trials 2 and 3) and spreading the granular urea and ammnium nitrate (Trial 1) are listed in Table 1. Table 1. Weather cnditins at the time f spraying UAN and time in days between the applicatin and rain. Pre-swing GS15 GS39 Birchip Laen Birchip Laen Birchip Laen Date May 6 June 22 July 20 Aug 10 Sep 15 Sep 28 Temp C Humidity % Delta T Days t rain* * Days befre a minimum f 5mm rain (t wash in N prduct) Results The seasn was very dry at bth trial sites and nt cnducive t high crp yields. In additin, bth sites were relatively high in sil available N at seeding (65 and 101 kg N/ha at Birchip and Laen respectively) hence fr the seasns rainfall and ptential yield the crps did nt require any additinal N. Trial 1. N prduct cmparisn There were n bservable differences in crp perfrmance at Birchip and Laen between the cntrl treatment (n N) and any f the three N prducts used. In additin, there were n differences in yield between the N prducts, r in relatin t the time they were applied (Table 2). This indicates that UAN did nt cause damage t the crp when used at the five leaf stage nr at the end f tillering. Table 2. N prduct (Urea; Ammnium Nitrate and UAN) applied at 25kgN/ha at three timings (pre-drill; five leaf (GS15); and end f tillering (GS30). Timing Pre-drill GS15 GS30 Site Birchip Laen Birchip Laen Birchip Laen Cntrl (n N) Urea Amm Nit UAN Significant difference: NS NS NS NS NS NS Trial 2. UAN applicatin flat fan vs. streaming nzzles There was n significant difference in yield between applying UAN with a flat fan nzzle cmpared t using streaming nzzles, at either Birchip (average yield 0.87

4 147 t/ha) r Laen (average yield 2.5 t/ha). The time when the prduct was applied (five leaf cmpared t end f tillering) was als nt significant. Trial 3. UAN cmpatibility with herbicides and fungicides Bilgical cmpatibility The effect f the UAN, as Easy N, applied n its wn r mixed with herbicides r fungicides was assessed n the level f leaf scrch. There was a lw level f leaf scrch with UAN mixed with MCPA500 plus Diurn applied at the five leaf stage, the crp grew ut f the lw level damage and within 3 weeks the effects were n lnger visible. N ther mixes applied at the five leaf stage resulted in leaf scrch (less than 2% damage t the yungest emerged leaf). Fungicides and herbicides applied late pst emergent (at full flag leaf emergence) had a higher level f leaf scrch (8% f flag leaf damaged) cmpared t the applicatin at five leaf. At the late applicatin there was n difference between the prducts applied in the level f leaf scrch (prducts cmpared were: 2,4 D Amine; Bumper, Flicur, Opus and Amistar Xtra). The effect f UAN as mixed with herbicides r fungicides n crp yield, prtein and screenings is presented in Table 3. Table 3. UAN, as Easy N, applied at 25kg f N/ha (mixed with 41L f water t make 100L/ha f spray slutin) mixed with herbicides and fungicides applied at three stages (IBS, GS30 and GS39). Prduct Timing Pesticide Rate Yield (t/ha) Prtein (%) Screenings (%) (/ha) Birchip Laen Birchip Laen Birchip Laen UAN IBS Triflur480 IBS 0.8L UAN GS Ally/LVE/ GS15 3g + 0.4L wetter + w 0.1% + Ally/LVE/ GS15 3g + 0.4L + 70ml w 0.1% Lntrel/wett er + Tigrex GS15 0.4L MCPA 500/ GS L L Diurn + GS15 40ml + 0.5% Tpik/uptake + Hegrass/ wetter GS15 1.5L+0.25% UAN GS Amicide625 GS39 1.2L Flicur GS L Bumper GS L Opus GS39 0.5L AmistarXtra GS39 0.4L

5 148 Interpretatin Sil nitrgen supply at swing was high and cnsidering the dry cnditins thrughut the seasn the N levels in the sil were able t match the crps N requirements. N fertiliser applicatins did nt add t yield. The applicatin f N did add t prtein (n N: 15.4% and 14.6% prtein; + N: 16.1% and 15.5% prtein at Birchip and Laen respectively). Screenings at Birchip ranged between 4 and 6% (n treatment affects) and at Laen screenings were very lw at 1%. Generally the late applicatins f nitrgen fertiliser at flag leaf emergence (regardless f prduct type) had higher prtein levels cmpared t applicatins earlier in the seasn. There were n differences fund in yield between N prduct (granular: urea, ammnium nitrate; and liquid: UAN). Nr were there differences fund in yield between hw the UAN was applied (n difference between flat fan r streaming nzzle applicatin). We recrded n serius scrching effects when UAN was mixed with herbicides r fungicides applied either early (five leaf) r late (flag leaf emergence). There were n significant effects n yield frm the applicatin f UAN in mixes with varius herbicides and fungicides at either Birchip r Laen. Applicatin cnditins were undertaken at relatively lw Delta T cnditins (reasnably humid) and little r n crp damage was bserved. It is pssible that little r n damage was bserved because the UAN was never applied neat, it was always applied in a mix with water (59L f UAN and 41L f water). In this trial the UAN was mixed with water first, then the herbicide r fungicide was added. With the 2,4 D Amine mix this resulted in separatin. When the 2,4 D Amine was mixed first with water befre the UAN there was n separatin and the prducts mixed very well. The trial wrk will be repeated this cming seasn. Cmmercial Practice Fllwing this years trial results we are cnfident that UAN can have a rle as an incrp N fertiliser. The benefits f UAN are: Ease f use (can be applied with a standard bm) Better distributin f N (spreaders rarely spread evenly) Lwer rates f N can easily be applied (with granular prducts it is difficult t apply much less than 50kg/ha f prduct) Fliar applied UAN appears t be mre efficient in uptake cmpared t spreading granular prducts Can be mixed with mst herbicides and fungicides If applied as a UAN and water mix, in the right cnditins little r n crp damage is likely Pssible t mix yur wn urea with water (needs set up) The negatives f UAN are: Price (in SE Australia the prduct is 30% mre expensive cmpared t in WA) Can be harsh n spraying equipment (UAN is crrsive and precautins have t be taken) UAN needs t be stred in special tanks. There is n extensive netwrk fr delivery f UAN in Victria.